FDA Clears IND Application of Recludix’s Oral STAT6, REX-8756

Recludix Pharma recently announced that the FDA has cleared its Investigational New Drug (IND) Application to advance REX-8756, an oral STAT6 inhibitor, into phase 1 clinical testing.¹

REX-8756 is an oral, selective STAT6 inhibitor with a novel therapeutic approach that targets STAT6’s SH2 domain—a key mediator of protein-protein interactions. According to the announcement, STAT6’s SH2 domain has previously been considered “undruggable.” In preclinical studies, REX-8756 demonstrated complete and sustained inhibition of STAT6 activity, thereby suppressing IL-4 and IL-13-induced inflammatory biomarkers.

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 JAK inhibitors, with the potential for fewer adverse effects. REX-8756 has demonstrated potent efficacy in models of asthma, acute lung inflammation, and dermatitis, comparable to that of an anti-IL-4/IL-13 antibody combination control.

“With REX-8756, we are excited by the opportunity to pioneer a new therapeutic class for patients with inflammatory diseases,” said Nancy Whiting, PharmD, president and chief executive officer of Recludix, in the news release. “We have demonstrated preclinically that our reversible, orally available STAT6 inhibitor can achieve efficacy comparable to that of clinically validated biologics. By targeting the pathological overactivation of STAT6 observed in many diseases—without necessitating protein degradation and with an anticipated improved hematologic safety profile relative to JAK inhibitors—we believe this approach could be an important therapeutic option for patients. We look forward to initiating a phase 1 clinical study of REX-8756 in healthy volunteers very shortly.”

About STAT6

STAT proteins are both signaling proteins and transcription factors that play a role in cell growth, differentiation, and function. STAT6 is a key nodal transcription factor that selectively mediates downstream signaling of IL-4 and IL-13, dominant and central cytokines in the pathophysiology of type 2 inflammatory diseases. A STAT6 inhibitor offers the potential for a novel first-in-class targeted oral therapy for patients with type 2 inflammatory diseases.

Recludix is initiating a phase 1 study of REX-8756 (also known as SAR448755), an oral inhibitor of STAT6, in a strategic development and commercialization partnership with Sanofi, where Recludix has the option to participate in an equal US profit/loss share. Abnormal activation of STAT6 is found in inflammatory diseases, such as atopic dermatitis, asthma, rheumatoid arthritis, and chronic spontaneous urticaria.

“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, MD, PhD, executive vice president and head of research and development of Recludix, in a previous news release. “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.”²

References

1. Recludix Pharma announces FDA clearance of Investigational New Drug Application for REX-8756, an oral STAT6 Inhibitor, to enter into the clinic. News release. Recludix Pharma. December 16, 2025. Accessed December 17, 2025. https://recludixpharma.com/recludix-pharma-announces-fda-clearance-of-investigational-new-drug-application-for-rex-8756-an-oral-stat6-inhibitor-to-enter-into-the-clinic/
2. Recludix Pharma announces development candidate nomination of first-in-class oral STAT6 inhibitor for inflammatory diseases and achievement of significant milestone under collaboration with Sanofi. News release. Recludix Pharma. June 2, 2025. Accessed December 17, 2025. https://recludixpharma.com/recludix-pharma-announces-development-candidate-nomination-of-first-in-class-oral-stat6-inhibitor-for-inflammatory-diseases-and-achievement-of-significant-milestone-under-collaboration-with-sanofi/