MEDSIR & Debiopharm Begin WIN-B Trial Dosing for Advanced Breast Cancer Treatment

Debiopharm, a Swiss-based biopharmaceutical company, and MEDSIR, an international clinical oncology research organization, have announced the commencement of the WIN-B clinical trial. This trial aims to assess the safety and preliminary efficacy of combining Debiopharm’s selective WEE1 inhibitor, Debio 0123, with Gilead’s antibody-drug conjugate, Trodelvy, in patients suffering from advanced HR+/HER2- and triple-negative breast cancers. The trial is sponsored by MEDSIR and funded by Debiopharm, with Gilead supplying Trodelvy.

In May 2024, Debiopharm and MEDSIR announced their collaboration to explore this therapeutic combination. Debio 0123 is a highly selective WEE1 kinase inhibitor with the ability to penetrate the brain, while Trodelvy is a Trop-2-directed antibody-drug conjugate approved in numerous countries for treating second-line or later metastatic triple-negative breast cancer (TNBC) and for certain patients with pre-treated HR+/HER2- metastatic breast cancer. Prior promising preclinical results for this combination were shared at the American Association for Cancer Research meeting in 2024.

The importance of this trial lies in the critical need for new treatments for these types of breast cancer. HR+/HER2- breast cancer, representing 70% of all breast cancer cases, involves cells that express estrogen or progesterone receptors. A significant challenge is that nearly one-third of early-stage HR+/HER2- cases become metastatic, with a five-year relative survival rate of only 30%. Often, these patients eventually develop resistance to endocrine-based therapies and newer treatments like Trodelvy, resulting in poor prognosis with single-agent chemotherapy.

Triple-negative breast cancer (TNBC), which accounts for 10-15% of breast cancer cases, is characterized by its aggressive nature and lack of estrogen, progesterone, or HER2 receptors. This subtype has a high risk of metastasis, either at diagnosis or upon relapse, leading to a significantly higher mortality rate compared to other breast cancer types. These factors underscore the urgent demand for innovative treatment options, such as the combination therapy being assessed in the WIN-B trial.

Esteban Rodrigo Imedio, Executive Medical Director of Oncology at Debiopharm, emphasized the importance of exploring novel treatment combinations to potentially achieve breakthroughs for cancer patients with unmet medical needs. Dr. Javier Cortés, MEDSIR's Senior Scientific Lead, echoed this sentiment, highlighting the trial’s potential to advance care for hard-to-treat breast cancers through collaborative efforts with Debiopharm and Gilead.

Debio 0123 functions as a brain-penetrant, selective WEE1 kinase inhibitor, targeting the G2/M and S phase checkpoints crucial for DNA damage response. By inhibiting WEE1, particularly alongside DNA-damaging agents, it causes an overload of DNA breaks. This disruption pushes the cells through the cycle without repair, promoting cell death in cancerous cells. Debio 0123 is currently under investigation in clinical trials for various solid tumors, both as a standalone treatment and in combination therapies, addressing significant unmet needs in difficult-to-treat cancers.

Founded in 2012, MEDSIR collaborates with global partners to innovate oncology research. Based in Spain and the United States, the organization manages clinical trials from conception to publication, utilizing a network of experts and technology to streamline operations. MEDSIR's strategic alliance with Oncoclínicas in Brazil exemplifies its commitment to advancing oncology research globally.

Debiopharm focuses on developing innovative therapies for high unmet needs in oncology and infectious diseases, bridging the gap between discovery and real-world patient access. By identifying promising compounds and demonstrating their safety and efficacy in clinical settings, Debiopharm aims to maximize global patient access through partnerships with pharmaceutical companies.