SOTIO Biotech: SOTIO Unveils Promising Preclinical Data on SOT109, a Next-Gen ADC Targeting Cadherin-17 (CDH17) for Colorectal Cancer

• SOT109 leverages exatecan-based payload to produce potential best-in-class ADC for validated CDH17 target
• SOT109 expected to enter a first-in-human Phase 1 clinical trial in 2026

SOTIO Biotech, a clinical-stage biopharmaceutical company owned by PPF Group, today presented the first preclinical data on SOT109, a novel antibody-drug conjugate (ADC) targeting cadherin-17 (CDH17). The data highlight SOT109's promising activity and tolerability profile across multiple disease models, reinforcing its potential to become a best-in-class therapeutic for the treatment of colorectal cancer and other gastrointestinal (GI) cancers. The findings were presented at the 15^th World ADC London 2025, taking place from March 3 to 6 at Novotel London West, London, UK.

"We are excited to share groundbreaking data on SOT109, an innovative ADC designed to treat colorectal cancer and other GI malignancies," said Martin Steegmaier, Ph.D., chief scientific officer of SOTIO. "CDH17 has long been recognized as a highly compelling therapeutic target, yet previous non-ADC and ADC approaches have faced significant obstacles. Our cutting-edge design overcomes these challenges, utilizing state-of-the-art linker-payload technology and an optimized antibody backbone to enhance efficacy and tumor selectivity. Preclinical data indicate that our candidate not only delivers potent tumor cell killing but does so with an excellent safety profile and high therapeutic index. We believe this represents a major advancement in ADC development for GI cancers, and we look forward to filing an Investigational New Drug (IND) application for this program in Q2 2026."

CDH17 is a highly promising target homogenously overexpressed in more than 90% of colorectal cancers (CRC) and abundantly expressed in other GI cancers, including gastric, pancreatic, and esophageal cancers. In contrast, its expression in normal adult tissues is largely restricted to the GI tract, reducing the risk of off-target toxicity.

As CDH17 is an abundantly expressed and rapidly internalizing transmembrane protein on GI cancer cells, CDH17 is ideally suited for an ADC-mediated drug delivery approach. SOT109 is a fully human and highly specific ADC with exceptional binding and internalization properties against CDH17. SOT109 utilizes Synaffix's clinically validated ADC platform, incorporating the SYNtecan E proprietary linker-payload system that contains an exatecan payload (DAR=4). For the treatment of CRC, SOT109's exatecan payload is expected to demonstrate superior activity, reduced susceptibility to resistance, and an enhanced bystander effect due to its high cell permeability, setting it apart from other ADC payloads utilized to date.

In preclinical studies presented at World ADC London, SOT109 exhibited strong anti-tumor activity across multiple mouse xenograft models, including complete responses. It demonstrated favorable tolerability in an exploratory mouse study at doses up to 150 mg/kg. Furthermore, data from a subsequent toxicity study in non-human primates (NHPs) revealed that SOT109 displays a favorable therapeutic index underscoring its potential as a transformative therapy for GI cancers.

About SOTIO Biotech

SOTIO Biotech (SOTIO) is shaping the future of cancer immunotherapies by translating compelling science into patient benefit. The company is advancing an innovative pipeline of mono- and bispecific solid tumor ADC programs at various stages of preclinical development. The SOTIO pipeline also includes two clinical-stage programs: BOXR1030, a metabolically-enhanced CAR-T cell therapy targeting GPC3-expressing tumors; and SOT201, a next-generation PD-1-targeting immunocytokine. SOTIO is a member of the PPF Group. For more information, please visit the company's website at www.sotio.com.

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

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