A narrative review of new strategies for immunotherapy combination treatment in platinum-resistant ovarian cancer: mechanisms, clinical evidence, and future directions

Platinum-resistant ovarian cancer (PROC) is a major challenge in gynecological tumor treatment, with poor prognosis and limited chemotherapy efficacy. Immune checkpoint inhibitors as monotherapy demonstrate low response rates, underscoring the need for effective combination therapies. This review aims to describe recent advances in immune combination therapy for PROC, explain synergistic mechanisms, summarize key clinical evidence, and discuss challenges and future directions. The search of PubMed and Web of Science (January 2018-January 2026) following PRISMA guidelines identified phase II/III trials, prospective cohorts, and preclinical studies. The narrative review found that combination strategies with anti-angiogenic agents achieved objective response rates (ORR) of 24-27% and median progression-free survival (PFS) of 4-5 months. Adding PARP inhibitors yielded an ORR of 18-31% with disease control rates of 65-81%. Furthermore, the antibody-drug conjugate (ADC) mirvetuximab soravtansine as monotherapy achieved an ORR of 42.3% in folate receptor alpha (FRα)-high PROC. Finally, the phase III KEYNOTE B96 trial reported a 4.2-month overall survival benefit with pembrolizumab plus chemotherapy in the PD-L1-positive population. These regimens substantially improve efficacy compared with historical single-agent chemotherapy (ORR 10-20%, PFS 3-4 months). In conclusion, immune combination therapy offers a novel therapeutic strategy for PROC. Future efforts should explore biomarkers, optimize regimens, overcome resistance, and validate efficacy through innovative trials to achieve personalized treatment.