Debiopharm aims to further characterize the safety, tolerability, and preliminary anti-tumor activity of its potent WEE1 inhibitor Debio 0123 as a monotherapy in three different expansion cohorts

Debiopharm (www.debiopharm.com), a privately-owned, Swiss-based biopharmaceutical company aiming to establish tomorrow’s standard-of-care to cure cancer and infectious diseases, today announced the first patient dosed in the expansion of its open-label, non-randomized, multicenter Phase 1 study evaluating Debio 0123, an oral, potent, highly selective and brain-penetrant WEE1 inhibitor, as a monotherapy in patients with recurrent or progressive solid tumors. The expansion of this Phase 1 study, NCT05109975, is to characterize the safety, tolerability, and initial signs of antitumor activity of Debio 0123 when administered as monotherapy. Two out of the three expansion arms of the study will be using biomarkers to pre-select patients with different solid tumors while the third arm will be treating patients with recurrent serous endometrial carcinoma. Currently, sites are open for enrollment in the United States, Spain, and Switzerland.

“Part of our strategy of utilizing OMICs* approaches to identify specific biomarkers and identify patient populations that will respond to Debio 0123 due to synthetic lethality will allow us to enroll patients who are most likely to benefit from treatment, thereby taking a truly precision medicine approach” expressed Dr. Victor Rodriguez-Freixinos, Medical Director, Debiopharm.

Uterine serous carcinoma (USC) is an uncommon, but aggressive subtype of endometrial cancer. It represents approximately 10% of all endometrial cases, which translates to more than 6,000 newly diagnosed patients each year in the United States ^1-2. Despite representing a small proportion of endometrial cancer cases, uterine serous carcinoma accounts for an alarming 39% of endometrial cancer-related deaths. Features highlighting the gravity of USC include the high rates of deep myometrial invasion, as well as metastatic spread to lymph nodes and peritoneal surfaces ¹. These features largely affect the 5-year overall survival but compared with more common endometrial cancer, the prognosis for USC is generally poor and the risk of relapse is high ³. Similar to USC, epithelial ovarian cancer (EOC) is known for its poor prognosis due to the aggressive clinical course and the tendency to metastasize. However, EOC accounts for about 90% of all ovarian cancers and affects more than 17,000 American women each year, of which about 30% survive for 5 years after diagnosis ^4-5.

“This study’s population is mainly female, burdened by fatal malignancies like Uterine Serous Carcinoma, Epithelial Ovarian Cancer and fallopian tube cancer which are well-known hard-to-treat cancers. These patients need new treatment options, as the current standard of care is insufficient in assuring long-term progression free survival.” Dr. Manish R. Sharma, Principal Investigator at the START Midwest, Michigan.

The Debio 0123 program originates from a growing awareness of DDR inhibition in fighting life-threatening cancers. Maximizing efficacy, while preserving safety are key elements that Debiopharm is eager to assess throughout the clinical development of Debio 0123. With the successful realization of these requirements, Debio 0123 could become the first choice WEE1 inhibitor.

About Debio 0123

Debio 0123 is a brain-penetrant, highly selective WEE1 kinase inhibitor. WEE1 is a key regulator of the G2/M and S phase checkpoints, activated in response to DNA damage, allowing cells to repair their DNA before resuming their cell cycle. WEE1 inhibition, particularly in combination with DNA damaging agents, induces an overload of DNA breaks. In conjunction with abrogation of other checkpoints such as G1, the compound pushes the cells through cycle without DNA repair, promoting mitotic catastrophe and inducing apoptosis of cancer cells. Currently in research for solid tumors in monotherapy and combination, Debio 0123 is being developed to respond to high unmet needs of patients living with the burden of difficult-to-treat cancers.

About DNA-Damage Response (DDR)

When cells have damaged DNA, they need to undergo a repair process called DDR to be able to survive. Cancer cells use their hyperactive DDR response to divide and grow uncontrollably, which promotes cancer expansion. Inhibition of DDR, particularly in combination with other anticancer agents, induces an overall arrest in the uncontrollable cancer cell cycle. This ultimately activates a self-destruction program in cancer cells. DDR inhibitors such as Debiopharm's WEE1 and USP1 inhibitors, are being tested in either clinical or preclinical studies.

Debiopharm’s commitment to patients

Debiopharm aims to develop innovative therapies that target high unmet medical needs in oncology and bacterial infections. Bridging the gap between disruptive discovery products and real-world patient reach, we identify high-potential compounds and technologies for in-licensing, clinically demonstrate their safety and efficacy, and then select large pharmaceutical commercialization partners to maximize patient access globally.

For more information, please visit www.debiopharm.com

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Sources

¹ Hamilton CA, et al. Br J Cancer. 2006 Mar 13;94(5):642-6. doi: 10.1038/sj.bjc.6603012. PMID: 16495918; PMCID: PMC2361201.

² Clement PB, Young RH. Adv Anat Pathol. 2004 May;11(3):117-42. doi: 10.1097/00125480-200405000-00001. PMID: 15096727.

³ Acharya S, et al. Lancet Oncol. 2005 Dec;6(12):961-71. doi: 10.1016/S1470-2045(05)70463-0. Erratum in: Lancet Oncol. 2006 Feb;7(2):105. PMID: 16321764.

⁴ American Cancer Society. Key Statistics for Ovarian Cancer.

⁵ Arter, Z.L., et al. Br J Cancer 130, 108–113 (2024). https://doi.org/10.1038/s41416-023-02471-z

* OMICs = technologies that are primarily aimed at the universal detection of genes (genomics), mRNA (transcriptomics), proteins (proteomics) and metabolites (metabolomics) in a specific biological sample

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