Phase II trial of the histone deacetylase inhibitor belinostat in women with platinum resistant epithelial ovarian cancer and micropapillary (LMP) ovarian tumours

Abstract Aim Micropapillary/borderline (LMP) ovarian tumours are rarely included in clinical trials and are intrinsically resistant to radiation and chemotherapy. Platinum resistant epithelial ovarian cancer (EOC) has a poor prognosis. The histone deacetylase inhibitor belinostat demonstrated antitumour activity in pre-clinical ovarian cancer models. Methods A phase II study was performed to evaluate the activity of belinostat in two patient populations: women with metastatic or recurrent platinum resistant (progression within 6 months) EOC and LMP ovarian tumours, both groups had received no more than 3 prior lines of chemotherapy. Belinostat 1000 mg/m 2 /d was administered iv days 1–5 of a 21 d cycle. Peripheral blood mononuclear cells (PBMCs) and tumour biopsies, where possible, for correlative studies were obtained prior to and following treatment. Results Eighteen patients with EOC and 14 patients with LMP tumours were enrolled on study. Belinostat was well tolerated with no grade four toxicity (179 cycles). Grade 3 toxicity consisted of thrombosis (3 patients), hypersensitivity (1) and elevated ALP (1). One patient with LMP tumour had a partial response (unconfirmed) and 10 had stable disease (SD), 3 were non-evaluable. Median progression-free survival (PFS) was 13.4 months (95% confidence interval (CI), 5.6 – not reached). Best response in patients with EOC was SD (nine patients) and median PFS was 2.3 months (95% CI, 1.2–5.7 months). An accumulation of acetylated histones H3 and H4 was noted in PBMCs and in tumour tissue. Conclusions Belinostat is well tolerated in both patient groups and shows some activity in patients with micropapillary (LMP) disease.