European Patent Office Confirms Patent Protection For SOT201, SOTIO's Clinical-Stage Immunocytokine Showing Promising Anti-Tumor Activity

During oral proceedings held in the beginning of July, the Boards of Appeal confirmed the validity of the patent and upheld the earlier Opposition Division decision maintaining the patent as granted. The patent is co-owned by Cytune Pharma (an affiliate of SOTIO Biotech), AP-HP (Assistance Publique – Hôpitaux de Paris), and INSERM (Institut National de la Santé et de la Recherche Médicale). Opposition proceedings were initiated by Sanofi and Strawman Limited, and the subsequent appeal was filed by Sanofi.

The patent covers immunocytokines comprising a conjugate of interleukin-15 (IL-15) with the sushi domain of the IL-15 receptor alpha and an immunomodulatory antibody, including PD-1 antagonists. The decision further strengthens protection of SOTIO's proprietary immunocytokine platform and the SOT201 program.

"We are pleased that the Boards of Appeal have upheld this important patent," said Radek Spisek, M.D., Ph.D., chief executive officer of SOTIO. "The decision validates the strength of the underlying invention and reinforces the intellectual property supporting SOT201. Importantly, this milestone comes as the program continues to generate encouraging clinical data, including objective responses in heavily pre-treated patients, underscoring the potential of this novel immunocytokine approach."

SOT201 is a PD-1-targeted, cis-acting attenuated IL-15 agonist designed to preferentially activate PD-1⁺CD8⁺ T cells and enhance anti-tumor immune responses. The investigational therapy is currently being evaluated in the international Phase 1 VICTORIA-01 study in patients with advanced unresectable or metastatic solid tumors.

About SOTIO Biotech
SOTIO Biotech (SOTIO) is a clinical-stage biopharmaceutical company advancing a focused pipeline of next-generation antibody-drug conjugates (ADCs) for solid tumors. The company is pursuing targeted therapies for cancers with significant unmet need and broad expansion potential.

SOTIO's two lead ADC programs, SOT106 and SOT109, are potential best-in-class therapies designed to rapidly advance to clinical proof of concept. SOT109, targeting CDH17 for the treatment of colorectal cancer, received Fast Track Designation from the U.S. FDA in July 2026 and is currently preparing to enter clinical phase. SOT106, targeting LRRC15 for sarcoma and other solid tumors, is in preclinical development and received Orphan Drug Designation (ODD) from the U.S. FDA in May 2026.

The broader pipeline also includes SOT201, a next-generation PD-1-targeting immunocytokine, currently being evaluated in the Phase 1 VICTORIA-01 study in patients with solid tumors. SOTIO is a member of the PPF Group. For more information, please visit the company's website at .

SOTIO is a registered trademark of SOTIO Biotech a.s. in selected countries.