Rucaparib (PARP inhibitor) + nivolumab (PD-1) maintenance misses primary PFS bar in advanced BTC, with signal in DDR/IDH1 subsets

Rucaparib is an oral PARP inhibitor paired here with nivolumab, a PD-1 antibody, as switch-maintenance after 4-6 months of first-line platinum chemotherapy in advanced biliary tract cancer (BilT-02; Phase 2, multicenter; n=31; NCT03639935). The primary endpoint was not met: 4-month PFS rate was 54.8% (95% CI, 36.0-72.7) vs a prespecified 63% null (and 85% alternative), with median PFS from start of maintenance (PFS1) 4.6 months and OS1 15.9 months; from start of first-line therapy, median PFS2 was 9.9 months and OS2 21.4 months, and ORR on maintenance was 6.4% (2 PRs). Grade ≥3 TRAEs included anemia (12.9%), neutropenia (9.7%), and elevated liver enzymes (12.9%); for context, modern first-line gem/cis + anti–PD-(L)1 standards (KEYNOTE-966 pembrolizumab+gem/cis) deliver median OS 12.7 months and median PFS 6.5 months from treatment start (ORR 29%), but those benchmarks are not directly comparable to a post-induction maintenance population enriched for chemotherapy non-progressors.