PRAGUE, Basel & Boston, Aug. 26, 2026

SOTIO Biotech announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to SOT106, the company’s investigational antibody-drug conjugate (ADC), for the treatment of soft tissue sarcoma (STS). The regulatory designation is intended to accelerate the clinical development and review of therapies addressing serious conditions with significant unmet medical needs. For SOTIO, the designation represents an important development milestone for SOT106 as the company prepares to move the program toward human clinical testing. SOT106 is designed to target LRRC15, a clinically validated target broadly expressed across multiple sarcoma subtypes, potentially allowing the ADC to address a broad patient population with limited treatment options.

SOTIO Advances LRRC15-Targeted ADC Program

SOT106 is being developed as a potentially best-in-class ADC targeting leucine-rich repeat-containing 15 (LRRC15), a protein that is broadly expressed across several prevalent sarcoma subtypes. The company is pursuing LRRC15 as a therapeutic target because of its potential relevance across multiple forms of soft tissue sarcoma. Advanced and recurrent STS remains a challenging treatment setting, with patients often facing limited therapeutic alternatives. SOTIO said the Fast Track designation reinforces the need for new approaches while supporting continued development of its targeted ADC strategy. The company aims to translate the differentiated design of SOT106 and its LRRC15-targeting mechanism into a potential treatment option for patients across multiple sarcoma subtypes. However, SOT106 remains an investigational therapy, and its safety and efficacy will need to be established through clinical studies.

FDA Fast Track Supports SOTIO Clinical Development

The FDA’s Fast Track Designation is intended to facilitate the development and expedite the review of therapies designed to treat serious conditions and address significant unmet medical needs. The designation can provide opportunities for more frequent interactions between a sponsor and the FDA during development and may support potential regulatory pathways such as rolling review and Priority Review, provided applicable criteria are met. For SOTIO, the designation adds regulatory momentum as it prepares to advance SOT106 into the clinic. The company has also received FDA Orphan Drug Designation for SOT106 in osteosarcoma, expanding the regulatory recognition of the program within high-need sarcoma indications. These designations do not establish clinical efficacy or guarantee approval, but they can provide development and regulatory advantages as clinical evidence is generated.

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SOTIO Plans First-in-Human SOT106 Trial

SOTIO expects to begin the first-in-human clinical trial of SOT106 later in 2026, representing the next major milestone for the program. The planned study will provide the first opportunity to evaluate the ADC in patients and generate clinical data on its safety, tolerability, dosing and preliminary activity. SOTIO is advancing the program with the goal of developing a targeted therapeutic approach for soft tissue sarcoma, where new treatment options remain needed for patients with advanced or recurrent disease. The company’s broader development strategy is centered on leveraging SOT106’s LRRC15-targeting approach to potentially reach multiple sarcoma subtypes rather than focusing on a single tumor type. The upcoming first-in-human study will therefore be critical in determining whether the preclinical rationale behind SOT106 can translate into meaningful clinical benefit. The Fast Track designation and previously granted Orphan Drug Designation provide regulatory support, while the planned clinical trial will establish the evidence needed for further development.

Source:SOTIO Biotech,, press relese