SOTIO Unveils Promising Preclinical Data for ADC Candidates SOT109 and SOT106, Signaling Best-in-Class Potential for Solid Tumor Therapies
SOTIO Biotech, a clinical-stage biotechnology company and part of the PPF Group, has presented compelling preclinical data for two of its leading antibody-drug conjugate (ADC) candidates—SOT109 and SOT106—at the prestigious American Association for Cancer Research (AACR) Annual Meeting held this week in Chicago, Illinois. These findings showcase the therapeutic potential of SOTIO’s next-generation ADC programs, which aim to address persistent unmet needs in the treatment of solid tumors.
The preclinical results provide early but robust evidence that SOT109 and SOT106 possess strong anti-tumor activity along with favorable safety profiles, positioning them as highly promising candidates for future clinical development. Both ADCs were tested across a variety of solid tumor models, with results underscoring their efficacy, specificity, and tolerability. These findings are particularly significant in light of the historical challenges associated with developing ADCs for certain tumor types, including colorectal cancer and soft tissue sarcomas.
SOT109: A First-in-Class Anti-CDH17 ADC Targeting Gastrointestinal Cancers
SOT109 is an ADC engineered to target cadherin-17 (CDH17), a cell surface protein that has emerged as a highly attractive therapeutic target for gastrointestinal cancers, especially colorectal cancer (CRC). Despite significant advances in cancer therapies over recent years, colorectal cancer remains one of the leading causes of cancer-related deaths globally. ADCs have shown limited clinical success in this indication so far, primarily due to the absence of target antigens that are both highly specific to tumor cells and sufficiently expressed across patient populations.
CDH17 offers a unique solution to this problem. It is overexpressed in over 90% of CRC cases and is also found in other gastrointestinal malignancies. Importantly, its expression in normal tissues is largely restricted to the gastrointestinal tract, minimizing the risk of off-target effects—a key limitation in ADC development.
SOT109 leverages a proprietary, fully human antibody with strong internalization properties. The ADC is built using Synaffix B.V.’s cutting-edge ADC technology platform, which incorporates an optimized linker-payload system designed to maximize both safety and efficacy. The payload is a cytotoxic agent conjugated through a stable, tumor-selective linker, enabling targeted delivery and minimizing systemic toxicity.
In preclinical studies, SOT109 exhibited potent anti-tumor activity. It achieved significant and sustained tumor regression in a range of in vivo colorectal cancer models, including both cell-derived and patient-derived xenografts (PDXs). These results demonstrate not only the compound’s efficacy but also its ability to remain active in more clinically relevant tumor models that better simulate human disease.
Additionally, the treatment was well tolerated in animal models. No dose-limiting toxicities were observed in mice at therapeutically effective doses. Follow-up studies in non-human primates confirmed the compound’s favorable pharmacokinetic and safety profile, providing further support for its advancement into human trials.
SOT106: A Novel Anti-LRRC15 ADC with Broad Potential Across Solid Tumors
SOTIO’s second ADC candidate, SOT106, targets leucine-rich repeat-containing protein 15 (LRRC15), a clinically validated cell surface antigen. Unlike CDH17, LRRC15 is expressed across a broader range of solid tumor types, including various subtypes of soft tissue sarcomas, head and neck squamous cell carcinoma, and non-small cell lung cancer (NSCLC). It is particularly interesting because of its tumor-restricted expression and association with aggressive, therapy-resistant cancers.
SOT106 is constructed using LigaChem Biosciences’ ConjuAll™ ADC platform, which enables the release of monomethyl auristatin E (MMAE)—a potent cytotoxin—specifically within tumor cells. This targeted delivery mechanism increases the therapeutic index and minimizes damage to healthy tissues.
In preclinical studies, SOT106 showed exceptional efficacy even in challenging models. It achieved robust tumor regression in an LRRC15 low-expressing PDX model of pediatric osteosarcoma—a context where a benchmark first-generation LRRC15-targeting ADC had failed to show activity. This suggests that SOT106 may overcome limitations related to low antigen expression, potentially expanding its clinical applicability to a wider patient population.
SOT106 also demonstrated potent activity in several additional tumor models, including:
- Soft tissue sarcomas,
- Head and neck squamous cell carcinoma, and
- A drug-resistant subtype of NSCLC.
In these models, complete responses and pronounced tumor regression were observed. Moreover, pharmacokinetic analysis confirmed that SOT106 maintains good in vivo stability, a favorable safety profile, and a high therapeutic index—important considerations for ADC success in the clinic.
Leadership Perspective and Strategic Significance
Commenting on the significance of the findings, Dr. Martin Steegmaier, Chief Scientific Officer of SOTIO, stated, “The data we presented at AACR this week highlights the strength of our next-generation ADCs by addressing areas of high unmet need in oncology. SOT109 continues to show excellent tolerability and strong anti-tumor activity across multiple preclinical models of colorectal cancer, while SOT106 offers a novel precision approach with broad applicability in LRRC15+ sarcomas and other solid tumors. These findings mark important progress in our pipeline and reinforce our commitment to developing highly differentiated ADCs for difficult-to-treat solid tumors.”
Dr. Steegmaier’s remarks underscore SOTIO’s broader vision: to create best-in-class immuno-oncology therapies that deliver durable responses with improved safety profiles. By focusing on novel, clinically relevant targets and leveraging advanced ADC platforms, the company aims to push the boundaries of precision cancer therapy.
The Broader ADC Landscape and SOTIO’s Competitive Position
The antibody-drug conjugate market is rapidly expanding, driven by the success of approved therapies such as Enhertu, Padcev, and Trodelvy. However, challenges remain, particularly in targeting tumors with low antigen expression or heterogeneous profiles, and in achieving the right balance between efficacy and tolerability.
SOTIO’s approach addresses these challenges head-on. Both SOT109 and SOT106 feature proprietary antibody components and utilize next-generation conjugation technologies to optimize the delivery of cytotoxic agents. Their ability to elicit meaningful anti-tumor responses in difficult-to-treat models, combined with strong safety data, positions them favorably in the competitive landscape.
Moreover, the use of both high and low antigen-expressing models in preclinical studies suggests that SOTIO is designing ADCs with real-world clinical variability in mind—a critical factor for achieving translational success.
Following the promising preclinical results presented at AACR, SOTIO is expected to continue advancing SOT109 and SOT106 toward clinical development. Preparations for Investigational New Drug (IND) submissions and early-phase clinical trials are likely underway or imminent, marking the next major milestones for the programs.
If early clinical data mirrors the preclinical success, SOTIO could establish itself as a key player in the ADC space, particularly in areas where existing treatment options are limited or ineffective. With solid backing from parent company PPF Group and partnerships with leading ADC technology developers like Synaffix and LigaChem, the company is well-positioned to bring these innovative therapies to patients worldwide.
