Nivolumab (Nivo) +/- Ipilimumab (Ipi) In Advanced Small-Cell Lung Cancer (Sclc): First Report Of A Randomized Expansion Cohort From Checkmate 032.

8503Background: Patients (pts) with advanced SCLC after first-line platinum-based chemotherapy (PLT-CT) have a poor prognosis and limited treatment options. CheckMate 032 is a phase I/II trial evaluating multiple regimens of nivo ± ipi in solid tumors, including advanced SCLC. Tolerability and efficacy of nivo ± ipi were demonstrated in early results from the initial treatment arms (Antonia, Lancet Oncol 2016), prompting long-term follow-up and the addition of a randomized expansion cohort to further evaluate nivo ± ipi in advanced SCLC. Methods: In the initial treatment arms, pts with advanced SCLC and disease progression after prior PLT-CT were assigned to nivo (3 mg/kg Q2W; n = 98) or nivo 1 + ipi 3 (1 mg/kg and 3 mg/kg Q3W x 4, then nivo 3 Q2W; n = 61); safety/efficacy was assessed with a follow-up of ~18 mo. In the subsequent SCLC expansion cohort, pts were randomized 3:2 to nivo vs nivo 1 + ipi 3 and stratified by number of prior therapies. The primary endpoint was objective response rate (ORR). Res...