Ovarian cancer data supports registration-enabling trial of luvelta for women with platinum-resistant ovarian cancer

Potential benefit to 8 out of 10 platinum-resistant ovarian cancer patients, including addressing unmet need in patients with low-medium FolRα expression

Promising clinical activity and tolerability of luvelta as both a monotherapy and in combination across multiple cancers may provide for a significant commercial opportunity

“Luvelta has been studied in over 180 patients to-date, and has demonstrated both promising clinical activity and a tolerable safety profile. We are optimistic about its potential to change the cancer treatment landscape,” said Bill Newell, Sutro’s Chief Executive Officer. “This includes the potential to be the first ADC to treat ovarian cancer patients with low to medium FolRα expression, which could double the current eligible patient population relative to the FolRα-targeting ADC on the market. In 2024, we look forward to advancing two synergistic registrational clinical trials for luvelta in ovarian cancer and CBF/GLIS AML, while continuing to progress the development of additional indications.”

The event will feature presentations by key members of Sutro's senior management team and external oncology expert, Bradley Monk, M.D., Professor, the Division of Gynecologic Oncology, University of Arizona College of Medicine and Creighton University School of Medicine and Vice President and Co-Director, GOG Partners. Sutro management and Dr. Monk will participate in a Q&A session at the end of the presentation.

Luvelta FolRα-targeting ADC Franchise Upcoming Milestones:

• The registration-directed trial, REFRαME-O1, in PROC is enrolling, with 26 active sites across 5 countries and an anticipated ~140 sites in ~20 countries by the end of 2024. Part 1 of the trial is expected to be completed in the first half of 2024.
• Initiation of REFRαME-P1, a registration-enabling trial for pediatric patients with CBF/GLIS AML, is planned for the first half of 2024.
• An Investigational New Drug (IND) application submission is planned in non-small cell lung cancer (NSCLC) in the first half of 2024.
• Continued clinical development is planned in endometrial cancer and in combination with bevacizumab for the treatment of ovarian cancer.

Compelling Luvelta Data:

• Sutro presented an aggregated analysis of nearly 100 women with ovarian cancer from Company’s Phase 1 program.
  • Treatment with luvelta demonstrated improved clinical outcomes and tolerability compared to historical results with standard of care chemotherapy in an evaluable patient population matching the eligibility criteria for the REFRαME-O1 trial.
  • The safety profile across the aggregated analysis remained consistent with previously reported data.
  • Safety data from an additional cohort with prophylactic G-CSF treatment showed significant reduction of neutropenia and resulting dose delays.
• New data in combination with bevacizumab demonstrated clinical activity in treated patients regardless of FolRα expression level.
• Preclinical data in a model of NSCLC demonstrated that a single dose of luvelta produced potent anti-tumor activity and that the combination of luvelta and PD-1 blockade (avelumab) demonstrated benefit and complete tumor regression.
• Promising clinical data in late-stage endometrial cancer and CBF/GLIS AML have been presented at ESMO and ASH in 2023.