No abstract

Platinum chemotherapy remains the cornerstone of treatment for epithelial ovarian cancer (OC) and Poly (ADP-ribose) polymerase inhibitors (PARPi) now have an established role as maintenance therapy. The mechanisms of action of these agents is, in many ways, complementary, and crucially reliant on the intracellular DNA Damage Repair (DDR) response. Here, we review mechanisms of primary and acquired resistance to treatment with platinum and PARPi, examining the interplay between both classes of agents. A key resistance mechanism appears to be the restoration of the Homologous Recombination (HR) repair pathway, through BRCA reversion mutations and epigenetic upregulation of BRCA1. Alterations in non-homologous end-joint (NHEJ) repair, replication fork protection, upregulation of cellular drug efflux pumps, reduction in PARP1 activity and alterations to the tumour microenvironment have also been described. These resistance mechanisms reveal molecular vulnerabilities, which may be targeted to re-sensitise OC to platinum or PARPi treatment. Promising therapeutic strategies include ATR inhibition, epigenetic re-sensitisation through DNMT inhibition, cell cycle checkpoint inhibition, combination with anti-angiogenic therapy, BET inhibition and G-quadruplex stabilisation. Translational studies to elucidate mechanisms of treatment resistance should be incorporated into future clinical trials, as understanding these biologic mechanisms is crucial to developing new and effective therapeutic approaches in advanced OC.

Based on evidence of human papillomavirus (HPV)-induced immune evasion, immunotherapy may be an attractive strategy in cervical cancer. Ipilimumab is a fully humanized monoclonal antibody that blocks cytotoxic T-lymphocyte antigen-4 (CTLA-4), which acts to downregulate the T-cell immune response. OBJECTIVE To assess the safety and antitumor activity of ipilimumab in recurrent cervical cancer. DESIGN, SETTING, AND PARTICIPANTS A multicenter trial was designed for patients with metastatic cervical cancer (squamous cell carcinoma or adenocarcinoma) with measurable disease and progression after at least 1 line of platinum chemotherapy. A run-in safety cohort using ipilimumab, 3 mg/kg, every 21 days for 4 cycles in 6 patients was followed by a phase II cohort of ipilimumab, 10 mg/kg, every 21 days for 4 cycles and then 4 cycles of maintenance therapy every 12 weeks for patients demonstrating radiologic response or stabilization. Immune correlative studies were performed on peripheral blood before and after therapy on archival tissue and fresh tumor obtained prior to registration and 7 days after cycle 2. The

Maintenance therapy with olaparib has improved progression-free survival in women with high-grade serous ovarian cancer (HGSOC), particularly those harboring mutations. The objective of this study was to characterize long-term (LT) versus short-term (ST) responders to olaparib. A comparative molecular analysis of Study 19 (NCT00753545), a randomized phase II trial assessing olaparib maintenance after response to platinum-based chemotherapy in HGSOC, was conducted. LT response was defined as response to olaparib/placebo >2 years, ST as <3 months. Molecular analyses included germline status, three-biomarker homologous recombination deficiency (HRD) score, methylation, and mutational profiling. Another olaparib maintenance study (Study 41; NCT01081951) was used as an additional cohort. Thirty-seven LT (32 olaparib) and 61 ST (21 olaparib) patients were identified. Treatment was significantly associated with outcome ( < 0.0001), with more LT patients on olaparib (60.4%) than placebo (11.1%). LT sensitivity to olaparib correlated with complete response to chemotherapy ( < 0.05). In the olaparib LT group, 244 genetic alterations were detected, with , and mutations being most common (90%, 25%, and 35%, respectively). mutations were enriched among the LT responders. methylation was not associated with response duration. High myriad HRD score (>42) and/or mutation was associated with LT response to olaparib. Study 41 confirmed the correlation of LT response with olaparib and mutation. Findings show that LT response to olaparib may be multifactorial and related to homologous recombination repair deficiency, particularly defects. The type of mutation warrants further investigation. .