Cabazitaxel/carbo + nivolumab/ipilimumab (PD-1/CTLA-4) hits 78% 6-mo rPFS in metastatic NEPC/AVPC

CHAMP (NCT04709276) is a multicenter, single-arm Phase 2 trial testing cabazitaxel (taxane microtubule inhibitor) + carboplatin (platinum) with dual checkpoint blockade nivolumab (PD-1) and ipilimumab (CTLA-4), followed by maintenance immunotherapy, in metastatic neuroendocrine prostate cancer or aggressive-variant prostate cancer (NEPC/AVPC) on ongoing ADT. In 40 enrolled patients (n=38 efficacy-evaluable; 75% visceral mets; 58% liver; 85% prior ARPI; 70% prior chemo), the primary endpoint was met with 6-mo iRECIST/PCWG3 rPFS 78% (one-sided 90% CI 69–100%) and median rPFS 12 months; ORR was 34% (CR 2.6%, PR 32%), median OS 12 months with 12-mo OS 46%. Grade 3–4 toxicity was substantial (50% G3; 18% G4), with common G3–4 AEs including anemia (n=15), neutropenia (n=5), sepsis (n=5), thrombocytopenia (n=5), colitis (n=5), and febrile neutropenia (n=4), but no treatment-related deaths—numerically longer disease control than historical platinum doublets in AVPC/NEPC where rPFS/PFS is often ~4–6 months and OS commonly ~7–11 months depending on setting and case-mix.