A Celltrion employee conducts an experiment at the company's R&D center in Songdo, Incheon. The company said Monday that its Phase 3 follow-up study of CT-P41, a biosimilar of the osteoporosis treatment Prolia, confirmed equivalence to the original drug. Courtesy of Celltrion

Celltrion, Samsung Bioepis and other global pharmaceutical companies are racing to take a share of the biosimilar of Amgen's osteoporosis drug Prolia, worth around 8 trillion won ($5.8 billion) in terms of global market size, which will open up next year, according to the companies, Monday.

A biosimilar is a medicine created to imitate biopharmaceutical drugs that have expired patents. It is made of biological ingredients through biotechnological processes such as cell culturing.

Using denosumab, a human monoclonal antibody, U.S. biotech company Amgen has been selling Prolia and Xgeva, a drug to prevent bone metastasis in cancer patients, and the patents for these two products will expire in February and November next year in the U.S. and Europe, respectively.

Considering Prolia and Xgeva posted global sales of over $6 billion, multinational pharmaceutical companies, including Celltrion and Samsung Bioepis, are trying to preempt the market for biosimilars of these blockbuster drugs.

Swiss pharmaceutical company Sandoz recently received an approval from the U.S. Food and Drug Administration (FDA) for its biosimilar, marking the first success story, and Celltrion and Samsung Bioepis also expect they will soon receive approvals.

On Monday, Celltrion announced that it had presented the 78-week clinical study results of its Prolia biosimilar CT-P41 at the World Congress on Osteoporosis (WCO) held in London until Sunday.

At the conference, Celltrion disclosed detailed data of the global clinical trial of CT-P41 involving 479 postmenopausal women with osteoporosis aged between 50 and 80.

The company said that the clinical trial showed no difference in treatment between patients administered with CT-P41 and those administered with Prolia, based on the clinical data of lumbar spine density over 52 weeks.

"The Phase 3.1 clinical results of CT-P41 were first revealed at the World Congress on Osteoporosis, reaffirming its efficacy, pharmacokinetic equivalence and similarity in safety compared to the original," a Celltrion spokesperson said.

Samsung Bioepis headquarters in Songdo, Incheon / Courtesy of Samsung Bioepis

Samsung Bioepis, a biosimilar development subsidiary of Samsung Biologics, is also proceeding with the global approval process for its Prolia biosimilar, SB16.

In December 2021, the company completed the global Phase 3 clinical trial of SB16 with 457 participants in Poland, and is currently pursuing domestic and international approvals.

Samsung Bioepis revealed clinical study data last October at the American Society for Bone and Mineral Research held in Vancouver, Canada, among which the Phase 3 study confirmed similarities in efficacy, pharmacokinetics, immunogenicity and safety compared to Prolia.