Celltrion’s Zymfentra Advances U.S. Market Expansion With Phase 3 Trial Approval for Rheumatoid Arthritis

Celltrion is moving to expand Zymfentra, its treatment for autoimmune diseases, into the major rheumatoid arthritis indication after receiving approval for its U.S. Phase 3 trial plan. As the world’s only subcutaneous infliximab treatment, Zymfentra has already grown rapidly in inflammatory bowel disease and now has a foothold for targeting the broader U.S. autoimmune disease market.

Significance of Phase 3 approval for rheumatoid arthritis

Celltrion disclosed on the 23rd that the U.S. Food and Drug Administration (FDA) approved the Phase 3 trial plan for CT-P13 SC (Zymfentra). The application was submitted on July 24 (local time), and the company confirmed approval after the maximum 60-day review period had elapsed, in accordance with the procedure under which the FDA does not issue a separate notice for new Phase 3 trial plan applications.

The global Phase 3 trial will enroll 296 patients with moderate to severe active rheumatoid arthritis and run for 52 weeks. It is randomized, placebo-controlled, double-blind and parallel-group. The primary objective is to demonstrate that CT-P13 SC is superior to placebo in clinical response based on ACR50 at Week 12.

Rheumatoid arthritis is the largest indication in the U.S. autoimmune disease market by both patient population and share of sales. Zymfentra is currently approved and prescribed in the U.S. and Europe for inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis. Adding rheumatoid arthritis as an indication could substantially expand its prescribing base beyond bowel diseases and into the broader U.S. market for autoimmune disease treatments.

Rapid sales growth and a two-track strategy

Zymfentra’s performance in the U.S. market is already climbing steeply. U.S. sales in the first half of this year surged 176.4% from the same period a year earlier, while global first-half sales combined with Remsima SC, its European brand name, reached 456.2 billion won. Insurance coverage has also been secured for more than 90% of all patients in the U.S., providing a foundation for expanded prescribing.

In addition to the Phase 3 rheumatoid arthritis trial, Celltrion submitted a Phase 4 trial plan to the FDA on Sept. 15 for a high dose (240 mg). The strategy is to establish a two-track prescribing system using the existing 120 mg and 240 mg doses, offering tailored treatment options based on patients’ conditions. A dual-formulation strategy is also being rolled out in the U.S. market, using Remsima IV, an intravenous formulation, to induce a rapid effect and Zymfentra, a subcutaneous formulation, for maintenance treatment.

According to data the Korea Health Industry Development Institute submitted to the National Assembly, Zymfentra has recorded an average annual growth rate of 61.5% over the past three years. Its global sales are estimated to reach 1.3556 trillion won this year and 2.1893 trillion won next year. The institute assessed Zymfentra as the leading candidate to surpass $1 billion in global sales next year and become the first global blockbuster in the history of Korea’s pharmaceutical and biotech industry.

A test of K-bio’s rise as a global leader

Zymfentra’s indication expansion and sales growth also symbolize a shift in the standing of Korea’s biotech industry. No new drug developed independently by a Korean company has yet met the global blockbuster threshold of $1 billion or more in annual sales. If Zymfentra breaks through that barrier, it is expected to become a major milestone for Korean pharmaceutical and biotech companies in global drug development and the establishment of direct-sales operations.

If the Phase 3 rheumatoid arthritis trial and high-dose Phase 4 trial are completed successfully, they will offer U.S. health care professionals greater convenience in care and prescribing flexibility, while giving patients a broader range of tailored treatment options that can be self-administered without a hospital visit. Through Zymfentra, the transition from being simply a biosimilar manufacturing country to becoming a technology innovator leading the global market with a reformulated drug is taking shape.