The U.S. market for the autoimmune disease treatment Stelara (ustekinumab) is rapidly shifting towards biosimilars. While prescriptions for the original drug have plummeted by over 60% in just one year, biosimilars from Celltrion and Samsung Bioepis, which entered the U.S. market last year, have experienced triple-digit growth rates.

According to a Daol Investment & Securities analysis of Bloomberg data, Johnson & Johnson's original Stelara subcutaneous injection (SC) saw its U.S. prescription volume drop to 483,000 units last month. This represents a 67.1% decrease from the same month last year and a 16.4% decline from the previous month. The drug's market share based on prescription volume now stands at 26.9%.

In contrast, Samsung Bioepis' Stelara biosimilar Pyzchiva saw prescriptions soar to 122,300 units, an astounding 938.9% increase compared to the same month last year. Its market share has climbed to 6.8%.

Celltrion's Steqeyma also experienced significant growth, with 261,000 units prescribed, a 139.0% increase from the same month last year. Its market share reached 14.5%, the highest among South Korean products. The combined market share of Steqeyma and Pyzchiva totals 21.3%, narrowing the gap with the original Stelara SC to just 5.6 percentage points.

Stelara, an interleukin (IL)-12 and IL-23 inhibitor, is used to treat autoimmune diseases such as plaque psoriasis, psoriatic arthritis, Crohn's disease, and ulcerative colitis. This blockbuster drug is projected to generate approximately 6.72 billion USD in U.S. revenue in 2024. The expiration of its U.S. patent has led to the emergence of multiple biosimilars, intensifying market competition since last year.

South Korean companies have aggressively targeted the U.S. market since last year. Samsung Bioepis launched Pyzchiva in February through its local partner, Sandoz. Samsung Bioepis handles development, approval, manufacturing, and supply, while Sandoz oversees U.S. commercialization. Celltrion followed a month later, launching Steqeyma in March.

A Samsung Bioepis spokesperson stated that its Stelara biosimilar has begun to penetrate the U.S. market since last year. While prescriptions for the original Stelara have decreased, Pyzchiva shows remarkable growth.

Celltrion attributes Steqeyma's prescription growth to expanded insurance coverage and competitive direct sales. From the outset, Steqeyma has been listed as a preferred drug in the formularies of major U.S. pharmacy benefit managers (PBMs), quickly improving patient access.

The company is also leveraging its existing sales network developed through other autoimmune disease products. Celltrion's U.S. subsidiary has built a robust network and distribution system by directly selling products like Inflectra and Yuflyma to specialists and insurance companies. Steqeyma benefits from this established infrastructure, as it targets a similar market.

A Celltrion representative commented that the recent expansion of Steqeyma prescriptions in the U.S. is a result of sales strategies tailored to local market characteristics and improved insurance coverage. It believes that effectively leveraging the established direct sales infrastructure and expertise in autoimmune disease products has significantly contributed to this prescription growth.

The U.S. market for the autoimmune disease treatment Stelara (ustekinumab) is rapidly shif …

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