A phase i clinical trial of guadecitabine and carboplatin in platinum-resistant, recurrent ovarian cancer: Clinical, pharmacokinetic, and pharmacodynamic analyses

Purpose: Epigenetic changes are implicated in acquired resistance to platinum. Guadecitabine is a next-generation hypomethylating agent (HMA). Here, we report the clinical results, along with pharmacokinetic (PK) and pharmacodynamic analyses of the phase I study of guadecitabine and carboplatin in patients with recurrent, platinum-resistant high-grade serous ovarian cancer, primary peritoneal carcinoma (PPC), or fallopian tube cancer (FTC). Experimental Design: Guadecitabine was administered once daily on days 1 to 5 followed by carboplatin i.v. on day 8 of a 28-day cycle. Patients had either measurable or detectable disease. Safety assessments used CTCAE v4. Results: Twenty patients were enrolled and treated. Median age was 56 years (38–72 years). The median number of prior regimens was 7 (1–14). In the first cohort (N ¼ 6), the starting doses were guadecitabine 45 mg/m ² and carboplatin AUC5. Four patients experienced dose-limiting toxicity (DLT; neutropenia and thrombocytopenia), leading to dose deescalation of guadecitabine to 30 mg/m ² and of carboplatin to AUC4. No DLTs were observed in the subsequent 14 patients. Grade 3 adverse events 10% were neutropenia, leukopenia, anemia, nausea, vomiting, ascites, constipation, hypokalemia, pulmonary embolism, small-intestinal obstruction, and thrombocytopenia. Three patients had a partial response (PR), and 6 patients had stable disease (SD) >3 months, for an overall response rate (ORR) and clinical benefit rate of 15% and 45%, respectively. LINE-1 demethylation in PBMCs and promoter demethylation/gene reexpression in paired tumor biopsies/ascites were recorded. Conclusions: Guadecitabine and carboplatin were tolerated and induced clinical responses in a heavily pretreated platinum-resistant ovarian cancer population, supporting a subsequent randomized phase II trial.