Samsung, Celltrion vie to approve Keytruda biosimilars

Competition over Keytruda's next market has begun between hospitals preparing drugs for patients and companies fine-tuning their regulatory filings. Celltrion has applied for domestic marketing approval of CT-P51, while SB27 from Samsung Bioepis entered the same process earlier. The two companies are positioning themselves among the leaders in South Korea.

Celltrion's application is based on clinical results from 228 melanoma patients who had undergone complete resection. CT-P51 targets key indications for Keytruda, including non-small cell lung cancer, melanoma, stomach cancer and head and neck cancer. The company said it confirmed pharmacokinetic equivalence with the original drug—that is, whether the level of drug exposure in the body met prespecified criteria—and obtained comparable results for safety and immunogenicity.

Keytruda is an immuno-oncology drug developed by MSD. It blocks the binding of the specific proteins PD-L1 and PD-1, which cancer cells use to evade immune responses, helping T cells, a type of immune cell, find and destroy cancer cells. Global sales last year were about $31.7 billion, making it the world's top-selling drug. As a result, the market related to Keytruda ahead of its patent expiry is attracting attention for its estimated size of 44 trillion won.

So what, specifically, will change? Celltrion plans to use its domestic application as a starting point for sequential approval applications in major markets including the United States, Europe and Canada. It aims to secure a competitive edge by leveraging its own manufacturing facilities and global direct-sales network, while expanding its oncology portfolio by adding CT-P51 to its existing cancer drugs Herzuma, Truxima and Vegzelma. Since the product has not yet received domestic marketing approval, actual sales and market share have not been determined.

The competition is not limited to Celltrion and Samsung Bioepis. Germany's Formycon ended the phase 3 trial of FYB206 earlier than scheduled and is preparing an application to the US Food and Drug Administration. Sandoz has completed both the phase 1 and phase 3 trials of GME 751, but has not disclosed the results or the timetable for applications in the United States and Europe. Amgen is conducting two global phase 3 trials of ABP 234 and is expected to disclose pharmacokinetic results as early as the end of this year and seek approval around 2028. To defend its patents, MSD is promoting subcutaneous Keytruda Qlex, which can be administered in just 1–2 minutes instead of the existing intravenous injection. The formulation generated $463 million in sales in the second quarter, up 262% from $128 million in the first quarter.