Introduction: Vorinostat is a small molecule inhibitor of histone deacetylase, and has shown preclinical activity in non-small cell lung cancer (NSCLC).
Methods: Patients with relapsed NSCLC were eligible. Patients received oral vorinostat, 400 mg daily. The primary objective was response rate, with the goal of at least one responder in the first 14 evaluable patients, according to the two-stage minimax design. Secondary objectives included time to progression (TTP), overall survival (OS), and safety.
Results: Sixteen patients enrolled from January 2006 to April 2007. The median age was 59.5 years. Thirteen patients were female. Two patients were not evaluable for response due to progressive disease within Cycle 1. No objective antitumor responses were seen in the 14 evaluable patients. Eight patients experienced stable disease (median 3.7 months, range 1.4-19.4). Median TTP was 2.3 months (range 0.9-19.4 months), median OS was 7.1 months (range 1.4-30.0+ months), and estimated 1 year OS rate was 19% (SE 10%). One patient died on study from an acute ischemic stroke; this event was deemed possibly related to treatment. Grade 3/4 adverse events possibly related to vorinostat included neutropenia, lymphopenia, fatigue, pulmonary embolus/deep vein thrombosis, dehydration, elevated alkaline phosphatase, and hypokalemia.
Conclusions: No objective antitumor activity was detected with single agent vorinostat in this setting; however, it yields TTP in relapsed NSCLC similar to that of other targeted agents. Further studies in NSCLC should focus on combining vorinostat with other antitumor agents.