As Johnson & Johnson (J&J)'s autoimmune disease therapy Stelara (ingredient ustekinumab) widens its treatment scope to pediatric inflammatory bowel disease, expectations are growing for market expansion by Korea's biosimilar makers such as Celltrion, Samsung Bioepis, and Dong-A ST.
The U.S. Food and Drug Administration (FDA) on the 28th of last month (local time) approved Stelara as a treatment for pediatric patients 2 and older with moderate to severe active ulcerative colitis. Earlier in Apr., it was also approved for pediatric patients in the same age group with moderate to severe active Crohn's disease.
As a result, Stelara has become a therapy that can be used for both pediatric Crohn's disease and ulcerative colitis. It is the first monoclonal antibody that does not target tumor necrosis factor-alpha (TNF-α).
◇ Stelara sales plunge 41%… biosimilar competition enters a new phase
Seven Stelara biosimilars have been approved by the FDA, including Amgen's "Wezlana." Among domestic corporations, Celltrion(068270), Samsung Bioepis, and Dong-A ST(170900) each have "Steqeyma," "Pizchiva," and "IMULDOSA." All three products have secured Stelara's key adult inflammatory bowel disease indications, including Crohn's disease and ulcerative colitis.
If a biosimilar is confirmed to have high similarity to the original medicine and no clinically meaningful differences, it can expand its approval scope through "extrapolation," which applies the efficacy and safety data verified in the original medicine to other indications.
Samsung Bioepis' Pizchiva also secured adult Crohn's disease and ulcerative colitis indications through this at the time of FDA approval. This is why the three domestic companies are expected to expand indications.
In the recent ustekinumab market, competition among biosimilars has intensified as Stelara sales have fallen. Stelara's sales, which reached $10.4 billion in 2024, dropped to $6.1 billion last year, down about 41% in a year. Second-quarter sales this year were $740 million, down 55.2% from a year earlier.
A Dong-A ST official said, "Considering the current market conditions and product competitiveness, local sales partners Intas Pharmaceuticals and Accord Biopharma are also expected to review and pursue indication expansion."
Samsung Bioepis and Celltrion are also said to be reviewing expansion into pediatric indications.
An industry official said, "As soon as the term of protection for related patents ends, they are preparing to add indications through extrapolation," and noted, "It could take as little as several months to as long as several years."
◇ Target the biggest market, the U.S.… K-biosimilars race to secure PBMs
According to IQVIA, the global ustekinumab market was about $18.609 billion (about 25.6 trillion won) last year. The U.S. is the largest market, accounting for about 70%.
Korean companies are laying the groundwork to compete with Stelara by securing preferred drug status in the formularies of major U.S. pharmacy benefit managers (PBMs).
PBMs manage drug formularies, prices, and rebate conditions on behalf of insurers. When designated as a preferred drug in a PBM formulary, patient access for those covered by the insurer improves and it can influence prescribers' choices.
The influence of PBM formularies was also seen in the case of AbbVie's autoimmune therapy Humira.
CVS Caremark, one of the U.S. PBM "big three," removed Humira from its 2024 formulary and switched more than 90% of eligible patients to biosimilars. Humira's U.S. sales fell from $18.6 billion in 2022 to $7.1 billion in 2024.
Dong-A ST's IMULDOSA is currently listed in the formularies of Express Scripts (ESI) and Optum. Samsung Bioepis' Pizchiva is in the ESI and CVS Caremark formularies, and Celltrion's Steqeyma is in two major PBM formularies, including Optum.
By current prescription share, Celltrion leads among the three domestic companies. As of May, based on data compiled by Daol Investment & Securities, U.S. ustekinumab prescription market shares were 13.3% for Celltrion's Steqeyma, 4.8% for Samsung Bioepis' Pizchiva, and 0.3% for Dong-A ST's IMULDOSA. Overall No. 1 is Stelara (36.8%).