Celltrion Launches U.S. Phase 4 Trial of High-Dose Zymfentra

[NA Eun-kyung, Edaily Reporter] Celltrion is launching a Phase 4 clinical trial in the United States to establish clinical evidence supporting a 240㎎ high-dose regimen of its autoimmune disease treatment Zymfentra, or infliximab.

The company said Tuesday that it submitted an investigational new drug application to the U.S. Food and Drug Administration for a Phase 4 trial of the 240㎎ Zymfentra regimen.

Celltrion’s autoimmune disease treatment Zymfentra. (Photo=Celltrion)

The trial will enroll 447 patients with Crohn‘s disease and ulcerative colitis at 55 sites across the United States. It will compare a high-dose intravenous formulation of infliximab with a 240㎎ dose of Zymfentra to evaluate whether the Zymfentra regimen is noninferior.

Through the trial, Celltrion aims to establish clinical evidence supporting the 240㎎ dose and broaden treatment options in the U.S., where prescriptions currently center on the 120㎎ dose. The company plans to give physicians greater flexibility to select a dosage based on a patient’s condition and disease severity.

Zymfentra is the subcutaneous formulation of Celltrion‘s infliximab biosimilar Remsima. It won FDA approval in 2023 through the regulatory pathway for new drugs and is currently marketed in the U.S. for the treatment of adults with Crohn’s disease and ulcerative colitis.

Celltrion has already used higher-dose regimens of Remsima SC in Europe. According to the company, Remsima SC held about a 32% market share in the five major European markets, known as the EU5, in the first quarter of this year. Celltrion initiated the U.S. trial as part of an effort to apply the dose-adjustment strategy used in Europe to the U.S. market.

The company is also seeking to expand Zymfentra‘s indications. Celltrion is conducting a global clinical trial to add rheumatoid arthritis to Zymfentra’s U.S. indications, which are currently limited to inflammatory bowel disease. If approved for the additional indication, Zymfentra could reach a broader pool of potential patients.

U.S. sales of Zymfentra are also growing. Sales reached 99.5 billion won ($73.8 million) in the first half of this year, up 176.4% from a year earlier. Celltrion said Zymfentra has secured insurance coverage for more than 90% of insured patients in the U.S. and is sold through the company‘s direct sales network.

Once it secures clinical data supporting the 240㎎ regimen, Celltrion plans to pursue a U.S. prescribing strategy offering both 120㎎ and 240㎎ doses. Along with the planned expansion into rheumatoid arthritis, the company aims to broaden Zymfentra’s prescribing base in the U.S.

“This trial is designed to broaden Zymfentra dosing options based on patients‘ conditions,” a Celltrion official said. “We will secure clinical data supporting the higher dose and expand Zymfentra’s prescribing base in the U.S. by broadening its indications.”