Celltrion said it submitted an investigational new drug (IND) application to the U.S. FDA for the phase 3 clinical trial of CT-P51, its Keytruda (ingredient: pembrolizumab) biosimilar.

This global clinical trial will evaluate the efficacy equivalence between CT-P51 and the original Keytruda in 606 patients with metastatic non-small cell lung cancer (NSCLC).

Keytruda, an immunotherapy for NSCLC and other indications, recorded approximately $25.1 billion in sales last year, making it the top-selling drug globally. The patent for Keytruda is set to expire in the U.S. in November 2029 and in Europe in January 2031.

Celltrion aims to expand its portfolio of oncology biosimilars with this IND submission. The company already markets three oncology biosimilars—Herzuma (trastuzumab) for breast and gastric cancer, Vegzelma (bevacizumab) for metastatic colorectal cancer, and Truxima (rituximab) for hematologic cancers.

In addition to oncology, Celltrion is rapidly expanding its treatment areas to include autoimmune diseases, bone diseases, and ophthalmologic conditions.

Last month, the company announced that Omlyclo, its biosimilar referencing Genentech and Novartis' Xolair (omalizumab), has received approval to become the first biosimilar of its kind in Europe.

"The global phase 3 IND submission for CT-P51 will help the company expand its oncology portfolio and secure additional future growth drivers,” a company official said. “Given the explosive growth of the global immunotherapy market, we anticipate significant revenue potential for CT-P51."