A phase I study of sorafenib and vorinostat in patients with advanced solid tumors with expanded cohorts in renal cell carcinoma and non-small cell lung cancer

Background This phase I study evaluated the safety, tolerability and preliminary efficacy of sorafenib combined with vorinostat in patients with solid tumors. Patients and methods Patients were treated with sorafenib 400 mg po bid daily and vorinostat 200-400 mg po days 1-14 of a 21 day cycle to establish the recommended phase II dose (RP2D). The tolerability and efficacy of the RP2D was further tested in two cohorts of 6-12 patients each with advanced RCC and NSCLC. Results 17 patients were treated in the dose escalation phase that established the RP2D at sorafenib 400 mg po bid daily, vorinostat 300 mg po days 1-14. Dose limiting toxicities (DLT) included intolerable grade 2 hand-foot syndrome and multiple grade 1 toxicities causing dose interruption for more than 14 days. Despite good tolerance in the all-comers population, the RP2D was poorly tolerated in the RCC and NSCLC cohorts with the majority being unable to finish 2 full cycles of therapy. Although there were no confirmed responses, 1 patient each with NSCLC adenocarcinoma and renal sarcoma had unconfirmed partial responses and 5 of 8 patients with RCC having durable minor responses (11-26 %), including 2 who were on treatment for nearly a year. Conclusions Although tolerable in other tumor types, sorafenib 400 mg po bid with vorinostat 300 mg po daily days 1-14 of a 21-day cycle is not tolerable without dose reductions/delays in RCC and NSCLC patients. These patients may require lower doses than the RP2D explored within this study. No confirmed responses were seen but minor responses particularly in RCC were observed.