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Background TRC102 inhibits base excision repair by binding abasic sites and preventing AP endonuclease processing; it potentiates the activity of alkylating agents, including temozolomide, in murine models. In published xenograft studies, TRC102 enhanced the antitumor effect of temozolomide regardless of cell line genetic characteristics, e.g., O6-methylguanine DNA methyltransferase (MGMT), mismatch repair (MMR), or p53 status. Materials and methods We conducted a phase 1 trial of TRC102 with temozolomide given orally on days 1-5 of 28-day cycles in adult patients with refractory solid tumors that had progressed on standard therapy. Tumor induction of nuclear biomarkers of DNA damage response (DDR) γH2AX, pNBs1, and Rad51 was assessed in the context of MGMT and MMR protein expression for expansion cohort patients. Results Fifty-two patients were enrolled (37 escalation, 15 expansion) with 51 evaluable for response. The recommended phase 2 dose was 125 mg TRC102, 150 mg/m2 temozolomide QDx5. Common adverse events (grade 3/4) included anemia (19%), lymphopenia (12%), and neutropenia (10%). Four patients achieved partial responses (1 non-small cell lung cancer, 2 granulosa cell ovarian cancer, and 1 colon cancer) and 13 patients had a best response of stable disease. Retrospective analysis of 15 expansion cohort patients did not demonstrate a correlation between low tumor MGMT expression and patient response, but treatment induced nuclear Rad51 responses in 6 of 12 patients. Conclusions The combination of TRC 102 with temozolomide is active, with 4 of 51 patients experiencing a partial response and 13 of 51 experiencing stable disease, and the side effect profile is manageable.

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.