Samsung Bioepis’ Ontruzant, a breast cancer treatment biosimilar referencing Roche’s Herceptin, won US Food and Drug Administration approval Saturday, expanding the list of Herceptin successors in the US market to three.

Ontruzant is the third FDA-approved biosimilar of Switzerland firm Roche’s blockbuster breast cancer antibody. Its FDA approval is preceded by Mylan’s Ogivri in December 2017, and Celltrion’s Herzuma in December 2018.

The three firms’ biosimilars are expected to simultaneously hit the US’ biopharmaceutical market in June, when patents related to Herceptin expire. Herceptin is one of the world’s most successful antibody drugs. Having received FDA approval in 1998, Herceptin has been Roche’s best-selling monoclonal antibody, generating estimated yearly sales of over $2.6 billion in the US and $7 billion worldwide.

Ontruzant is already being sold in the UK since March, 2018, after gaining European Medicine Agency approval in November, 2017. Pfizer’s Trazimera, Celltrion’s Herzuma, Amgen and partner Allergan’s Kanjinti are also approved by the EMA.

In the US, Ontruzant will be commercialized by Merck Sharp & Dohme, the same company that sells Samsung Bioepis’ the other biosimilar in the US, Renflexis. Available in the US since July 2017, Renflexis is a tumor necrosis factor blocker used to treat Crohn’s Disease, Rheumatoid Arthritis among many others.

Samsung Bioepis is a joint venture of Samsung BioLogics and Biogen. The former faced accusations of accounting irregularities around the time of its stock market listing. Samsung BioLogics’ stock transactions were temporarily suspended for a month before it was normalized in December.

By Lim Jeong-yeo (kaylalim@heraldcorp.com)