Samsung Bioepis files for domestic approval of Keytruda biosimilar, staking claim as first mover

Samsung Bioepis has filed for domestic regulatory approval of a biosimilar to Keytruda — the world's top-selling drug — positioning itself at the front of the global race to bring a Keytruda biosimilar to market. Having already become the first company in the world to publish Phase 3 trial data, the company has now entered the approval review stage in Korea ahead of all rivals, cementing its lead through sheer development speed.

Samsung Bioepis recently submitted an application to the Ministry of Food and Drug Safety for approval of SB27 (generic name: pembrolizumab), its Keytruda biosimilar candidate. Keytruda, the reference drug, is an immune-oncology treatment developed by US multinational pharmaceutical company MSD. It recorded global sales of about 46 trillion won ($32.5 billion) last year, making it the world's best-selling drug and a blockbuster of the highest order.

Keytruda is widely regarded as a defining third-generation cancer treatment that has reshaped the oncology paradigm. It works by binding to PD-1, a receptor on the body's immune cells (T cells), blocking cancer cells from evading the immune system and enabling T cells to attack tumors directly. The drug overcame the severe side effects of first-generation chemotherapy and the resistance limitations of second-generation targeted therapies, significantly improving long-term survival rates.

The approval application covers 16 major cancer types for which the original drug is indicated, including melanoma, non-small cell lung cancer and head and neck cancer. If approved, the filing lays the groundwork for prescription expansion across the broader immune-oncology market, not limited to any single cancer type.

A vial and syringe are placed in front of the Keytruda logo. [Reuters]

The filing is particularly notable given the fierce race among global developers. On June 29, Samsung Bioepis became the first company in the world to publish Phase 3 trial results for a Keytruda biosimilar, releasing data from a study involving 555 patients across 14 countries and demonstrating medical equivalence to the original drug.

Based on typical approval timelines, domestic approval of SB27 is expected to be completed between the second half of 2027 and early 2028. Keytruda's compound patent is set to expire in Korea in 2028, in the United States in November 2029 and in Europe in January 2031. Samsung Bioepis is expected to launch the first domestically approved biosimilar version in Korea in tandem with the 2028 patent expiry, then pursue approvals and launches in the United States and Europe timed to their respective patent cliffs.

The strategy — securing a fully completed global Phase 3 trial and getting ahead of rivals in the approval process ahead of the patent cliff — positions Samsung Bioepis as a high-value first mover aimed at entering the massive market first and capturing an outsized share of early prescriptions.

Competition at the front of the global Keytruda biosimilar field remains intense. Germany's Formycon is in talks with the FDA over an expedited pathway based on Phase 1 results, while Celltrion is also in pursuit with CT-P51, having applied to reduce its Phase 3 patient enrollment. Against that backdrop, Samsung Bioepis has widened its lead by becoming the first to complete Phase 3 and the first to enter the approval process.

However, a key commercial variable is MSD's move to defend its market position with Keytruda Qurex, a subcutaneous formulation. Even so, analysts expect the intravenous biosimilar to achieve strong early market penetration, given its significant price competitiveness and the broader policy drive to reduce national health insurance fiscal burdens.

"We will faithfully explain our research and development results and carry out all relevant procedures without delay, so that we can provide treatment options to patients in Korea as soon as possible," said Shin Dong-hoon, executive vice president of Samsung Bioepis.

silverpaper@heraldcorp.com