A 79% confirmed response rate from a Phase 1 cohort of 29 evaluable patients is the kind of early number that earns a fast track to Phase 3, and Lilly’s sofetabart mipitecan (Sofe-M) plus bevacizumab data in platinum-sensitive ovarian cancer, presented at ESMO 2026, is exactly that. Every patient in the cohort achieved disease control, six had complete responses, and median duration of response had not been reached. As of the July 6, 2026 data cutoff, median follow-up was 6.2 months for duration of response and 10.2 months for progression-free survival, with median PFS also not reached.
The finding that matters most for trial design comes from the PARPi-pretreated subgroup. Two-thirds of the 33-patient cohort had prior PARP inhibitor exposure, a population where platinum re-challenge produces meaningfully lower response rates in published real-world data. Sofe-M held its 79%-or-higher response rate in both PARPi-treated and PARPi-naïve patients, and it did so regardless of folate receptor alpha (FRα) expression level. That expression-level independence matters because mirvetuximab soravtansine (Elahere), the FDA-approved FRα-targeting ADC, carries an FRα-positive indication requirement. Sofe-M’s polysarcosine linker and exatecan payload appear designed to work at lower expression thresholds, and the Phase 1 data support that design intent, though Phase 3 confirmation is still needed.
Tolerability held up reasonably well for a combination regimen in a heavily pretreated group. Patients had received a median of three prior systemic therapies. Epistaxis and nausea each occurred in 73% of patients, neutropenia in 55%, and Grade 3 or higher neutropenia in 42%, with dose reductions in 42% of patients. Only 6% discontinued for an adverse event, and any-grade neuropathy was 9% with no severe cases, a meaningful contrast to tubulin-targeting payloads that accumulate neuropathy in this population.
Lilly’s FRAmework-01 master protocol now has three Phase 3 parts running in parallel: monotherapy in platinum-resistant disease, and two combination arms in platinum-sensitive disease separated by PARPi history. The arm most directly enabled by these data is Part B, which specifically targets patients who progressed on or within six months of completing a PARPi. Whether the response durability suggested by an unreached median DOR at 6.2 months of follow-up survives into that randomized setting is the number to watch when Part B interim data arrive.
Correction, October 24, 2026: an earlier version of this article said the source did not specify the sample size or the maturity of the data. Lilly’s release did report the cohort size, the data cutoff and median follow-up. Those figures have been added and the article has been rewritten from the full release.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
