Phase I/II study of docetaxel combined with resminostat, an oral hydroxamic acid HDAC inhibitor, for advanced non-small cell lung cancer in patients previously treated with platinum-based chemotherapy

Objectives To determine the recommended dose and efficacy/safety of docetaxel combined with resminostat (DR) in non-small cell lung cancer (NSCLC) patients with previous platinum-based chemotherapy. Materials and Methods A multicenter, open-label, phase I/II study was performed in Japanese patients with stage IIIB/IV or recurrent NSCLC and prior platinum-based chemotherapy. The recommended phase II dose was determined using a standard 3 + 3 dose design in phase I part. Resminostat was escalated from 400 to 600 mg/day and docetaxel fixed at 75 mg/m². In phase II part, the patients were randomly assigned to docetaxel alone (75 mg/m²) or DR therapy. Docetaxel was administered on day 1 and resminostat on days 1–5 in the DR group. Treatment was repeated every 21 days until progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). Results A total of 117 patients (phase I part, 9; phase II part, 108) were enrolled. There was no dose-limiting toxicity in phase I part; the recommended dose for resminostat was 600 mg/day with 75 mg/m² of docetaxel. In phase II part, median PFS (95% confidence interval [CI]) was 4.2 (2.8–5.7) months with docetaxel group and 4.1 (1.5–5.4) months with DR group (hazard ratio [HR]: 1.354, 95% CI: 0.835–2.195; p = 0.209). Grade ≥ 3 adverse events significantly more common with DR group than docetaxel group were leukopenia, febrile neutropenia, thrombocytopenia, and anorexia. Conclusion In Japanese NSCLC patients previously treated with platinum-based chemotherapy, DR therapy did not improve PFS compared with docetaxel alone and increased toxicity.