Phase III randomized study of ipilimumab (IPI) plus dacarbazine (DTIC) versus DTIC alone as first-line treatment in patients with unresectable stage III or IV melanoma.

Abstract

LBA5 Background: IPI monotherapy (3mg/kg) improved overall survival (OS) in a phase III study of previously treated, unresectable or metastatic melanoma. Current study in 1st line metastatic melanoma evaluates combination of DTIC (a global standard of care) plus IPI. Methods: In this double-blind phase 3 study, patients (pts) with metastatic melanoma, ECOG PS 0/1, and no prior therapy for advanced disease, were randomized 1:1 to IPI (10 mg/kg) + DTIC (850 mg/m2) or placebo + DTIC (850 mg/m2) at Wks 1, 4, 7, 10 followed by DTIC q3 wks through Wk 22 (induction). Eligible pts received IPI or placebo q12 wks as maintenance. Primary endpoint was OS; 2-sided log-rank test was performed, stratified by baseline M stage and ECOG PS. Results: Of 502 pts, 56% had M1c disease, 40% elevated LDH, and 26% adjuvant therapy. 37% in IPI + DTIC and 65% in DTIC alone arms received 4 induction doses. A significant improvement in OS (HR=0.72; P=0.0009) and higher estimated 1, 2 and 3 yr survival rates were seen with IPI + DTIC (Table). 56% in IPI +DTIC (n=247) and 27% in DTIC alone (n=251) arms had grade 3/4 adverse events (AEs, regardless of attribution), including: elevated ALT (22% vs 1%); diarrhea (4% vs 0%); rash (1% vs 0%). No intestinal perforations or hypophysitis were noted. There were no drug-related deaths in IPI + DTIC and one in DTIC alone arm [gastrointestinal (GI) hemorrhage]. Conclusions: IPI (10mg/kg) + DTIC significantly improved OS in 1st line metastatic melanoma vs DTIC alone; durable survival and objective responses were noted in some pts after follow-up for up to 4yrs. Type of AEs was consistent with prior IPI studies; however, frequencies of some AEs differed with a higher transaminitis and lower diarrhea/colitis/ GI perforation rates than expected. No drug-related deaths were noted in IPI arm. OS benefit of IPI is confirmed in treatment-naive metastatic melanoma. [Table: see text]