On September 23. 2026 SOTIO Biotech, a clinical-stage biopharmaceutical company owned by PPF Group, reported that the U.S. Food and Drug Administration has granted SOT106 Orphan Drug Designation for the treatment of soft tissue sarcoma (STS) and Fast Track Designation for the treatment of osteosarcoma, supporting its planned clinical development as a potentially best-in-class investigational antibody-drug conjugate (ADC) across multiple sarcoma subtypes.
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With these additions, SOT106 has now received both Orphan Drug and Fast Track Designations for osteosarcoma and STS. Its potential across these indications is rooted in selective binding to leucine-rich repeat-containing 15 (LRRC15), a clinically validated target broadly expressed across multiple highly prevalent sarcoma subtypes. Preclinical data, including patient-derived xenograft models of both osteosarcoma and STS, indicate that SOT106 is potent and well-tolerated, with a high therapeutic index and strong anti-tumor activity.
"These additional designations mark another important milestone for SOT106 and reflect the growing momentum behind our ADC portfolio," said Radek Spisek, M.D., Ph.D., chief executive officer of SOTIO. "Patients with sarcoma continue to face limited treatment options, underscoring the need for innovative targeted therapies. As we advance SOT106 toward the clinic, we believe it has the potential to become an important treatment option for patients in need."
SOT106 combines SOTIO’s proprietary LRRC15-targeting antibody with LigaChem Biosciences’ ConjuAll site-specific conjugation and beta-glucuronidase-cleavable linker, which is designed to remain stable in circulation and release the payload selectively within the tumor.
Fast Track Designation (FTD) and Orphan Drug Designation (ODD) are intended to support the development of promising therapies for rare diseases and areas of high unmet need, providing opportunities for enhanced regulatory engagement and other incentives that may help accelerated development.
SOTIO expects to initiate a first-in-human clinical trial of SOT106 later this year.
(Press release, SOTIO, SEP 23, 2026, View Source [SID1234671043])