Abstract 833P
Background
MIRV is an ADC comprising a FRα-binding antibody, cleavable linker, and the maytansinoid DM4, a potent tubulin-targeting agent. MIRV is being evaluated with carboplatin and BEV in recurrent platinum-sensitive (RPS) ovarian cancer.
Methods
Pts had RPS ovarian cancer (last platinum-free interval (PFI) >6 mo), 1 or 2 prior lines of therapy, and FRα-positivity by IHC (medium/high expression; ≥ 50%/ ≥75% of cells with PS2+ staining intensity). MIRV was given at 6 mg/kg (adjusted ideal body weight) with CARBO (AUC 5) and BEV (15 mg/kg) IV on Day 1 of a 21-day cycle. MIRV and BEV were continued as maintenance after completing CARBO. Responses were assessed with RECIST 1.1.
Results
41 pts received full dosing, median age of 63 years; 73% had 1 prior line of therapy; 42% had prior PARPi; 24% had prior BEV; 54% had a PFI of 6 to ≤ 12 mos; 9 pts remain on study, with a 17 mo median duration of follow-up. The most common treatment-related AEs were consistent with the safety profile of MIRV, albeit more frequent: diarrhea (all grades, 83%; [gr 3, 10%]), nausea (76%; [2%]), fatigue (76%; [5%]), and vision blurred (68%; [0%]). AEs seen with CARBO, thrombocytopenia [51% ≥ gr 3], neutropenia [39% ≥ gr 3], and infusion related reactions (12%; [gr 4 2%]), and BEV, hypertension (gr 3,10%), were also observed. Grade 2 peripheral neuropathy was seen in 22% (no ≥ gr 3 events), and alopecia in 2%. The confirmed ORR was 81%, (95% CI, 65, 91), with a median duration of response (DOR) of 10.7 mos (95% CI, 8,14) and median progression free survival (PFS) of 12.0 mos (95% CI, 9, 15) for all pts. In pts with 1 prior, the ORR was 90%, (95% CI, 74, 98), DOR of 9.7 mos (95% CI, 8,14) and PFS of 11.9 mos (95% CI 9, 15).
Conclusions
MIRV was readily combined with standard dosing of BEV and CARBO, with a manageable AE profile as anticipated for this triplet. The clinical activity is encouraging, similar to outcomes with current standard of care. These results support further exploration of this novel combination as an alternative to current treatment regimens for recurrent platinum sensitive disease.
Clinical trial identification
NCT02606305.
Editorial acknowledgement
Legal entity responsible for the study
ImmunoGen.
Funding
ImmunoGen.
Disclosure
D.M. O'Malley, I.B. Vergote, K.N. Moore: Advisory/Consultancy: ImmunoGen. P.A. Zweidler-mckay: Full/Part-time employment: ImmunoGen. All other authors have declared no conflicts of interest.