Randomized phase II study of dacarbazine with or without sorafenib in patients with advanced melanoma

Abstract

8511 Background: Sorafenib (SOR), a potent and selective multi-kinase inhibitor, exerts its anti-tumor and anti-angiogenic effects via inhibition of VEGFR-1, -2, -3, PDGFR-a, -β, and Raf. Dacarbazine (DTIC) is an FDA-approved cytotoxic agent for advanced melanoma. Phase I/II results of SOR + DTIC were encouraging and prompted this randomized phase II study. Methods: This was a multi- center, double-blinded, placebo-controlled study; eligibility criteria included measurable disease by RECIST, no prior cytotoxic chemotherapy, and no active brain metastases. Advanced melanoma patients (pts) stratified by stage (unresectable III vs IVM1a/M1b vs M1c) and ECOG PS (0 vs 1) were randomized to receive DTIC 1,000 mg/m2 q 21 days + oral placebo (PL) or oral SOR 400 mg bid continuously until the occurrence of progressive disease or intolerable toxicity. The primary endpoint was progression-free survival (PFS) of DTIC+SOR vs DTIC+PL. Using a two-sided test with a = 0.05, 77 PFS events were needed to detect a hazard ratio (HR) of 0.5 (SOR/PL) with 86 % power. The secondary endpoint was overall survival and tertiary endpoints were objective response rate (ORR), time to progression, and duration of response. Results: 101 pts were enrolled over 12 months (51 DTIC+SOR, 50 DTIC+PL). Treatment arms were balanced for age (median 58 yrs), gender (male 70%), PS (ECOG 1 39%), stage (Stage IV M1c 52%) and baseline LDH (>ULN 29%). At the time of analysis by independent assessment, the median PFS of DTIC+PL vs DTIC+SOR was 11.7 wks (95% CI 6.1, 17.9) vs 21.1 wks (95% CI: 16, 28); HR 0.67 [p=0.07]; PFS rate at Day 180 was 18% vs 41%; and ORR was 12% vs 24%. Survival data are immature. Toxicities of Grade 3 or higher (DTIC+PL vs DTIC+SOR) included neutropenia (12% vs 33%), leukopenia (6% vs 14%), thrombocytopenia (18% vs 35%), thrombosis/embolism (0% vs 6%), hypertension (0 vs 8%), hand-foot skin reaction (0 vs 4%), and CNS hemorrhage (0% vs 8%). 3 of the 4 pts with CNS hemorrhage had new brain metastases. No treatment-related deaths occurred in either arm. Conclusions: DTIC+SOR was well tolerated and showed a strong efficacy trend compared with DTIC+PL in median PFS, PFS rate at 6 months and ORR in chemotherapy-naïve pts with advanced melanoma. This regimen warrants further evaluation in larger clinical trial settings. No significant financial relationships to disclose.