Randomized, double-blind, placebo-controlled phase II study of carboplatin and paclitaxel with or without vorinostat, a histone deacetylase inhibitor (HDAC), for first-line therapy of advanced non-small cell lung cancer (NCI 7863)
8004 Background: Vorinostat, a HDAC inhibitor, enhances paclitaxel and platinum-mediated anti-cancer activity in preclinical studies by enhanced tubulin acetylation and DNA fragmentation respectively. Promising activity with carboplatin (C), paclitaxel (P), and vorinostat in patients with advanced NSCLC in the phase I study (Ramalingam et al, Clin Cancer Res, 2007) prompted this placebo-controlled, randomized phase II study. Methods: Pts. with stage IIIB (wet) or IV NSCLC, performance status (PS) 0/1, no prior therapy and adequate bone marrow, renal and hepatic function were randomized (2:1) for therapy with PC with either vorinostat or placebo. Treatment consisted of C: AUC=6 mg/ml.min; and P 200 mg/m2 both given on day 3 along with either vorinostat (400 mg PO QD) or placebo on days 1–14 of each 3 wk cycle to a maximum of 6 cycles. The estimated sample size to demonstrate a 50% improvement in response rate for vorinostat over placebo was 93 pts. (one-sided P, type I error 10%). Results: Ninety-four pts. were enrolled (vorinostat-64; placebo-32). Pts. baseline characteristics were similar between the two arms (median age 64, male 60%, PS 0 40%, brain mets 16%). Median # cycles: vorinostat-3.5; placebo - 4. The confirmed response rate was superior with vorinostat over placebo (34% vs. 12.5%, P = 0.02). At the time of analysis, the preliminary median PFS for vorinostat and placebo were 5.75 and 4.1 m respectively (ITT). Follow up for survival is ongoing. Common grade 3/4 toxicities (vorinostat vs. placebo): neutropenia (44% vs. 47%); thrombocytopenia (33% vs. 16%); fatigue (13% vs. 3%); hyponatremia (21% vs. 6%); diarrhea (5% vs. 0). Discontinuation from study after cycle 1 was higher with vorinostat (27% vs. 16%). Biomarker studies on baseline tumor tissue and peripheral blood cells are ongoing. Conclusions: Administration of vorinostat with carboplatin and paclitaxel resulted in a significantly superior response rate for pts.with advanced NSCLC. HDAC inhibition is a novel therapeutic strategy for treatment of NSCLC. Supported by ASCO Career Development Award to S.S.Ramalingam, and NCI NO1-CM-62209, NO1-CM-62201, NO1-CM-62208. [Table: see text]