Carboplatin + nivolumab (PD-1) misses primary PFS endpoint in 1L mTNBC, signal in PD-L1+ (SP142 IC≥1%)

Carboplatin plus nivolumab is a platinum chemotherapy + anti–PD-1 checkpoint inhibitor regimen tested vs carboplatin alone in a randomized Phase II first-line metastatic TNBC trial (NCT03414684). In the mITT population (n=62), median PFS was 4.2mo with carbo+nivo vs 5.5mo with carbo (primary endpoint not met), while median OS was 16.8 vs 11.1mo; in the PD-L1+ subgroup by SP142 IC≥1% (n=24), median PFS was 8.3 vs 4.7mo and median OS was 17.6 vs 10.7mo. Grade ≥3 AEs were common but similar (56.8% combo vs 65.8% control), and the efficacy benchmarks for today’s PD-L1+ 1L mTNBC standard are pembrolizumab+chemo in CPS≥10 (KEYNOTE-355 median PFS 9.7 vs 5.6mo) and historically atezolizumab+nab-paclitaxel in SP142 IC≥1% (IMpassion130 median PFS ~7.4–7.5 vs 4.8–5.0mo; OS signal reported but regulatory status has shifted), so this carbo+nivo dataset looks more “biomarker-hypothesis-generating” than SOC-challenging.