The US FDA has granted Fast Track Designation to SOTIO Biotech’s investigational antibody-drug conjugate (ADC) SOT109 for the treatment of patients with advanced unresectable or metastatic colorectal cancer who have exhausted standard treatment options.

The designation comes as the clinical-stage biotechnology company prepares to begin a Phase 1/2 clinical trial of the therapy in the third quarter of 2026, marking an important step in the development of a new targeted treatment for one of the world’s most common cancers.

SOT109 targets cadherin-17 (CDH17), a protein expressed in more than 90% of colorectal cancers and across a range of gastrointestinal malignancies. Because CDH17 has limited expression in healthy tissues, researchers believe it may provide a promising target for ADCs, which are designed to deliver potent anti-cancer drugs directly to tumour cells while reducing damage to normal tissue.

Colorectal cancer remains a major global health challenge, particularly for patients whose disease progresses after standard therapies. Although advances in targeted medicines and immunotherapy have improved outcomes for some patients, treatment options remain limited in later-line disease, creating demand for new therapeutic approaches.

Fast Track Designation is intended to speed the development and review of medicines that address serious conditions and unmet medical needs. The programme enables more frequent communication with the FDA during development and may allow companies to seek accelerated approval or priority review if eligibility criteria are met.

SOTIO expects to initiate its Phase 1/2 study of SOT109 in patients with advanced unresectable or metastatic colorectal cancer during the third quarter of this year. The trial will provide the first opportunity to evaluate the safety and early anti-tumour activity of the ADC in patients.

Vivi Boura, chief medical officer of SOTIO, said: “Advanced colorectal cancer remains an area of profound unmet need, particularly for patients whose disease has progressed after standard therapies.

“SOT109 is designed to capitalize on the unique biology of CDH17, a highly prevalent target that is broadly and consistently expressed across colorectal tumors, while having limited expression in healthy tissues. We believe Fast Track Designation underscores both the urgent need for new treatment options and the potential of SOT109 to expand the benefits of targeted ADC therapy to a substantially broader patient population.”

SOT109 is one of two lead ADC programmes in SOTIO’s oncology pipeline. The company is developing the therapy as a potential treatment for solid tumours expressing CDH17, while its second lead ADC candidate, SOT106, targets LRRC15 and is being developed for sarcoma and other solid tumours.

The wider pipeline also includes SOT201, a next-generation PD-1-targeting immunocytokine currently being evaluated in the ongoing Phase 1 Victoria-01 trial in patients with solid tumours.

The latest FDA designation reflects growing interest in expanding the use of ADCs beyond established targets by identifying tumour-associated proteins that are highly expressed in cancer cells but largely absent from healthy tissue. If successful, this strategy could broaden the number of patients able to benefit from precision oncology treatments.