LONDON — September 8, 2026
Greywolf Therapeutics announced that it has dosed the first participants with axial spondyloarthritis (axSpA) in the multiple ascending dose (MAD) portion of its Phase 1/2 EAST-1 study, advancing its lead oral ERAP1 inhibitor GRWD0715 into patient testing. The milestone follows completion of the single ascending dose (SAD) portion of the study in healthy volunteers, where Greywolf reported dose-proportional pharmacokinetics (PK), clear evidence of ERAP1 target engagement, and no safety or tolerability concerns. GRWD0715 is being developed as a first-in-class oral ERAP1 inhibitor designed to address CD8+ T cell-mediated autoimmunity. The company is positioning the program as a potential new approach to autoimmune disease by targeting antigen presentation mechanisms associated with disease pathology. The ongoing axSpA study represents an important clinical development milestone for Greywolf as it works to establish the pharmacological and clinical profile of its lead program.
Phase 1/2 Data to Guide Proof-of-Concept Development
The MAD portion of EAST-1 is expected to generate PK/PD, translational biomarker, and preliminary clinical endpoint data that will help Greywolf determine the appropriate dose for a planned placebo-controlled Phase 2a proof-of-concept study. The company expects the Phase 2a portion to begin in the second half of 2027, making the ongoing patient dosing an important step toward the next stage of clinical development. Greywolf is developing GRWD0715 around the genetic and biological role of ERAP1 in axSpA, where ERAP1 is reported to have one of the strongest genetic associations after HLA-B27. The company’s development strategy is focused on determining whether inhibition of ERAP1 can translate target engagement into clinical benefits for patients with axSpA. Progression from healthy-volunteer evaluation into patients provides Greywolf with an opportunity to generate disease-specific data while establishing the dose and biomarker framework required for later-stage development.
U.S. Patent Strengthens GRWD0715 Position
Greywolf has also secured U.S. composition-of-matter patent protection for GRWD0715, adding an important intellectual property milestone as the company advances its lead program through clinical development. The patent strengthens the commercial and development position of the ERAP1 inhibitor while Greywolf continues to build a broader autoimmune pipeline around antigen modulation. The company said ERAP1 and ERAP2 represent some of the most consistently observed genetic associations across autoimmune diseases, supporting its strategy of investigating ERAP biology beyond the initial axSpA indication. Intellectual property protection alongside clinical progression provides Greywolf with a stronger foundation for continued investment in GRWD0715 and potential expansion into additional autoimmune indications. The combination of clinical validation, target engagement, and U.S. patent protection marks a significant development phase for the company as it moves toward proof-of-concept testing.
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Genomics Partnership Supports Autoimmune Expansion
Greywolf’s strategic partnership with Genomics is supporting its planned expansion of GRWD0715 into a broader range of autoimmune diseases, using large-scale genetic data alongside clinical and translational insights to identify potential ERAP-associated indications. Genomics is analyzing variants in ERAP1 and ERAP2 across diseases including inflammatory bowel disease (IBD) and psoriatic arthritis, helping Greywolf prioritize opportunities beyond axSpA. The partnership forms part of the company’s broader strategy to use genetic evidence to guide indication selection and strengthen the rationale for ERAP inhibition across autoimmune conditions. With GRWD0715 now being evaluated in patients with axSpA, a planned Phase 2a study in 2027, new U.S. patent protection, and continued indication research through the Genomics collaboration, Greywolf is building a differentiated autoimmune development platform centered on ERAP biology. These milestones provide the company with multiple avenues for pipeline expansion while it evaluates the potential of antigen modulation in diseases driven by aberrant immune responses.
Source:Greywolf Therapeutics press release
