Real-world overall survival with mirvetuximab soravtansine compared with chemotherapy after multiple lines of platinum therapy in gynecologic cancers.

e17567 Background: Mirvetuximab soravtansine (MIRV) is FDA-approved for FRα-high, platinum-resistant ovarian cancer, with improved survival demonstrated in randomized trials. However, real-world comparative outcomes in heavily pretreated patients remain limited. We evaluated overall survival (OS) with MIRV versus standard chemotherapy following multiple platinum exposures in routine clinical practice. Methods: Using the TriNetX database (2020–2025), we identified adults with ovarian, fallopian tube, or primary peritoneal cancer who received at least three prior platinum therapies. To enrich for platinum-sensitive or partially sensitive disease, patients were required to receive a subsequent platinum agent within 7–180 days of initial platinum therapy before index treatment. Patients subsequently treated with MIRV or investigator’s choice chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan) were included. FRα status was unknown. Cohorts were propensity score–matched (1:1) on demographics, comorbidities, disease characteristics, prior treatments, and laboratory values. OS was assessed from treatment initiation and capped at 4 years. Kaplan–Meier and Cox proportional hazards models were used. Results: Before matching, 559 MIRV and 11,508 chemotherapy patients met inclusion criteria; 515 patients per group were analyzed after matching. MIRV was associated with a modest but statistically significant OS advantage compared with chemotherapy (4-year survival 47% vs 46%; median OS 44.2 vs 39.9 months; HR 0.80, 95% CI 0.65–0.99; p = 0.0346). One-year survival was higher with MIRV (88% vs 82%; p = 0.0224). Among MIRV-treated patients, 185 subsequently received bevacizumab, with a median time to initiation of 6.9 months. Conclusions: In a heavily pretreated, platinum-exposed real-world population, MIRV demonstrated a small but significant survival advantage over standard chemotherapy. These findings support MIRV’s clinical benefit in later-line practice and highlight frequent post-MIRV bevacizumab use. Further studies are warranted to define optimal sequencing and combination strategies.