Sutro Biopharma announced updated data from its Phase 1b study of luveltamab tazevibulin (luvelta) in combination with bevacizumab, demonstrating encouraging antitumor activity in patients with late-stage epithelial ovarian cancer (EOC). The data, presented at the 2024 European Society for Medical Oncology (ESMO) Congress, highlight a potential non-biomarker-driven treatment approach for EOC, irrespective of Folate Receptor-α (FRα) expression.
Promising Response Rates
The study revealed that a 4.3 mg/kg dose of luvelta in combination with a standard dose of bevacizumab (15 mg/kg) every three weeks resulted in a 56% objective response rate (ORR) in patients with late-stage ovarian cancer. This dose was selected as the recommended phase 2 dose (RP2D). Across all explored dose ranges, the combination demonstrated a 35% ORR.
Jane Chung, Sutro’s President and Chief Operating Officer, stated, “We are encouraged by these results achieved with luvelta in combination with bevacizumab, which may offer the opportunity to benefit ovarian cancer patients regardless of FRα expression.”
Study Details and Patient Population
The Phase 1b study enrolled 18 patients, with one patient remaining on treatment at the time of the data cutoff. Among 17 RECIST evaluable patients, the ORR at the RP2D was 56% (5/9). In patients with ≥25% FRα expression, the ORR was 44% (4/9), while in patients with <25% FRα expression, the ORR was 29% (2/7). The median duration of response was 9.3 months.
Safety Profile
Importantly, no new safety signals were observed with the combination of luvelta and bevacizumab compared to either agent alone. The most common adverse event was neutropenia, consistent with previous reports on luvelta's safety profile.
Ongoing Expansion Phase
The expansion phase of the study is ongoing at the RP2D, with an additional 23 patients enrolled. Initial data from this expansion phase are expected in the first half of 2025.
Luvelta: A Targeted Approach
Luveltamab tazevibulin (luvelta) is an antibody-drug conjugate (ADC) targeting FRα, designed to treat a broad range of patients with ovarian cancer, including those with lower FRα expression. It is being developed using Sutro’s cell-free XpressCF® platform. The FDA has granted luvelta Fast Track designation for Ovarian Cancer, as well as Orphan and Rare Pediatric Disease designations for CBF/GLIS2 Pediatric AML.
