Recludix Pharma, a leader in the discovery of inhibitors of challenging targets for inflammatory disease, today announced that the company has nominated a lead development candidate REX-8756, an oral, selective and reversible small molecule inhibitor of STAT6, and completed the GLP toxicology studies for the compound.

Many allergic and inflammatory diseases -- such as asthma, COPD, and atopic dermatitis -- are caused by Type 2 inflammation, driven by the production of the cytokines Interleukin-4 (IL-4) and Interleukin-13 (IL-13). STAT6 is required for IL-4 and IL-13 signaling but is downstream in the disease pathway from other drug targets, and therefore, its inhibition has been shown in preclinical studies to be a more selective approach than Janus Kinase (JAK) family inhibitors, with potential for fewer side effects.

“There is significant opportunity to develop oral medicines with biologic-like activity and favorable safety profiles to provide alternatives to current therapies, such as JAK inhibitors which can impact viral immunity and hematopoiesis,” said Nancy Whiting, Pharm.D., president and chief executive officer of Recludix. “At Recludix, we are driven to discover and develop best-in-class drug candidates that have the potential to become transformative medicines. We and our partner Sanofi are pleased to have reached this significant milestone in this important program and look forward to advancing REX-8756 to the clinic in the near term.”

In preclinical studies, REX-8756 achieved complete and durable STAT6 inhibition, without degradation of the protein. STAT6 inhibition disrupted the production of IL-4/13 stimulated inflammatory biomarkers and has demonstrated potent efficacy in models of asthma, acute lung inflammation and dermatitis. REX-8756 inhibits STAT6 through its SH2 domain, which plays a key role in mediating protein-protein interactions and had been previously deemed undruggable. Through Recludix’s proprietary platform that integrates new chemical approaches and technologies, the company has created massive custom SH2 domain-focused DNA-encoded libraries and proprietary selection assays, enabling the development of precision small molecule medicines against the SH2 domain of high-interest targets.

“We have discovered a number of oral STAT6 SH2 domain inhibitors that performed impressively in preclinical studies, speaking to the power of our platform,” said Ajay Nirula, M.D., Ph.D., executive vice president and head of research and development of Recludix. “Following our recently presented preclinical data at the May 2025 American Thoracic Society Conference that further demonstrated the robust efficacy and differentiated safety profile of our STAT6 inhibitors, we are excited to advance REX-8756 as a potential first-in-class oral therapy for patients with immune-related inflammatory disease.”