SOTIO Biotech has reported positive preclinical results for SOT106, its LRRC15-targeted antibody-drug conjugate (ADC) for the treatment of sarcoma, including soft tissue sarcoma and osteosarcoma. The data were presented at the Connective Tissue Oncology Society (CTOS) Annual Meeting in Boca Raton, Florida.

In vitro studies demonstrated that SOT106 induces potent, antigen-specific cytotoxicity with nanomolar activity and a pronounced bystander effect. In vivo, the ADC showed dose-dependent tumour regression in patient-derived xenograft (PDX) models, including complete responses at 1 mg/kg. The results were consistent across both soft tissue sarcoma and osteosarcoma models, including those with low-to-medium LRRC15 expression and in orthotopic osteosarcoma.

An exploratory non-human primate (NHP) study indicated that SOT106 has a favourable pharmacokinetic profile and a high therapeutic index, with dose-limiting toxicities consistent with known MMAE effects.

Amy Jensen-Smith, chief scientific officer at SOTIO, said: “Sarcomas continue to represent a significant unmet medical need, with limited therapeutic progress over the past several decades. LRRC15 is a clinically validated target broadly expressed across sarcoma subtypes, making it an ideal candidate for a differentiated ADC approach. These NHP data reinforce our confidence in SOT106’s therapeutic potential and mark a critical step toward delivering a novel treatment option for patients facing these aggressive diseases.”

SOTIO is advancing SOT106 through IND-enabling studies, with an anticipated IND filing in Q4 2026. The company has also developed a proprietary, highly sensitive LRRC15 immunohistochemistry assay to support patient selection in upcoming clinical trials.

The SOT106 data were presented in a poster titled “Targeting leucine-rich repeat-containing protein 15 (LRRC15): SOT106 antibody-drug conjugate for soft tissue sarcoma and osteosarcoma treatment,” with Lenka Palova Jelinkova as presenter. Materials from the presentation will be available upon request following the event.