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Biosimilar Samfenet wins patent invalidation against Herceptin in Korea

Samsung Bioepis’ breast cancer treatment biosimilar Samfenet, known as Ontruzant outside of Korea, won a patent invalidation suit against the original Roche drug Herceptin (trastuzumab), according to industry sources Monday.

Korea’s Intellectual Property Trial and Appeal Board on Thursday last week accepted Samsung Bioepis’ claim that Roche’s patent for “Protein Purification by Ion-Exchange Chromatography” lacks patentability. The patent had been registered with the IPTAB in 2011 and was to expire in May. 


A trial for the invalidation of a patent may be demanded even after the expiration of the patent rights. Samsung Bioepis had requested invalidation of Roche’s patent in July 2017.

A patent right is deemed never to have existed if a trial decision invalidating a patent becomes final and conclusive. However, when the invalidation decision is based on a reason that arose after the granting of a patent, the patent right is deemed not to have existed from the time when such a reason originated.

The IPTAB’s decision clears hurdles of any injunction Roche could file against Samfenet’s sale in Korea.

Samsung Bioepis gained the Korean Ministry of Food and Drug Safety’s approval for commercialization of Samfenet in 2017. The biosimilar is Samsung Bioepis’ first cancer-fighting biosimilar, and has been distributed domestically by Daewoong Pharmaceutical since March 2018.

Samsung Bioepis and Daewoong Pharmaceutical said they would use the opportunity to expand Samfenet’s market share here.

Roche’s original blockbuster Herceptin is the world’s eighth best selling drug and records annual sales of 80 billion won ($70.7 million) in Korea and 8 trillion won globally.

Celltrion, the Korean biosimilar company that produces another Herceptin biosimilar called Herzuma, also invalidated the original drug’s patent for a “monoclonal or multiclonal antibody freeze-drying substance” in 2015. Herzuma gained the Drug Ministry’s approval in 2014. In 2018, the biosimilar recorded 7.7 billion won in sales.

By Lim Jeong-yeo (
Korea Herald Youtube