Indianapolis, Indiana, USA, October 24, 2026
Eli Lilly and Company has announced promising early clinical findings for its investigational cancer medicine sofetabart mipitecan (Sofe-M) in combination with bevacizumab for patients with platinum-sensitive ovarian cancer. The Phase 1 study demonstrated a confirmed objective response rate of 79.3% and a disease control rate of 100% among patients with measurable disease. The findings were announced on October 24, 2026, ahead of their presentation at the European Society for Medical Oncology (ESMO) Congress in Madrid, Spain. Sofe-M is a next-generation folate receptor alpha (FRα)-targeting antibody-drug conjugate (ADC) designed to deliver an anticancer agent directly to tumor cells. The results provide an encouraging clinical signal for a patient population that continues to face treatment challenges following recurrence, particularly after previous maintenance therapy with poly (ADP-ribose) polymerase inhibitors (PARPi). Lilly is continuing to evaluate Sofe-M in a global Phase 3 clinical development program.
Phase 1 Trial Shows Promising Antitumor Activity
The Phase 1 study evaluated Sofe-M in combination with bevacizumab in patients with advanced solid tumors, including a cohort of 33 women with platinum-sensitive ovarian cancer. Participants received Sofe-M at 4 mg/kg alongside bevacizumab at 15 mg/kg. Among the 29 patients with measurable disease, 23 achieved a confirmed response, including six complete responses and 17 partial responses, resulting in a confirmed objective response rate of 79.3%. The disease control rate reached 100%, indicating that all 29 evaluable patients experienced a complete response, partial response or stable disease. Clinical activity was observed across different levels of FRα expression and among patients with and without prior PARP inhibitor exposure. Approximately 67% of the cohort had previously received a PARP inhibitor, while 70% had received bevacizumab. The median duration of response and median progression-free survival had not been reached at the reported data cutoff of July 6, 2026. Median follow-up was 6.2 months for duration of response and 10.2 months for progression-free survival. These early findings are encouraging, although the small cohort and limited follow-up mean that larger studies are necessary to establish the durability and clinical significance of the treatment effect.
Sofe-M Targets Folate Receptor Alpha in Tumors
Sofetabart mipitecan is an antibody-drug conjugate designed to target FRα, a cell-surface protein frequently overexpressed in ovarian cancer. The investigational medicine combines a humanized monoclonal antibody that recognizes FRα with exatecan, a topoisomerase I inhibitor that interferes with DNA replication. A proprietary cleavable linker connects the antibody to the anticancer payload, enabling delivery into target-expressing tumor cells. This targeted approach is intended to concentrate anticancer activity in tumors while limiting exposure to healthy tissues, although the degree of selectivity and clinical benefit must be confirmed through ongoing research. Bevacizumab works through a different mechanism by inhibiting vascular endothelial growth factor (VEGF), a protein involved in blood vessel formation that can support tumor growth. Combining these agents may offer complementary anticancer effects. Lilly is investigating whether this strategy can provide meaningful treatment responses across a broad range of FRα expression levels, including in patients previously treated with PARP inhibitors. The combination remains investigational and has not been established as a new standard of care for platinum-sensitive ovarian cancer.
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Phase 3 FRAmework-01 Program Advances Development
Lilly is evaluating Sofe-M through its FRAmework-01 global Phase 3 clinical development program, which includes three study parts covering platinum-resistant and platinum-sensitive ovarian cancer. Part A investigates Sofe-M as a monotherapy for platinum-resistant disease. Part B evaluates Sofe-M plus bevacizumab in platinum-sensitive disease that progressed on or within six months of completing PARP inhibitor treatment. Part C evaluates the combination in patients with platinum-sensitive disease who have not received prior PARP inhibitor treatment. The program is designed to assess progression-free survival alongside additional outcomes, including overall survival, objective response rate, duration of response and safety. In the Phase 1 combination cohort, the most frequently reported treatment-emergent adverse events included nosebleeds, nausea, anemia, neutropenia and fatigue. Severe neutropenia and anemia were also reported, emphasizing the importance of ongoing safety evaluation. Six percent of patients discontinued treatment because of adverse events. Further clinical data will be needed to determine the treatment’s benefit-risk profile and its potential role in future ovarian cancer care. The Phase 3 studies will be critical to confirming whether the promising early response rates translate into sustained clinical benefits for patients.
Source: Eli Lilly press release
