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In this first-in-human phase 1 study (NCT02964013; MK-7684-001), we investigated the safety and efficacy of the anti-TIGIT (T cell immunoglobulin and ITIM domain) antibody vibostolimab as monotherapy or in combination with pembrolizumab.Part A enrolled patients with advanced solid tumors, and part B enrolled patients with non-small-cell lung cancer (NSCLC). Patients received vibostolimab 2.1-700 mg alone or with pembrolizumab 200 mg in part A and vibostolimab 200 mg alone or with pembrolizumab 200 mg in part B. Primary endpoints were safety and tolerability. Secondary endpoints included pharmacokinetics and objective response rate (ORR) per RECIST v1.1.Part A enrolled 76 patients (monotherapy, 34; combination therapy, 42). No dose-limiting toxicities were reported. Across doses, 56% of patients receiving monotherapy and 62% receiving combination therapy had treatment-related adverse events (TRAEs); grade 3-4 TRAEs occurred in 9% and 17% of patients, respectively. The most common TRAEs were fatigue (15%) and pruritus (15%) with monotherapy and pruritus (17%) and rash (14%) with combination therapy. Confirmed ORR was 0% with monotherapy and 7% with combination therapy. In part B, 39 patients had anti-PD-1 (programmed cell death protein 1)/PD-L1 (programmed death-ligand 1)-naive NSCLC (all received combination therapy), and 67 had anti-PD-1/PD-L1-refractory NSCLC (monotherapy, 34; combination therapy, 33). In patients with anti-PD-1/PD-L1-naive NSCLC: 85% had TRAEs-the most common were pruritus (38%) and hypoalbuminemia (31%); confirmed ORR was 26%, with responses occurring in both PD-L1-positive and PD-L1-negative tumors. In patients with anti-PD-1/PD-L1-refractory NSCLC: 56% receiving monotherapy and 70% receiving combination therapy had TRAEs-the most common were rash and fatigue (21% each) with monotherapy and pruritus (36%) and fatigue (24%) with combination therapy; confirmed ORR was 3% with monotherapy and 3% with combination therapy.Vibostolimab plus pembrolizumab was well tolerated and demonstrated antitumor activity in patients with advanced solid tumors, including patients with advanced NSCLC.

Purpose New immuno-oncology therapies targeting programmed cell death receptor 1 (PD-1) have improved patient outcomes in a broad range of cancers. The objective of this analysis was to evaluate the PK, pharmacodynamics (PDy), and safety of dostarlimab monotherapy in adult patients with previously-treated advanced solid tumors who participated in parts 1 and 2A of the phase 1 GARNET study. Methods Part 1 featured a 3 + 3 weight-based dose–escalation study, in which 21 patients received dostarlimab 1, 3, or 10 mg/kg intravenously every 2 weeks. The 2 fixed-dose nonweight-based dosing regimens of dostarlimab 500 mg every 3 weeks (Q3W) and 1000 mg every 6 weeks (Q6W) were evaluated using a modified 6 + 6 design in part 2A (n = 13). In parts 1 and 2A, treatment with dostarlimab could continue for up to 2 years or until progression, unacceptable toxicity, patient withdrawal, investigator’s decision, or death. Results The dostarlimab PK profile was dose proportional, and maximal achievable receptor occupancy (RO) was observed at all dose levels in the weight-based and fixed-dose cohorts. Trough dostarlimab concentration after administration of dostarlimab 500 mg Q3W was similar to that after dostarlimab 1000 mg Q6W, the values of which (≈40 µg/mL) projected well above the lowest dostarlimab concentration required for full peripheral RO. No dose-limiting toxicities were observed. Conclusions Dostarlimab demonstrated consistent and predictable PK and associated PDy. The observed safety profile was acceptable and characteristic of the anti-PD-1 drug class. Trial registration: ClinicalTrials.gov, NCT02715284. Registration date: March 9, 2016.

Purpose:In this first-in-human study (NCT03564691) in advanced solid tumors, we investigated a novel first-in-class human IgG4 monoclonal antibody targeting the immunoglobulin-like transcript 4 (ILT4) receptor, MK-4830, as monotherapy and in combination with pembrolizumab.Patients and Methods:Patients with histologically/cytologically confirmed advanced solid tumors, measurable disease by RECIST v1.1, and evaluable baseline tumor sample received escalating doses of intravenous MK-4830 every 3 weeks as monotherapy (parts A and B) and in combination with pembrolizumab (part C). Safety and tolerability were the primary objectives. Pharmacokinetics, objective response rate per RECIST v1.1, and molecular biomarkers were also evaluated.Results:Of 84 patients, 50 received monotherapy and 34 received combination therapy. No dose-limiting toxicities were observed; maximum tolerated dose was not reached. MK-4830 showed dose-related target engagement. Eleven of 34 patients in the dose-escalation phase who received combination therapy achieved objective responses; 5 previously had progressive disease on anti–PD-1/PD-L1 therapies. Exploratory evaluation of the association between response and pretreatment gene expression related to interferon-gamma signaling in tumors suggested higher sensitivity to T-cell inflammation with combination therapy than historically expected with pembrolizumab monotherapy, with greater response at more moderate levels of inflammation.Conclusions:This first-in-class MK-4830 antibody dosed as monotherapy and in combination with pembrolizumab was well tolerated with no unexpected toxicities, and demonstrated dose-related evidence of target engagement and antitumor activity. Inflammation intrinsic to the ILT4 mechanism may be facilitated by alleviating the myeloid-suppressive components of the tumor microenvironment, supporting the target of ILT4 as a potential novel immunotherapy in combination with an anti–PD-1/PD-L1 agent.

This first-in-human phase I study (NCT03179436) investigated anti-cytotoxic T-lymphocyte-associated protein 4 monoclonal antibody quavonlimab and anti-programmed death 1 monoclonal antibody pembrolizumab in patients with advanced solid tumors. The study was conducted in two parts: dose-escalation (part 1) and dose-confirmation (part 2). First-line treatment with quavonlimab + pembrolizumab conferred encouraging antitumor activity (objective response rate [ORR], 28%-40%) and was generally well tolerated (grade ≥ 3 treatment-related adverse events [TRAEs] were lowest with quavonlimab 25 mg every 6 weeks [Q6W] at 30% and highest with quavonlimab 75 mg Q3W at 57%) in non-small cell lung cancer. We present data from patients with extensive-stage small cell lung cancer (SCLC) receiving second-line or later therapy.Patients with stage III/IV SCLC received quavonlimab 75 mg Q6W plus pembrolizumab 200 mg Q3W for ≤ 2 years. Primary endpoints were safety and tolerability; ORRs as assessed by blinded independent central review per Response Evaluation Criteria In Solid Tumorsv1.1 was a secondary endpoint. Progression-free survival (PFS), overall survival (OS), and the correlation of response with PD-L1 expression were exploratory endpoints.Forty patients with extensive-stage SCLC received treatment; median follow-up was 13 months. Dose-limiting toxicity occurred in 4 patients (10%). TRAEs occurred in 80% of patients; grade 3 events occurred in 33% of patients and no grade 4/5 events were reported. Confirmed ORRs (95% CI) were 18% (7-33) among all patients, 7% (1-34) for PD-L1-positive tumors (n = 14), and 19% (5-42) for PD-L1-negative tumors (n = 21). Response duration ranged from 2.9 to 19.1+ months. Median PFS was 2.0 months; 6-month PFS rate was 26%. Median OS was 11.0 months; 6-month OS rate was 66%.Encouraging antitumor activity was observed with quavonlimab + pembrolizumab in patients with extensive-stage SCLC; responses were observed in PD-L1-positive and PD-L1-negative tumors. The combination was tolerable with manageable toxicities.

Summary Background Despite advances in the first-line treatment of metastatic renal cell carcinoma (RCC), there is an unmet need for options to address disease progression during or after treatment with immune checkpoint inhibitors (ICIs). Pembrolizumab and lenvatinib are active as monotherapies in RCC; thus, we aimed to evaluate the combination of lenvatinib plus pembrolizumab in these patients. Methods We report results of the metastatic RCC cohort from an open-label phase 1b/2 study of lenvatinib plus pembrolizumab in patients aged at least 18 years with selected solid tumours and an Eastern Cooperative Oncology Group performance status of 0–1. Oral lenvatinib at 20 mg was given once daily along with intravenous pembrolizumab at 200 mg once every 3 weeks. Patients remained on study drug treatment until disease progression, development of unacceptable toxicity, or withdrawal of consent. Efficacy was analysed in patients with clear cell metastatic RCC receiving study drug by previous therapy grouping: treatment naive, previously treated ICI naive (previously treated with at least one line of therapy but not with an anti-PD-1 or anti-PD-L1 ICI), and ICI pretreated (ie, anti-PD-1 or anti-PD-L1) patients. Safety was analysed in all enrolled and treated patients. The primary endpoint was the objective response rate at week 24 per immune-related Response Evaluation Criteria In Solid Tumors (irRECIST) by investigator assessment. This trial is registered with ClinicalTrials.gov ( NCT02501096 ) and with the EU Clinical Trials Register (EudraCT2017-000300-26), and is closed to new participants. Findings Between July 21, 2015, and Oct 16, 2019, 145 patients were enrolled in the study. Two patients had non-clear cell RCC and were excluded from the efficacy analysis (one in the treatment-naive group and one in the ICI-pretreated group); thus, the population evaluated for efficacy comprised 143 patients (n=22 in the treatment-naive group, n=17 in the previously treated ICI-naive group, and n=104 in the ICI-pretreated group). All 145 enrolled patients were included in the safety analysis. The median follow-up was 19·8 months (IQR 14·3–28·4). The number of patients with an objective response at week 24 by irRECIST was 16 (72·7%, 95% CI 49·8–89·3) of 22 treatment-naive patients, seven (41·2%, 18·4–67·1) of 17 previously treated ICI-naive patients, and 58 (55·8%, 45·7–65·5) of 104 ICI-pretreated patients. Of 145 patients, 82 (57%) had grade 3 treatment-related adverse events and ten (7%) had grade 4 treatment-related adverse events. The most common grade 3 treatment-related adverse event was hypertension (30 [21%] of 145 patients). Treatment-related serious adverse events occurred in 36 (25%) patients, and there were three treatment-related deaths (upper gastrointestinal haemorrhage, sudden death, and pneumonia). Interpretation Lenvatinib plus pembrolizumab showed encouraging antitumour activity and a manageable safety profile and might be an option for post-ICI treatment of metastatic RCC. Funding Eisai and Merck Sharp & Dohme.

Tumor progression and immune evasion result from multiple oncogenic and immunosuppressive signals within the tumor microenvironment. The combined blockade of VEGF and inhibitory immune checkpoint signaling has been shown to enhance immune activation and tumor destruction in preclinical models. The LEAP clinical trial program is evaluating the safety and efficacy of lenvatinib (a multikinase inhibitor) plus pembrolizumab (a PD-1 inhibitor) across several solid tumor types. Preliminary results from ongoing trials demonstrate robust antitumor activity and durable responses across diverse tumor types with a manageable safety profile. Thus, lenvatinib plus pembrolizumab is anticipated to be an important potential new regimen for several solid cancers that currently have limited therapeutic options. Clinical trial registration: NCT03884101 , NCT03713593 , NCT03820986 , NCT03776136 , NCT03797326 , NCT03829319 , NCT03829332 , NCT03976375 , NCT04428151 , NCT04199104 , NCT03898180 , NCT04246177 (ClinicalTrials.gov).

Budigalimab is a humanized, recombinant, Fc mutated IgG1 monoclonal antibody targeting programmed cell death 1 (PD‐1) receptor, currently in phase I clinical trials. The safety, efficacy, pharmacokinetics (PKs), pharmacodynamics (PDs), and budigalimab dose selection from monotherapy dose escalation and multihistology expansion cohorts were evaluated in patients with previously treated advanced solid tumors who received budigalimab at 1, 3, or 10 mg/kg intravenously every 2 weeks (Q2W) in dose escalation, including Japanese patients that received 3 and 10 mg/kg Q2W. PK modeling and PK/PD assessments informed the dosing regimen in expansion phase using data from body‐weight‐based dosing in the escalation phase, based on which patients in the multihistology expansion cohort received flat doses of 250 mg Q2W or 500 mg every four weeks (Q4W). Immune‐related adverse events (AEs) were reported in 11 of 59 patients (18.6%), of which 1 of 59 (1.7%) was considered grade ≥ 3 and the safety profile of budigalimab was consistent with other PD‐1 targeting agents. No treatment‐related grade 5 AEs were reported. Four responses per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 were reported in the dose escalation cohort and none in the multihistology expansion cohort. PK of budigalimab was approximately dose proportional and sustained > 99% peripheral PD‐1 receptor saturation was observed by 2 hours postdosing, across doses. PK/PD and safety profiles were comparable between Japanese and Western patients, and exposure‐safety analyses did not indicate any trends. Observed PK and PD‐1 receptor saturation were consistent with model predictions for flat doses and less frequent regimens, validating the early application of PK modeling and PK/PD assessments to inform the recommended dose and regimen, following dose escalation.

BackgroundBDB001 is an intravenously administered TLR 7/8 dual agonist immune modulator capable of reprogramming dendritic cells to produce antitumor activities. BDB001 monotherapy has demonstrated favorable tolerability and robust systemic immune activation leading to durable clinical responses in a Phase I trial. Here, we report on the safety and efficacy of BDB001 in combination with atezolizumab in a Phase I dose escalation/expansion trial in advanced solid tumors (NCT04196530).MethodsBDB001-102 is a Phase 1, open label, dose escalation/expansion trial of BDB001 (IV, Q1W) in combination with an anti-PD-L1 antibody, atezolizumab (IV, Q3W), in patients with advanced solid tumors. The primary endpoint was safety and tolerability. Secondary endpoints included efficacy, pharmacokinetics and pharmacodynamic profiling of immune activation.ResultsForty-one subjects with 17 different tumor types were enrolled across 4 dose levels. Fifty-nine percent were female, median age was 67 years (range, 32–80), median number of prior therapies was 3 (range, 0–8), and 63% of tumors had progressed on prior anti-PD-(L)1 therapy. Overall, BDB001 in combination with atezolizumab was well tolerated and 13 (31.7%) subjects did not experience any treatment related adverse events (TRAEs). No dose-limiting toxicities were observed. Common TRAEs were transient Grade 1 or 2 fatigue (31.7%), fever (26.8%) and chills/rigor (26.8%). Only 3 (7.3%) subjects experienced Grade 3 TRAEs of fatigue and nausea. There were no Grade 4 or 5 TRAEs and no new safety concerns. Pharmacodynamic evaluation of plasma cytokine levels showed robust increases in interferon gamma and interferon inducible protein-10 (IP-10) at BDB001 Dose Level 4. IP-10 induction was associated with clinical responses. Preliminary efficacy evaluation of the 19 subjects at Dose Level 4 showed durable and deep clinical responses in 3 (16%) subjects, 2 with urothelial carcinoma and 1 with anti-PD-1 mAb refractory NSCLC. All responders remain on treatment, with a duration of response ranging from 7.1+ to 34.1+ weeks. Ten (53%) subjects had stable disease (DCR 68%), 3 of whom had a reduction in tumor burden and were on treatment for over 18 weeks (up to 56 weeks).ConclusionsIntravenous BDB001 in combination with atezolizumab is well tolerated. Deep and durable clinical responses were observed in PD-1 refractory and naive patients, supported by robust systemic immune activation. BDB001 in combination with atezolizumab is a promising therapeutic option for patients with advanced solid tumors. A phase 2 trial (NCT03915678) of BDB001 in combination with atezolizumab and radiotherapy is currently enrolling patients.Ethics ApprovalThis study was approved by the institutional review boards at the five participating institutions. All subjects signed informed consent before enrolling in the clinical trial.

Background: Palbociclib is one of three CDK 4/6 inhibitors approved in combination with an aromatase inhibitor for treatment of hormone receptor-positive breast cancer. Although this combination therapy has been found effective in some patients, resistance often develops. To aid in developing new therapies for CDK4/6-resistant breast cancer and better understand resistance mechanisms, we established a PDX model, designated ST1799, from a patient with luminal A breast cancer which was responsive to palbociclib in vivo and then conditioned the model with chronic drug administration until resistant. The resistant model, designated ST1799/PBR, and the parent were characterized for receptor expression, genomic alterations and in vivo drug sensitivity. Methods: ST1799 was established from an axillary lymph node FNA taken from a 66-year-old woman pretreated with various chemo and hormone therapies. The resulting model was passaged and a cohort challenged with chronic palbociclib treatment to produce drug resistance. The parent ST1799 and resistant ST1799/PBR were subjected to various comparative analyses including receptor expression, NGS and RNAseq and response to various relevant therapies. Results: Both models retained high ER staining (3+) expression and demonstrated comparable histopathology. DNA-based analysis of the parent model confirmed variants concordant with clinical mutation analysis. Comparison of the parent and resistant clone using RNAseq identified several alterations in variants and expression. In vivo palbociclib reported significant (p Citation Format: Lizette Gamez, Alyssa Moriarty, Tomoyuki Mashimo, Kyriakos Papadopoulos, Drew Rasco, Amita Patnaik, Michael J Wick. Establishment and characterization of paired palbociclib-sensitive and resistant luminal A breast PDX models [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-03-10.

Purpose: STM 434 is a soluble receptor ligand trap targeting activin A, a protein in the TGFβ family that plays important roles in growth, differentiation, and cancer cachexia. This study evaluated the safety, antitumor activity, and metabolic effects of STM 434 in a first-in-human, multicenter, phase I clinical trial (NCT02262455). Patients and Methods: Patients with advanced solid tumors were enrolled in 8 dose cohorts ranging from 0.25 mg/kg every 4 weeks to 8 mg/kg every 2 weeks via a 3 + 3 dose-escalation design. The primary endpoint was maximum tolerated dose (MTD). Secondary endpoints included safety, pharmacokinetics, and response. As activin A is implicated in metabolism and muscle function, changes in key metabolic parameters, including lean body mass and 6-minute walk test, were serially measured. Results: Thirty-two patients were treated on study. The most common treatment-related adverse events were fatigue (41%) and mucocutaneous bleeding complications including epistaxis (34%) and gingival bleeding (22%), likely related to off-target inhibition of bone morphogenetic protein 9 (BMP9). STM 434 treatment resulted in the expected follicle-stimulating hormone level decreases in most patients and in metabolic parameter changes, including an increase in total lean body mass and 6-minute walk test distance. No responses were observed in the 30 evaluable patients, but the stable disease rate in patients with granulosa cell ovarian cancer was 10 of 12 (80%). Conclusions: Although no direct antitumor efficacy was documented, potentially clinically meaningful dose-related metabolic effects, including treatment of cancer cachexia, were observed that support further exploration of activin A inhibitors that limit BMP9 blockade. See related commentary by Bonilla and Oza, p. 5432

Background: Ibrutinib, a first-in-class, once-daily inhibitor of Bruton’s tyrosine kinase, is approved in the United States for the treatment of various B-cell malignancies. Preclinical data suggest synergistic antitumor activity of ibrutinib with programmed death-ligand 1 (PD-L1) inhibitors in solid tumors. This study evaluated ibrutinib plus durvalumab, a PD-L1-targeting antibody, in patients with relapsed/refractory solid tumors. Methods: This open-label, multicenter, phase 1b/2 study enrolled previously treated patients with stage III/IV pancreatic adenocarcinoma, breast cancer, or non-small cell lung cancer (NSCLC). Phase 1b determined the recommended phase 2 dose (RP2D). In phase 2, patients were treated at the RP2D to evaluate the safety and antitumor activity of ibrutinib plus durvalumab. Results: The RP2D was identified as ibrutinib 560 mg p.o. daily and durvalumab 10 mg/kg i.v. every 2 weeks, with 122 patients treated at the RP2D. Median age was 61 years, and the majority of patients (94%) had stage IV disease. Overall response rates (complete or partial responses) were 2% for pancreatic cancer, 3% for breast cancer, and 0% for NSCLC. Median progression-free survival was 1.7, 1.7, and 2.0 months in the pancreatic cancer, breast cancer, and NSCLC cohorts, respectively. Median overall survival was 4.2, 4.2, and 7.9 months in the pancreatic cancer, breast cancer, and NSCLC cohorts, respectively. The safety profiles observed across tumor types were consistent with the known safety profiles for ibrutinib and durvalumab. Grade ≥3 adverse events in ≥5% of all patients were hyponatremia (10%), dyspnea (7%), maculopapular rash (7%), pneumonia (7%), anemia (6%), and diarrhea (6%). Conclusions: The combination of ibrutinib 560 mg daily and durvalumab 10 mg/kg every 2 weeks had an acceptable safety profile. The antitumor activity of the ibrutinib-durvalumab combination was limited in our study population.

Purpose: Avadomide is a novel, small-molecule therapeutic agent that modulates cereblon E3 ligase activity and exhibits potent antitumor and immunomodulatory activities. This first-in-human phase I study (NCT01421524) evaluated the safety and clinical activity of avadomide in patients with advanced solid tumors, non-Hodgkin lymphoma (NHL), and multiple myeloma. Patients and Methods: Thirty-four patients were treated with avadomide in 7 dose-escalation cohorts using a 3 + 3 design (0.5–3.5 mg, 28-day continuous dosing cycles). The primary objectives were to determine the dose-limiting toxicity (DLT), nontolerated dose (NTD), maximum tolerated dose (MTD), recommended phase II dose, and pharmacokinetics of avadomide. The secondary objective was to determine preliminary avadomide efficacy. Exploratory objectives included evaluation of pharmacodynamic effects of avadomide. Results: DLTs were reported in 2 patients, and grade ≥3 treatment-emergent adverse events (TEAEs) occurred in 14 patients (41%). The most common TEAEs (≥15%) were fatigue, neutropenia, and diarrhea. The NTD and MTD were 3.5 and 3.0 mg, respectively. Of 5 patients with NHL, 1 achieved a complete response, and 2 had partial responses. Although no objective responses were observed in patients with solid tumors, 5 of 6 patients with brain cancer experienced nonprogression of ≥6 months. A dose-dependent relationship between Aiolos degradation in peripheral B and T cells occurred within 5 hours of the first dose of avadomide administered, starting at 0.5 mg. Conclusions: Avadomide monotherapy demonstrated acceptable safety and favorable pharmacokinetics in patients with solid tumors, NHL, and multiple myeloma. In addition, 3 objective responses were observed in NHL.

Background GB1275 is a first-in-class CD11b modulator that reduced myeloid-derived suppressor cells (MDSCs) and tumor associated macrophages (TAMs), repolarized M2 immunosuppressive TAMs to an M1 phenotype, and increased tumor infiltration of activated CD8+ T cells in preclinical models. Preclinical anti-tumor activity was observed with single-agent therapy and in combination with chemotherapy or immuno-oncology therapies.1 We report results from the dose escalation portion of an ongoing, first-in-human study of GB1275 monotherapy and combined with pembrolizumab in patients with specific advanced solid tumors. (NCT04060342) Methods This study comprises phase 1 dose escalation followed by phase 2 expansion in specific tumor types. In phase 1, cohorts of 3 to 6 patients with histologically confirmed, locally advanced/metastatic pancreatic, esophageal, gastric, MSS colorectal, metastatic castrate-resistant prostate cancer, or triple negative breast cancer are sequentially assigned to one of the ascending dose levels of GB1275 orally twice daily (BID) in 1 of 3 regimens: A (GB1275 monotherapy); B (GB1275 + pembrolizumab) commenced after completion of two cohorts of A; and C (GB1275 + nab-paclitaxel + gemcitabine) will be initiated after A. Patients in Regimens A and B had previously exhausted standard of care treatment options. Dose escalation was based on safety, including dose-limiting toxicity (DLT). Serial blood samples were collected for pharmacokinetic (PK) and biomarker analyses; tumor tissue was also collected for biomarker analysis. Results As of July 28, 2020, 36 patients were treated, 23 in Regimen A (GB1275 100 mg to 1200 mg BID) and 13 in Regimen B (GB1275 100 mg to 800 mg BID + pembrolizumab). No DLTs or adverse events requiring steroid treatment were reported. GB1275-related adverse events were reported in 19 (52.8%) patients; most were Grade 1 and most frequent events (≥10%) were dysesthesia (13.9%) and photosensitivity reaction (11.1%). Stable disease was reported in 4 (17%) patients in Regimen A and 6 (46%) in Regimen B with a median (range) exposure of 84 days (35–172). A dose-dependent increase in GB1275 exposure was observed. An increase in tumor infiltrating lymphocyte (TIL) counts was noted in both Regimens A and B. Other biomarker analyses in serial blood and tumor tissue are ongoing. Conclusions Dose escalation of GB1275, up to 1200 mg and 800 mg BID in Regimens A and B, respectively, demonstrated tolerability as monotherapy and combined with pembrolizumab. The maximum tolerated dose has not been reached. Preliminary observation of an increase in TILs after treatment is encouraging. Ethics Approval This ongoing study is being conducted in accordance with the Declaration of Helsinki and Council for International Organizations of Medical Sciences (CIOMS) International Ethical Guidelines. The study was approved by the Ethics Boards of the University of Colorado Hospital, Washington University School of Medicine - Siteman Cancer Center, Memorial Sloan Kettering Cancer Center, The Sarah Cannon Research Institute/Tennessee Oncology, South Texas Accelerated Research Therapeutics, and The Royal Marsden NHS Foundation Trust. Reference Panni RZ, Herndon JM, Zuo C, et al. Agonism of CD11b reprograms innate immunity to sensitize pancreatic cancer to immunotherapies. Sci Transl Med 2019 Jul 3;11(499).

Background GB1275 is a first-in-class CD11b modulator in development as monotherapy and in combination with pembrolizumab or chemotherapy for the treatment of advanced solid tumors. Nonclinical data show that GB1275 reduced influx of tumor-associated myeloid-derived suppressor cells (MDSCs) and macrophages (TAMs), and repolarized M2 immuno-suppressive TAMs towards an M1 phenotype. We hypothesize that GB1275 administration can alleviate myeloid cell-mediated immunosuppressive effects and improve cancer treatment outcomes. A phase 1 trial evaluating GB1275 as monotherapy and in combination with pembrolizumab in specified advanced tumors in ongoing (NCT04060342). Methods Blood gene expression variations as well as core tissue biopsies pre- and post-treatment were assessed following GB1275 monotherapy and combination with pembrolizumab. After obtaining informed consent, peripheral blood for MDSCs was collected from 21 patients pre- and two weeks post-treatment; core tissue biopsies were collected from 13 patients pre- and post-treatment. The frequency of MDSCs in whole blood was measured using the Serametrix MDSC FACS Assay. Gene expression transcriptome profiles were generated using NovaSeq platform. CD8 staining was performed at Neogenomics, and tumor infiltrating lymphocyte (TIL) quantification was performed by an independent pathologist. Results Preliminary statistical analysis of MDSC immunophenotyping pre- and post- treatment is consistent with the proposed mechanism of GB1275, showing modulation of peripheral blood MDSCs in some patients. Preliminary gene expression analysis in the blood showed dose-dependent clusters following treatment with GB1275 alone. Moreover, the transcriptomic analysis revealed two unique expression patterns for patients treated with GB1275 monotherapy or in combination with pembrolizumab. Gene Set Enrichment Analysis showed that the CD11b pathway is downregulated in patients treated with GB1275. Analyses of TIL count revealed an increase in lymphocyte trafficking into the tumor after treatment with GB1275 alone or in combination with pembrolizumab. CD8 expression and transcriptomic analysis are underway and will be presented. Conclusions GB1275 alone or in combination with pembrolizumab demonstrates biological activity, which may be dose dependent. The observed increase in TILs after treatment is supportive of the mechanism of action of GB1275. Further biomarker analyses in blood and tissues are ongoing and will be correlated with clinical activity in a larger number of patients. Ethics Approval This ongoing study is being conducted in accordance with the the Declaration of Helsinki and Council for International Organizations of Medical Sciences (CIOMS) International Ethical Guidelines. The study was approved by the Ethics Boards of University of Colorado Hospital, Washington University School of Medicine - Siteman Cancer Center, Memorial Sloan Kettering Cancer Center, The Sarah Cannon Research Institute/Tennessee Oncology, South Texas Accelerated Research Therapeutics, and The Royal Marsden NHS Foundation Trust.

Background TLR agonists mediate antitumor activity through dendritic cell (DC) activation. Most TLR agonists in development are administered intratumorally allowing for less than 30% of advanced solid tumor to be treated. BDB001 is an intravenously administered novel TLR7/8 agonist that activates plasmacytoid and myeloid DCs and has shown to have activity in preclinical studies. Here we report on BDB001 administration in patients with advanced solid tumors. Methods BDB001-101 is a Phase 1, open label, dose escalation/expansion trial of BDB001 administered intravenously weekly in patients with advanced solid tumors. The primary endpoint was safety and tolerability. Secondary endpoints included efficacy, pharmacokinetics and pharmacodynamic profiling of immune activation. Results Thirty-six subjects with 16 different tumor types were enrolled across 5 dose levels. Sixty seven percent were female, median age was 66 years (range, 38–88), median number of prior therapies was 4 (range, 0–12), and 61% of tumors had progressed on prior anti-PD-(L)1 therapy. BDB001 was well tolerated and a maximum tolerated dose was not reached. Eleven (30.5%) subjects had no treatment related adverse events (AEs) and the majority of AEs were Grade 1 or 2. Three (8.3%) subjects had Grade 3 AEs, including 2 with a cytokine release syndrome, both of whom were clinically stable and had symptoms fully resolved within 2 to 5 days. There were no Grade 4 or 5 AEs. The most common AEs included chills/rigor (19.4%), fever (19.4%), fatigue (11.1%), nausea (11.1%) and pruritus (11.1%). Of 32 subjects evaluable for efficacy, best overall response rate was: 6% durable partial response, 56% stable disease, 38% progressive disease, for a disease control rate of 62%. Durable responses were seen in renal cell carcinoma and non-small cell lung cancer. Interestingly, clinical activity favored subjects with tumors that had progressed on prior anti-PD-(L)1 therapy, compared to prior DNA-damaging chemotherapy, within 6 months of BDB001 initiation. Median time on treatment was 12.1 weeks (range, 3.1 – 68.0). Transcriptional profiling showed up-regulation of interferon inducible genes, activation of dendritic cells and macrophages. BDB001 also significantly increased serum levels of interferon gamma and interferon inducible protein-10 (IP-10). Conclusions Intravenously administered BDB001 monotherapy was well tolerated. Clinical responses were achieved, supported by BDB001-induced immune activation. Preliminary findings suggest that BDB001 is a promising therapeutic option for patients with tumors that progress on anti-PD-(L)1 therapy. BDB001 is also being evaluated in combination with pembrolizumab (anti-PD-1, NCT03486301) and with atezolizumab (anti-PD-L1, NCT04196530). Trial Registration NCT03486301 Ethics Approval This study was approved by the institutional review boards at the four participating institutions. All subjects signed informed consent before enrolling in the clinical trial.

PURPOSE To evaluate the safety, pharmacokinetics, and preliminary activity of bemarituzumab in patients with FGFR2b-overexpressing gastric and gastroesophageal junction adenocarcinoma (GEA). PATIENTS AND METHODS FPA144-001 was a phase I, open-label, multicenter trial consisting of the following 3 parts: part 1a involved dose escalation in patients with recurrent solid tumors at doses ranging from 0.3 to 15 mg/kg; part 1b involved dose escalation in patients with advanced-stage GEA; and part 2 involved dose expansion in patients with advanced-stage GEA that overexpressed FGFR2b at various levels (4 cohorts; high, medium, low, and no FGFR2b overexpression) and 1 cohort of patients with FGFR2b-overexpressing advanced-stage bladder cancer. RESULTS Seventy-nine patients were enrolled; 19 were enrolled in part 1a, 8 in part 1b, and 52 in part 2. No dose-limiting toxicities were reported, and the recommended dose was identified as 15 mg/kg every 2 weeks based on safety, tolerability, pharmacokinetic parameters, and clinical activity. The most frequent treatment-related adverse events (TRAEs) were fatigue (17.7%), nausea (11.4%), and dry eye (10.1%). Grade 3 TRAEs included nausea (2 patients) and anemia, neutropenia, increased AST, increased alkaline phosphatase, vomiting, and an infusion reaction (1 patient each). Three (10.7%) of 28 patients assigned to a cohort receiving a dose of ≥ 10 mg/kg every 2 weeks for ≥ 70 days reported reversible grade 2 corneal TRAEs. No TRAEs of grade ≥ 4 were reported. Five (17.9%; 95% CI, 6.1% to 36.9%) of 28 patients with high FGFR2b-overexpressing GEA had a confirmed partial response. CONCLUSION Overall, bemarituzumab seems to be well tolerated and demonstrated single-agent activity as late-line therapy in patients with advanced-stage GEA. Bemarituzumab is currently being evaluated in combination with chemotherapy in a phase III trial as front-line therapy for patients with high FGFR2b-overexpressing advanced-stage GEA.

Background Quavonlimab (MK-1308), a novel anti-CTLA-4 antibody, in combination with pembrolizumab was investigated in a phase I study. Patients and methods Dose-escalation (DE) phase: patients with advanced/metastatic solid tumors received an initial flat dose of quavonlimab as monotherapy [25 mg (cohort 1), 75 mg (cohort 2), or 200 mg (cohort 3)] followed by four treatments of the same quavonlimab dose plus pembrolizumab every 3 weeks (Q3W). Dose-confirmation phase (DC): patients with stage IIIB/IV non-small-cell lung cancer (NSCLC) received first-line quavonlimab [25 mg Q3W (arm A), 25 mg Q6W (arm B), 75 mg Q6W (arm C), or 75 mg Q3W (arm E)] plus pembrolizumab. Primary objectives were safety and tolerability and establishment of the recommended phase II dose (RP2D) of quavonlimab when used with pembrolizumab. Objective response rate (ORR) was a secondary endpoint. Efficacy based on PD-L1 expression, tumor mutational burden (TMB), and changes in circulating CD4+/CD8+ cells were exploratory endpoints. Results Thirty-nine patients were enrolled in DE [n = 14 (cohort 1); n = 17 (cohort 2); n = 8 (cohort 3)] and 134 in DC [n = 40 (arm A); n = 40 (arm B); n = 40 (arm C); n = 14 (arm E)]. Maximum-tolerated dose was not reached. Grade 3-5 treatment-related adverse events (AEs; graded according to NCI CTCAE v4.03) occurred in 0%, 23.5%, and 75.0% of patients in DE cohorts 1, 2, and 3, respectively, and 35.0%, 30.0%, 35.0%, and 57.1% of patients in DC arms A, B, C, and E, respectively. Efficacy was observed at all dose levels/schedules in patients with NSCLC. ORRs were 40.0% [95% confidence interval (CI), 24.9-56.7; arm A], 37.5% (95% CI, 22.7-54.2; arm B), 27.5% (95% CI, 14.6-43.9; arm C), and 35.7% (95% CI, 12.8-64.9; arm E). PD-L1 expression and total number of circulating CD4+ cells correlated with ORR. Conclusions Quavonlimab 25 mg Q6W plus pembrolizumab demonstrated similar efficacy and a better safety profile among all quavonlimab doses/schedules evaluated; this regimen was the chosen RP2D.

PURPOSE Modulation of vascular endothelial growth factor–mediated immune suppression via angiogenesis inhibition may augment the activity of immune checkpoint inhibitors. We report results from the dose-finding and initial phase II expansion of a phase Ib/II study of lenvatinib plus pembrolizumab in patients with selected advanced solid tumors. METHODS Eligible patients had metastatic renal cell carcinoma (RCC), endometrial cancer, squamous cell carcinoma of the head and neck (SCCHN), melanoma, non–small-cell lung cancer (NSCLC), or urothelial cancer. The primary objective of phase Ib was to determine the maximum tolerated dose (MTD) for lenvatinib plus pembrolizumab (200 mg intravenously every 3 weeks). In the preplanned phase II cohort expansion, the primary objective was objective response rate at week 24 (ORRweek 24) at the recommended phase II dose. RESULTS Overall, 137 patients were enrolled during phase Ib (n = 13) and the initial phase II expansion (n = 124). Two dose-limiting toxicities (DLTs; grade 3 arthralgia and grade 3 fatigue) were reported in the initial dose level (lenvatinib 24 mg/d plus pembrolizumab). No DLTs were observed in the subsequent dose–de-escalation cohort, establishing the MTD and recommended phase II dose at lenvatinib 20 mg/d plus pembrolizumab. ORRweek24 was as follows: RCC, 63% (19/30; 95% CI, 43.9% to 80.1%); endometrial cancer, 52% (12/23; 95% CI, 30.6% to 73.2%); melanoma, 48% (10/21; 95% CI, 25.7% to 70.2%); SCCHN, 36% (8/22; 95% CI, 17.2% to 59.3%); NSCLC, 33% (7/21; 95% CI, 14.6% to 57.0%); and urothelial cancer 25% (5/20; 95% CI, 8.7% to 49.1%). The most common treatment-related adverse events were fatigue (58%), diarrhea (52%), hypertension (47%), and hypothyroidism (42%). CONCLUSION Lenvatinib plus pembrolizumab demonstrated a manageable safety profile and promising antitumor activity in patients with selected solid tumor types.

The phase I study characterized the safety, pharmacokinetics, anti-tumor activity, and recommended phase II dose/schedule of LY3164530 in patients with advanced or metastatic cancer. Patients received LY3164530 on days 1 and 15 (Schedule 1: 300, 600, 1000, and 1250 mg) or Days 1, 8, 15, and 22 (Schedule 2: 500 and 600 mg) of each 28 days cycle. Dose escalation used a modified toxicity probability interval model. Dose escalation defined a maximum tolerated dose (MTD) of 1000 mg on Schedule 1 and 500 mg on Schedule 2. Treatment-emergent adverse events related to study treatment were consistent with epidermal growth factor receptor (EGFR) inhibition and included maculopapular rash/dermatitis acneiform (83%, Grade 3/4 17%), hypomagnesemia (55%, Grade 3/4 7%), paronychia (35%), fatigue (28%, Grade 3/4 3%), skin fissures (24%), and hypokalemia (21%, Grade 3/4 7%). Partial response was achieved in three patients on Schedule 2 with colorectal cancer (n = 2) or squamous cell cancer. Overall response rate (ORR) was 10.3%, disease control rate (ORR + stable disease [SD]) was 51.7 and 17.2% of patients had SD ≥ 4 months. The in vivo stability of the bispecific antibody was confirmed. Schedule 2 provided greater and more consistent inhibition of mesenchymal-epithelial transition (MET)/EGFR throughout the dosing interval than Schedule 1. Although this study defined the LY3164530 MTD and pharmacokinetics on both schedules, significant toxicities associated with EGFR inhibition and lack of a potential predictive biomarker limit future development. Nonetheless, the results provide insight into the development of bispecific antibody therapy.

Background Epidermal growth factor receptor (EGFR) alterations are associated with multiple cancers. Current EGFR-directed therapies have led to increased efficacy but are associated with specific side effects. The antibody-drug conjugate depatuxizumab mafodotin (depatux-m) targets EGFR with a monoclonal antibody linked to a cytotoxin, and is highly tumor-specific. Methods This phase 1/2 study evaluated the safety, pharmacokinetics, and efficacy of depatux-m in patients who had advanced solid tumors with known wild-type EGFR overexpression, amplification, or mutated EGFR variant III. A 3 + 3 dose escalation was used, and 2 dosing schedules were evaluated. Depatux-m also was manufactured under an alternate process to reduce the drug load and improve the safety profile, and it was tested at the maximum tolerated dose (MTD). In another cohort, prolonged infusion time of depatux-m was evaluated; and a cohort with confirmed EGFR amplification also was evaluated at the MTD. Results Fifty-six patients were treated. The MTD and the recommended phase 2 dose for depatux-m was 3.0 mg/kg. Common adverse events (AEs) were blurred vision (48%) and fatigue (41%). A majority of patients (66%) experienced 1 or more ocular AEs. Grade 3 or 4 AEs were observed in 43% of patients. One patient with EGFR-amplified, triple-negative breast cancer had a partial response. Stable disease was observed in 23% of patients. Pharmacokinetics revealed that depatux-m exposures were approximately dose-proportional. Conclusions Depatux-m resulted in infrequent nonocular AEs but increased ocular AEs. Patient follow-up confirmed that ocular AEs were reversible. Lowering the drug-antibody ratio did not decrease the number of ocular AEs. A partial response in 1 patient with EGFR-amplified disease provides the opportunity to study depatux-m in diseases with a high incidence of EGFR amplification. Cancer 2018;124:2174-83. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

BackgroundCOM701, a novel first-in-class immune checkpoint inhibitor (ICI) binds to poliovirus receptor related immunoglobulin domain containing (PVRIG) leading to enhanced activation of T and NK-cells. COM701 in combination with nivolumab has a favorable safety profile, is well tolerated and demonstrates antitumor activity.1 We hypothesized that the addition of BMS-986207 as a triplet thereby inhibiting the DNAM axis will have an acceptable safety/tolerability profile. We present preliminary results on safety/tolerability and pharmacokinetics (PK) parameters.MethodsUsing an accelerated titration and 3+3 study design we enrolled 14 patients (pts) with advanced solid tumors. Doses of COM701 were 0.3, 1, 3, 10 or 20 [mg/kg IV Q4 wks]; in combination with nivolumab and BMS-986207 (both 480 mg IV Q4 wks). Key objectives were to evaluate the safety and tolerability, to determine the recommended dose for expansion (RDFE) and to characterize preliminary pharmacokinetic parameters. Key inclusion criteria: Age ≥ 18 yrs, histologically confirmed locally advanced or metastatic solid malignancy and has exhausted all available standard treatments. Key exclusion criteria: history of immune-related toxicities on prior immunotherapy treatment leading to discontinuation.ResultsIn the safety population [N=14], 12 pts reported treatment emergent adverse events (TEAEs). The most frequent TEAES [≥3 pts] were fatigue 5 pts (36%), pyrexia 3 pts (21%), vomiting 3 pts (21%). No DLTs were reported in any of the dose levels. The most frequent tumor types enrolled: CRC (n=3), and prostate, melanoma and OVCA/primary peritoneal cancer (n=2 each). Median number of prior therapies was 10 (range 1–19). Four pts had received prior immunotherapy. Serious adverse events [≥2 pts] were 2 pts (14%) with G3 abdominal pain, 2 pts (14%) with vomiting (1pt with G1/2 vomiting, 1 pt with G3 vomiting) all assessed by the investigator as unrelated to study drug. Preliminary PK profiles of COM701 were generally dose proportional.ConclusionsCOM701 in combination with BMS-986207 and nivolumab demonstrates a favorable safety, tolerability and PK profiles. COM701 20 mg/kg has been selected as the RDFE in combination with BMS-986207 and nivolumab (both 480 mg) all administered IV Q4 wks. The expansion cohorts are enrolling pts with platinum resistant ovarian cancer and endometrial cancer. Data cutoff 28 Jun 2021.AcknowledgementsThis study is in collaboration with Bristol Myers Squibb.Trial RegistrationNCT04570839ReferencesVaena, DA, Fleming GF et al. COM701 with or without nivolumab: Results of an ongoing phase 1 study of safety, tolerability and preliminary antitumor activity in patients with advanced solid malignancies (NCT03667716). J Clin Oncol 2021;39: (suppl 15; abstr 2504).Ethics ApprovalThe study obtained ethics approval form all the participating sites. All study participants gave informed consent before taking part.- 0002: START2020.15- 0003: 20210109- 0005: IRB20-1549- 0006: 21-060- 0007: IRB-AAAT4904- 0012: 2020-0755- 0013: STMW2020.16- 0015: 20210109

BackgroundCOM902 is an IgG4 fully human high-affinity monoclonal antibody, inhibitor of TIGIT (T cell Ig and immunoreceptor tyrosine-based inhibitory motif [ITIM] domain) binding to poliovirus receptor (PVR). TIGIT blockade by COM902 was shown to enhance anti-tumor immunity in pre-clinical models. We hypothesized that COM902 as monotherapy will have an acceptable safety and tolerability profile in subjects with advanced solid tumors.MethodsUtilizing an accelerated titration and 3+3 study design we enrolled 18 patients (pts) at the following COM902 doses 0.01, 0.03, 0.1, 0.3, 1, 3 and 10 mg/kg IV Q3 wks. Key primary objectives were to evaluate the safety, tolerability (CTCAE v5.0), to characterize the pharmacokinetics (PK) and to select a recommended dose for expansion (RDFE). An exploratory objective was evaluation of peripheral receptor occupancy (RO). Key inclusion criteria: Age ≥18 yrs, histologically/cytologically confirmed advanced malignancy who have exhausted all available standard therapy or not a candidate for standard therapy. Patients with performance status ECOG 0-1, prior ICI permissible. Dose-limiting toxicities (DLTs) were evaluated within a 21-day window in the 1st cycle of dose escalation.ResultsIn the safety population [N=18], 12 pts reported treatment emergent adverse events (TEAEs). The most frequent TEAES [≥2pts] were fatigue 7 pts (39%) all G1/2, diarrhea 3 pts (17%) all G1/2. Two pts reported DLTs deemed related to study drug, a pt with G2 nausea (single pt cohort, 0.01 mg/kg) and a pt with G3 atrial fibrillation (1 mg/kg). Serious adverse events were reported in 2 pts, 1 pt with atrial fibrillation (deemed by the investigator as possibly related to COM902) and 1 pt with spinal cord compression (deemed by the investigator as unrelated to COM902, related to disease). Preliminary PK profiles were generally dose proportional and peripheral RO above 90% was reported from 0.1 mg/kg dose.ConclusionsCOM902 has an acceptable safety, tolerability and PK profiles. A COM902 3 mg/kg IV Q3 wks is the RDFE. Enrollment into combination cohort (COM902 + COM701), for evaluation of safety/tolerability at the RDFE of both study drugs, combination dose expansion (COM902 + COM701) in pts with HNSCC, NSCLC and CRC-MSS and COM902 monotherapy dose expansion (pts with multiple myeloma) all at the RDFE of study drug(s) are planned. Data cut June 28, 2021.Trial RegistrationNCT04354246Ethics ApprovalThe study obtained approval from IRBs of the participating clinical trial sites. The study participants gave informed consent before taking part.o 0002: MOD01006350 (START)o 0003: 20202320 (West Cancer Center)o 0012: 2020–0195 (MDACC)o 0013: MOD01006350 (START midwest)o 0014: 20202320 (OSU)

Background: To date, anti-HER2 monoclonal antibodies are the only immune therapies approved for treating pts with HER2-over-expressing cancers. Intratumoral delivery of immunostimulatory adjuncts such as toll-like receptor (TLR) 7/8 agonists can activate tumor resident antigen-presenting cells (APCs) to promote antitumor immunity. To optimize intratumoral delivery while leveraging favorable preclinical biology we developed a novel, systemically delivered ISAC (BDC-1001). BDC-1001 consists of an investigational trastuzumab biosimilar chemically conjugated to a TLR 7/8 agonist (payload) with an intervening non-cleavable linker. BDC-1001 activates human myeloid APCs and retains antibody-mediated effector functions such as antibody-dependent cellular cytotoxicity/phagocytosis. Our trastuzumab-based ISACs seem to elicit potent and durable immune-mediated antitumor efficacy including tumor regression in a TLR- and Fc receptor-dependent manner in xenograft and syngeneic tumor resistant models (Ackerman et al. Nat Cancer 2020). BDC-1001 did not induce interstitial lung disease, cytokine release syndrome, or thrombocytopenia in non-human primate studies. A four-part phase 1/2, first-in-human study was initiated in 2020 to evaluate BDC-1001 with or without (±) pembro in pts with HER2-overexpressing or amplified advanced solid tumors. Methods: This phase 1/2 dose-escalation/expansion study will enroll up to 390 pts with HER2-overexpressing (IHC2+ or 3+) or HER2-amplified (by in situ hybridization or next-generation sequencing) advanced solid tumors. Patients may have received prior anti-HER2 therapies. Primary objectives of dose-escalation are safety and tolerability, and establishing a recommended phase 2 dose of BDC-1001 alone administered IV q3w (Part 1) and combined with pembro (Part 2). Primary endpoints of Parts 1 & 2 include assessment of safety and tolerability; dose-limiting immune-related toxicities in a 3+3 design. The dose-expansion phase 2 portion will evaluate preliminary antitumor activity of BDC-1001 alone (Part 3) and with pembro (Part 4) using RECIST v1.1 and iRECIST. The primary endpoint of the phase 2 is best\ overall response rate; with secondary endpoints of duration of response, disease control rate, and progression-free survival. Exploratory objectives include pharmacokinetic parameters and pharmacodynamic biomarkers associated with drug exposure to help elucidate mechanism of action and identify biomarkers to improve selection of pts most likely to benefit from the single therapy or combination. Recruitment is ongoing (NCT04278144). Citation Format: Manish R. Sharma, Richard D. Carvajal, Daniel Catenacci, Leisha A. Emens, Glenn J. Hanna, Dejan Juric, Yoon-Koo Kang, Jeeyun Lee, Keun-Wook Lee, Bob T. Li, Kathleen Moore, Mark D. Pegram, Paula R. Pohlmann, Drew Rasco, Alexander Spira, Arielle L. Heeke, Ding Wang, Lawrence Garbo, Sudhir Manda, Jasgit Sachdev, Shelley E. Ackerman, Heidi LeBlanc, David Dornan, Marcin Kowanetz, Michael N. Alonso, Amreen Husain, Edith A. Perez, Ecaterina Ileana Dumbrava. Phase 1/2 study of a novel HER2 targeting TLR7/8 immune-stimulating antibody conjugate (ISAC), BDC-1001, alone and in combination with pembrolizumab (pembro) in patients (pts) with HER2-expressing advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT218.

Background: The RAS-RAF-MEK-ERK pathway is commonly upregulated in human cancers. This is an open-label Phase 1 study of ASTX029, a dual-mechanism extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor, in subjects with relapsed/refractory solid tumors (NCT03520075). Methods: The primary objectives are to identify a maximum tolerated dose and/or recommended Phase 2 dose. ASTX029 was administered orally daily of 21-day cycles as powder-in-bottle (PiB, Cohort 1/10mg) and tablet formulation (beginning with Cohort 6/80 mg) under fed conditions, and as tablet formulation under fasting conditions (beginning with Cohort 8/40 mg). Dose escalation occurred according to a “3+3 design” based on dose-limiting toxicity (DLT) events. Disease response was evaluated according to RECIST v1.1 and exploratory indicators, including tumor variant allele frequency changes detected by cell-free DNA (cfDNA) quantitation. Results: 56 subjects were treated with at least one dose of ASTX029 in Phase 1A (dose escalation). Of 46 subjects with data, 35 (76%) had any RAS mutations and 4 (9%) had BRAF mutations; 1 subject had both. At the 200 mg dose level (Cohort 5, PiB/fed), one of six evaluable subjects developed a DLT (grade 3 maculopapular rash). At the 280 mg dose level (Cohort 12, tablet/fasting), two subjects experienced grade 2 central serous retinopathy adverse events (CSR AEs) within a few days of dosing. These were the only CSR AEs noted and one event was declared a DLT. Both subjects recovered to baseline within days of dose interruption. One cohort level below this dose was expanded (Cohort 11/200 mg, tablet/fasting); this dose level was deemed safe (without a DLT or grade ≥2 visual AE in 7 subjects) and was selected for Phase 1B dose expansion. Mean pharmacokinetic (PK) exposure was 151% of target exposure, which is defined as the level expected to have biological activity based on animal studies. The most frequent grade ≥2 AEs assessed as drug-related included nausea (4 subjects, grade 2) and transaminitis (4 subjects: 3 grade 2, 1 grade 3). The grade 3 transaminitis occurred in a subject with metastatic sarcoma involving the liver. There was one serious AE of malaise considered related to study drug. Two subjects, one with KRAS-G12A and BRAF-D549N non-small cell lung cancer (120 mg) and one with KRAS-G12D metastatic pancreatic cancer (200 mg), achieved partial responses (cycle 15/ongoing and cycle 3/ongoing, respectively). In 2 subjects with stable disease as the best response, longitudinal cfDNA sequencing showed a decrease of tumor variant allele frequencies after 2 cycles of ASTX029, followed by a return to baseline levels before disease progression. The most common reason for ASTX029 discontinuation was disease progression. Conclusions: This Phase 1A study of the ERK1/2 inhibitor ASTX029 has identified a dose level of 200 mg daily of a 21-day cycle for investigation in the Phase 1B portion of the study. Pharmacokinetic and pharmacodynamic data suggest target exposures are achieved with preliminary clinical activity. Citation Format: Patricia LoRusso, Drew Rasco, Geoffrey Shapiro, Filip Janku, Alain Mita, Nilofer Azad, Marcia Toguchi, Chris Hindley, Shannon Bradley, Danna Chan, Harold Keer, Kim-Hien Dao, Ryan J. Sullivan, Alexander Spira. A first-in-human, Phase 1 study of ASTX029, a dual-mechanism inhibitor of ERK1/2, in relapsed/refractory solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT108.

Background: ARQ 087 is an orally administered pan-FGFR inhibitor with multi-kinase activity. This Phase 1 study evaluated safety, pharmacokinetics, and pharmacodynamics of ARQ 087 and defined the recommended Phase 2 dose (RP2D). Methods: Patients with advanced solid tumours received ARQ 087 administered initially at 25 mg every other day and dose-escalated from 25 to 425 mg daily (QD) continuous dosing. FGF19, 21, 23, and serum phosphate were assessed as potential biomarkers of target engagement. Results: 80 patients were enrolled, 61 in dose-escalation/food-effect cohorts and 19 with pre-defined tumour types in the expansion cohort. The most common ARQ 087-related adverse events were fatigue (49%), nausea (46%), aspartate aminotransferase (AST) increase (30%), and diarrhoea (23%). Four patients (5%) experienced grade 1 treatment-related hyperphosphataemia. Dose-limiting toxicity was reversible grade 3 AST increase. The RP2D was 300 mg QD. Pharmacokinetics were linear and dose-proportional from 25 to 325 mg QD, and were unaffected by food. Statistically significant changes (P-value

Purpose: This phase Ib study (NCT02179918) evaluated the safety, antitumor activity, pharmacokinetics, and pharmacodynamics of utomilumab, a fully human IgG2 mAb agonist of the T-cell costimulatory receptor 4-1BB/CD137 in combination with the humanized, PD-1–blocking IgG4 mAb pembrolizumab in patients with advanced solid tumors. Experimental Design: Utomilumab (0.45–5.0 mg/kg) and pembrolizumab (2 mg/kg) were administered intravenously every 3 weeks. Utomilumab dose escalation was conducted using the time-to-event continual reassessment method. Results: Twenty-three patients received combination treatment with no dose-limiting toxicities. Treatment-emergent adverse events were mostly grades 1 to 2, without any treatment-related discontinuations. Six patients (26.1%) had confirmed complete or partial responses. Pharmacokinetics and immunogenicity of utomilumab and pembrolizumab were similar when administered alone or in combination. A trend toward higher levels of activated memory/effector peripheral blood CD8+ T cells was observed in responders versus nonresponders. Conclusions: The safety, tolerability, and clinical activity demonstrated by utomilumab in combination with pembrolizumab support further investigation in patients with advanced solid tumors. Clin Cancer Res; 23(18); 5349–57. ©2017 AACR. See related commentary by Pérez-Ruiz et al., p. 5326

At clinically relevant ixazomib concentrations, in vitro studies demonstrated that no specific cytochrome P450 (CYP) enzyme predominantly contributes to ixazomib metabolism. However, at higher than clinical concentrations, ixazomib was metabolized by multiple CYP isoforms, with the estimated relative contribution being highest for CYP3A at 42%. This multiarm phase 1 study (Clinicaltrials.gov identifier: NCT01454076) investigated the effect of the strong CYP3A inhibitors ketoconazole and clarithromycin and the strong CYP3A inducer rifampin on the pharmacokinetics of ixazomib. Eighty‐eight patients were enrolled across the 3 drug‐drug interaction studies; the ixazomib toxicity profile was consistent with previous studies. Ketoconazole and clarithromycin had no clinically meaningful effects on the pharmacokinetics of ixazomib. The geometric least‐squares mean area under the plasma concentration‐time curve from 0 to 264 hours postdose ratio (90%CI) with vs without ketoconazole coadministration was 1.09 (0.91‐1.31) and was 1.11 (0.86‐1.43) with vs without clarithromycin coadministration. Reduced plasma exposures of ixazomib were observed following coadministration with rifampin. Ixazomib area under the plasma concentration‐time curve from time 0 to the time of the last quantifiable concentration was reduced by 74% (geometric least‐squares mean ratio of 0.26 [90%CI 0.18‐0.37]), and maximum observed plasma concentration was reduced by 54% (geometric least‐squares mean ratio of 0.46 [90%CI 0.29‐0.73]) in the presence of rifampin. The clinical drug‐drug interaction study results were reconciled well by a physiologically based pharmacokinetic model that incorporated a minor contribution of CYP3A to overall ixazomib clearance and quantitatively considered the strength of induction of CYP3A and intestinal P‐glycoprotein by rifampin. On the basis of these study results, the ixazomib prescribing information recommends that patients should avoid concomitant administration of strong CYP3A inducers with ixazomib.

Treatment options for relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) are limited, with no standard of care; prognosis is poor, with 4- to 6-month median survival. Avadomide (CC-122) is a cereblon-modulating agent with immunomodulatory and direct antitumor activities. This phase 1 dose-expansion study assessed safety and clinical activity of avadomide monotherapy in patients with de novo R/R DLBCL and transformed lymphoma. Additionally, a novel gene expression classifier, which identifies tumors with a high immune cell infiltration, was shown to enrich for response to avadomide in R/R DLBCL. Ninety-seven patients with R/R DLBCL, including 12 patients with transformed lymphoma, received 3 to 5 mg avadomide administered on continuous or intermittent schedules until unacceptable toxicity, disease progression, or withdrawal. Eighty-two patients (85%) experienced ≥1 grade 3/4 treatment-emergent adverse events (AEs), most commonly neutropenia (51%), infections (24%), anemia (12%), and febrile neutropenia (10%). Discontinuations because of AEs occurred in 10% of patients. Introduction of an intermittent 5/7-day schedule improved tolerability and reduced frequency and severity of neutropenia, febrile neutropenia, and infections. Among 84 patients with de novo R/R DLBCL, overall response rate (ORR) was 29%, including 11% complete response (CR). Responses were cell-of-origin independent. Classifier-positive DLBCL patients (de novo) had an ORR of 44%, median progression-free survival (mPFS) of 6 months, and 16% CR vs an ORR of 19%, mPFS of 1.5 months, and 5% CR in classifier-negative patients (P = .0096). Avadomide is being evaluated in combination with other antilymphoma agents. This trial was registered at www.clinicaltrials.gov as #NCT01421524.

PURPOSE To evaluate the safety, pharmacokinetics, and pharmacodynamics of Hu5F9-G4 (5F9), a humanized IgG4 antibody that targets CD47 to enable phagocytosis. PATIENTS AND METHODS Adult patients with solid tumors were treated in four cohorts: part A, to determine a priming dose; part B, to determine a weekly maintenance dose; part C, to study a loading dose in week 2; and a tumor biopsy cohort. RESULTS Sixty-two patients were treated: 11 in part A, 14 in B, 22 in C, and 15 in the biopsy cohort. Part A used doses that ranged from 0.1 to 3 mg/kg. On the basis of tolerability and receptor occupancy studies that showed 100% CD47 saturation on RBCs, 1 mg/kg was selected as the priming dose. In subsequent groups, patients were treated with maintenance doses that ranged from 3 to 45 mg/kg, and most toxicities were mild to moderate. These included transient anemia (57% of patients), hemagglutination on peripheral blood smear (36%), fatigue (64%), headaches (50%), fever (45%), chills (45%), hyperbilirubinemia (34%), lymphopenia (34%), infusion-related reactions (34%), and arthralgias (18%). No maximum tolerated dose was reached with maintenance doses up to 45 mg/kg. At doses of 10 mg/kg or more, the CD47 antigen sink was saturated by 5F9, and a 5F9 half-life of approximately 13 days was observed. Strong antibody staining of tumor tissue was observed in a patient at 30 mg/kg. Two patients with ovarian/fallopian tube cancers had partial remissions for 5.2 and 9.2 months. CONCLUSION 5F9 is well tolerated using a priming dose at 1 mg/kg on day 1 followed by maintenance doses of up to 45 mg/kg weekly.

2512 Background: BDB001 is an intravenously administered TLR 7/8 dual agonist immune modulator capable of reprogramming dendritic cells to produce antitumor activities. BDB001 monotherapy has demonstrated favorable tolerability and robust systemic immune activation leading to durable clinical responses in a phase I dose escalation trial. Here, we report on the safety and efficacy of BDB001 in combination with pembrolizumab in a phase I dose escalation trial in advanced solid tumors (NCT03486301). Methods: BDB001-101 is a phase 1, open label, dose escalation/expansion trial of BDB001 (IV, Q1W) in combination with pembrolizumab (IV, Q3W) in patients with advanced solid tumors. The primary endpoint was safety and tolerability. Secondary endpoints included efficacy, pharmacokinetics and pharmacodynamic profiling of immune activation. Results: Twenty-three subjects with 13 different tumor types were enrolled across 4 dose levels. Sixty one percent were female, median age was 63 years (range, 33-86), median number of prior therapies was 3 (range, 1-8), and 48% of tumors had progressed on prior anti-PD-(L)1 therapy. Overall, BDB001 in combination with pembrolizumab was well tolerated and dose-limiting toxicities were not observed. The most common treatment related adverse events (TRAEs) were fever (39.1%), fatigue (39.1%), chills/rigor (34.8%), pruritus/rash (21.7%), and nausea (13.0%). Most of these TRAEs were grade 1 or 2 and transient. Only 3 (13.0%) subjects experienced grade 3 TRAEs of fatigue, rash, stomatitis, and alkaline phosphatase elevation. There were no grade 4 or 5 TRAEs. Pharmacodynamic evaluation of plasma cytokine levels showed robust increases in interferon gamma and interferon inducible protein-10 (IP-10) at BDB001 Dose Level 3 and 4. Preliminary efficacy evaluation of the 14 subjects treated at Dose Level 3 and 4 showed durable and deep clinical responses in 4 (29%) subjects with anti-PD-(L)1 mAb refractory melanoma, hepatocellular carcinoma, cholangiocarcinoma, and platinum-resistant ovarian carcinoma. The responses were observed by the initial efficacy assessment at 9-weeks, with some seen as early as 4-weeks. In addition, 4 (29%) subjects had stable disease for a disease control rate of 57%. To date, median time on treatment is 14.4 weeks (range, 6.0 – 42.1+) with 3 subjects still active on treatment. Conclusions: Intravenously administered BDB001 in combination with pembrolizumab is well tolerated. Rapid and deep clinical responses were observed, supported by robust systemic immune activation. BDB001 in combination with pembrolizumab is a promising novel therapeutic option for patients with advanced solid tumors and is being evaluated in an ongoing dose expansion trial. Clinical trial information: NCT03486301.

3104 Background: Enhancer of Zeste homolog 2 (EZH2) is a histone methyltransferase and the catalytic subunit of Polycomb Repressive Complex 2 (PRC2). EZH2 is frequently overexpressed in cancers and correlates with poor prognosis. CPI-0209 is an oral, small molecule, second-generation, selective inhibitor of EZH2 designed to achieve comprehensive target coverage through extended on-target residence time. The compound demonstrates more potent anti-tumor activity in preclinical cancer models, compared to first-generation EZH2 inhibitors. CPI-0209 is currently being evaluated in a Phase 1/2, open-label, FIH study (NCT04104776). Methods: Patients (pts) with advanced tumors were enrolled in a 3+3 design. Primary objective is to determine maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) of CPI-0209. Secondary objectives are to evaluate the safety, PK, and PD in pts who received CPI-0209 QD in 28 days cycles (C). Results: As of December 16, 2020, 33 pts were treated: pancreatic cancer (n = 6), mesothelioma, breast, colorectal, and ovarian cancer (n = 5 each), leiomyosarcoma, melanoma, cholangiocarcinoma, prostate, bladder, endometrial clear cell and gastric cancer (n = 1 each). Pts received CPI-0209 at 50 mg (n = 4), 100 mg, 137.5 mg, and 187.5 mg (n = 6 each), 225 mg (n = 7), and 275 mg (n = 4) daily dose. Median treatment duration was 43 days (range 1-239); 4 pts are ongoing. Median age was 64 yrs (range 24-79); 15 (45%) pts were male. Patients were heavily pretreated, with 67% of pts had ≥ 3 prior lines of therapy. No dose limiting toxicities have been observed. The most frequent treatment-emergent adverse events (TEAEs) (≥10%) were fatigue (27%), diarrhea (24%), nausea (21%), abdominal pain, alopecia, anemia, thrombocytopenia, and dysgeusia (15% each), and vomiting, headache, decreased appetite, and alkaline phosphatase increased (12% each); usually grade 1 or 2 in severity. Thrombocytopenia was dose-dependent and not associated with bleeding or clinical sequalae. Three pts (9%) discontinued CPI-0209 due to TEAEs. Comprehensive target engagement (assessed by global reduction in H3K27me3 levels in monocytes) was observed within the first cycle at all dose levels. CPI-0209 also increased the expression of PRC2-controlled gene sets in blood in a dose-dependent manner. Updated safety, PK, PD, and preliminary efficacy results from Phase 1 will be presented. Conclusions: CPI-0209 achieved robust PD effects and a PK-PD relationship has been established. CPI-0209 monotherapy was generally well tolerated, and treatment related AEs were manageable and reversible. The MTD has not been reached. Clinical trial information: NCT04104776.

2504 Background: COM701 is a novel first in class humanized IgG4 monoclonal antibody that binds with high affinity to poliovirus receptor related immunoglobulin domain containing (PVRIG), blocking its interaction with its ligand, PVRL2. Blocking of PVRIG leads to enhanced activation of T/NK cells and in mouse models inhibits tumor growth. We report new and updated results on safety/tolerability/pharmacokinetics and antitumor activity from this ongoing study including final results in dose escalation combination cohort, monotherapy expansion cohort (MEC). Methods: We enrolled a total of 51 DLT-evaluable pts: Arm A (COM701 mono dose escalation), 16 pts in 8 cohorts (0.01 – 20 mg/kg IV Q3/4 wks); Arm B (COM701 0.3 – 20 mg/kg + nivolumab (NIVO) 360 mg/480 mg IV Q3/Q4 wks), 15 pts in 5 cohorts; 20 pts in MEC (NSCLC, OVCA, breast, endometrial and CRC) at the recommended dose for expansion(RDFE), 20 mg/kg IV Q4 wks. Key inclusion criteria: Age ≥18 yrs, histologically confirmed metastatic solid malignancy, has exhausted available standard tx, ECOG 0-1, prior ICI permissible (except prior tx with a PVRIG inhibitor). Key exclusion criteria: active autoimmune disease requiring systemic tx, hx inflammatory lung disease. Primary objectives – safety/tolerability of COM701 ± NIVO (AEs, CTCAE v4.03), PK, RDFE. Key secondary/exploratory objectives - antitumor activity of COM701 ± NIVO (RECIST v1.1), evaluation of PVRL2 expression in tumor biopsy, blood cytokines and immunophenotyping. Results: No DLTs were reported in Arms A or B. COM701 PK profile similar in Arm A, 20 mg/kg IV Q4 wks (cohort 8) and Arm B cohort 5 (COM701 20 mg/kg + NIVO 480 mg; all IV Q4 wks). Frequency of TEAEs in safety population (N=54 pts): pts on COM701 mono (N=38)- No AE (4), Grade≤2 (21), G3 (11), G4 (1), G5 (1, PD), pts on combo (N=16) - Grade≤2 (8), G3 (7), G5 (1, PD). Serious TEAE: pts on COM701 mono 11/38, pts on combo 6/16. Most frequent AEs in Arm A: Grade ≤2 fatigue 12/38 pts (31%), nausea 9/38 (23%); Arm B: fatigue 7/16 pts (44%) and AST increased 4/16 pts (25%). Antitumor activity - in Arm A (cohort 8), a pt with platinum resistant primary peritoneal cancer had confirmed PR ongoing 14 months. In Arm B (COM701 10 mg/kg + NIVO 480 mg, all IV Q4 wks), a pt with anal SCCA; confirmed CR, ongoing 18 months, last tx with prior PD on NIVO. In addition, a pt with renal cell CA had confirmed SD [ongoing 13 months, COM701 0.3 mg/kg + NIVO 360mg; IV Q3 wks],] In MEC, 30% (6/20 pts) had best response of SD [1-endometrial, 3 NSCLC, 2 OVCA], 2 pts [NSCLC, OVCA] ongoing at 6/4 months. Overall 16pts had prior tx-refractory disease, 9(56%) had best response of ≥SD. Of 18 pts with prior tx with ICI, 13 (72%) had best response of ≥SD. Datacut 14Dec2020. Conclusions: COM701 ± NIVO well tolerated with no new safety signals. Encouraging signal of antitumor activity including in pts with prior tx with ICI or prior tx-refractory disease. Clinical trial information: NCT03667716..

2505 Background: GB1275 is a first-in-class, oral CD11b modulator that reduced myeloid-derived suppressor cells (MDSCs) and tumor associated macrophages (TAMs), repolarized M2 immunosuppressive TAMs to an M1 phenotype, resulting in increased tumor infiltration of activated CD8+ T cells and antitumor efficacy in preclinical models. Here, we report preliminary results from an ongoing, first-in-human dose-escalation study in specific advanced tumors using GB1275 alone or with pembrolizumab. (NCT04060342) Methods: Phase 1 comprises dose escalation and expansion. During dose escalation, cohorts of 3 to 6 subjects were sequentially assigned to ascending dose levels of GB1275 from 100 mg to 1200 mg BID in one of two dosing regimens: Regimen A [GB1275 monotherapy orally (PO) twice a day (BID)] and Regimen B [GB1275 PO BID plus pembrolizumab 200 mg IV every 3 weeks (q3wks)]. Dose escalation was based on safety including dose-limiting toxicities (DLTs). Following dose escalation, up to 40 subjects with specific tumor types are to be treated in expansion with the selected GB1275 dose plus pembrolizumab to assess safety, pharmacokinetics, and preliminary clinical and biomarker activity. Results: As of January 8, 2021, 45 subjects were treated [44 in dose escalation: 23, Regimen A; 21, Regimen B. 1 in expansion, Regimen B], with median (range) GB1275 exposure of 42.0 days (4-263). No DLTs were reported. GB1275-related adverse events occurred in 24/45 (53.3%) subjects; photosensitivity reaction (20.0%), dysesthesia (13.3%) and pruritus (13.3%) were most frequent (≥10%). Stable disease was reported in 6/19 (31.6%) response-evaluable subjects in Regimen A and 9/16 (56.3%) in Regimen B. In Regimen B (800 mg), one partial response was reported in a subject with MSS-CRC treated for 263 days, and one prolonged stable disease (227 days) was reported in a gastric cancer (GC) subject previously treated with pembrolizumab plus bavituximab for less than 3 months due to progression; both subjects are continuing study treatment. A dose-dependent increase in GB1275 systemic exposure was observed up to 800 mg BID. Down-regulation of peripheral MDSCs was seen with both regimens. Regimen-dependent gene clusters in whole blood were noted. An increase in tumor infiltrating lymphocyte (TIL) counts was noted in both Regimens A and B. Conclusions: Dose escalation of GB1275, up to 1200 mg in Regimens A and B, demonstrated tolerability as monotherapy and combined with pembrolizumab in subjects with advanced cancers. Encouraging antitumor activity in Regimen B (800 mg) was observed in subjects with MSS-CRC and GC. Biological activity reflected by MDSC modulations in blood and TIL Increases in tumor biopsies with GB1275 alone and with pembrolizumab supports the mechanism of GB1275. GB1275 800 mg BID plus pembrolizumab 200 mg IV q3wks was selected for evaluation in the expansion phase. Clinical trial information: NCT04060342.

2549 Background: BDC-1001 is a novel ISAC consisting of an investigational trastuzumab biosimilar chemically conjugated to a TLR 7/8 agonist with a non-cleavable linker. BDC-1001 was designed to activate the innate immune system, eliciting antibody-mediated effector functions (eg, antibody-dependent cellular phagocytosis) and a durable adaptive immune response. In preclinical tumor models resistant to anti-HER2 treatments, BDC-1001 demonstrated potent and durable immune-mediated antitumor efficacy. Methods: A 4-part, phase 1/2 dose-escalation/expansion study was initiated to evaluate BDC-1001 ± PD1 inhibitor pembrolizumab in pts with HER2-expressing solid tumors who had progressive disease on standard of care (NCT04278144). Preliminary results of the monotherapy dose escalation (Part 1) are reported. Pts with advanced metastatic HER2-expressing (IHC2/3+) or amplified solid tumors received BDC-1001 IV q3w in a 3+3 design w/ 12 pts/cohort backfill allowed. Primary objectives were to evaluate safety, tolerability, dose-limiting toxicities (DLTs) and determine a phase 2 dose; secondary objectives were to assess pharmacokinetics (PK), pharmacodynamics and preliminary anti-tumor activity. Results: As of Jan 29, 2021, 20 pts w/ a median age of 65 (46-85) have enrolled in 4 dose levels (0.15mg/kg to 5 mg/kg). Cancer types include breast, biliary, cervical, colorectal (CRC), lung, gastroesophageal, salivary, urinary tract and endometrial. Pts had received a median of 4 (1-7) prior therapies; 65% received >1 prior anti-HER2 therapy. All pts completed the 21-day DLT period; no DLTs or drug-related serious adverse events (AEs) have been observed. AEs deemed related to BDC-1001 have been mild to moderate including infusion-related reactions. The MTD has not been reached (treatment duration 5-17+wk); enrollment is ongoing. PK evaluations showed Cmax levels consistent with predicted modeling based on non-human primates (NHP). One pt with microsatellite stable (MSS) HER2+ CRC with lung metastases had a confirmed partial response after 4 cycles and remains on study; 2 additional pts with metastatic MSS HER2+ CRC had stable disease (SD) and a pt with heavily pretreated MSS endometrial cancer with lung metastases had confirmed SD and remains on treatment 17+ wk; 3 of these pts had received 2 prior anti-HER2 therapies. Conclusions: In this first-in-human study, BDC-1001 appears to be well-tolerated up to the dose tested to date (5 mg/kg), with Cmax levels achieved as predicted by NHP modeling. Evidence of clinical activity have been observed, including in pts previously treated with anti-HER2 therapy. Dose escalation is ongoing and will be followed by combination dosing with CPI and the phase 2 component in selected tumors. Clinical trial information: NCT04278144.

This phase I study evaluated the safety, tolerability, and pharmacokinetics of copanlisib, an intravenously administered pan-phosphatidylinositol 3-kinase inhibitor in patients with advanced solid tumors or non-Hodgkin's lymphoma. Copanlisib was well tolerated with a manageable safety profile, with anti-tumor activity in both advanced solid tumors and hematological malignancies., Background To evaluate the safety, tolerability, pharmacokinetics, and maximum tolerated dose (MTD) of copanlisib, a phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors or non-Hodgkin's lymphoma (NHL). Patients and methods Phase I dose-escalation study including patients with advanced solid tumors or NHL, and a cohort of patients with type 2 diabetes mellitus. Patients received three weekly intravenous infusions of copanlisib per 28-day cycle over the dose range 0.1–1.2 mg/kg. Plasma copanlisib levels were analyzed for pharmacokinetics. Biomarker analysis included PIK3CA, KRAS, BRAF, and PTEN mutational status and PTEN immunohistochemistry. Whole-body [18F]-fluorodeoxyglucose positron emission tomography (18FDG-PET) was carried out at baseline and following the first dose to assess early pharmacodynamic effects. Plasma glucose and insulin levels were evaluated serially. Results Fifty-seven patients received treatment. The MTD was 0.8 mg/kg copanlisib. The most frequent treatment-related adverse events were nausea and transient hyperglycemia. Copanlisib exposure was dose-proportional with no accumulation; peak exposure positively correlated with transient hyperglycemia post-infusion. Sixteen of 20 patients treated at the MTD had reduced 18FDG-PET uptake; 7 (33%) had a reduction >25%. One patient achieved a complete response (CR; endometrial carcinoma exhibiting both PIK3CA and PTEN mutations and complete PTEN loss) and two had a partial response (PR; both metastatic breast cancer). Among the nine NHL patients, all six with follicular lymphoma (FL) responded (one CR and five PRs) and one patient with diffuse large B-cell lymphoma had a PR by investigator assessment; two patients with FL who achieved CR (per post hoc independent radiologic review) were on treatment >3 years. Conclusion Copanlisib, dosed intermittently on days 1, 8, and 15 of a 28-day cycle, was well tolerated and the MTD was determined to be 0.8 mg/kg. Copanlisib exhibited dose-proportional pharmacokinetics and promising anti-tumor activity, particularly in patients with NHL. ClinicalTrials.gov NCT00962611; https://clinicaltrials.gov/ct2/show/NCT00962611.

Purpose: p38 MAPK regulates the production of cytokines in the tumor microenvironment and enables cancer cells to survive despite oncogenic stress, radiotherapy, chemotherapy, and targeted therapies. Ralimetinib (LY2228820 dimesylate) is a selective small-molecule inhibitor of p38 MAPK. This phase I study aimed to evaluate the safety and tolerability of ralimetinib, as a single agent and in combination with tamoxifen, when administered orally to patients with advanced cancer. Experimental Design: The study design consisted of a dose-escalation phase performed in a 3+3 design (Part A; n = 54), two dose-confirmation phases [Part B at 420 mg (n = 18) and Part C at 300 mg (n = 8)], and a tumor-specific expansion phase in combination with tamoxifen for women with hormone receptor–positive metastatic breast cancer refractory to aromatase inhibitors (Part D; n = 9). Ralimetinib was administered orally every 12 hours on days 1 to 14 of a 28-day cycle. Results: Eighty-nine patients received ralimetinib at 11 dose levels (10, 20, 40, 65, 90, 120, 160, 200, 300, 420, and 560 mg). Plasma exposure of ralimetinib (Cmax and AUC) increased in a dose-dependent manner. After a single dose, ralimetinib inhibited p38 MAPK–induced phosphorylation of MAPKAP-K2 in peripheral blood mononuclear cells. The most common adverse events, possibly drug-related, included rash, fatigue, nausea, constipation, pruritus, and vomiting. The recommended phase II dose was 300 mg every 12 hours as monotherapy or in combination with tamoxifen. Although no patients achieved a complete response or partial response,19 patients (21.3%) achieved stable disease with a median duration of 3.7 months, with 9 of these patients on study for ≥6 cycles. Conclusions: Ralimetinib demonstrated acceptable safety, tolerability, and pharmacokinetics for patients with advanced cancer. Clin Cancer Res; 22(5); 1095–102. ©2015 AACR.

Purpose: Study objectives included evaluating the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of VX15/2503 in advanced solid tumor patients. Experimental Design: Weekly i.v. doses were administered on a 28-day cycle. Safety, immunogenicity, PK, efficacy, T-cell membrane–associated SEMA4D (cSEMA4D) expression and saturation, soluble SEMA4D (sSEMA4D) serum levels, and serum biomarker levels were evaluated. Results: Forty-two patients were enrolled into seven sequential cohorts and an expansion cohort (20 mg/kg). VX15/2503 was well tolerated. Treatment-related adverse events were primarily grade 1 or 2 and included nausea (14.3%) and fatigue (11.9%); arthralgia, decreased appetite, infusion-related reaction, and pyrexia were each 7.3%. One pancreatic cancer patient (15 mg/kg) experienced a Grade 3 dose-limiting toxicity; elevated γ-glutamyl transferase. Complete cSEMA4D saturation was generally observed at serum antibody concentrations ≥0.3 μg/mL, resulting in decreased cSEMA4D expression. Soluble SEMA4D levels increased with dose and infusion number. Neutralizing anti-VX15/2503 antibodies led to treatment discontinuation for 1 patient. VX15/2503 Cmax and AUC generally increased with dose and dose number. One patient (20 mg/kg) experienced a partial response, 19 patients (45.2%) exhibited SD for ≥8 weeks, and 8 (19%) had SD for ≥16 weeks. Subjects with elevated B/T lymphocytes exhibited longer progression-free survival. Conclusions: VX15/2503 was well tolerated and produced expected PD effects. The correlation between immune cell levels at baseline and progression-free survival is consistent with an immune-mediated mechanism of action. Future investigations will be in combination with immunomodulatory agents. Clin Cancer Res; 22(4); 827–36. ©2015 AACR.

Background: Tumor influx of CD11b-expressing myeloid-derived suppressor cells (MDSCs) and M2 tumor-associated macrophages (TAMs) creates an immunosuppressive tumor microenvironment associated with resistance to anti-PD-1 antibody therapy. GB1275 is a novel, first-in-class, CD11b modulator that, in vivo, reduced MDSCs and TAMs at the tumor site, repolarized M2 immunosuppressive TAMs to an M1 phenotype, and increased tumor infiltration of activated CD8+ T cells. In combination with an anti-PD-1 antibody or chemotherapy, these immunomodulatory effects translated into potent anti-tumor effects and prolonged survival in orthotopic PDAC models. We hypothesize that GB1275-based therapy can alleviate myeloid cell-mediated immunosuppression and improve cancer treatment outcomes. Methods: This is an open-label, first-in-human study comprising phase 1 dose escalation of GB1275 monotherapy (Regimen A) and GB1275 plus pembrolizumab (Regimen B) in patients with previously treated, locally advanced or metastatic PDA, esophageal, gastric/GEJ, triple negative breast, castration-resistant prostate, or microsatellite-stable colorectal cancer (MSS CRC), and GB1275 plus nab-paclitaxel and gemcitabine (Nab-P+Gem) (Regimen C) in mPDAC. This is followed by phase 2 expansion in three disease cohorts: 1) newly diagnosed stage IV mPDAC (GB1275+Nab-P+Gem), 2) MSS CRC (GB1275+pembrolizumab), and 3) PD-L1+ gastric/GEJ cancer (GB1275+pembrolizumab). Patients are enrolled in Regimen A initially, with Regimen B commencing after completion of the first few cohorts of Regimen A. Regimen C will initiate when Regimen A is completed. Eligible patients are ≥18 years of age, with histologically confirmed locally advanced/metastatic tumor specified and ECOG 0-1 PS; prior immunotherapy is permissible during Regimen A and B dose escalation, but not Regimen C or during the expansion phase. Patients are excluded for untreated or symptomatic CNS metastasis, prior myeloid targeting treatment or other prohibited medications, or a history of clinically significant cardiovascular disease. Patients with active autoimmune disease requiring systemic therapy will be excluded from Regimen B and from expansion cohorts 2 and 3. Primary objectives for phase 1 are to determine the maximum tolerated dose/recommended phase dose and pharmacokinetic profile of GB1275 alone and combination with pembrolizumab, and safety in combination with Nab-P+Gem, and for phase 2, to assess efficacy.Statistical Considerations: A 3+3 design is used for the dose escalation phase and Simon's 2-stage design for the expansion phase. Adverse events are graded per CTCAE v5.0, responses per RECIST v1.1. This study is open for recruitment (NCT04060342). Citation Format: Andrea Wang-Gillam, Drew W. Rasco, Wungki Park, Eileen O'Reilly, Wells Messersmith, David G. DeNardo, Vineet Gupta, Lei Zhou, Anna Galkin, Debbie Slee, Laura L. Carter, David Nickle, Rebecca Tran, Jack Li, Beatrice Ferguson, Marya F. Chaney, Luisa Salter-Cid, Jakob Dupont, Johanna C. Bendell. A phase 1/2 study of GB1275, a first-in-class CD11b modulator, as monotherapy and with an anti-PD-1 antibody in specified advanced solid tumors or with chemotherapy in metastatic pancreatic cancer (KEYNOTE-A36) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT247.

Introduction: COM701 is a novel first-in-class Immune checkpoint inhibitor (ICI) that binds with high affinity to poliovirus receptor related immunoglobulin domain containing (PVRIG) blocking its interaction with its ligand, PVRL2 and regulating the activity of T/NK cells through the DNAM/TIGIT axis. In preclinical experiments inhibition of PVRIG alone and in combination with anti-PD1 and/or TIGIT leads to tumor growth inhibition and activation of T-cells in the microenvironment generating an antitumor response. Methods: A total of 28 pts (Arm A/B 16/12) with a variety of cancer types were enrolled. Hybrid accelerated (1st 4 dose cohorts in Arm A) and 3+3 study design (cohorts 5-8 in Arm A and all cohorts in Arm B). Patients with performance status ECOG 0-1 and advanced or metastatic solid tumors who failed standard of care tx were eligible. Prior ICIs were permissible. In Arm A pts received COM701 monotherapy 0.01, 0.03, 0.1, 0.3, 1, 3, 10mg/kg (all IV Q 3 weeks (wks)) and 20 mg/kg (IV Q 4 wks). In Arm B, pts received COM701 at 0.3, 1 or 3mg/kg plus nivolumab 360mg IV q3 wks (3 pts/dose cohort) and 3 pts received 10mg/kg plus nivolumab 480mg IV q4 wks. Treatment emergent adverse events (TEAEs) were reported per CTCAE v4.03 and responses per RECIST v1.1. Dose-limiting toxicities (DLTs) were evaluated within a 21-day or 28-day window (for 3- or 4-wks dosing schedule respectively). Data cutoff date was January 23, 2020. Results: The median number of prior anticancer therapies were: Arm A, 7 (range 2-15), Arm B, 5 (range 2-9). No DLTs have been reported in any of the dose cohorts. Tx was well tolerated with no subjects discontinuing tx due to toxicity, the most frequent TEAEs in Arm A were fatigue (46%), nausea (31%) and anxiety (23%) - all G1-2. In Arm B ≥4 pts - anemia, lower extremity edema, rash and fatigue the majority being grade 1-2 (88%). In Arms A+B: partial response (PR) + stable disease (SD) was 57% (16/28). Of note: Arm A (COM701 20mg/kg IV q4 wks): confirmed PR in a pt with primary peritoneal cancer ongoing on tx > 15 weeks. Arm B: unconfirmed PR in a pt with MSS-CRC on COM701 0.3mg/kg plus nivolumab 360mg IV q3 wks, ongoing on tx >34 wks). Overall 11/28 pts remain on study tx including 3 pts who have not reached 1st imaging assessment. Conclusion: COM701 is well tolerated as monotherapy and in combination with nivolumab in a variety of heavily pretreated pts with advanced or metastatic solid tumors. COM701 demonstrates encouraging preliminary antitumor activity with objective responses as monotherapy and in combination with nivolumab in hard to treat tumor types (primary peritoneal and MSS-CRC). Citation Format: Ryan Sullivan, Drew Rasco, Emerson Lim, Manish Sharma, Dale Shepard, Amita Patnaik, Erika Hamilton, Gini Fleming, Kyri Papadopoulos, Adam ElNaggar, Adeboye Henry Adewoye, Bartosz Chmielowski, Ecaterina Dumbrava, Dan Vaena. COM701 demonstrates preliminary antitumor activity as monotherapy and in combination with nivolumab in patients with advanced solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT031.

Background: Immunosuppressive tumor associated macrophages (TAMs) have been shown to correlate with poor prognosis. SNDX-6352 is a humanized, high-affinity monoclonal IgG4 antibody that blocks dual ligand activation of colony stimulating factor- 1 receptor (CSF-1R), which regulates monocyte migration, proliferation and differentiation into TAMs. By inhibiting and reducing TAM numbers, SNDX-6352 may slow tumor growth and enhance anti-tumor immunotherapeutic approaches. Methods: SNDX-6352-0502 was a multi-center Phase 1 study consisting of Phase 1a (monotherapy) and Phase 1b (combination with durvalumab) in patients with pretreated, advanced solid tumors. The primary objective was determining the MTD and RP2D of SNDX-6352 alone and in combination with durvalumab. Dose regimens of 1, 2, 3 and 6 mg/kg bi-weekly (q2wks) and 6 mg/kg once monthly (q4wks) were administered in 1a, and 1, 2, and 3 mg/kg bi-weekly in 1b. Drug pharmacokinetics (PK) and pharmacodynamic (PD) biomarkers were measured. Results: Thirty-two patients with advanced solid tumors were enrolled with a median age of 61. The median number of prior therapies was 5 (range 2-12) and 72% of patients had ECOG performance status of 1. Median exposure in terms of cycles was 2, maximum was 10. Three patients had SD greater than 4 months. Most common (> 10%) treatment-related AEs were fatigue (31%), periorbital edema (31%) aspartate aminotransferase increased (22%), blood creatinine phosphokinase increased (22%) nausea (13%) and decreased appetite (13%). Grade 3/4 related AEs were observed in 12 patients (38%) with ≥ 2 events in CPK (5), amylase (3), AST (3) and lipase (2). One possibly related SAE of pneumonitis at 6 mg/kg q2wks was reported. DLTs reported in two subjects were G3 fatigue at 2 mg/kg and G3 pneumonitis at 6 mg/kg q2wks. Laboratory abnormalities included increases in blood creatinine phosphokinase, ALT, AST, amylase, and lipase. These abnormalities were all asymptomatic and are consistent with the known class effect of CSF-1Ri. There was no evidence of hepatocellular toxicity. Plasma concentrations of SNDX-6352 increased in a dose-proportional manner with drug accumulation observed at > 1 mg/kg. Plasma CSF1 and IL-34 concentrations increased with treatment and remained elevated at all doses > 1 mg/kg. CSF1 receptor occupancy was saturated at 4 hours post-dose in all treatment cohorts. Circulating non-classical monocytes (CD14+CD16hi) were ablated at all dose levels within 24 hrs and remained suppressed at all doses >1 mg/kg. Conclusion: SNDX-6352 demonstrates tolerability at the highest dose level evaluated (6 mg/kg) with robust PD biomarker modulation at doses as low as 1 mg/kg. A RP2D of 6mg/kg q4wks will be explored in future solid tumor studies. Citation Format: Nilo Azad, Drew Rasco, Sunil Sharma, Matthew Taylor, Christine Quaranto, David L. Tamang, Robert Nordness, Michael L. Meyers, Serap Sankoh, Peter Ordentlich, Anthony W. Tolcher. SNDX-6352-0502 - A phase 1, open-label, dose escalation trial to investigate the safety, tolerability, pharmacokinetics and pharmacodynamic activity of SNDX-6352 monotherapy in patients with unresectable, recurrent, locally-advanced, or metastatic solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT149.

3508 Background: APG-1387 is an IAP (inhibitor of apoptosis proteins) antagonist that has strong antitumor activity in multiple xenograft cancer models and acts as a host immune modulator, supporting its exploration for use in combination with checkpoint inhibitors for cancer therapy. Methods: This “3+3” dose escalation and dose expansion study evaluated APG-1387 combined with pembrolizumab in patients with refractory or intolerant advanced solid tumors (NCT03386526). APG-1387 was administered IV once weekly with pembrolizumab 200 mg on day 1 of a 21-day cycle. Study aims were to assess safety/tolerability, recommended phase 2 dose (RP2D), pharmacokinetics (PK), pharmacodynamics (PD), and efficacy. Results: As of December 25, 2019, total 28 patients had been treated in 3 dose cohorts of APG-1387: 20 mg (n = 4), 30 mg (n = 3), and 45 mg (n = 21, 18 in dose expansion). The median line of prior systemic cancer therapies was 3.0 (1-12). No dose-limiting toxicity was observed. The most common treatment-related adverse events (TRAEs; ≥10%) were fatigue (28.6%), arthralgia (14.3%), headache (14.3%), and tumor pain (10.7%). One patient in the 45-mg cohort had grade 2 Bell’s Palsy. G3+ TRAEs were autoimmune colitis, hypoxia, increased lipase, mucosal inflammation, pneumonitis, and tumor pain in 1 patient each (3.6%). Treatment-related SAEs were 1 G3 autoimmune colitis, 1 G2 myocarditis, and 1 G3 pneumonitis. The maximum tolerated dose (MTD)/RP2D for APG-1387 was 45 mg. Among 25 efficacy-evaluable patients, 1 with ER+, HER2‒ breast cancer receiving APG-1387 30 mg after failing 5 lines of therapy (PD-1 treatment-naïve, microsatellite stable) achieved confirmed PR (-79.2%) for 6 cycles but discontinued due to pneumonitis; another patient with PD-L1‒ non‒small-cell lung cancer treated at 45 mg had confirmed PR (-65.0%) for 6 cycles (ongoing). Other 11 patients had SD for 2-11 cycles. The disease control rate was 52%. Preliminary PK data showed a dose-proportional increase in APG-1387 exposure from 20 mg to 45 mg. Preliminary PD data showed that APG-1387 induced rapid degradation of cellular IAP1 and X-linked IAP in peripheral blood mononuclear cell samples; Increased serum release of interleukins (IL-12, IL-10) and monocyte chemotactic protein 4 was dose and time dependent. Conclusions: APG-1387 combined with pembrolizumab is well tolerated. Encouraging antitumor effects were observed in patients with several tumor types. The ongoing study will further evaluate the efficacy of this combination. Clinical trial information: NCT03386526 .

3509 Background: Targeting Bcl-2/Bcl-xL proteins is considered as an important approach for anticancer drug development. Palcitoclax (APG-1252) was being developed to reduce on-target platelet toxicity without diminishing antitumor potency. Methods: The phase 1 study was to evaluate the safety/tolerability, pharmacokinetics (PK), and preliminary efficacy (assessed per RECIST 1.1) of palcitoclax in US patients with metastatic small-cell lung cancer (SCLC) or other solid tumors (NCT03080311). A standard “3+3” design was applied to the dose-escalation stage. Palcitoclax was administered IV infusion for 30 minutes, twice a week (BIW) or once a week (QW) for 3 weeks in a 28-day cycle. Once the maximum tolerated dose / recommended phase 2 dose (MTD/RP2D) was determined, additional patients were treated in a dose-expansion stage. Results: The dose-escalation phase has been completed with 42 patients (31 on BIW and 11 on QW) who received palcitoclax at 8 dose cohorts ranging 10 mg - 400 mg. Most adverse events (AEs) were grade 1 or 2 (G1 or G2), and 26.2% patients had ≥ G3 TRAEs. The most common TRAEs were platelet count decreased (14.3%), aspartate aminotransferase increased (9.5%), and alanine aminotransferase increased (7.1%). Rapid platelet drop was observed in patients treated at 320 mg and 400 mg, which was transient and resolved rapidly within 2-6 days. Palcitoclax at 240 mg once weekly was determined to be MTD/RP2D. Of 36 efficacy-evaluable patients, 3 patients with SCLC, neuroendocrine prostate cancer, and ovarian cancer respectively achieved partial response (PR) and 8 patients had stable disease (SD) as their best overall response. One patient with SCLC had a PR that lasted over 21 cycles. Preliminary PK analyses showed that Cmax and AUC were approximately dose proportional over the range of 10 mg to 320 mg following the IV infusion on Day 1, with a mean T1/2 of 3.0-13.0 hours. Conclusions: Palcitoclax is safe and well tolerated, with a favorable platelet toxicity profile. Its promising antitumor effect supports its further development in combination therapies for treatment of patients with SCLC and other solid tumors. Clinical trial information: NCT03080311 .

3085 Background: GB1275 is a first-in-class CD11b modulator that reduced myeloid-derived suppressor cells (MDSCs) and tumor associated macrophages (TAMs) at the tumor site, repolarized M2 immunosuppressive TAMs to an M1 phenotype, and increased tumor infiltration of activated CD8+ T cells in preclinical models. When combined with an anti-PD-1 antibody or chemotherapy, these immunomodulatory effects translated into potent anti-tumor effects and prolonged survival in orthotopic PDAC models [Panni RZ, et al. Sci Transl Med. 2019 Jul 3;11(499)]. This ongoing first-in-human study consists of dose escalation of GB1275 monotherapy (Regimen A), GB1275 + pembrolizumab (Regimen B), and GB1275 + nab-paclitaxel + gemcitabine (Regimen C), followed by Phase 2 expansion in newly diagnosed metastatic pancreatic, MSS colorectal, and PD-L1-positive gastric/GEJ cancers. Here we report interim results of the dose escalation portion of the trial. Methods: The dose escalation phase is based on a standard oncology phase 1, 3+3 design. Cohorts of 3 to 6 patients (pts) with histologically confirmed locally advanced/metastatic pancreatic, esophageal, gastric, MSS colorectal, prostate, or breast cancer were sequentially assigned to ascending dose levels of GB1275 taken orally twice daily (BID) in 1 of 3 regimens: Regimen A was initiated first; Regimen B commenced after completion of the first two cohorts of Regimen A, and Regimen C will be initiated when Regimen A is completed. Dose escalation was based on assessment of safety including dose-limiting toxicity (DLT). Serial blood and tumor samples were collected for pharmacokinetic (PK) and biomarker analyses. Results: As of January 21, 2020, 13 pts were treated, with 3 each in Regimen A (GB1275 100mg, 200 mg and 400 mg BID) dose levels and 4 in Regimen B with GB1275 100 mg BID + pembrolizumab. No DLTs have been reported. GB1275 treatment-related adverse events were reported in 5 pts; all were Grade 1 in severity. Preliminary PK analyses showed a mean elimination half-life of ~7 hours. Reduction in peripheral MDSCs was observed in the majority of pts with serial samples. Biomarker analysis in serial tumor tissue is ongoing. Conclusions: Preliminary data show minimal treatment-related toxicities with the studied regimens. PK data support BID dosing. Dose escalation is ongoing. Updated data will be presented. Clinical trial information: NCT04060342 .

TPS23 Background: COM701 is a novel 1st-in-class monoclonal antibody that binds with high affinity to poliovirus receptor related immunoglobulin domain containing (PVRIG) blocking its interaction with its ligand, PVRL2. In preclinical experiments inhibition of PVRIG alone and in combination with a PD-1 inhibitor leads to activation of T cells in the tumor microenvironment generating an anti-tumor immune response leading to tumor growth inhibition. Novel checkpoint therapies are needed for the treatment of patients with advanced malignancies. We hypothesized that COM701 monotherapy and in combination with nivolumab will be safe and tolerable and demonstrate preliminary antitumor activity in pts with advanced solid malignancies. Methods: This ongoing phase 1 study (NCT03667716) is evaluating the safety and tolerability of escalating doses of COM701 monotherapy IV Q3 or Q4 weekly and in combination with nivolumab 360 mg IV Q3 weekly or 480 mg IV Q4 weekly. Key Inclusion Criteria: Age ≥18 yrs, histologically or cytologically confirmed advanced solid malignancy and has exhausted all available standard therapy, ECOG performance status 0-1, prior ICI permissible. Key Exclusion Criteria: Symptomatic interstitial lung disease or inflammatory pneumonitis, untreated or symptomatic central nervous system metastases. Primary outcome measures are the incidence of adverse events and dose-limiting toxicities (21-day or 28-day DLT window), pharmacokinetics of COM701 and to identify the maximum tolerated dose and/or the recommended dose for expansion. Key secondary outcome measures are to characterize the immunogenicity and preliminary antitumor activity of COM701 as monotherapy and in combination with nivolumab. Study Design: Hybrid accelerated titration and 3+3 study design. Statistical Considerations: Adverse events graded as per CTCAE v4.03, responses as per RECIST v1.1. Analyses of all study objectives are descriptive and hypothesis generating. As of the date of this submission dose level 8 of COM701 monotherapy and dose level 3 of the combination arm are open to enrollment. Updated data will be presented at the conference. Clinical trial information: NCT03667716.

Purpose: This large two-part, three-arm phase I study examined the safety and tolerability of CC-486 (an oral formulation of azacitidine, a hypomethylating agent) alone or in combination with the cytotoxic agents, carboplatin or nab-paclitaxel, in patients with advanced unresectable solid tumors. Patients and Methods: Part 1 (n = 57) was a dose escalation of CC-486 alone (arm C) or with carboplatin (arm A) or nab-paclitaxel (arm B). The primary endpoint was safety, MTD, and recommended part 2 dose (RP2D) of CC-486. In part 2 (n = 112), the primary endpoint was the safety and tolerability of CC-486 administered at the RP2D for each treatment arm, in tumor-specific expansion cohorts. Secondary endpoints included pharmacokinetics, pharmacodynamics, and antitumor activity of CC-486. Results: At pharmacologically active doses CC-486 in combination with carboplatin or nab-paclitaxel had a tolerable safety profile and no drug–drug interactions. The CC-486 RP2D was determined as 300 mg (every day, days 1–14/21) in combination with carboplatin (arm A) or as monotherapy (arm C); and 200 mg in the same dosing regimen in combination with nab-paclitaxel (arm B). Albeit limited by the small sample size, CC-486 monotherapy resulted in partial responses (three/eight) and stable disease (four/eight) in patients with nasopharyngeal cancer. Three of the stable disease responses lasted more than 150 days. Conclusions: CC-486 is well tolerated alone or in combination with carboplatin or nab-paclitaxel. Exploratory analyses suggest clinical activity of CC-486 monotherapy in nasopharyngeal cancer and provided the basis for an ongoing phase II clinical trial (ClinicalTrials.gov identifier: NCT02269943). Clin Cancer Res; 24(17); 4072–80. ©2018 AACR.

Purpose The phase I study characterized the safety, pharmacokinetics, anti-tumor activity, and recommended phase II dose/schedule of LY3164530 in patients with advanced or metastatic cancer. Methods Patients received LY3164530 on days 1 and 15 (Schedule 1: 300, 600, 1000, and 1250 mg) or Days 1, 8, 15, and 22 (Schedule 2: 500 and 600 mg) of each 28 days cycle. Dose escalation used a modified toxicity probability interval model. Results Dose escalation defined a maximum tolerated dose (MTD) of 1000 mg on Schedule 1 and 500 mg on Schedule 2. Treatment-emergent adverse events related to study treatment were consistent with epidermal growth factor receptor (EGFR) inhibition and included maculopapular rash/dermatitis acneiform (83%, Grade 3/4 17%), hypomagnesemia (55%, Grade 3/4 7%), paronychia (35%), fatigue (28%, Grade 3/4 3%), skin fissures (24%), and hypokalemia (21%, Grade 3/4 7%). Partial response was achieved in three patients on Schedule 2 with colorectal cancer (n = 2) or squamous cell cancer. Overall response rate (ORR) was 10.3%, disease control rate (ORR + stable disease [SD]) was 51.7 and 17.2% of patients had SD ≥ 4 months. The in vivo stability of the bispecific antibody was confirmed. Schedule 2 provided greater and more consistent inhibition of mesenchymal-epithelial transition (MET)/EGFR throughout the dosing interval than Schedule 1. Conclusions Although this study defined the LY3164530 MTD and pharmacokinetics on both schedules, significant toxicities associated with EGFR inhibition and lack of a potential predictive biomarker limit future development. Nonetheless, the results provide insight into the development of bispecific antibody therapy. Electronic supplementary material The online version of this article (10.1007/s00280-018-3623-7) contains supplementary material, which is available to authorized users.

Background An ongoing open-label, multiarm, multicenter, phase I study of the anti–CTLA-4 antibody MK-1308 in combination with pembrolizumab in advanced solid tumors (NCT03179436) revealed manageable safety and promising efficacy in patients (pts) with advanced non-small cell lung cancer receiving first-line therapy [Perets et al. J Clin Oncol. 2019;37(suppl):2558]. Here we report data from the small cell lung cancer (SCLC) cohort of this study. Methods In the dose confirmation phase, pts with advanced SCLC received MK-1308 at 75 mg Q6W + pembrolizumab 200 mg Q3W (up to 35 cycles). The primary end point was safety, and the secondary end point was ORR based on blinded independent central review (BICR) per RECIST v1.1. PFS based on BICR per RECIST v1.1 and OS were exploratory end points. The database cutoff date for this analysis was June 3, 2019. Results Forty pts with previously treated advanced SCLC (second-line or beyond) were enrolled and dosed; median duration of follow-up was 11 mo. At data cutoff, 32 pts (80%) discontinued study treatment—23 (58%) due to progressive disease, 4 (10%) due to AE, 2 (5.0%) due to clinical progression—and 3 (7.5%) withdrew consent. Median age was 66 years; 60% of pts were male and 65% had ECOG PS 1 at baseline. Seven pts achieved partial response according to BICR assessment, for an ORR of 18% (95% CI, 7.3-33). Eight pts (20%) had a best overall response of stable disease and 21 (53%) had progressive disease. Response duration ranged from 2.9 to 8.4+ mo. At the time of the data cutoff, 5 of 7 responses (71%) were ongoing. Median time to response was 2.1 mo (range, 1.1-12). Median PFS was 2.0 mo (95% CI, 1.9-3.9), and the 6-mo PFS rate was 26%. Median OS was 11 mo (95% CI, 5.9-not reached), and the 6-mo OS rate was 66%. Treatment-related adverse events (TRAEs) as determined by the investigator occurred in 32 pts (80%). Grade 3 TRAEs were reported in 11 pts (28%); no grade 4-5 events were reported. Three pts (7.5%) discontinued treatment due to TRAEs. Conclusion In heavily pretreated pts with SCLC, MK-1308 + pembrolizumab was generally well tolerated with encouraging antitumor activity. Clinical trial identification NCT03179436. Editorial acknowledgement Medical writing and/or editorial assistance was provided by Holly C. Cappelli, PhD, CMPP, and Dana Francis, PhD, of the ApotheCom pembrolizumab team (Yardley, PA, USA) and funded by Merck Sharp & Dohme Corp, a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Legal entity responsible for the study Merck Sharp and Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Funding Merck Sharp and Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Disclosure B.C. Cho: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (self): Novartis; Honoraria (self), Research grant / Funding (self): Bayer; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): AstraZeneca; Honoraria (self), Research grant / Funding (self): MOGAM Institute; Honoraria (self), Research grant / Funding (self): Dong-A ST; Honoraria (self), Research grant / Funding (self), Licensing / Royalties: Champions Oncology; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Janssen; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Yuhan; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): Ono; Honoraria (self), Research grant / Funding (self): Dizal Pharma; Honoraria (self), Advisory / Consultancy, Research grant / Funding (self): MSD; Advisory / Consultancy: Boehringer-Ingelheim; Advisory / Consultancy: Roche; Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Takeda; Shareholder / Stockholder / Stock options: TheraCanVac Inc; Shareholder / Stockholder / Stock options: Bridgebio Therapeutics; Shareholder / Stockholder / Stock options: Gencurix Inc. K. Yoh: Research grant / Funding (institution): MSD. J. Bar: Advisory / Consultancy, Research grant / Funding (self), Research grant / Funding (institution): AstraZeneca; Advisory / Consultancy: MSD; Advisory / Consultancy, Research grant / Funding (institution): Boehringer Ingelheim; Advisory / Consultancy, Research grant / Funding (institution): Roche; Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb; Advisory / Consultancy: Takeda; Advisory / Consultancy, Research grant / Funding (institution): Abbvie; Advisory / Consultancy: OncoHost; Advisory / Consultancy: VBL; Research grant / Funding (institution): Pfizer. A. Nagrial: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): MSD; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): AZ; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Roche; Research grant / Funding (institution): Beigene; Research grant / Funding (institution): Incyte. D.R. Spigel: Leadership role: Centennial Medical Center; Travel / Accommodation / Expenses: AstraZeneca; Travel / Accommodation / Expenses: Boehringer-Ingelheim; Travel / Accommodation / Expenses: Celgene; Travel / Accommodation / Expenses: Eli Lilly; Travel / Accommodation / Expenses: EMD Serono; Travel / Accommodation / Expenses: Bristol-Myers Squibb; Travel / Accommodation / Expenses: Genentech; Travel / Accommodation / Expenses: Genzyme; Travel / Accommodation / Expenses: Intuitive Surgical; Travel / Accommodation / Expenses: Merck; Travel / Accommodation / Expenses: Pfizer; Travel / Accommodation / Expenses: Purdue Pharma; Travel / Accommodation / Expenses: Spectrum Pharmaceuticals; Travel / Accommodation / Expenses: Sysmex. M. Gutierrez: Shareholder / Stockholder / Stock options: COTA; Advisory / Consultancy, Speaker Bureau / Expert testimony: Eli Lilly; Advisory / Consultancy: Esanex; Advisory / Consultancy: Guardant 360; Speaker Bureau / Expert testimony: Merck; Speaker Bureau / Expert testimony: Bristol-Myers Squibb; Speaker Bureau / Expert testimony: Foundation Medicine. D-W. Kim: Research grant / Funding (institution): Alpha Biopharma; Research grant / Funding (institution): AstraZeneca/Medimmune; Research grant / Funding (institution): Hanmi; Research grant / Funding (institution): Janssen; Research grant / Funding (institution): Merus; Research grant / Funding (institution): Mirati Therapeutics; Research grant / Funding (institution): MSD; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): ONO Pharmaceutical; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Roche/Genentech; Research grant / Funding (institution): Takeda; Research grant / Funding (institution): TP Therapeutics; Research grant / Funding (institution): Xcovery; Research grant / Funding (institution): Yuhan. D. Rasco: Research grant / Funding (institution): Merck; Research grant / Funding (institution): Regeneron. M. Satouchi: Honoraria (self), Research grant / Funding (institution): MSD. M-J. Ahn: Honoraria (self), Advisory / Consultancy: Bristol-Myers Squibb; Honoraria (self), Advisory / Consultancy: ONO; Honoraria (self), Advisory / Consultancy: MSD; Honoraria (self), Advisory / Consultancy: AstraZeneca; Honoraria (self), Advisory / Consultancy: Takeda; Advisory / Consultancy: Lilly; Advisory / Consultancy: Alpha Pharm. D.H. Lee: Honoraria (self): AbbVie; Honoraria (self): AstraZeneca; Honoraria (self): Boehringer-Ingelheim; Honoraria (self): Bristol-Myers Squibb; Honoraria (self): ChongKunDang; Honoraria (self): CJ Healthcare; Honoraria (self): Eli Lilly; Honoraria (self): Janssen; Honoraria (self): Menarini; Honoraria (self): Merck; Honoraria (self): MSD; Honoraria (self): Mundipharma; Honoraria (self): Novartis; Honoraria (self): Ono; Honoraria (self): Pfizer; Honoraria (self): Roche; Honoraria (self): Samyang Biopharm; Honoraria (self), Advisory / Consultancy: ST Cube; Honoraria (self): Takeda. C. Maurice-Dror: Travel / Accommodation / Expenses: Janssen; Travel / Accommodation / Expenses: Pfizer; Travel / Accommodation / Expenses: Roche. S. Siddiqi: Full / Part-time employment: Merck & Co., Inc.. X. Li: Full / Part-time employment: Merck & Co., Inc.. J. Cyrus: Leadership role, Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Merck & Co., Inc.. R.A. Altura: Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment: Merck & Co., Inc.. R. Perets: Advisory / Consultancy: Karyopharm; Advisory / Consultancy: BiolineRx. All other authors have declared no conflicts of interest.