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Purpose: Soft-tissue sarcomas (STS) are a rare, heterogeneous group of mesenchymal tumors. For decades the mainstay of treatment for advanced, unresectable STS has been palliative chemotherapy. High levels of activated MET receptor have been reported in various sarcoma cell lines, together with elevated vascular endothelial growth factor (VEGF) levels in patients with STS, suggesting that dual targeting of the VEGF and MET pathways with the multi-receptor tyrosine kinase inhibitor cabozantinib would result in clinical benefit in this population. Patients and Methods: We performed an open-label, multi-institution, single-arm phase II trial of single-agent cabozantinib in adult patients with advanced STS and progressive disease after at least 1 standard line of systemic therapy. Patients received 60 mg oral cabozantinib once daily in 28-day cycles, and dual primary endpoints of overall response rate and 6-month progression-free survival (PFS) were assessed. Changes in several circulating biomarkers were assessed as secondary endpoints. Results: Six (11.1%; 95% CI, 4.2%–22.6%) of the 54 evaluable patients enrolled experienced objective responses (all partial responses). Six-month PFS was 49.3% (95% CI, 36.2%–67.3%), with a median time on study of 4 cycles (range, 1–99). The most common grade 3/4 adverse events were hypertension (7.4%) and neutropenia (16.7%). Patients' levels of circulating hepatocyte growth factor (HGF), soluble MET, and VEGF-A generally increased after a cycle of therapy, while soluble VEGFR2 levels decreased, regardless of clinical outcome. Conclusions: Cabozantinib single-agent antitumor activity was observed in patients with selected STS histologic subtypes (alveolar soft-part sarcoma, undifferentiated pleomorphic sarcoma, extraskeletal myxoid chondrosarcoma, and leiomyosarcoma) highlighting the biomolecular diversity of STS.

Purpose: The Wee1 kinase inhibitor adavosertib abrogates cell-cycle arrest, leading to cell death. Prior testing of twice-daily adavosertib in patients with advanced solid tumors determined the recommended phase II dose (RPh2D). Here, we report results for once-daily adavosertib. Patients and Methods: A 3 + 3 dose-escalation design was used, with adavosertib given once daily on days 1 to 5 and 8 to 12 in 21-day cycles. Molecular biomarkers of Wee1 activity, including tyrosine 15–phosphorylated Cdk1/2 (pY15-Cdk), were assessed in paired tumor biopsies. Whole-exome sequencing and RNA sequencing of remaining tumor tissue identified potential predictive biomarkers. Results: Among the 42 patients enrolled, the most common toxicities were gastrointestinal and hematologic; dose-limiting toxicities were grade 4 hematologic toxicity and grade 3 fatigue. The once-daily RPh2D was 300 mg. Six patients (14%) had confirmed partial responses: four ovarian, two endometrial. Adavosertib plasma exposures were similar to those from twice-daily dosing. On cycle 1 day 8 (pre-dose), tumor pY15-Cdk levels were higher than baseline in four of eight patients, suggesting target rebound during the day 5 to 8 dosing break. One patient who progressed rapidly had a tumor WEE1 mutation and potentially compensatory PKMYT1 overexpression. Baseline CCNE1 overexpression occurred in both of two responding patients, only one of whom had CCNE1 amplification, and in zero of three nonresponding patients. Conclusions: We determined the once-daily adavosertib RPh2D and observed activity in patients with ovarian or endometrial carcinoma, including two with baseline CCNE1 mRNA overexpression. Future studies will determine whether CCNE1 overexpression is a predictive biomarker for adavosertib.

Background: TRC102 binds to abasic sites in DNA, inhibiting the base excision repair (BER) pathway, which is implicated in resistance to alkylating agents. Preclinical xenograft studies in mice demonstrated a synergistic anti-tumor effect when TRC102 was combined with alkylating agents. TRC102 given in combination with temozolomide in a phase 1 trial demonstrated acceptable toxicity and antitumor activity in patients (pts) with colorectal cancer (CRC), non-small cell lung cancer (NSCLC, squamous cell carcinoma) and granulosa cell ovarian cancer (Oncotarget 2020). Pharmacodynamic (PD) analysis revealed treatment-induced induction of nuclear Rad51 signal, indicating DNA damage repair (DDR) response and tumor biopsy data indicated MGMT methylation correlated with tumor response in CRC (Cancer Cell, 2020). Here we report data from a phase II expansion cohort of this combination in pts with NSCLC. Methods: We conducted a single arm open label trial in a pt cohort with advanced NSCLS, who had received at least one line of therapy in the metastatic setting. Pts who received immunotherapy (ICI) and/or molecularly targeted therapy were eligible. Pts received 125 mg TRC102 (100 mg for BSA < 1.6) and 150 mg/m2 TMZ given orally daily for days 1-5 of 28-day cycle (C). Restaging CT scans were carried out after every 2 C and evaluated using RECIST 1.1. Blood from all pts was analyzed for circulating tumor cells (CTCs) at baseline and the beginning of each C. A two-stage design was employed, with at least 2 objective responses needed among the first 16 pts treated on study in order to proceed to the second stage. Results: Sixteen pts with NSCLC (12 adenocarcinoma, 4 squamous) were enrolled between 11/2016 and 6/2021; 12 men and 4 women, median age of 69 yrs (range 33-80), 1 Hispanic, 3 Asian, 2 Black/African American, and 10 Caucasian. Pts received a median of 3 prior lines of therapy (range 1-7), including ICI in all but 1 pt. Twelve pts were evaluable for response. Three pts experienced clinical progression before completing C 2, and 1 pt withdrew consent before completing C 2. Median number of Cs received by pts was 3 (range 1-14); 9 pts experience stable disease (SD) as best response lasting median of 12 wks (range 8-56 wks), and 4 pts experienced prolonged SD lasting greater than 6 Cs (24 wks). Treatment-related grade 3 adverse events reported include lymphopenia (4) and anemia (1). No grade 4 or 5 events were noted. Conclusion: TRC102 in combination with temozolomide was well tolerated with notable efficacy. Although no objective tumor responses were observed in this heavily pretreated population, 9 of 15 pts experienced SD, lasting ≥ 24 wks in 4 pts. Given the limited options for NSCLC treatment following ICI and TKI treatment, this regimen merits further evaluation. Analysis of CTCs is ongoing, as well as additional biomarker evaluation in other treatment cohorts. Funded by NCI Contract No. HHSN261200800001E Citation Format: Mohamad A. Salkeni, Geraldine O’Sullivan Coyne, Jennifer Zlott, Naoko Takebe, Ning Ma, Larry Rubinstein, Richard Piekarz, Jared Foster, Brandon Miller, Ralph Parchment, Abdul R. Naqash, Andrea Voth, James Doroshow, Alice Chen. Phase II trial of TRC102 (methoxyamine HCl) in combination with temozolomide (TMZ) in patients with advanced non-small cell lung cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P049.

Purpose Following promising responses to the DNA methyltransferase (DNMT) inhibitor 5-fluoro-2′-deoxycytidine (FdCyd) combined with tetrahydrouridine (THU) in phase 1 testing, we initiated a non-randomized phase 2 study to assess response to this combination in patients with advanced solid tumor types for which tumor suppressor gene methylation is potentially prognostic. To obtain pharmacodynamic evidence for DNMT inhibition by FdCyd, we developed a novel method for detecting expression of tumor suppressor protein p16/INK4A in circulating tumor cells (CTCs). Methods Patients in histology-specific strata (breast, head and neck [H&N], or non-small cell lung cancers [NSCLC] or urothelial transitional cell carcinoma) were administered FdCyd (100 mg/m2) and THU (350 mg/m2) intravenously 5 days/week for 2 weeks, in 28-day cycles, and progression-free survival (PFS) rate and objective response rate (ORR) were evaluated. Blood specimens were collected for CTC analysis. Results Ninety-three eligible patients were enrolled (29 breast, 21 H&N, 25 NSCLC, and 18 urothelial). There were three partial responses. All strata were terminated early due to insufficient responses (H&N, NSCLC) or slow accrual (breast, urothelial). However, the preliminary 4-month PFS rate (42%) in the urothelial stratum exceeded the predefined goal—though the ORR (5.6%) did not. An increase in the proportion of p16-expressing cytokeratin-positive CTCs was detected in 69% of patients evaluable for clinical and CTC response, but was not significantly associated with clinical response. Conclusion Further study of FdCyd + THU is potentially warranted in urothelial carcinoma but not NSCLC or breast or H&N cancer. Increase in the proportion of p16-expressing cytokeratin-positive CTCs is a pharmacodynamic marker of FdCyd target engagement.

Background: NCI ALMANAC, a systematic in vitro combination drug screen study, identified greater-than-additive activity for the combination of the proteasome inhibitor bortezomib and the nucleoside analog clofarabine. The combination also yielded strong, greater-than-single-agent activity in human tumor xenograft models. Our preclinical findings postulate that the activity of this drug pair may be due to modulation of DNA damage and the intrinsic apoptotic cascade. In an ongoing phase I trial, we evaluate the safety and activity of bortezomib and clofarabine in refractory solid tumors, lymphomas, and myelodysplastic syndromes (MDS). Methods: This is an open-label trial with a 3+3 design, enrolling at least one solid tumor/lymphoma and one MDS patient (pt) at each dose level. Starting doses were clofarabine 1 mg/m2 intravenously (IV) on days (D) 1-5 and bortezomib 0.8 mg/m2 subcutaneously (SC) on D1 and D4 of 21-day cycles. Response was determined per RECIST 1.1, Lugano criteria, and IWG, respectively. Exploratory endpoints include markers of DNA damage and epithelial-to-mesenchymal phenotype transition in blood. Once MTD is declared, a biopsy expansion cohort will enroll to evaluate the mechanism of action for the combination using validated apoptosis multiplex and next-generation sequencing assays. Results: As of October 2020, 22 pts were enrolled with advanced solid tumors (n=18), lymphoma (1), and MDS (3). Median pt age is 62 (range 41-80). Median lines of prior therapy is 3 (range 1-8). Three pts had DLTs in the solid tumor/lymphoma cohort: grade 3 anemia at dose level (DL) 3 (clofarabine 1.5 mg/m2, bortezomib 1 mg/m2); grade 4 neutropenia and grade 4 thrombocytopenia at DL 5 (clofarabine 2 mg/m2, bortezomib 1.3 mg/m2); and grade 4 neutropenia at DL 5. In the solid tumor/lymphoma cohort, grade 3 toxicities possibly attributed to study drugs were anemia (3), lymphopenia (3), thrombocytopenia (1), and frequent premature ventricular contractions (1); grade 4 toxicities were lymphopenia (5), neutropenia without infection (2), and thrombocytopenia (1). The only toxicity possibly attributed to study drugs in the MDS cohort was grade 3 febrile neutropenia in one pt. In the solid tumor/lymphoma cohort, 6 pts achieved a best response of stable disease (SD); 3 patients experienced prolonged SD of ≥ 6 months (1 pt each with colorectal adenocarcinoma, pancreatic adenocarcinoma, and cholangiocarcinoma). In the MDS cohort, 2 pts had SD as a best response (8 months in 1 pt following hypomethylating agent failure). Pharmacodynamic analyses in circulating tumor cells are ongoing. Conclusions: Treatment with bortezomib and clofarabine demonstrated prolonged SD in one pt each with colon adenocarcinoma, pancreatic adenocarcinoma, cholangiocarcinoma, and MDS. Hematological DLTs were seen in 2 pts on DL 5. Currently, patients are enrolling on DL 4 for the solid tumor/lymphoma cohort. Funded by NCI Contract No. HHSN261200800001E. Citation Format: James Q. Nguyen, Geraldine O'Sullivan Coyne, Larry Rubinstein, Shivaani Kummar, Lamin Juwara, Jennifer Zlott, Abdul Rafeh Naqash, Murielle Hogu, Jerry Collins, Apurva Srivastava, Brandon Miller, Ralph E. Parchment, Robert Meehan, Christopher S. Hourigan, Steven Pavletic, James H. Doroshow, Alice P. Chen, Naoko Takebe. Phase I trial of the combination of bortezomib and clofarabine in adults with refractory solid tumors, lymphomas, or myelodysplastic syndromes [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 CT138.

Purpose Wee1 tyrosine kinase phosphorylates and inactivates cyclin-dependent kinase (Cdk) 1/2 in response to DNA damage. AZD1775 is a first-in-class inhibitor of Wee1 kinase with single-agent antitumor activity in preclinical models. We conducted a phase I study of single-agent AZD1775 in adult patients with refractory solid tumors to determine its maximum-tolerated dose (MTD), pharmacokinetics, and modulation of phosphorylated Tyr15-Cdk (pY15-Cdk) and phosphorylated histone H2AX (γH2AX) levels in paired tumor biopsies. Patients and Methods AZD1775 was administered orally twice per day over 2.5 days per week for up to 2 weeks per 21-day cycle (3 + 3 design). At the MTD, paired tumor biopsies were obtained at baseline and after the fifth dose to determine pY15-Cdk and γH2AX levels. Six patients with BRCA-mutant solid tumors were also enrolled at the MTD. Results Twenty-five patients were enrolled. The MTD was established as 225 mg twice per day orally over 2.5 days per week for 2 weeks per 21-day cycle. Confirmed partial responses were observed in two patients carrying BRCA mutations: one with head and neck cancer and one with ovarian cancer. Common toxicities were myelosuppression and diarrhea. Dose-limiting toxicities were supraventricular tachyarrhythmia and myelosuppression. Accumulation of drug (t1/2 approximately 11 hours) was observed. Reduction in pY15-Cdk levels (two of five paired biopsies) and increases in γH2AX levels (three of five paired biopsies) were demonstrated. Conclusion This is the first report of AZD1775 single-agent activity in patients carrying BRCA mutations. Proof-of-mechanism was demonstrated by target modulation and DNA damage response in paired tumor biopsies.

Background: We initiated the systematic NCI-ALMANAC in vitro combination drug screen of FDA-approved anticancer drugs in the NCI-60 tumor cell line panel to explore novel and effective drug combinations (Holbeck et al., Cancer Res 2017). In this screen and in preclinical xenograft models, the BCR-ABL kinase inhibitor nilotinib demonstrated greater-than-additive activity in combination with the anti-tubulin agent paclitaxel. Additionally, recent preclinical findings suggest a reduced incidence of peripheral neuropathy for this combination relative to paclitaxel monotherapy (Leblanc et al., J Clin Invest 2018). We are performing a phase 1 study to establish the safety, tolerability, and maximum tolerated dose (MTD) of this combination in patients (pts) with advanced solid tumors, and to examine the pharmacokinetic (PK) and pharmacodynamic (PD) effects of the combination to better understand the mechanism of synergy. Materials and Methods: Nilotinib was given orally twice-daily (BID), while paclitaxel was administered intravenously on days 1, 8, and 15 of each 28-day cycle. A 1- or 2-day paclitaxel-only run-in during the first cycle enabled comparison of the PK and PD effects of the combination vs. single-agent paclitaxel. Dose-limiting toxicities (DLTs) were assessed during cycle 1, and response was evaluated by CT per RECIST 1.1. Results: Thirty pts have been enrolled to date. The MTD was 300 mg nilotinib BID and 80 mg/m2 paclitaxel given on days 1, 8, and 15; DLTs were grade 4 rash and grade 3 myelosuppression. Only 2 pts (7%) have experienced grade 2 peripheral neuropathy, no grade ≥3 neuropathy events occurred. Of the 24 pts assessable for response to date, there are 4 confirmed partial responses (PRs; 17%, 1 pt with endometrial cancer, 1pt with anal cancer and 2 pts with granulosa cell of the ovary) and 12 pts with a best response of stable disease (SD; 50%), including 6 pts with SD for ≥ 8 cycles. Mean time on study to date is 8.7 months (range: 2 – 41 months). Three of 4 responding pts had undergone prior paclitaxel-based therapy and experienced a best response of only SD (1 pt) or progressive disease (2 pts) to carboplatin/paclitaxel or paclitaxel monotherapy, respectively. PK data demonstrate dose-dependent plasma paclitaxel concentrations (for 60 vs. 80 mg/m2 paclitaxel), and no substantial effects of nilotinib on paclitaxel plasma concentrations. Conclusions: The combination of nilotinib and paclitaxel is well-tolerated. Consistent with recent preclinical findings, no grade ≥ 3 peripheral neuropathy has been observed, as compared to rates of 8-30% in prior studies of 80-100 mg/m2 weekly paclitaxel monotherapy in pts with metastatic breast cancer (Rivera and Cianfrocca, Cancer Chemother Pharmacol 2015). PK data indicate dose-dependent plasma paclitaxel concentrations, with no substantial nilotinib-induced changes in plasma paclitaxel levels. Preliminary response data are promising, especially considering the PRs observed in pts who had previously been unresponsive to paclitaxel therapy. Accrual to the expansion cohort and PD analyses of circulating tumor cells and tumor biopsy specimens are ongoing. Citation Format: Geraldine O'Sullivan Coyne, Shivaani Kummar, Jennifer Zlott, Lamin Juwara, Naoko Takebe, Murielle Hogu, Larry Anderson, Jerry Collins, Richard Piekarz, Howard Streicher, Elad Sharon, Arjun Mittra, Sabrina Khan, Brandon Miller, Tony Navas, Apurva Srivastava, Ralph Parchment, Laurence Rubinstein, James H Doroshow, Alice P Chen. Tolerability and antitumor activity of paclitaxel is improved by the addition of nilotinib in patients with refractory solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C008. doi:10.1158/1535-7163.TARG-19-C008

Background: The NCI ALMANAC study carried out a systemic in vitro drug screen with 2.8 million dose combinations to identify drug pairs with greater than additive activity. This was followed by patient-derived xenograft models, which demonstrated that the combination of the proteasome inhibitor bortezomib and the nucleoside analog clofarabine was highly active. Both agents have been approved by FDA: bortezomib for multiple myeloma & mantle cell lymphoma, and clofarabine for acute lymphoblastic leukemia. However, neither agent is approved for solid tumors or myelodysplastic syndrome (MDS). Our pre-clinical models suggest that the activity of this drug pair may be due to modulation of DNA damage and enhancement of the intrinsic apoptotic cascade. While both drugs can initiate apoptosis, bortezomib resistance occurs when the drug fails to upregulate the apoptotic promoter BAX; however, clofarabine can stabilize BAX and facilitate apoptosis via alternate pathways (unpublished data). We are conducting an ongoing phase 1 trial to evaluate the activity of bortezomib and clofarabine in refractory solid tumors, lymphomas, and MDS. Methods: The trial uses a 3+3 design, enrolling at least one solid tumor/lymphoma and one MDS patient (pt) at each dose level. The occurrence of pre-defined hematologic dose limiting toxicity (DLT) or a second instance of a grade 2 hematologic toxicity triggers expansion of the dose level into separate cohorts: (1) solid tumor/lymphoma & (2) MDS. Starting dose of clofarabine was 1 mg/m2 administered intravenously (IV) on day (D)1-5, with bortezomib 0.8 mg/m2 SQ on D1-4 of 21-day cycles. Response was measured using RECIST 1.1, Lugano criteria, and IWG, respectively. Exploratory endpoints include DNA damage and epithelial-to-mesenchymal phenotype transition in blood and malignant tissue. Results: As of July 2019, 15 pts were enrolled with advanced solid tumors (n=11), lymphoma (1) & MDS (3). Median patient age is 62 (48-80 yrs). Median lines of prior therapy is 3 (1-7). One pt had a DLT (grade 3 anemia in a solid tumor pt at dose level 3), leading to the separation into solid tumor/lymphoma and MDS cohorts. In the MDS cohort, 2 pts had stable disease (SD) as best response (1pt with >8 months duration of response [DOR] following hypomethylating agent [HMA] failure). In the solid tumor/lymphoma cohort, 2 pts achieved a best response of SD (1pt with > 7 months DOR, with colorectal adenocarcinoma). The only toxicity possibly attributed to treatment in the MDS cohort was grade 3 neutropenia. In the solid tumor/lymphoma cohort, the grade 3 toxicities were anemia (2) and lymphopenia (4); there was one grade 4 lymphopenia, and no grade 3/4 neutropenia or thrombocytopenia. Conclusions: This unique trial design demonstrates that conducting a phase 1 study with both solid tumors and hematologic malignancies is feasible and efficient, eliminating the need for a larger sample size or two separate trials. Treatment with bortezomib and clofarabine has shown early activity in a colon cancer pt and an MDS pt post HMA failure, where treatment options are critically limited. Dose escalation and pharmacodynamic studies are ongoing. Future studies include assessment of drug pair mechanism of action using a validated apoptosis multiplex assay and next-generation sequencing. Funded by NCI Contract No. HHSN261200800001E Citation Format: Sabrina S. Khan, Geraldine O'Sullivan, Larry Rubinstein, Shivaani Kummar, Lamin Juwara, Jennifer Zlott, Arjun Mittra, Murielle Hogu, Jerry Collins, Apurva Srivastava, Brandon Miller, Ralph E. Parchment, Christopher S. Hourigan, Steven Pavletic, James Doroshow, Alice P. Chen, Naoko Takebe. Phase I trial of the combination of bortezomib and clofarabine in adults with refractory solid tumors, lymphomas, or myelodysplastic syndromes [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A071. doi:10.1158/1535-7163.TARG-19-A071

Background: The base excisional repair (BER) pathway plays an important role in the development of resistance to alkylating agents. TRC102 (methoxyamine HCL) inhibits BER by binding apurinic/apyrimidinic sites, which increases temozolomide (TMZ)-induced DNA strand breaks and apoptosis. We conducted a multihistology phase I/II trial of TRC102 in combination with TMZ in patients (pts) with refractory solid tumors (NCT01851369); here we report the clinical activity of this combination in the phase II refractory colorectal carcinoma (CRC) cohort. The phase I portion of the study demonstrated anemia to be the major dose limiting toxicity of this combination; the recommended phase II doses (RP2D) for the combination were: 125 mg TRC 102 + 150 mg/m2 TMZ (PO, D1-5 of 28-day cycles). The expanded phase II trial utilized a 3-arm Simon 2-stage design based on objective responses documented during the phase I portion of the study (CRC, NSCLC, and granulosa cell ovarian cancer). Methods: Phase II pts were treated at the RP2D, except that pts with BSA < 1.6 m2 received 100 mg of TRC102. Eligibility for the CRC cohort included pts with recurrent, metastatic, histologically confirmed colorectal adenocarcinoma after ≥ 2 lines of therapy, adequate organ function, and an ECOG performance status (PS) ≤ 1. Overall response rate (ORR) was defined as a partial response (PR) or a complete response (CR), per RECIST 1.1 criteria. Results: During the phase I trial, one pt with KRAS mutant CRC experienced a sustained PR of 21 cycles (maximum 70% decrease by RECIST). This pt decided to stop treatment due to travel constraints, but at 17 months off treatment had not progressed. Based on this response, 16 pts were enrolled in the CRC cohort of the phase II trial (3 rectal, 13 colon), all heavily pretreated (median: 6 lines of prior therapy, range: 3-14). Median pt age was 64 years (range: 46-80 years); all had an ECOG PS of 1. Median time on study was 2 cycles (range: 1 to 5 cycles) including 5 pts who came off study for early clinical progression. ORR for this cohort was 6% (1 PR). Nine pts had KRAS mutant disease, including the partial responder, who also was the only pt (of the 10 tested by tumor IHC) with MGMT-negative disease. Grade 3 and 4 protocol treatment-related toxicities included thrombocytopenia (2 pts), hemolysis (1 pt), and diarrhea (1 pt). No pts discontinued the protocol because of toxicity and only 1 pt required dose reduction (thrombocytopenia). Conclusions: Despite a promising phase I result from a pt with CRC, a phase II study of combined TRC102 and TMZ treatment in patients with metastatic colon or rectal adenocarcinoma displayed an ORR of 6%. Assessing tumor MGMT status may help identify pts who could benefit from this combination and pharmacodynamic studies are underway to assess drug activity in responding and non-responding patients. Supported in part by NCI Contract HHSN261200800001E. Citation Format: Geraldine OSullivan Coyne, Cecilia Monge Bonilla, Jennifer Zlott, Naoko Takebe, Robert Meehan, Lamin Juwara, Richard Piekarz, Laurence Rubinstein, Deborah F. Wilsker, Robert J. Kinders, Ralph E. Parchment, Shahanawaz Jiwani, Shivaani Kumar, James H. Doroshow, Alice P. Chen. A Phase II trial of TRC102 (methoxyamine HCl) in combination with temozolomide in patients with relapsed metastatic colorectal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-293.

Lessons Learned The combination of the antiangiogenic agent ziv-aflibercept and the heat shock protein 90 inhibitor ganetespib was associated with several serious and unexpected adverse events and was not tolerable on the dosing schedule tested. Studies such as these emphasize the importance of considering overlapping toxicities when designing novel treatment combination regimens. Background Although inhibition of angiogenesis is an effective strategy for cancer treatment, acquired resistance to antiangiogenic therapy is common. Heat shock protein 90 (Hsp90) is a molecular chaperone that regulates various oncogenic signaling pathways involved in acquired resistance and has been shown to play a role in angiogenesis. Combining an antiangiogenic agent with an Hsp90 inhibitor has therefore been proposed as a strategy for preventing resistance and improving antitumor activity. We conducted a single-arm phase I study evaluating the combination of ziv-aflibercept, an antiangiogenic drug, with the Hsp90 inhibitor ganetespib. Methods Adult patients were eligible if they had recurrent or metastatic gastrointestinal carcinomas, nonsquamous non-small cell lung carcinomas, urothelial carcinomas, or sarcomas that had progressed after at least one line of standard therapy. Ziv-aflibercept was administered intravenously on days 1 and 15, and ganetespib was administered intravenously on days 1, 8, and 15, of each 28-day cycle. Results Five patients were treated with the combination. Although three patients achieved stable disease, study treatment was associated with several serious and unexpected adverse events. Conclusion The dose escalation phase of this study was not completed, but the limited data obtained suggest that this combination may be too toxic when administered on this dosing schedule.

Background: Modulation of BRCA1 and ATR has been postulated as an activation mechanism of checkpoint 1 (Chk1), which in turn triggers homologous recombination repair through modulation of BRCA2-Rad51, and the initiation of cell cycle checkpoints through phosphorylation and activation of Wee1. Wee1 is a tyrosine kinase implicated in the inhibitory phosphorylation of cyclin-dependent kinase 1 (CDK1/CDC2)-bound cyclin B, resulting in G2 cell cycle arrest in response to DNA damage. AZD1775 is a first-in-class selective inhibitor of Wee1 kinase that directly prevents phosphorylation of CDC2 at Tyr15. Model data show single-agent antitumor activity in multiple cancer cell lines across the NCI-60 and in both p53 intact and deficient tumor xenografts. We are conducting a phase I trial of AZD1775 in patients (pts) with refractory solid tumors, both with and without germline BRCA1/2 mutations (BRCA+), evaluating two different dosing schedules. We have previously reported on initial antitumor activity and proof-of-mechanism (Do et al, J Clin Oncol. 2015). This abstract reports the efficacy seen in the BRCA+ population. Methods: AZD1775 was administered orally twice daily (BID) for 5 doses [D1-3 and 8-10, Cohort A (A)] or once daily for 5 days [D1-5 and 8-12, Cohort B (B)] during weeks 1 and 2 of a 21-day cycle; 3+3 design. Primary objectives: establish safety, tolerability and PK of AZD1775. Secondary objectives: determine the effect of AZD1775 on markers of DNA damage and apoptosis in tumor tissue/circulating tumor cells, and antitumor activity. Dose-limiting toxicity (DLT) was determined during Cycle 1. Response defined by RECIST 1.1 on CT. Results: A total of 17 BRCA+ pts have enrolled; 9 pts on A (one pt withdrew for other therapy), and 8 pts on B. Nine pts with BRCA1, 7 pts with BRCA2: ovarian (9 pts), breast (2), pancreas (1), prostate (1), Fallopian tube (1), and peritoneal (1) cancer. Partial responses (PR) were confirmed on 2/8 pts (25%) in A with BRCA1 papillary serous ovarian cancer and squamous cell carcinoma of tongue. Two additional PRs (25%) were confirmed in BRCA1 serous ovarian cancer pts in B. Two further BRCA1 ovarian pts trended near PR. All 4 responders received prior platinum therapy; 3/3 ovarian cancer pts received and responded to prior PARP inhibitor therapy. No differences were noted in severity or rate of toxicity in pts with/without BRCA+: common grade 3/4 toxicities include anemia (6 pts, 37%), lymphopenia (5, 31%), neutropenia (4, 25%), and thrombocytopenia (3, 18%), occurring in responders and nonresponders. Conclusions: AZD1775 has single-agent antitumor activity in a BRCA deficient population, especially BRCA1. Responses were observed in pts with prior exposure to platinum and a PARP inhibitor. Additional accrual on a safety expansion cohort is ongoing, and assessment of PD biomarkers is planned for paired biopsies (NCT01748825). Citation Format: Geraldine OSullivan Coyne, Shivaani Kummar, Naoko Takebe, Khanh Tu Do, Robert Meehan, Richard Piekarz, Jennifer Zlott, Lamin Juwara, Mary Quinn, Elad Sharon, Howard Streicher, Lawrence Rubinstein, Chana Levine, James H. Doroshow, Alice P. Chen. Single agent AZD 1775, a Wee1 inhibitor, shows activity in BRCA deficient patients [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr B079.

2518 Background: TRC102 inhibits BER by binding to abasic sites and acting as a topo II poison to cause DNA strand breaks; it potentiates the activity of alkylating agents including TMZ in murine models. In xenograft studies, TRC102 efficiently enhanced the antitumor effect of TMZ regardless of cell line genetic characteristics, e.g., O6-methylguanine DNA-methyltransferase, mismatch repair (MMR), or p53 status. This is the first report for the expansion phase (the escalation phase was reported previously (ASCO2016)). Methods: We conducted a phase 1 trial of TRC102with TMZ in patients (pts) with refractory solid tumors. Eligibility criteria included adults that had progressed on standard therapy, ECOG PS of 0-2, and adequate organ function. TRC102 and TMZ were given orally days 1-5, in 28-day cycles. The pharmacokinetic and pharmacodynamic profile of TRC102 with TMZ was evaluated. Antitumor responses were determined using RECIST 1.1 criteria. The DNA damage response (DDR) markers γH2Ax, pNbs1, and Rad51 were evaluated in the expansion cohort at DL6, tested by previously described methods on paired tumor biopsies prior to and after the first course of therapy. Results: After the recommended Phase 2 Dose was defined as DL6 (TRC102 125mg, TMZ 150mg/m2 D1-5), 15 pts were accrued to the expansion cohort between 9/2015 to 11/2016. A total of 52 pts were enrolled (37 escalation, 15 expansion). Grade 3/4 adverse events included neutropenia (13%), anemia (the DLT;10%), thrombocytopenia (7%), hemolysis (5%) or hypophosphatemia (3%). 4 pts had a partial response (PR) (NSCLC, ovarian (2), and colon); 13 pts had stable disease (SD), 29 progressive disease (PD), and 6 were not evaluable; three pts remain on study. 11/14 paired biopsies were suitable for analysis. Rad51 signal was induced in 6/11pts. One patient showed γH2Ax and 2 showed pNbs1 induction. 4/5 colon cancer specimens had evidence of DDR marker induction. Conclusions: The combination of TRC 102/TMZ is active with 4 PRs and 13 SDs, and the side effect profile is manageable. DDR markers were induced in 4 of 5 paired colon biopsies indicating DNA damage following treatment. A phase 2 trial of patients with colon cancer, NSCLC, and granulosa cell ovarian cancer is accruing. Clinical trial information: NCT01851369.

2518Background: TRC102 inhibits BER by binding to abasic sites and acting as a topo II poison to cause DNA strand breaks; it potentiates the activity of alkylating agents including TMZ in murine models. In xenograft studies, TRC102 efficiently enhanced the antitumor effect of TMZ regardless of cell line genetic characteristics, e.g., O6-methylguanine DNA-methyltransferase, mismatch repair (MMR), or p53 status. This is the first report for the expansion phase (the escalation phase was reported previously (ASCO2016)). Methods: We conducted a phase 1 trial of TRC102with TMZ in patients (pts) with refractory solid tumors. Eligibility criteria included adults that had progressed on standard therapy, ECOG PS of 0-2, and adequate organ function. TRC102 and TMZ were given orally days 1-5, in 28-day cycles. The pharmacokinetic and pharmacodynamic profile of TRC102 with TMZ was evaluated. Antitumor responses were determined using RECIST 1.1 criteria. The DNA damage response (DDR) markers γH2Ax, pNbs1, and Rad51 wer...

Background: Base excision repair (BER), one of the pathways of DNA damage repair, has been implicated in chemoresistance. TRC102 acts through a novel mechanism to inhibit BER and cause DNA strand breaks, potentiating the antitumor activity of TMZ in preclinical models. We conducted a phase I trial of TRC102 in combination with TMZ to determine the safety, tolerability, and maximum tolerated dose of the combination; to evaluate the pharmacokinetics (PK) of each agent alone and in combination; and to assess DNA damage response (percent nuclear area of γH2AX foci) in circulating tumor cells (CTCs). Methods: Eligible pts were required to have refractory advanced solid tumors that had progressed following standard therapy; ≥ 18 yrs of age; ECOG PS 0-2; and adequate organ function. TRC102 and TMZ were administered orally once daily, D1-5 of q28d cycles; Starting dose level (DL 1) was TRC102 25 mg and TMZ 125mg/m2. Accrual to DL6 (TRC102 125 mg; TMZ 150 mg/m2) is ongoing. CTCs were obtained during C1 and on C2D1. Blood samples for PK analysis were obtained during C1. Results: Twenty pts have been enrolled to date; median age 59 yrs (range 45-78 yrs); median # of prior therapies: 3.5 (1-9); Dx: GI (6), H&N (4), breast (3), GYN (3), lung (2), soft tissue sarcoma (2). Fourteen pts are evaluable for response; 2 partial responses by RECIST have been observed to date (≥ 6 cycles; NSCLC and granulosa cell tumor of the ovary). Grade 3/4 toxicities (#pts): neutropenia (2), thrombocytopenia (1), lymphopenia (1), anemia (1), leucopenia (1), hypophosphatemia (1). PK in combination was similar to single agent PK reported for both drugs, with no evidence of a PK interaction. TRC102 levels required for preclinical activity (50ng/mL) were achieved at DL1. T1/2 of TRC102 was 26 hr. CTC analysis is ongoing. Conclusions: Combination of TRC102 with TMZ is well tolerated and clinical activity was observed with 2 partial responses to date. MTD has not been reached; accrual is ongoing. Paired tumor biopsies to assess for evidence of DNA damage response and apoptosis are planned at the MTD in the expansion phase. Citation Format: Woondong Jeong, Khanh Do, Alice Chen, Jennifer Zlott, Lamin Juwara, Yvonne Horneffer, Robert Kinders, Lihua Wang, Priya Balasubramanian, Larry Anderson, Elad Sharon, Howard Streicher, Richard Piekarz, Barbara Conley, Jerry Collins, James H. Doroshow, Shivaani Kummar. A phase I trial of oral TRC102 (methoxyamine HCl) in combination with temozolomide (TMZ) in patients with relapsed solid tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT316. doi:10.1158/1538-7445.AM2015-CT316

2503 Background: Wee1 tyrosine kinase phosphorylates and inactivates Cdk1, causing G2 cell cycle arrest in response to DNA damage. AZD1775 is a novel inhibitor of Wee1 kinase with single-agent anti...