The U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to NS-229, an investigational therapy developed by NS Pharma for the treatment of Eosinophilic Granulomatosis With Polyangiitis (EGPA).

About EGPA and NS-229

EGPA is a rare autoimmune disease characterised by vasculitis affecting small to medium-sized blood vessels. It can lead to inflammation and tissue damage in organs such as the lungs, sinuses, skin, nerves, and kidneys. NS-229 is being investigated as a selective Janus kinase 1 (JAK1) inhibitor designed to regulate immune cell function and reduce inflammation-driven tissue damage.

“There are several factors associated with the inflammatory response in EGPA that could be regulated by JAK1,” explained NS Pharma Vice President, Research & Development, Takeshi Seita. “Our therapy has been designed to target this specific enzyme.”

About the Clinical Trial

A randomised, double-blind phase 2 study (ClinicalTrials.gov Identifier: NCT06046222) is currently evaluating the efficacy and safety of NS-229 compared to placebo over a 28-week treatment period. The trial includes participants with EGPA who are receiving background oral corticosteroids with or without treatment using Mepolizumab or Benralizumab. During the study, corticosteroid doses will be tapered.

The primary endpoint of the trial is clinical remission, defined as a Birmingham Vasculitis Activity Score (BVAS) of 0 and a daily prednisolone/prednisone dose of 4 mg or less at week 28.

The FDA’s Orphan Drug Designation is reserved for therapies targeting rare diseases that affect fewer than 200,000 people in the U.S. This status provides NS Pharma with benefits, including a seven-year period of market exclusivity, supporting continued development and evaluation of NS-229.

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References:

ClinicalTrials.gov. A Trial of Efficacy and Safety of NS-229 Versus Placebo in Patients With Eosinophilic Granulomatosis With Polyangiitis. ClinicalTrials.gov Identifier: NCT06046222. Updated May 13, 2024. Available at: https://clinicaltrials.gov/study/NCT06046222. 

NS Pharma, Inc. FDA Grants Orphan Drug Designation to NS-229 for the Treatment of Eosinophilic Granulomatosis with Polyangiitis Published April 21, 2025. Available at: https://www.nspharma.com/fda-grants-orphan-drug-designation-to-ns-229-for-the-treatment-of-eosinophilic-granulomatosis-with-polyangiitis.