Debiopharm to Unveil New Pre-Clinical and Clinical Research Advances in DDR Inhibition, Dual Payload ADCs, and AI-Driven Biomarkers at AACR 2026

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, will release groundbreaking new data at the 2026 Annual American Association for Cancer Research (AACR) meeting in San Diego, California. A major highlight of this year’s conference participation is the first clinical data disclosure from the MYTHIC Study (NCT04855656), a Phase I trial evaluating the combination of Debiopharm’s WEE1 inhibitor, zedoresertib (Debio 0123), with the PKMYT1 inhibitor lunresertib (Debio 2513) in patients with advanced solid tumors harboring CCNE1, FBXW7, or PPP2R1A genomic alterations. The oral presentation on April 19^th 2026 will be given by Dr. Timothy A. Yap, a Medical Oncologist and Physician-Scientist based at the University of Texas MD Anderson Cancer Center and Principal Investigator of the MYTHIC study.

Comprehensive pre-clinical results will also be presented for the MultiLINK™ ADC Technology Suite, showcasing the potential of novel dual payload antibody drug conjugates (ADCs) to enhance therapeutic efficacy. Two translational research posters will also be featured: the first highlighting the development of a Deep Learning-based “virtual” Cyclin E1 biomarker to predict protein overexpression in gynecological malignancies from H&E slides; the second unveiling how multiplexed spatial profiling and 3D cluster analysis are being used to reconcile RNASeq, mass spectrometry, and IHC data to refine therapeutic strategies for HER3 bispecific antibody and ADC programs.

“The first clinical results of the MYTHIC study mark an important milestone for the program. Early data readouts suggest strong synergistic activity between zedoresertib and lunresertib, with tumor regressions observed in patients,” explained Esteban Rodrigo Imedio, Executive Medical Director, Oncology, Debiopharm

“Dual payload ADC technology has the potential to be a game changer for cancer patients. As patients need innovative solutions for hard-to-treat cancers, we hope that our dual payload research using MLINK Duo ADC linker technology will help us reshape how complex cancers are targeted and treated,” expressed Antoine Attinger, Director, Translational Pharmacology, Debiopharm.

SESSION DETAILS

• Session Type: Clinical Trials Plenary Session

AACR 2026 Oral Presentation	Debiopharm Compound	Title	Presenter
- Sun, April 19 - Time: 2:00 PM - Hall H	zedoresertib (Debio 0123) & lunresertib (Debio 2513)	First data disclosure of the Phase I trial of the first-in-class combination of WEE1 inhibitor zedoresertib with PKMYT1 inhibitor lunresertib in patients with advanced solid tumors harboring CCNE1, FBXW7, or PPP2R1A genomic alterations	Dr. Timothy A. Yap, Medical Oncologist, University of Texas MD Anderson Cancer Center, Houston, TX

• Session Title: Antibody Drug Conjugates and Linker Engineering 1

AACR 2026 Poster Presentation	Debiopharm Technology	Title	Author
- Mon, April 20 - Display: 9:00 AM – 12:00 PM - Poster #: 1683 - Section: 12	MLINK Duo	Enhancing therapeutic efficacy and overcoming resistance with a novel dual payload antibody drug conjugate technology	Antoine Attinger et al., Translational Medicine, Debiopharm International SA, Lausanne

• Session Title: Digital Pathology 3

AACR 2026 Poster Presentation	Debiopharm Program	Title	Author
- Tue, April 21 - Display: 9:00 AM – 12:00 PM - Poster #: 4155 - Section: 3	zedoresertib (Debio 0123)	Development of a virtual Cyclin E1 biomarker using Deep Learning from H&E slides for predicting Cyclin E1 overexpression in gynecological malignancy	Jeannette Fuchs et al., Translational Medicine, Debiopharm International SA, Lausanne

• Session Title: Molecular Targets 2

AACR 2026 Poster Presentation	Debiopharm Program	Title	Author
- Tue, April 21 - Display: 2:00 PM – 5:00 PM - Poster #: 5738 - Section: 13	HER3 ADCs	Beyond bulk: Resolving RNASeq/mass spectrometry/IHC discrepancies with multiplexed spatial profiling and 3D cluster analysis to refine HER3 (bs)Ab and (bs)ADC therapeutic strategies	Jeannette Fuchs et al., Translational Medicine, Debiopharm International SA, Lausanne

ABOUT DNA DAMAGE REPAIR (DDR)

When cells have damaged DNA, they must undergo a repair process known as DDR to survive. Cancer cells rely heavily on DDR as they divide and grow uncontrollably. Inhibition of DDR, particularly in combination with other anticancer agents, prevents cancer cells from repairing their DNA, ultimately activating a programmed cell death process. DDR inhibitors such as zedoresertib (Debio 0123), Debiopharm’s WEE1 inhibitor, are currently being investigated in clinical and preclinical studies.

ABOUT PKMYT1 INHIBITION

Lunresertib (Debio 2513) is a first-in-class, oral PKMYT1 inhibitor designed to exploit specific genetic vulnerabilities in solid tumors, such as CCNE1 amplification. By targeting PKMYT1, the drug induces synthetic lethality, preventing cancer cells from repairing DNA damage and forcing them into programmed cell death. As the most advanced PKMYT1 inhibitor in clinical development, lunresertib has shown encouraging proof-of-concept results both as monotherapy and in combination therapies within the ongoing MYTHIC trial.

DEBIOPHARM’S ADC PORTFOLIO

We are developing fit-for-purpose antibody drug conjugates through a tailored “Trifecta” approach: strategic target selection, innovative MultiLINK™ linker technology and smart payload choices. Our broad and balanced portfolio of 1st-in-class and best-in-class ADCs includes Debio 0633 (undisclosed target), Debio 1562M, a CD37-targeted ADC for the treatment of acute myeloid leukemia (AML) and Myelodysplastic syndromes (MDS), as well as other ADCs with undisclosed targets including bispecific ADCs.

https://www.debiopharm.com/our-expertise/adcs/

To allow both high DAR and high stability, our ADCs are designed utilizing our innovative proprietary MultiLINK™ linker technology suite, a comprehensive toolbox of options allowing linker optimization for specific antibody, payload and clinical contexts. We are leveraging key collaborations and our in-house capabilities including ADC conjugation, optimization, PK/PD, toxicology, translational medicine, clinical development and supply chain to produce novel ADCs that respond to the high unmet needs of cancer patients.

https://www.debiopharm.com/pipeline/multilink/

DEBIOPHARM’S COMMITMENT TO CANCER PATIENTS

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

Learn more about the MYTHIC trial: Solid Tumors - Debiopharm - Patients

Visit us: www.debiopharm.com/drug-development/ and www.debiopharm.com/manufacturing-science

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