Celltrion announced on the 24th that it has submitted a global Phase 3 clinical trial plan (IND) to the U.S. Food and Drug Administration (FDA) to expand the rheumatoid arthritis (RA) indication for its autoimmune disease treatment CT-P13 SC (product name: Zymfentra). The clinical trial application date is July 24, 2026, based on local time.

This clinical trial is a global Phase 3 study utilizing a randomized, placebo-controlled, double-blind, parallel-group design to evaluate the efficacy and safety of CT-P13 SC in patients with moderate to severe active rheumatoid arthritis. The company has set the ACR50 response rate at week 12 as the primary endpoint, aiming to demonstrate superior efficacy compared to placebo. The trial plans to enroll 296 participants with a treatment duration of 52 weeks.

CT-P13 SC (Zymfentra) is a subcutaneous (SC) injection formulation of RemsimaIV, an infliximab biosimilar, developed to improve patient dosing convenience and provide broader access to treatment. The product has already received marketing approval in multiple countries, including the United States and Europe, for adult ulcerative colitis and Crohn's disease indications. Celltrion expects that through this Phase 3 rheumatoid arthritis trial, it can expand indications and offer treatment options to a larger patient population.

The company explained that this trial also aims to secure additional data by diversifying participant race and prior treatment history, reflecting commercial-stage differentiation strategies and the regulatory trend of emphasizing patient diversity. The content of this disclosure will also be used for future press releases and IR materials.

However, Celltrion cautioned investors by noting that the statistical probability of a clinical trial drug ultimately receiving final approval is approximately 10%, meaning that commercialization plans may be altered or discontinued if results during the clinical trial and approval process fall short of expectations.