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Background: Addition of PI3K/mTOR inhibitor after progression on CDK4/6 inhibitor (CDK4/6i) and endocrine therapy (ET) can potentially restore sensitivity to CDK4/6i and prevent adaptive activation of the PI3K/mTOR pathway. To evaluate this hypothesis, we conducted a Phase Ib study of gedatolisib (G), a dual inhibitor of PI3K/mTOR, palbociclib (P) a CDK4/6i, and ET (with letrozole [LET] or fulvestrant [FUL]) in women with hormone receptor positive (HR+)/HER2- advanced breast cancer (ABC). Manageable toxicity and preliminary antitumor activity were observed in 35 patients(pts) enrolled in the dose escalation portion of the study (Forero-Torres, ASCO 2018) and 103 pts enrolled in the expansion portion of the study (Layman, SABCS 2021). Here, we report updated efficacy and safety data and sub-group analysis by PIK3CA mutation status in the four expansion study arms with a March 3, 2022, data cut-off. Methods: Pts with HR+/HER2- ABC were treated in four expansion arms: A) G+P+LET as first-line treatment, B) G+P+FUL as 2nd line treatment in pts without prior CDK4/6i; C & D) G+P+FUL as 2nd or 3rd line therapy in pts with prior CDK4/6i. P, LET, and FUL were administered at standard doses. G 180 mg was intravenously administered weekly in Arms A, B, and C and three weeks on/one week off in Arm D. The primary endpoint was investigator assessed objective response rate (ORR). Secondary endpoints included safety, duration of response and progression free survival (PFS). Results: Of the 103 pts treated with G+P+ ET in the expansion arms (A-D), 100% had measurable disease at baseline, 71% (73/103) lacked PIK3CA mutations (wild type; WT), 27% (28/103) had PIK3CA-mutations (MT), 70% (72/103) had evidence of bone metastases, and 59% (61/103) had liver metastases. The most frequent grade 3 and 4 treatment related AEs (TRAE) with G+P+ET included neutropenia (63%), stomatitis (27%), rash (20%), fatigue (11%) and hyperglycemia (7%). Treatment discontinuation due to TRAEs was 6.5% in Arm A, 15.4% in Arm B, 9.4% in Arm C and 3.7% in Arm D. Efficacy data for each arm is presented in Table 1. Promising ORR and PFS were seen in all arms regardless of PIK3CA mutation status. In Arm D, ORR was 63% overall, 73% in PIK3CA-MT pts, and 60% in PIK3CA-WT pts. Median PFS in Arm D was 12.9 months with a median follow up of 29 months. 60% and 48% of pts in the PIK3CA-MT and PIK3CA-WT Arm D sub-groups, respectively, were progression free at 12 months. Conclusions: These preliminary data demonstrate promising activity of G+P+ET combination in pts who were CDK4/6i-naïve and in those whose disease progressed on or after CDK4/6i therapy regardless of PIK3CA mutation status. Encouraging results in CDK4/6i treatment naïve patients warrant further evaluation of gedatolisib in combination with CDK4/6i treatment in the front-line setting. Arm D results provide a strong basis for the initiated Phase 3 study (VIKTORIA-1) in pts whose disease progressed on or after CDK4/6i therapy. Table 1. Efficacy Data by Expansion Arms Citation Format: Robert Wesolowski, Hope Rugo, Erica Stringer-Reasor, Hyo S. Han, Jennifer M. Specht, E. Claire Dees, Peter Kabos, Ulka Vaishampayan, Seth A. Wander, Janice Lu, Keerthi Gogineni, Alexander I. Spira, Anne F. Schott, Maysa Abu-Khalaf, Pratima Nayak, Brian F. Sullivan, Igor Gorbatchevsky, AND Rachel M. Layman. PD13-05 Updated results of a Phase 1b study of gedatolisib plus palbociclib and endocrine therapy in women with hormone receptor positive advanced breast cancer: Subgroup analysis by PIK3CA mutation status [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD13-05.

PURPOSE: This study evaluated whether patients with de novo metastatic breast cancer (MBC) have superior outcomes compared to those with recurrent MBC in a contemporary treatment era and examined factors related to outcome differentials. METHODS: Using an institutional database, we examined patient and tumor characteristics, treatment response, and outcome among 232 patients with de novo and 612 patients with recurrent MBC diagnosed between 2011 and 2017. RESULTS: De novo MBC had 9-month (m) longer overall survival (OS) than recurrent MBC (36.4 vs 27.4 m, p < 0.001). Contributions to this difference included nearly twofold more HER2-positive (29.3% vs 15.2%) and significantly fewer triple-negative breast cancers (20.3% vs 32.4%, both p < 0.001) in de novo compared with recurrent MBC cohorts. Stratified by clinical subtype, progression-free survival (PFS) on first-line therapy was significantly longer in de novo MBC in all but the triple-negative subtype, 25.5 vs 11.6 m (p < 0.001) among 390 patients with hormone receptor-positive, HER2-negative, 11.4 vs 5.4 m (p = 0.002) among 142 patients with HER2-positive, and 4.0 vs 3.0 m (p = 0.121) among 162 with triple-negative MBC. In multivariable analysis, de novo status remained independently associated with improved OS (hazard ratio 0.63, 95% CI 0.49–0.80), regardless of subtype and other features. CONCLUSION: Patients with de novo MBC have better outcomes than those with recurrent MBC. Differences in clinical subtype and response to therapy in the metastatic setting contribute to, but do not fully explain, this difference. Longer PFS to first-line therapy in de novo MBC suggests biologic differences compared to recurrent MBC, which may be intrinsic or due to acquired resistance from treatment for prior localized breast cancer in recurrent disease.

Previous work from our group and others has shown that patients with breast cancer can generate a T cell response against specific human epidermal growth factor 2 (HER2) epitopes. In addition, preclinical work has shown that this T cell response can be augmented by Ag-directed mAb therapy. This study evaluated the activity and safety of a combination of dendritic cell (DC) vaccination given with mAb and cytotoxic therapy. We performed a phase I/II study using autologous DCs pulsed with two different HER2 peptides given with trastuzumab and vinorelbine to a study cohort of patients with HER2-overexpressing and a second with HER2 nonoverexpressing metastatic breast cancer. Seventeen patients with HER2-overexpressing and seven with nonoverexpressing disease were treated. Treatment was well tolerated, with one patient removed from therapy because of toxicity and no deaths. Forty-six percent of patients had stable disease after therapy, with 4% achieving a partial response and no complete responses. Immune responses were generated in the majority of patients but did not correlate with clinical response. However, in one patient, who has survived >14 y since treatment in the trial, a robust immune response was demonstrated, with 25% of her T cells specific to one of the peptides in the vaccine at the peak of her response. These data suggest that autologous DC vaccination when given with anti-HER2–directed mAb therapy and vinorelbine is safe and can induce immune responses, including significant T cell clonal expansion, in a subset of patients.

Purpose: GSK2126458 (GSK458) is a potent inhibitor of PI3K (α, β, γ, and δ), with preclinical studies demonstrating broad antitumor activity. We performed a first-in-human phase I study in patients with advanced solid tumors.Materials and Methods: Patients received oral GSK458 once or twice daily in a dose-escalation design to define the maximum tolerated dose (MTD). Expansion cohorts evaluated pharmacodynamics, pharmacokinetics, and clinical activity in histologically and molecularly defined cohorts.Results: One hundred and seventy patients received doses ranging from 0.1 to 3 mg once or twice daily. Dose-limiting toxicities (grade 3 diarrhea, n = 4; fatigue and rash, n = 1) occurred in 5 patients (n = 3 at 3 mg/day). The MTD was 2.5 mg/day (MTD with twice daily dosing undefined). The most common grade ≥3 treatment-related adverse events included diarrhea (8%) and skin rash (5%). Pharmacokinetic analyses demonstrated increased duration of drug exposure above target level with twice daily dosing. Fasting insulin and glucose levels increased with dose and exposure of GSK458. Durable objective responses (ORs) were observed across multiple tumor types (sarcoma, kidney, breast, endometrial, oropharyngeal, and bladder cancer). Responses were not associated with PIK3CA mutations (OR rate: 5% wild-type vs. 6% mutant).Conclusions: Although the MTD of GSK458 was 2.5 mg once daily, twice-daily dosing may increase duration of target inhibition. Fasting insulin and glucose levels served as pharmacodynamic markers of drug exposure. Select patients achieved durable responses; however, PIK3CA mutations were neither necessary nor predictive of response. Combination treatment strategies and novel biomarkers may be needed to optimally target PI3K. Clin Cancer Res; 22(8); 1932–9. ©2015 AACR.

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PDF file, 584K, Supplementary Figures: S1. MLN8237 dose-escalation schema for relative bioavailability sub-study; S2. Relative bioavailability study schema: MLN8237 ECT versus PIC formulation. S3. Scans showing durable partial response after treatment with MLN8237 in a 52-year-old patient with platinum- and radiation-refractory ovarian cancer.

Supplementary Table 1. Pharmacokinetic Parameters on Day 1 Following Once daily and Twice Daily Administration of GSK458 Supplementary Table 2. Best Objective Tumor Response by Dose Level (supplementary)

Duration of therapy and best objective response in the expansion cohorts (Breast, Bladder, Renal, and Endometrial Cancer)

Purpose: This phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of the investigational oral drug MLN8237 (alisertib), a small-molecule Aurora A kinase (AAK) inhibitor, in 87 adult patients with advanced solid tumors.Experimental Design: Sequential cohorts of patients received MLN8237 5 to 150 mg orally once daily or twice daily for 7, 14, or 21 days, followed by 14 days' rest per cycle. MLN8237 pharmacokinetics was characterized, and the relative bioavailability of an enteric-coated tablet (ECT) formulation was evaluated in reference to the original powder-in-capsule (PIC) formulation. Pharmacodynamic effects of MLN8237 on inhibition of AAK activity were evaluated in skin biopsies. Tolerability and response to treatment were assessed.Results: Common toxicities included fatigue, nausea, and neutropenia. Plasma exposures increased dose proportionally (5–150 mg/d), and were similar for PIC and ECT. The terminal half-life was 23 hours. At the maximum tolerated dose of 50 mg twice daily on the 7-day schedule, the mitotic index of the skin basal epithelium was increased within 24 hours after MLN8237 administration on days 1 and 7, a finding consistent with AAK inhibition. One (1%) patient achieved a partial response lasting for more than 1 year and received MLN8237 for 51 cycles; 20 (23%) patients achieved stable disease for ≥3 months.Conclusions: This first-in-human trial of MLN8237 showed tolerability and favorable pharmacokinetics in this patient population. The recommended phase II dose of MLN8237 is 50 mg twice daily orally for 7 days in 21-day cycles, which is being evaluated further in the treatment of various solid tumors and hematologic malignancies. Clin Cancer Res; 18(17); 4775–84. ©2012 AACR.

PDF file, 59K, Summary of pharmacokinetic parameters for MLN8237 PIC formulation after multiple dose oral administration dosing in the 7-, 14-, and 21-day schedules.

Supplementary Figure 2 from Phase I Assessment of New Mechanism-Based Pharmacodynamic Biomarkers for MLN8054, a Small-Molecule Inhibitor of Aurora A Kinase

Supplementary Tables 1-5 from Phase I Assessment of New Mechanism-Based Pharmacodynamic Biomarkers for MLN8054, a Small-Molecule Inhibitor of Aurora A Kinase

Supplementary Figure 1 from Phase I Assessment of New Mechanism-Based Pharmacodynamic Biomarkers for MLN8054, a Small-Molecule Inhibitor of Aurora A Kinase

Purpose: H3B-6545, a novel Selective ERα Covalent Antagonist (SERCA), inactivates both and wild-type and mutant ERα by targeting cysteine 530 and enforcing antagonist conformation. H3B-6545 demonstrated preclinical high activity in breast cancer models with constitutively active ESR1 mutations (Furman C, SABCS 2020) and clinical activity in pretreated women with ER+ breast cancer (Hamilton EP, ASCO 2021). Patients and Methods: The primary objective of the phase II is to estimate the objective response rate (ORR), clinical benefit rate (CBR), progression-free survival (PFS), and secondary objectives include safety. Results: 94 pts were treated with 450 mg daily, the recommended phase II dose: 11 in the phase I and 83 in the phase II parts of the trial. Patients and tumor characteristics were presented previously (Hamilton EP, ASCO, 2021). As of March 31, 2021, grade (gr) 2 or higher adverse events (AE) reported in ≥10% were anemia (19%), nausea (17%), fatigue (16%), and diarrhea (12%). Laboratory gr 2 or higher abnormalities reported in ≥10% pts were creatinine clearance decrease (39%), hemoglobin decrease (38%), Lymphocytes decrease (37%), ALT increase (14%), AST increase (13%), bilirubin increase (12%), and creatinine increase (12%). AE of gr 1 sinus bradycardia (asymptomatic) was reported in 35% and gr 2 (symptomatic, no intervention needed) was reported in 5%. Gr 2 and 3 QTcF prolongation were reported in 2 and 3 pts, respectively. There were no treatment-related deaths. Efficacy estimates are presented in Table 1. CI: Confidence interval. N: total number of pts in full analysis set, used in PFS analysis. n: number of response-evaluable pts, used in ORR and CBR analysis. Efficacy estimates were consistent across the various subgroups. Responses were demonstrated in heavily pretreated pts, pts with visceral metastases, pts with constitutionally active ESR1 Y537S mutations, and in pts who received chemotherapy in the metastatic setting. Numerically higher response rate and longer PFS were observed in pts with ESR1 Y537s. Conclusions: H3B-6545 has a manageable safety profile and demonstrated single-agent anti-tumor activity in heavily pretreated ER+, HER2- mBC patients. Clinical activity was consistent across the various subgroups. Tumors harboring the constitutionally active ESR1 Y537S mutation may present higher ERα activity, and consequently enrich for luminal A traits and demonstrate greater lineage dependence on ERα. Table 1.Consistency of H3B-6545 activity across the key subgroupsEfficacyClinical CharacteristicORR % (95% CI)CBR % (95% CI)Median PFS mo (95% CI)Overall population (N=94, n=72)16.7 (8.9, 27.3)40.3 (28.9, 52.5)5.1 (3.2, 6.2)Liver and/or lung metastases (N=76, n=62)17.7 (9.2, 29.5)41.9 (29.5, 55.2)5.4 (1.8, 7.2)≥3 prior regimens (N=49, n=39)20.5 (9.3, 36.5)48.7 (32.4, 65.2)5.4 (3.5, 7.3)Prior chemotherapy (N=47, n=35)17.1 (6.6, 33.6)51.4 (34.0, 68.6)5.5 (3.6, 7.3)PgR+ (N=38, n=32)15.6 (5.3, 32.8)50.0 (31.9, 68.1)5.4 (2.0, 8.8)ESR1 clonal Y537S (N=10, n=10)30.0 (6.7, 65.2)60.0 (26.2, 87.8)7.3 (0.8, 11.2)ESR1 clonal D538G (N=19, n=17)0.0 (0.0, 19.5)35.3 (14.2, 61.7)5.4 (1.7, 7.2) Citation Format: Erika P Hamilton, Judy S Wang, Timothy Pluard, Aki Morikawa, E Claire Dees, Robert H Jones, Barbara Haley, Anne Armstrong, Adam L Cohen, Pamela Munster, Gail S Wright, Fadi Kayali, Lisa Cantagallo, Manav Korpal, Jenny Long, Jianjun Xiao, Benoit Destenaves, Lei Gao, Tarek Sahmoud, Antonio Gualberto, Dejan Juric. H3B-6545, a novel selective estrogen receptor covalent antagonist (SERCA), in estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer - A phase II study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-17-10.

Purpose: Washout periods and concomitant medication exclusions are common in cancer clinical trial protocols. These exclusion criteria are often applied inconsistently and without evidence to justify their use. The authors sought to determine how washout period and concomitant medication allowances can be broadened to speed trial enrollment and improve the generalizability of trial data to a larger oncology practice population without compromising the safety of trial participants. Experimental Design: A multistakeholder working group was convened to define problems associated with excessively long washout periods and exclusion of patients due to concomitant medications. The group performed a literature search and evaluated study data from the Pancreatic Cancer Action Network (PanCAN), Emory University School of Medicine (Atlanta, GA), and the FDA to understand recent approaches to these eligibility criteria. The group convened to develop consensus recommendations for broadened eligibility criteria. Results: The data analysis found that exclusion criteria based on washout periods and concomitant medications are frequently inconsistent and lack scientific rationale. Scientific rationale for appropriate eligibility criteria are presented in the article; for washout periods, rationale is presented by treatment type. Conclusions: Arbitrary or blanket washout and concomitant medication exclusions should be eliminated. Where there is evidence to support them, clinically relevant washout periods and concomitant medication–related eligibility criteria may be included. See related commentary by Giantonio, p. 2369

Background: This study investigates whether high body mass index (BMI) in women diagnosed with early breast cancer (BC) is associated with patient-reported symptom severity during chemotherapy.Methods: Women with Stage I-III BC completed toxicity reports for 17 side effects during regularly scheduled chemotherapy infusions. Toxicity reports were compared in women with obesity (BMI >=30) versus no obesity (BMI Results: In a sample of 286 patients, Black women comprised 23% of the sample. The obesity rate was 76% among Black patients and 31% among White patients (pConclusions: Among women with early BC, patients with obesity reported higher chemotherapy toxicity as compared to patients without obesity; however, this did not result in differences in treatment completion.

Purpose. This study evaluated whether patients with de novo metastatic breast cancer (MBC) have superior outcomes compared to those with recurrent MBC in a contemporary treatment era and examined factors related to outcome differentials.Methods. Using an institutional database, we examined patient and tumor characteristics, treatment response, and outcome among 232 patients with de novo and 612 patients with recurrent MBC diagnosed between 2011-2017.Results. De novo MBC had 9-month (m) longer overall survival (OS) than recurrent MBC (36.4 vs 27.4m, pnovo compared with recurrent MBC cohorts. Stratified by clinical subtype, progression-free survival (PFS) on first-line therapy was significantly longer in de novo MBC in all but the triple negative subtype: 25.5 vs 11.6m (pde novo status remained independently associated with improved OS (hazard ratio 0.63, 95% CI 0.49-0.80), regardless of subtype and other features. Conclusion. Patients with de novo MBC have better outcomes than those with recurrent MBC. Differences in clinical subtype and response to therapy in the metastatic setting contribute to, but do not fully explain, this difference. Longer PFS to first-line therapy in de novo MBC suggests biologic differences compared to recurrent MBC, which may be intrinsic or due to acquired resistance from treatment for prior localized breast cancer in recurrent disease.

BACKGROUND To the authors' knowledge, it is unknown whether patient-reported symptom severity and symptom interference with daily activities differ between younger (aged

Capecitabine is important in breast cancer treatment but causes diarrhea and hand-foot syndrome (HFS), affecting adherence and quality of life. We sought to identify pharmacogenomic predictors of capecitabine toxicity using a novel monitoring tool. Patients with metastatic breast cancer were prospectively treated with capecitabine (2000 mg/m2/day, 14 days on/7 off). Patients completed in-person toxicity questionnaires (day 1/cycle) and automated phone-in assessments (days 8, 15). Correlation of genotypes with early and overall toxicity was the primary endpoint. Two hundred and fifty-nine patients were enrolled (14 institutions). Diarrhea and HFS occurred in 52% (17% grade 3) and 69% (9% grade 3), respectively. Only 29% of patients completed four cycles without dose reduction/interruption. In 39%, the highest toxicity grade was captured via phone. Three single nucleotide polymorphisms (SNPs) associated with diarrhea—DPYD*5 (odds ratio [OR] 4.9; P = 0.0005), a MTHFR missense SNP (OR 3.3; P = 0.02), and a SNP upstream of MTRR (OR 3.0; P = 0.03). GWAS elucidated a novel HFS SNP (OR 3.0; P = 0.0007) near TNFSF4 (OX40L), a gene implicated in autoimmunity including autoimmune skin diseases never before implicated in HFS. Genotype-gene expression analyses of skin tissues identified rs11158568 (associated with HFS via GWAS) with expression of CHURC1, a transcriptional activator controlling fibroblast growth factor (beta = − 0.74; P = 1.46 × 10–23), representing a previously unidentified mechanism for HFS. This is the first cancer pharmacogenomic study to use phone-in self-reporting, permitting augmented toxicity characterization. Three germline toxicity SNPs were replicated, and several novel SNPs/genes having strong functional relevance were discovered. If further validated, these markers could permit personalized capecitabine dosing.

BackgroundCyclin-dependent kinases (CDK) 4 and 6 regulate G1 to S cell cycle progression and are often altered in cancers. Abemaciclib is a selective inhibitor of CDK4 and CDK6 approved for administration on a continuous dosing schedule as monotherapy or as combination therapy with an aromatase inhibitor or fulvestrant in patients with advanced or metastatic breast cancer. This Phase 1b study evaluated the safety and tolerability, pharmacokinetics, and antitumor activity of abemaciclib in combination with endocrine therapy for metastatic breast cancer (MBC), including aromatase inhibitors (letrozole, anastrozole, or exemestane) or tamoxifen.Patients and MethodsWomen ≥18 years old with hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) MBC were eligible for enrollment. Eligibility included measurable disease or non-measurable but evaluable bone disease by Response Evaluation Criteria in Solid Tumours (RECIST) v1.1, Eastern Cooperative Oncology Group performance status 0–1, and no prior chemotherapy for metastatic disease. Adverse events were graded by the National Cancer Institute Common Terminology Criteria for Adverse Events v4.0 and tumor response were assessed by RECIST v1.1.ResultsSixty-seven patients were enrolled and received abemaciclib 200 mg every 12 hours in combination with letrozole (Part A, n=20), anastrozole (Part B, n=16), tamoxifen (Part C, n=16), or exemestane (Part D, n=15). The most common treatment-emergent adverse events (TEAE) were diarrhea, fatigue, nausea, and abdominal pain. Grade 4 TEAEs were reported in five patients (one each with hyperglycemia, hypertension, neutropenia, procedural hemorrhage, and sepsis). There was no effect of abemaciclib or endocrine therapy on the pharmacokinetics of any combination study drug. Across all treated patients, the median progression-free survival was 25.4 months (95% confidence interval: 18.0, 35.8). The objective response rate was 38.9% in 36 patients with measurable disease.ConclusionsAbemaciclib in combination with multiple endocrine therapy options exhibited manageable safety and promising antitumor activity in patients with HR+, HER2- MBC.Clinical Trial Registrationhttps://clinicaltrials.gov/, identifier NCT02057133

Background: Rintodestrant (G1T48) is a potent oral selective estrogen receptor degrader (SERD) that competitively binds to the estrogen receptor (ER) and blocks ER signaling in tumors resistant to other endocrine therapies. Preliminary results from Part 1 dose escalation showed robust target engagement on 18F-fluoroestradiol positron emission tomography (FES-PET), a favorable safety profile, and encouraging antitumor activity in patients with heavily pretreated ER+/HER2- advanced breast cancer (ABC), including those with ESR1 mutations (Dees et al., ESMO 2019 [abstract #3587]). Here, we present updated results from dose escalation and expansion (Parts 1 and 2). Methods: This Phase 1, first-in-human, open-label study evaluated rintodestrant monotherapy in women with ER+/HER2- ABC after progression on endocrine therapy. Part 1 was a 3+3 dose escalation (200-1000 mg once daily [QD]); Part 2 expanded 600 and 1000 mg QD; and Part 3 was added to assess rintodestrant with palbociclib in patients in earlier lines in the advanced setting. Primary objectives included dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), safety, and recommended Phase 2 dose. Secondary objectives included pharmacokinetics and antitumor activity (RECIST v1.1). Exploratory objectives included pharmacodynamic inhibition of ER target engagement (FES-PET), mutation profiling (cell-free DNA [cfDNA]), and change in ER expression from baseline to on-treatment tumor biopsies. Results: As of May 13, 2020, 67 patients (Part 1: n = 26; Part 2: n = 41) were treated, with a median age of 61 years (range 34-83) and ECOG PS of 0 (49%) or 1 (51%). Median number of prior lines in the advanced setting was 2 (range 0-9), including prior fulvestrant (64%), CDK4/6 inhibitor (69%), mTOR inhibitor (22%), and/or chemotherapy (46%). Median number of prior lines of endocrine therapy in the advanced setting was 2 (range 0-5), with 61% of patients having received ≥2 lines. Treatment-related adverse events (TRAEs) were reported in 70% of patients. The most common TRAEs in ≥10% of patients included hot flush (24%), fatigue (21%), nausea (19%), diarrhea (18%), and vomiting (10%), mostly grade 1 or 2. No DLTs were reported and MTD was not reached. Dose reduction due to TRAEs occurred in 1 patient (1%), with elevated transaminases (grade 3 ALT and grade 2 AST) at 600 mg. Serious TRAEs occurred in 2 patients at 1000 mg (grade 5 cerebral hemorrhage in the setting of low molecular weight heparin and grade 2 upper abdominal pain). Two patients (3%) discontinued treatment due to TRAEs. Overall, the frequency of patients with TRAEs at 800 mg was comparable with that at 600 mg (57% vs 63%) and less than that at 1000 mg (81%). Of 67 patients, 16 were on study treatment for ≥24 weeks and 3 (n = 1 at 600 mg; n = 2 at 1000 mg, including 1 with ESR1 mutation) had a confirmed partial response (clinical benefit rate [CBR]: 28%). FES-PET standard uptake values decreased at week 4 with a mean reduction of 87% (±8%) at doses ≥ 600 mg. Of 59 patients tested for baseline cfDNA, 41% harbored ≥1 ESR1 mutation, with a similar CBR in both groups (33% in ESR1 mutant and 29% in ESR1 wild-type). Seven of 9 patients had a decrease in ER immunohistochemistry H-score at both 600 and 1000 mg (median [range]: -27.8% [-33.8%, -3.4%]), irrespective of ESR1 mutation status. Based on safety, efficacy, and ER degradation, 800 mg was selected as the optimal dose for further study. Conclusions: Rintodestrant continues to demonstrate an excellent safety/tolerability profile across all doses, with promising antitumor activity in patients with heavily pretreated ER+/HER2- ABC, including those with tumors harboring ESR1 mutations. Part 3 of this study, evaluating rintodestrant 800 mg QD with palbociclib in a more endocrine-sensitive population, is ongoing (NCT03455270). Citation Format: Philippe Aftimos, Patrick Neven, Mark Pegram, Catharina Willemien Menke-van der Houven van Oordt, E. Claire Dees, Carolien Schröder, Agnes Jager, Iurie Bulat, Linnea Chap, Marina Maglakelidze, Erika Hamilton, Massimo Cristofanilli, Susanna Ulahannan, Jorianne Boers, Ramsha Iqbal, Adrian Crijanovschi, Curt D Wolfgang, Wenli Tao, Christina Sipes, Rajesh Malik, Sarika Jain. Rintodestrant (G1T48), an oral selective estrogen receptor degrader in ER+/HER2- locally advanced or metastatic breast cancer: Updated phase 1 results and dose selection [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS12-04.

Background: Adoptive T cell therapies have led to remarkable advances in hematologic cancers but with less effect in ST. Actively recruited tumor associated macrophages (TAM) are abundant in the ST microenvironment (TME) and typically display immunosuppressive behavior. Macrophages engineered to be proinflammatory may be an ideal vector for adoptive ST cellular therapy. Engineered CAR-M selectively recognize and phagocytose antigen overexpressing cancer cells, reprogram TME and present neoantigens to T cells, leading to epitope spreading and immune memory. Human Epidermal Growth Factor Receptor 2 (HER2) overexpression promotes tumorigenesis in many cancers (Table 1). CT-0508 is a cell product comprised of autologous monocyte-derived proinflammatory macrophages expressing an anti-HER2 CAR. Pre-clinical studies show that CT-0508 induces targeted cancer cell phagocytosis while sparing normal cells, decreases tumor burden and prolongs survival, and was safe and effective in a semi-immunocompetent mouse model of human HER2-overexpressing ovarian cancer. Methods: This FIH Phase 1 study is evaluating safety, tolerability, cell manufacturing feasibility, trafficking, and preliminary efficacy in 18 subjects with locally advanced/unresectable or metastatic ST overexpressing HER2, with progression on available therapies, including anti-HER2 therapies. Filgrastim is used to mobilize autologous hematopoietic progenitor cells for monocyte collection by apheresis prior to CT-0508 CAR macrophage infusion. Group 1 subjects receive CT-0508 on D1, 3, & 5. Group 2 subjects will receive full dose on D1. A Safety Review Committee will review dose limiting toxicities. Pre/post-treatment biopsies and blood samples will be collected for correlative analysis of immunogenicity, trafficking (PCR, RNA scope), CT-0508 persistence in blood and tumor, target antigen engagement, TME modulation (single cell RNA sequencing), immune response (TCR sequencing) and others. Table 1. Her2 Overexpression Across Tumor Types Tumor HER2 Overexpression (%) Bladder 8–70 Salivary duct 30–40 Gastric 7–34 Ovarian 26 Breast 11–25 Salivary mucoepidermoid 17.6 Esophageal 12–14 Gallbladder 9.8–12.8 Cholangiocarcinoma 6.3–9 Colorectal 1.6–5 Cervical 2.8–3.9 Uterine 3 Testicular 2.4 Citation Format: Kim A. Reiss, Yuan Yuan, Naoto T. Ueno, Yara Abdou, Debora Barton, Ramona F. Swaby, Amy Ronczka, Daniel J. Cushing, Sascha Abramson, Thomas Condamine, Michael Klichinsky, E. Claire Dees. A phase 1, first in human (FIH) study of autologous anti-HER2 chimeric antigen receptor macrophages (CAR-M) in HER2-overexpressing solid tumors (ST) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT524.

Atezolizumab with chemotherapy has shown improved progression-free and overall survival in patients with metastatic PD-L1 positive triple negative breast cancer (TNBC). Atezolizumab with anthracycline- and taxane-based neoadjuvant chemotherapy has also shown increased pathological complete response (pCR) rates in early TNBC. This trial evaluated neoadjuvant carboplatin and paclitaxel with or without atezolizumab in patients with clinical stages II-III TNBC. The co-primary objectives were to evaluate if chemotherapy and atezolizumab increase pCR rate and tumor infiltrating lymphocyte (TIL) percentage compared to chemotherapy alone in the mITT population. Sixty-seven patients (ages 25-78 years; median, 52 years) were randomly assigned - 22 patients to Arm A, and 45 to Arm B. Median follow up was 6.6 months. In the modified intent to treat population (all patients evaluable for the primary endpoints who received at least one dose of combination therapy), the pCR rate was 18.8% (95% CI 4.0-45.6%) in Arm A, and 55.6% (95% CI 40.0-70.4%) in Arm B (estimated treatment difference: 36.8%, 95% CI 8.5-56.6%; p = 0.018). Grade 3 or higher treatment-related adverse events occurred in 62.5% of patients in Arm A, and 57.8% of patients in Arm B. One patient in Arm B died from recurrent disease during the follow-up period. TIL percentage increased slightly from baseline to cycle 1 in both Arm A (mean ± SD: 0.6% ± 21.0%) and Arm B (5.7% ± 15.8%) (p = 0.36). Patients with pCR had higher median TIL percentages (24.8%) than those with non-pCR (14.2%) (p = 0.02). Although subgroup analyses were limited by the small sample size, PD-L1-positive patients treated with chemotherapy and atezolizumab had a pCR rate of 75% (12/16). The addition of atezolizumab to neoadjuvant carboplatin and paclitaxel resulted in a statistically significant and clinically relevant increased pCR rate in patients with clinical stages II and III TNBC. (Funded by National Cancer Institute).

PURPOSE Cancer-related cognitive impairment (CRCI) is common during adjuvant chemotherapy and may persist. TAILORx provided a novel opportunity to prospectively assess patient-reported cognitive impairment among women with early breast cancer who were randomly assigned to chemoendocrine therapy (CT+E) versus endocrine therapy alone (E), allowing us to quantify the unique contribution of chemotherapy to CRCI. METHODS Women with a 21-gene recurrence score of 11 to 25 enrolled in TAILORX were randomly assigned to CT+E or E. Cognitive impairment was assessed among a subgroup of 552 evaluable women using the 37-item Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) questionnaire, administered at baseline, 3, 6, 12, 24, and 36 months. The FACT-Cog included the 20-item Perceived Cognitive Impairment (PCI) scale, our primary end point. Clinically meaningful changes were defined a priori and linear regression was used to model PCI scores on baseline PCI, treatment, and other factors. RESULTS FACT-Cog PCI scores were significantly lower, indicating more impairment, at 3, 6, 12, 24, and 36 months compared with baseline for both groups. The magnitude of PCI change scores was greater for CT+E than E at 3 months, the prespecified primary trial end point, and at 6 months, but not at 12, 24, and 36 months. Tests of an interaction between menopausal status and treatment were nonsignificant. CONCLUSION Adjuvant CT+E is associated with significantly greater CRCI compared with E at 3 and 6 months. These differences abated over time, with no significant differences observed at 12 months and beyond. These findings indicate that chemotherapy produces early, but not sustained, cognitive impairment relative to E, providing reassurance to patients and clinicians in whom adjuvant chemotherapy is indicated to reduce recurrence risk.

Background: The addition of CDK4/6, PI3K-α, or mTOR inhibitors to endocrine therapy (ET) improves progression free survival (PFS) in first and later lines of therapy for estrogen receptor positive (ER+), HER2-negative metastatic breast cancer (MBC). We hypothesized that simultaneous inhibition of these pathways would improve treatment efficacy. We conducted a phase Ib study of triplet therapy with gedatolisib (G), a dual inhibitor of PI3K/mTOR, palbociclib (P) a CDK4/6 inhibitor, and ET with letrozole (L) or fulvestrant (F) in women with ER+/HER2-negative MBC. Manageable toxicity and preliminary antitumor activity were observed in 35 patients enrolled on the dose escalation portion of the study (ASCO 2018). We now report results from the dose expansion study arms. Methods: Patients with ER+/HER2- MBC were treated in four-arms: A) G+P+L as first-line treatment, B) G+P+F as 2-line treatment in patients without prior CDK4/6 inhibitor therapy; C) G+P+F in patients with prior CDK4/6 inhibitor therapy; D) G+P+F in patients whose most recent regimen included a CDK4/6 inhibitor. Palbociclib, letrozole and fulvestrant were administered at standard doses. Gedatolisib 180 mg was intravenously administered weekly in Arms A, B, and C and three weeks on/one week off in Arm D. Pre-/peri-menopausal women received ovarian suppression. The primary endpoint was objective response assessed by the investigator. Secondary endpoints included safety, duration of response (DOR), and PFS.Results: A total of 103 patients were enrolled: Arm A (n=31); Arm B (n=13); Arm C (n=32); Arm D (n=27). Median age was 54, 62, 59.5, and 59 years in each arm respectively. Progressed on last line of endocrine therapy in < 6 months (refractory): Arms B: 4/13 (31%), Arm C: 15/32 (47%), Arm D: 7/27 (26%). ORR in evaluable patients, including unconfirmed responses: 84%; 75%, 33% and 64%. Median PFS (months) was not reached in Arm A, and for arms B, C and D was 11.9, 5.1, 12.9 respectively. Most common (≥50%), treatment emergent adverse events (TEAE) across all arms were: nausea 81.6% (all Gr1-2, no ≥Gr3), stomatitis 80.6% (27.2% Gr3), fatigue 79.6% (10.7% Gr3), vomiting 51.5 % (1% Gr3), neutropenia/neutrophil count decrease 79.6% (66.7% ≥Gr3). Most common (≥2%) treatment emergent SAEs were febrile neutropenia 4.9%, acute kidney injury and pyrexia 2.9% each. Hyperglycemia was reported in 26.2% (6.8% ≥Gr3) of patients regardless of relation to treatment. Most common reason for treatment discontinuation was disease progression.; 8.7% (9 out of 103) patients discontinued therapy due to a related AE across all arms. No treatment discontinuation due to TEAE and no SAE of stomatitis were observed in Arm D. Seventeen patients are continuing therapy at the time of data cut of May 10, 2021.Conclusions: The addition of Gedatolisib to palbociclib and endocrine therapy demonstrated promising antitumor activity in both first and later line settings for ER+ MBC that compared favorably to historical controls. Responses were also observed in patients refractory to the last treatment. Therapy was well tolerated with manageable toxicity and low number of treatment discontinuation due to related AE. The favorable safety profile and antitumor activity observed in patients treated with the three weeks on/one week off gedatolisib regimen supports use of this dosing schedule in future studies. A phase 3 study evaluating gedatolisib in patients with ER+/HER2- MBC is planned. Table 1.Arm A, n=31Arm B, n=13Arm C, n=32Arm D, n=27EfficacyEvaluable for response25122725ORR in evaluable patients84% (21/25)75% (9/12)33% (9/27)64% (16/25)DCR (CR, PR, SD)92%92%48%85%Treatment DiscontinuationAll64.5% (20/31)76.9% (10/13)100% (32/32)85.2% (23/27)PD/general deterioration38.7% (12/31)61.5% (8/13)75% (24/32)70.4% (19/27)TEAE (related)9.7% (3/31)7.7% (1/13)12.5% (4/32)3.7% (1/27)Stomatitis3.2% (1/31)7.7% (1/13)9.4% (3/32)0TEAE (not related)07.7% (1/13)00Withdrew9.7% (3/31)012.5% (4/32)0Other6.5% (2/31)0011.1% (3/27)Treatment Emergent SAEAll22.6% (7/31)30.8% (4/13)21.9% (7/32)14.8% (4/27)Stomatitis3.2% (1/31)000 Citation Format: Rachel Layman, Robert Wesolowski, Hyo Han, Jennifer M Specht, Erica M Stringer-Reasor, E. Claire Dees, Peter Kabos, Ingrid A Mayer, Ulka Vaishampayan, Janice Lu, Keerthi Gogineni, Aditya Bardia, Anne F Schott, Maysa Abu-Khalaf, Doug Howkins, Brian Sullivan, Igor Gorbatchevsky, Hope Rugo. Phase Ib expansion study of gedatolisib in combination with palbociclib and endocrine therapy in women with ER+ metastatic breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD13-02.

We report the results from a phase I study of buparlisib, an oral pan-class I phosphotidyinositol-3-kinase inhibitor, combined with capecitabine in patients with metastatic breast cancer. The maximum tolerated dose of the combination was buparlisib 100 mg daily and capecitabine 1000 mg/m(2) twice daily. A complete response was seen in 1 patient with a basal-like tumor. Pharmacokinetic analysis suggested that a pharmacokinetic interaction might exist between the 2 agents. BACKGROUND: Buparlisib is an oral pan-class I phosphotidyinositol-3-kinase (PI3K) inhibitor. The present phase I study evaluated the safety, pharmacokinetics, and efficacy of buparlisib with capecitabine in patients with metastatic breast cancer. PATIENTS AND METHODS: Patients received buparlisib once daily (range, 50 to 100 mg) for 3 weeks with capecitabine twice daily (range, 1000 to 1250 mg/m(2)) for 2 weeks with a 1-week break. Dose escalation used a traditional “3 + 3” design with standard definitions of dose-limiting toxicity (DLT) and maximum tolerated dose. RESULTS: Of the 25 patients enrolled, 23 were evaluable for DLT and 17 were evaluable for response. The maximum tolerated dose of the combination was buparlisib 100 mg daily and capecitabine 1000 mg/m(2) twice daily. DLTs included grade 3 hyperglycemia and grade 3 confusion. The most common grade 3 toxicities were diarrhea and elevation of aspartate aminotransferase and alanine transaminase. One patient exhibited a complete response to treatment and four had a confirmed partial response. In cohorts 3 and 4, in which the buparlisib dose remained constant but the capecitabine dose was increased, significant increases in the buparlisib plasma concentration were noted. CONCLUSION: The combination of buparlisib with capecitabine in patients with metastatic breast cancer was generally well-tolerated, with several patients demonstrating prolonged responses. Unexpectedly low rates of PIK3CA mutations (3 of 17) were seen, and only 2 of 7 tumors with subtyping were luminal, making exploration of these putative predictive markers impossible. Further study of the combination is not unreasonable, with expanded pharmacokinetics and sequencing analysis to better elucidate potential drug–drug interactions and more accurate predictive biomarkers of response.

Background Given the wide adoption of human epidermal growth factor receptor 2 (HER2)-targeted therapies for advanced HER2–positive breast cancer, we studied the natural history of patients with HER2–positive breast cancer brain metastases (BCBM) over time. Patients and Methods Patients with HER2–positive BCBM identified from a prospectively maintained database at the University of North Carolina were divided into 3 cohorts by year of BCBM diagnosis. Cohorts were selected by year of HER2–targeted therapy US Food and Drug Administration approval. Overall survival (OS), time to first metastasis, time to BCBM, and BCBM survival were estimated by the Kaplan-Meier method. Associations between OS after BCBM and clinical variables were assessed by Cox proportional hazards regression models. Results One hundred twenty-three patients were identified. Median age was 51 years, and 58% were white and 31% African American. OS from initial breast cancer diagnosis improved over time: 3.6 years (95% confidence interval [CI], 2.8-6.1) in the 1998-2007 cohort, 6.6 years (95% CI, 4.5-8.6) in the 2008-2012 cohort, and 7.6 years (95% CI, 4.4-9.6) in the 2013-2015 cohort (P = .05). While time from initial diagnosis to first metastasis did not differ (P = .12), time to BCBM increased over time (2.6 years [95% CI, 1.3-3.5] for 1998-2007; 2.6 years [95% CI, 2.1-4.3] for 2008-2012, and 3.3 years [95% CI, 2.2-6] for 2013-2015; P = .05). Although OS from BCBM did not significantly differ by cohort, patients who received HER2–targeted therapy after BCBM had a prolonged OS (2.1 years [95% CI, 1.6-2.6] vs. 0.65 years [95% CI, 0.4-1.3]; P = .001). Conclusion OS from initial breast cancer diagnosis significantly improved over time for patients with HER2–positive breast cancer who develop BCBM, now exceeding 7 years; survival from BCBM diagnosis may now exceed 2 years.

Background: Rintodestrant is an orally bioavailable, potent and selective estrogen receptor degrader (SERD) that inhibits estrogen receptor (ER) gene transcription, degrades the ER, and delays tumor proliferation in preclinical models. Preliminary results from Part 1 dose escalation (200-1000 mg once daily) demonstrated that rintodestrant has a favorable safety profile and encouraging antitumor activity in patients (pts) with heavily pretreated ER+/HER2- advanced breast cancer (ABC) (Dees et al., ESMO 2019 [abstract #3587]). Here, we report the pharmacodynamic (PD) analysis in peripheral blood and tumor biopsies from pts who received rintodestrant in Part 1 and 2 (600 and 1000 mg dose expansion) to characterize the pt population and mechanisms of response. Methods: This Phase 1, first-in-human, open-label study evaluated rintodestrant in women with ER+/HER- ABC after progression on endocrine therapy. PD analysis included inhibition of ER target engagement with 18F-fluoroestradiol positron emission tomography (FES-PET), mutational profiling (cell-free DNA [cfDNA]), and circulating tumor cell (CTC) enumeration. Tumor biopsies sampled at baseline and 6 weeks on treatment were evaluated for ER degradation (immunohistochemistry [IHC]) and proliferation (Ki67, IHC) to understand the on-target effects of rintodestrant. Results: As of May 13, 2020, 67 pts had been treated. FES-PET data were obtained in 14 pts and showed a decrease in all pts, with maximum standard uptake values (SUVmax) ranging from 70% to 98% after 4 weeks of rintodestrant monotherapy across all doses. Fifty-nine pts were tested for cfDNA at baseline; 95% (n = 56) harbored ≥1 somatic variant (median = 3 mutations per pt). Among pts with somatic variants, 41% had ESR1 mutations, with D538G being the most common (58%). Additionally, 46% and 42% of pts harbored mutations in TP53 and PIK3CA, respectively, and 10% had mutations in both ESR1 and PIK3CA. Similar clinical benefit rates were observed in wild-type vs ESR1 and/or PIK3CA mutant tumors. An analysis of change of variant allele fraction (VAF) in 55 pts between baseline and 2 weeks of treatment revealed that 58% had a decrease in mean VAF, with a decrease in ESR1 VAF in 16/20 pts that had ESR1 mutations at baseline. Furthermore, of 24 pts who had samples collected at baseline and progression, 16 (67%) developed additional variants (median [range]: 2 [1, 15]), including EGFR, ERBB2, TP53, and ESR1. CTC analysis (n = 45) showed the mean value of Epi+CD45- CTCs decreased from 2.8 cells/mL to 1.8 cells/mL after 8 weeks of treatment. Tumor biopsies were collected in 9 pts (5 received 600 mg and 4 received 1000 mg) at baseline and 6 weeks on treatment. Of the 7/9 pts that had a decrease in the ER H-score (median [range]: -27.8% [-33.8%, -3.4%]), 4 had ≥1 variant in ESR1 at baseline. Overall, 4 pts had a decrease in Ki67, with reductions mostly observed in pts who received 600 mg rintodestrant. Additional analyses, including correlations with clinical response, are ongoing and will be presented. Conclusions: Rintodestrant demonstrated robust ER target engagement on FES-PET, as well as substantial decreases in ER H-score, cfDNA VAF, and Epi+CD45- CTCs. These data, along with promising clinical benefit in pts with heavily pretreated ER+/HER2- ABC, regardless of ESR1 or PIK3CA mutation status, warrant additional investigation of rintodestrant (NCT03455270). Citation Format: Philippe Aftimos, Marina Maglakelidze, Andor WJM Glaudemans, Erika Hamilton, Linnea Chap, Elisabeth de Vries, Catharina Willemien Menke-van der Houven van Oordt, Agnes Jager, E. Claire Dees, Massimo Cristofanilli, Mark Pegram, Susanna Ulahannan, Patrick Neven, Iurie Bulat, Ruhi Rai, Wenli Tao, Sarika Jain, Andrew P Beelen, Jessica A Sorrentino. Pharmacodynamic analysis from a phase 1 study of rintodestrant (G1T48), an oral selective estrogen receptor degrader, in ER+/HER2- locally advanced or metastatic breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD8-07.

Since November 2017, the University of North Carolina (UNC) Brain Tumor Program has performed next generation sequencing (NGS) on newly diagnosed brain tumors through the Strata Trial, which uses the StrataNGS assay to evaluate genomic variants in 94 genes. Brain tumors were analyzed from 77 patients revealing 137 total molecular alterations. We defined actionable alterations as: (1) revealing potential enrollment into biomarker-driven clinical trials (regardless of histology); (2) allowing for off-label use of targeted therapy; (3) identifying occult and non-canonical alterations that lead to changes in prognosis and management. At UNC we’ve identified 26 brain tumors with actionable alterations (34%), and 18 brain tumors (23%) eligible for a nationally-available biomarker-driven trial. These results have provided useful data to inform feasibility of biomarker-driven clinical trials using targeted therapies to treat brain tumor patients seen at UNC. Furthermore, NGS of brain tumors has allowed us to utilize precision medicine in a population of patients with very few treatment options. In particular, we’ve exploited a BRAF V600E mutation to treat progressive glioblastoma (GBM) with BRAF-targeting agents. The patient rapidly responded to therapy and recovered functionality previously lost while on standard of care therapy. Additionally, NGS identified 1 GBM and 2 anaplastic astrocytoma (AA) patients with MET alterations, which are uncommon in high grade gliomas. Two of these patients enrolled in a biomarker-driven clinical trial at UNC, which would not have been possible without NGS. The patient with GBM has maintained disease control for over 6 months. Our experiences highlight the importance of routine NGS in the management of patients with brain tumors.

Introduction: The PD-1 receptor-ligand pathway can be used by tumors to evade immune surveillance, thereby allowing neoplastic growth. Pembrolizumab is a highly selective, humanized IgG4/kappa isotype mAb designed to block PD-1 interaction with its ligands PD-L1 and PD-L2, thereby reactivating the immune system to eradicate tumors. Methods: This is a multi-center, non-randomized trial of single agent MK-3475 treatment given intravenously at 10 mg/kg every 2 weeks, in patients with recurrent/metastatic triple-negative (ER, PR, and HER2 negative) breast cancer (TNBC). PD-L1 expression in tumor or stroma was required for study entry. PD-L1 status was determined by immunohistochemical analysis of patient’s tumor tissues using the Merck proprietary 22C3 antibody. Primary objectives of this study were to determine the safety, tolerability, and anti-tumor activity of MK-3475 in patients with PD-L1 positive, advanced TNBC. Secondary objectives included assessments of progression-free survival, overall survival, and response duration. Adverse events (AEs) reported in any patient receiving at least 1 dose of study treatment were monitored and graded using NCI CTCAE v. 4.0. Radiographic imaging was obtained every 8 weeks and evaluated by both investigator and an independent radiologist to assess clinical responses as defined by RECIST 1.1. This study (Clinicaltrials.gov: NCT01848834) is being conducted in conformance with Good Clinical Practices. Results: A total of 32 female patients with a median age of 50.5 years (range 29 – 72 years) with PD-L1 positive, recurrent/metastatic TNBC were enrolled in the study. Most of these patients had received and progressed on multiple lines of therapy for advanced disease. A preliminary analysis of data collected as of 23May2014 indicates that 5 patients (15.6%) experienced at least one drug-related serious adverse event (SAE); each of 4 patients experienced one of the following: Grade 3 anemia, headache, aseptic meningitis or pyrexia, and a fifth patient experienced disseminated intravascular coagulation (DIC) with thrombocytopenia and decreased blood fibrinogen. The patient who experienced DIC died. Preliminary analysis of data collected from investigators as of 23May2014 indicates that no patient had a complete response, 16.1% of patients had a partial response, 9.7% had stable disease, and 64.5% had progressive disease. As of 23May2014, all but one of the responders, in addition to three patients with stable disease, remain on treatment. Conclusion: This is the first report of clinical activity of an immune checkpoint inhibitor in TNBC. The preliminary results from this study suggest that single agent MK-3475 is a well-tolerated and effective treatment with significant therapeutic activity in a subset of heavily pre-treated patients with recurrent/metastatic triple-negative breast cancer. Citation Format: Rita Nanda, Laura Q Chow, E Claire Dees, Raanan Berger, Shilpa Gupta, Ravit Geva, Lajos Pusztai, Marisa Dolled-Filhart, Kenneth Emancipator, Edward J Gonzalez, Jennifer Houp, Kumudu Pathiraja, Vassiliki Karantza, Robert Iannone, Christine K Gause, Johnathan D Cheng, Laurence Buisseret. A phase Ib study of pembrolizumab (MK-3475) in patients with advanced triple-negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S1-09.

Summary Background Alisertib is an investigational, oral, selective inhibitor of aurora kinase A. We aimed to investigate the safety and activity of single-agent alisertib in patients with predefined types of advanced solid tumours. Methods We did a multicentre phase 1/2 study at 40 centres in four countries (Czech Republic, France, Poland, and the USA). Here, we report results from phase 2; enrolment for the study began on Feb 16, 2010, and ended on May 3, 2013. Adult patients were eligible for the study if they had either breast cancer, small-cell lung cancer, non-small-cell lung cancer, head and neck squamous-cell carcinoma, or gastro-oesophageal adenocarcinoma that had relapsed or was refractory to chemotherapy. Patients had to have undergone two or fewer previous cytotoxic regimens (four or fewer for breast cancer patients), not including adjuvant or neoadjuvant treatments. Enrolment followed a two-stage design: to proceed to the second stage, two or more objective responses were needed in the first 20 response-assessable patients in each of the five tumour cohorts. Alisertib was administered orally in 21-day cycles at the recommended phase 2 dose of 50 mg twice daily for 7 days followed by a break of 14 days. The protocol-specified primary endpoint was the proportion of patients with an objective response, assessed by Response Evaluation Criteria In Solid Tumors version 1.1 in the response-assessable population (ie, patients with measurable disease who received at least one dose of alisertib and had undergone at least one post-baseline tumour assessment). This completed trial is registered with ClinicalTrials.gov, NCT01045421. Findings By May 31, 2013, 249 patients had been treated, 53 with breast cancer, 60 with small-cell lung cancer, 26 with non-small-cell lung cancer, 55 with head and neck squamous-cell carcinoma, and 55 with gastro-oesophageal adenocarcinoma. Among response-assessable patients, an objective response was noted in nine (18%, 95% CI 9−32) of 49 women with breast cancer, ten (21%, 10−35) of 48 participants with small-cell lung cancer, one (4%, 0−22) of 23 patients with non-small-cell lung cancer, four (9%, 2−21) of 45 people with head and neck squamous-cell carcinoma, and four (9%, 2−20) of 47 individuals with gastro-oesophageal adenocarcinoma; all were partial responses. Adverse events were similar across tumour types. The most frequent drug-related grade 3–4 adverse events included neutropenia (n=107 [43%]), leukopenia (53 [21%]), and anaemia (26 [10%]). Serious drug-related adverse events were reported in 108 (43%) patients. Interpretation These data support further clinical assessment of alisertib in patients with solid tumours, particularly those with breast cancer and small-cell lung cancer. Funding Millennium Pharmaceuticals, Inc, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited.

Cytotoxic chemotherapies have a narrow therapeutic window, with high peaks and troughs of plasma concentration. Novel nanoparticle formulations of cytotoxic chemotherapy drugs can enhance pharmacokinetic characteristics and facilitate passive targeting of drugs to tumors via the enhanced permeability and retention effect, thus mitigating toxicity. Nanoparticle vehicles currently in clinical use or undergoing clinical investigation for anticancer therapies include liposomes, polymeric micelles, protein-drug nanoparticles, and dendrimers. Multiple nanoparticle formulations of existing cytotoxic chemotherapies are approved for use in several indications, with clinical data indeed showing optimization of pharmacokinetics and different toxicity profiles compared with their parent drugs. There are also many new nanoparticle drug formulations in development and undergoing early- and late-phase clinical trials, including several that utilize active targeting or triggered release based on environmental stimuli. Here, we review the rationale for nanoparticle formulations of existing or previously investigated cytotoxic drugs, describe currently approved nanoparticle formulations of drugs, and discuss some of the most promising clinical trials currently underway.

Purpose LCL161 antagonizes the function of inhibitor of apoptosis proteins (IAPs), thereby promoting cancer cell death. This first-in-human dose-escalation study assessed the maximum-tolerated dose (MTD), safety, pharmacokinetics, and pharmacodynamics of LCL161 in patients with advanced solid tumors. A second part of the study assessed the relative bioavailability of a tablet versus solution formulation. Patients and Methods LCL161 was administered orally, once weekly, on a 21-day cycle to adult patients with advanced solid tumors by using an adaptive Bayesian logistic regression model with overdose control–guided dose escalation. Results Fifty-three patients received at least one dose of LCL161 (dose range, 10 to 3,000 mg). LCL161 was well tolerated at doses up to 1,800 mg. Cytokine release syndrome (CRS) was the only dose-limiting toxicity (in three [6%] of 53 patients) and was the most common grades 3 to 4 event (in five [9%] of 53 patients). Vomiting, nausea, asthenia/fatigue, and anorexia were common but not severe. Although the MTD was not formally determined, an 1,800-mg dose was selected in compliance with the protocol for additional study, given the dose-limiting CRS at higher doses and pharmacodynamic activity at lower doses. LCL161 was rapidly absorbed, and exposure was generally increased with dose. The tablet formulation of LCL161 was better tolerated than the solution; tablet and solution formulations had similar exposures, and the solution was discontinued. No patient had an objective response. LCL161 induced degradation of cellular IAP1 protein in the blood, skin, and tumor and increased circulating cytokine levels. Conclusion The 1,800-mg dose of LCL161, administered as a single agent once weekly, in tablet formulation is the recommended dose for additional study. This combined dose and formulation was well tolerated and had significant pharmacodynamic activity, which warrants additional investigation.

Withdrawn by Author Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-12-02.

The complex nature of the pharmacologic aspects of cancer therapeutics has become more apparent in the past several years with the arrival of a cascade of target-based agents and the difficult challenge of bringing individualized precision medicine to oncology. Interpatient variability in drug action, singularly in novel agents, is in part caused by pharmacogenomic (PG), pharmacokinetic, and pharmacodynamic (PD) factors, and drug selection and dosing should take this into consideration to optimize the benefit for our patients in terms of antitumor activity and treatment tolerance. In this regard, somatic genetic evaluation of tumors is useful in not only predicting response to initial targeted therapies but also in anticipating and guiding therapy after the development of acquired resistance; therapeutic drug monitoring of novel small molecules and monoclonal antibodies must be incorporated in our day-to-day practice to minimize the negative effect on clinical outcome of interindividual variability on pharmacokinetic processes of these drugs for all patients, but especially for fragile patient populations and those with organ dysfunction or comorbidities. For these populations, incorporating frailty assessment tools into trials of newer agents and validating frailty-based dose adjustment should be an important part of further drug development.

BACKGROUND Therapy for acute myeloid leukemia (AML) has largely remained unchanged, and outcomes are unsatisfactory. We sought to analyze outcomes of AML patients enrolled in phase I studies to determine whether overall response rates (ORR) and mortality rates have changed over time. METHODS A retrospective analysis was performed on 711 adult AML patients enrolling in 45 phase I clinical trials supported by the Cancer Therapy Evaluation Program of the National Cancer Institute from 1986 to 2009. Changes in ORR and mortality rates for patients enrolled in 1986 to 1990, 1991 to 1995, 1996 to 2000, 2001 to 2005, and 2006 to 2009 were estimated with multivariable logistic regression models. All statistical tests were two-sided. RESULTS There was a statistically significant increase in AML patients enrolling in phase I clinical trials over time (1986 to 1990: n = 61; 2006 to 2009: n = 256; P = .03). The ORR for the entire cohort was 15.4% (1986 to 1990: 8.9%, 1991 to 1995: 21.1%; 1996 to 2000: 7.0%; 2001 to 2005: 10.0%; 2006 to 2009: 22.6%), and it statistically significantly improved over time (P < .001). There was a statistically significant improvement in ORRs with novel agents in combination vs single agents (ORR = 22.8% vs 4.7%, respectively, odds ratio = 5.95, 95% confidence interval = 3.22 to 11.9, P < .001). The 60-day mortality rate for the entire cohort was 22.6%, but it statistically significantly improved over time (P = .009). CONCLUSIONS There has been an encouraging increase in AML patients enrolling in phase I clinical studies over time. The improvement in ORRs appears to be partly because of the increase in combination trials and the inclusion of previously untreated poor-risk AML. Continued enrollment of AML patients in early phase clinical trials is vital for drug development and improvement in therapeutic outcomes.

This multicenter, open-label phase II study was conducted to evaluate sunitinib monotherapy in patients with either metastatic or locoregionally recurrent advanced breast cancer. Patients received sunitinib 37.5 mg on a continuous daily dosing schedule. The primary endpoint was objective response rate (ORR); the predefined target ORR was 25 %. All 83 patients enrolled into the study received study treatment. The majority of patients (90 %) had metastatic disease; 92 % had received prior systemic therapies, and 60 % had received two or more regimens for early and/or advanced disease. The ORR was 8 % (95 % exact CI, 4-17), comprising seven partial responses. In patients with superficial lesions (defined as cutaneous or palpable chest wall lesions), the ORR was 20 % (three of 15 evaluable patients), which was higher than that in patients with non-superficial disease (9 %; six of 64 patients). Median progression-free survival in the overall population was 3.6 months (95 % CI, 2.4-3.9); median overall survival was 15.6 months (95 % CI, 14.0-22.7). No new or unexpected safety findings were reported. The most commonly reported adverse events (AEs) were fatigue (60 %), diarrhea (54 %), and nausea (49 %). The most commonly reported grade 3/4 AEs were fatigue (17 %), neutropenia (16 %), and thrombocytopenia (11 %). Four patients (5 %) had a dose reduction due to an AE, and 39 patients (47 %) had temporary discontinuations of therapy due to AEs. Two on-study deaths were reported, one due to a pulmonary embolism (considered related to treatment) and one attributed to dyspnea and a myocardial infarction (considered unrelated to treatment). Patient-reported outcomes suggested that sunitinib treatment did not have a negative impact overall on patients' functional domains or the majority of symptom scales. The trial did not meet its prespecified primary endpoint, and in view of the negative results obtained in several other trials, sunitinib will not be developed further for this indication.

Purpose. This phase I study assessed the toxicity and safety of combining daily lapatinib with radiation therapy. Sequential tumor biopsies were obtained to evaluate changes in biomarkers, such as epidermal growth factor receptor (EGFR) and human EGFR-2 (HER2) signaling pathways. Methods. Eligibility for this dose-escalation study included unresectable and locally recurrent or chemotherapy-refractory and locally advanced breast cancer, and adequate organ function. Patients underwent three serial biopsies: at baseline, after 1 week of lapatinib alone, and after 1 week of lapatinib and radiation. Endpoints included determination of toxicity, maximum tolerated dose, and analysis of the effect of lapatinib with or without radiation on EGFR and HER2 signaling pathways by immunohistochemistry. Results. Doses of lapatinib up to 1,500 mg/day were well tolerated. Toxicity of grade 3 or more was limited to radiation dermatitis and pain. Out of 19 patients treated, in field responses per Response Evaluation Criteria in Solid Tumors criteria were complete in four patients and partial in six patients. Serial biopsies were obtained in 16 patients with no complications. Total Her2 was relatively unchanged while phospho-Her2, phospho-Akt, and phospho-ERK showed variable responses to both lapatinib alone and dual therapy with lapatinib and radiation. Conclusions. The combination of lapatinib and radiation was well tolerated in this patient cohort. Overall local response rates were comparable to those reported in other studies in this patient population. Biopsies were safely performed at all time points. Inhibition of HER2 and downstream signaling pathways was identified, although no strong correlation with response was seen.

Purpose: This phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of the investigational oral drug MLN8237 (alisertib), a small-molecule Aurora A kinase (AAK) inhibitor, in 87 adult patients with advanced solid tumors. Experimental Design: Sequential cohorts of patients received MLN8237 5 to 150 mg orally once daily or twice daily for 7, 14, or 21 days, followed by 14 days' rest per cycle. MLN8237 pharmacokinetics was characterized, and the relative bioavailability of an enteric-coated tablet (ECT) formulation was evaluated in reference to the original powder-in-capsule (PIC) formulation. Pharmacodynamic effects of MLN8237 on inhibition of AAK activity were evaluated in skin biopsies. Tolerability and response to treatment were assessed. Results: Common toxicities included fatigue, nausea, and neutropenia. Plasma exposures increased dose proportionally (5–150 mg/d), and were similar for PIC and ECT. The terminal half-life was 23 hours. At the maximum tolerated dose of 50 mg twice daily on the 7-day schedule, the mitotic index of the skin basal epithelium was increased within 24 hours after MLN8237 administration on days 1 and 7, a finding consistent with AAK inhibition. One (1%) patient achieved a partial response lasting for more than 1 year and received MLN8237 for 51 cycles; 20 (23%) patients achieved stable disease for ≥3 months. Conclusions: This first-in-human trial of MLN8237 showed tolerability and favorable pharmacokinetics in this patient population. The recommended phase II dose of MLN8237 is 50 mg twice daily orally for 7 days in 21-day cycles, which is being evaluated further in the treatment of various solid tumors and hematologic malignancies. Clin Cancer Res; 18(17); 4775–84. ©2012 AACR.

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate comprised of trastuzumab and the cytotoxic agent DM1 (derivative of maytansine) linked by a stable linker N-succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC). T-DM1 targets an epitope located at subdomain IV of human epidermal growth factor receptor 2 (HER2). Pertuzumab is a monoclonal antibody that targets an epitope located at subdomain II of HER2, distinct from the epitope recognized by T-DM1. The pharmacokinetics (PK), safety, and efficacy of T-DM1 combined with pertuzumab were studied in a phase 1b/2 trial in 67 patients with HER2-positive, locally advanced or metastatic breast cancer (MBC). The therapeutic protein-drug interaction (TP-DI) potential of T-DM1 plus pertuzumab was evaluated. The PK of T-DM1-related analytes and pertuzumab were compared with historical PK data. The results show that the exposure of T-DM1 and DM1, as estimated by noncompartmental analyses, was comparable with that reported by historical single-agent studies in patients with HER2-positive MBC. T-DM1 clearance and volume of distribution in the central compartment, as estimated by population PK analysis, were also comparable between this study and historical single-agent studies in patients with HER2-positive MBC. Summary statistics of pertuzumab trough and maximal exposure (concentrations at predose and 15-30 minutes after the end of infusion at cycle 1 and at steady state) were similar with those observed in a representative historical single-agent study with the same dosing regimen. The visual predictive check plot by population simulation further confirmed that T-DM1 did not alter pertuzumab PK. Based on these data and the PK and pharmacodynamic properties of T-DM1 and pertuzumab, the risk of TP-DI appears to be low when T-DM1 and pertuzumab are given together.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Paclitaxel and rosiglitazone are primarily metabolized by CYP2C8 and their in vitro metabolism by human liver microsomes is correlated. Probe assays that quantify the in vivo activity of CYP enzymes which are important in drug metabolism have been developed for use in clinical pharmacology research. A probe of CYP2C8 that is easy to administer and interpret may be valuable for individualized dosing of paclitaxel. WHAT THIS STUDY ADDS • This pilot study demonstrates for the first time that there is an in vivo correlation between paclitaxel and rosiglitazone exposure. The finding, that a single rosiglitazone plasma concentration after oral dosing may explain significant variance in paclitaxel exposure, suggests that rosiglitazone may satisfy the requirements of a clinically useful in vivo probe. However, it is acknowledged that there is a need for further studies evaluating the use of rosiglitazone as a CYP2C8 probe and quantifying the relationship, in order to guide dosing of narrow therapeutic index drugs metabolized primarily by CYP2C8, such as paclitaxel. AIMS To evaluate the use of rosiglitazone and the erythromycin breath test (ERMBT), as probes of CYP2C8 and CYP3A4, respectively, to explain inter-individual variability in paclitaxel exposure. METHODS The concentration of rosiglitazone at 3 h and ERMBT results were included in a regression model to explain the variability in paclitaxel exposure in 14 subjects. RESULTS Rosiglitazone concentration was significantly correlated with paclitaxel exposure (P= 0.018) while ERMBT had no predictive value (P= 0.47). CONCLUSIONS The correlation between the exposure of rosiglitazone and paclitaxel likely reflects mutual dependence on the activity of CYP2C8. Rosiglitazone or similar agents may have value as in vivo probes of CYP2C8 activity.