Nivolumab (nivo) ± ipilimumab (ipi) in advanced small-cell lung cancer (SCLC): First report of a randomized expansion cohort from CheckMate 032.

Abstract

8503 Background: 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). Results: Updated efficacy/safety results from the initial (non-randomized) nivo and nivo 1 + ipi 3 arms are summarized in the table. Responses were durable and occurred regardless of PD-L1 expression or PLT-sensitivity; safety was consistent with prior nivo ± ipi studies. In the expansion cohort, 247 pts were randomized to nivo or nivo 1 + ipi 3. The presentation will contain the first report of efficacy/safety results and subgroup analyses from this randomized expansion cohort. Conclusions: Durable responses are observed with nivo and nivo + ipi in pts with previously treated SCLC. The expansion cohort represents the first randomized evaluation of combined immune checkpoint blockade in SCLC. Clinical trial information: NCT01928394. [Table: see text]