Sutro Biopharma, Inc. announced initial results from a Phase 1 dose-expansion study of luveltamab tazevibulin (luvelta), a novel Folate receptor alpha (FolRa)-targeting ADC, in patients with endometrial cancer, in a mini oral presentation at the 2023 European Society For Medical Oncology (ESMO) Congress in Madrid, Spain. Initial data from the Phase 1 dose-expansion study of luvelta were presented by Bhavana Pothurri, M.D., Professor, Department of Obstetrics and Gynecology at NYU Grossman School of Medicine and Director, Gynecologic Oncology Research at NYU Langone, Perlmutter Cancer Center. Advanced endometrial cancer is the only gynecologic malignancy with increasing incidence and mortality in both the US and Europe.

Estimated incidence in the EU: 92,746 pts with 23,047 deaths (2022)2 and in the US: 66,000 pts with 13,030 deaths (2023).FolRa is a validated anti-tumor target in ovarian cancer that is overexpressed in endometrial cancer compared with normal tissue5. As presented in June 2023 at the American Society of Clinical Oncology, luvelta has already demonstrated compelling preliminary efficacy and safety in patients with a broad range of FolRa-expressing recurrent epithelial ovarian cancers (EOC) in a Phase 1 dose escalation/expansion study. ESMO Presentation Highlights: 17 patients were enrolled and initial data were presented on 16 patients with at least one post baseline scan; Luvelta demonstrated encouraging preliminary anti tumor activity in patients with FolRa-expressing endometrial cancer; In patients with TPS >25% FolRa expression (n=7): Confirmed partial response (PR) was seen in 29% (2/7); and Disease Control Rate (DCR) was 86% (6/7).

In patients with TPS =1% FolRa expression (n=16): Confirmed PR was seen in 19% (3/16); and DCR was 69% (11/16). Consistent with previous reported luvelta safety results, the most common adverse event was neutropenia; no new safety signals were observed.