Combined pembrolizumab and pegylated liposomal doxorubicin in platinum resistant ovarian cancer: A phase 2 clinical trial.

OBJECTIVE: Pegylated liposomal doxorubicin (PLD) in vitro may have immunomodulatory abilities and preclinical evidence suggests it synergizes with immune checkpoint blockade. We hypothesized that combining PLD and pembrolizumab would be active in patients with platinum-resistant ovarian cancer (PROC). METHODS: This was a single-arm, multi-center phase II trial. Eligible patients had PROC with ≤2 prior lines of cytotoxic therapy for recurrent or persistent disease. Twenty-six patients were enrolled and given pembrolizumab 200 mg intravenously (IV) every 3 weeks and PLD 40 mg/m2 IV every 4 weeks. Patients were assessed radiographically every 8 weeks. The primary endpoint was clinical benefit rate (CBR), defined as complete response (CR) + partial response (PR) + stable disease (SD) ≥24 weeks. The study was powered to detect an improvement in CBR from 25% to 50%, with rejection of the null hypothesis if at least 10 patients achieved clinical benefit. T-cell inflamed gene expression profiles (GEP) and PD-L1 were assessed and correlated with clinical outcome. RESULTS: Twenty-three patients were evaluable for best overall response. The study satisfied its primary endpoint, with 12 patients achieving clinical benefit for a CBR of 52.2% (95% CI 30.6-73.2%). There were 5 PRs (21.7%) and 1 CR (4.3%), for an overall response rate (ORR) of 26.1%. Six patients had SD lasting at least 24 weeks. Combination therapy was well tolerated without unexpected toxicities. CONCLUSIONS: The combination of pembrolizumab and PLD was manageable, without unexpected toxicities, and showed preliminary evidence of clinical benefit in the treatment of platinum resistant ovarian cancer. ORR and median PFS of combination therapy in this study was higher than historical comparisons of PLD alone or anti-PD-1/PD-L1 agents alone. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02865811.

The poly (ADP ribose) polymerase inhibitor niraparib: Management of toxicities.

Niraparib is an oral poly(ADP ribose) polymerase (PARP) inhibitor that is currently approved by the United States Food and Drug Administration (US FDA) as well as recently approved by the European Medicines Agency (EMA) for the maintenance treatment of women with recurrent ovarian cancer who are in complete or partial response to platinum-based chemotherapy. The mechanisms of action of niraparib include inhibition of PARP enzymatic activity as well as increased formation of PARP-DNA complexes through "trapping" the PARP enzyme on damaged DNA. Phase I and III studies have demonstrated activity and benefit of niraparib in both BRCA mutated (BRCAm) and BRCA wild-type (BRCAwt) cancers. Phase I testing of niraparib established the maximally tolerated dose of 300mg by mouth (PO) daily, and the phase 3 ENGOT-OV16/NOVA study demonstrated the benefit of niraparib maintenance therapy compared to placebo after completion of and response to platinum-based chemotherapy in both BRCAm and BRCAwt ovarian cancer patient populations. Toxicities seen with niraparib include hematologic, gastrointestinal, fatigue, and cardiovascular. Hematologic toxicities include thrombocytopenia, anemia, neutropenia and leukopenia; upfront dose modification to 200mg niraparib for patients with baseline weight of ≤77kg and/or baseline platelets of ≤150,000K/uL should be considered to avoid significant hematologic toxicity, especially thrombocytopenia, based on recent analyses of the ENGOT-OV16/NOVA study. Cardiovascular toxicities include hypertension, tachycardia, as well as palpitations, and patients should be monitored for hypertension. PARP inhibitors have been associated with low risks of acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS), and the overall risk of AML and MDS is 0.9% of all patients treated with niraparib. Niraparib testing is ongoing in newly diagnosed ovarian cancer patients as maintenance therapy following completion of platinum-based chemotherapy, in BRCAwt cancers as treatment, as well as in combinations with other biologic drugs such as immunotherapy and anti-angiogenic agents.

A Randomized Phase II Trial of Epigenetic Priming with Guadecitabine and Carboplatin in Platinum-resistant, Recurrent Ovarian Cancer.

PURPOSE: Platinum resistance in ovarian cancer is associated with epigenetic modifications. Hypomethylating agents (HMA) have been studied as carboplatin resensitizing agents in ovarian cancer. This randomized phase II trial compared guadecitabine, a second-generation HMA, and carboplatin (G+C) against second-line chemotherapy in women with measurable or detectable platinum-resistant ovarian cancer. PATIENTS AND METHODS: Patients received either G+C (guadecitabine 30 mg/m2 s.c. once-daily for 5 days and carboplatin) or treatment of choice (TC; topotecan, pegylated liposomal doxorubicin, paclitaxel, or gemcitabine) in 28-day cycles until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints were RECIST v1.1 and CA-125 response rate, 6-month PFS, and overall survival (OS). RESULTS: Of 100 patients treated, 51 received G+C and 49 received TC, of which 27 crossed over to G+C. The study did not meet its primary endpoint as the median PFS was not statistically different between arms (16.3 weeks vs. 9.1 weeks in the G+C and TC groups, respectively; P = 0.07). However, the 6-month PFS rate was significantly higher in the G+C group (37% vs. 11% in TC group; P = 0.003). The incidence of grade 3 or higher toxicity was similar in G+C and TC groups (51% and 49%, respectively), with neutropenia and leukopenia being more frequent in the G+C group. CONCLUSIONS: Although this trial did not show superiority for PFS of G+C versus TC, the 6-month PFS increased in G+C treated patients. Further refinement of this strategy should focus on identification of predictive markers for patient selection.