Objective: Platinum-resistant epithelial ovarian cancer (EOC), recurrent endometrial cancer (EC), and triple negative breast cancer (TNBC) are difficult to treat after failing standard therapies. This phase I study evaluated mirvetuximab soravtansine (MIRV) and gemcitabine in patients with recurrent FRα-positive EOC, EC, or TNBC to determine the maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D) (primary endpoint).
Methods: FRα-positive patients with platinum-resistant EOC, EC, or TNBC with ≤4 prior chemotherapy regimens (2 for EC) were enrolled. FRα expression requirement varied among eligible tumors and changed during the study.
Results: Twenty patients were enrolled; 17 were evaluable for DLT. Half the patients received ≥3 prior chemotherapy lines. Most EOC and EC patients (78%) were medium (50-74%) or high(75-100%) FRα expressors. TNBC patients were low (25-49%) FRα expressors. The MTD/RP2D was MIRV 6 mg/kg AIBW D1 and gemcitabine 800 mg/m2 IV, D1 and D8, every 21 days (Dose Level [DL] 3), where 5/7 patients demonstrated a partial response (PR) as their best response, including 2 confirmed ovarian responses whose time-to-progression and duration of response were 7.9/5.4 and 8.0/5.7 months respectively. Most common treatment-related adverse events at MTD were anemia and neutropenia (3/7 each, 43%), diarrhea, hypophosphatemia, thrombocytopenia, and leukopenia (2/7 each, 29%). DLTs were thrombocytopenia (DL1), oral mucositis (DL4) and diarrhea (DL4). Nine of 20 patients (45%; 95% CI: 21.1-68.9%) achieved PR as their best response, with 3/20 patients or 15% (95%CI, 0-32.1%) confirmed PR.
Conclusion: MIRV and gemcitabine demonstrate promising activity in platinum resistant EOC at RP2D, but frequent hematologic toxicities.
Competing Interests: Declaration of Competing Interest MC: Regeneron Pharmaceuticals Inc. (current Regeneron employee); Grant support to institution (National Comprehensive Cancer Network (NCCN) Oncology Research Program from general research support provided by ImmunoGen Corp and Cancer Center Support Grant P30CA033572). DS: no conflicts. TS: no conflicts. NR: no conflicts. JM: Consulting fees (GE Healthcare). EW: no conflicts. AJ: no conflicts. SW: no conflicts. GK: Grant support to institution (Lilly, Merck); Consulting fees (GOG Foundation, Mersana, Immunogen); Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events (Speakers bureau GSK, Merck, Immunogen); Payment for expert testimony (Foundation Medicine); Participation on a Data Safety Monitoring Board or Advisory Board (Repare). ME: no conflicts. LK: no conflicts. EH: no conflictsTD: no conflicts. AH: no conflicts. SL: no conflicts. RM: no conflicts. MW: Regeneron Pharmaceuticals Inc. (current Regeneron employee). PF: no conflicts.
(Copyright © 2023. Published by Elsevier Inc.)