Authors: Elise Hildebrandt, PharmD; Sara Bouberhan, MD; Joseph Elijah, PharmD, BCOP, BCPS
Learning Objective: Describe the real-world effectiveness of mirvetuximab soravtansine-gynx (MIRV) ± bevacizumab in patients with platinum-resistant ovarian cancer (PROC) treated at Massachusetts General Hospital (MGH).
Background/Objective: PROC has limited treatment options. MIRV improved outcomes in FORWARD II and MIRASOL, leading to FDA approval for folate receptor alpha (FRα)-high disease. Real-world data remain limited. This study evaluates MIRV ± bevacizumab in PROC at MGH.
Methods: This single-center retrospective case series included adults (≥18 years) treated at MGH with platinum-resistant ovarian, fallopian tube, or primary peritoneal cancer and FRα expression of 25-100%. Eligible patients received MIRV ± bevacizumab with a cycle 1 starting dose ≥ 5 mg/kg using adjusted ideal body weight and routine premedications per the MIRV package insert. Patients enrolled in MIRV clinical trials or who had not received the recommended premedications were excluded. Primary outcomes were progression-free survival (PFS), best overall response (BoR), time on treatment (ToT), and duration of response (DoR); the secondary outcome was overall survival (OS). Baseline characteristics were summarized descriptively. PFS and OS were estimated using Kaplan-Meier methods with log-rank comparisons. BoR, DoR, and ToT were summarized overall and compared between platinum-free interval (PFI) subgroups (<3 vs 3-6 months) using Mann-Whitney U and chi-square tests where appropriate.
Results: A total of 61 patients were included: 3 (4.9%) had FRα expression 25-49%, 7 (11.5%) had 50-74%, and 51 (83.6%) had ≥ 75%. Twenty-four patients (39.3%) had a PFI <3 months and 37 (60.7%) had a PFI of 3-6 months. Median PFS, DoR, and OS were 4.99, 3.04, and 9.66 months. No complete responses were observed; 10 (16.4%) achieved partial response (PR), 24 (39.3%) had stable disease (SD), and 13 (21.3%) had progressive disease (PD). Four patients (7.3%) discontinued due to toxicity. Patients with PFI of 3-6 months had a numerically longer DoR, though this was not statistically significant (p = 0.383). BoR did not differ significantly by PFI (p = 0.876), although more patients experienced PR or SD in the 3-6 month group.
Conclusions: Among patients with platinum-resistant FRα-positive ovarian cancer, MIRV demonstrated modest real-world activity, with lower PFS, BoR, and OS compared to MIRASOL and FORWARD II. Similar to MIRASOL, most patients achieved SD rather than PR despite comparable prior lines of therapy. Although not statistically significant, patients with longer PFI tended to have longer DoR, suggesting potential benefit in this subgroup.
Self-Assessment Question:Which statement most accurately reflects the real-world outcomes of MIRV in PROC patients at MGH?
- MIRV resulted in high rates of CR with minimal adverse events, and outcomes were comparable across PFI groups
- MIRV demonstrated modest activity with the majority of patients achieving PR or SD
- MIRV showed minimal activity with no disease activity, and most patients discontinued due to toxicity, with significant differences based on PFI
- MIRV led to durable responses in a majority of patients, with OS exceeding 12 months regardless of PFI
