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Top 5 Most-Read Gastroenterology Articles of 2025
Explore this year's advancements in gastroenterology biosimilars, highlighting key FDA approvals and market dynamics impacting IBD treatment options.
The gastroenterology biosimilar landscape is undergoing rapid transformation, dominated primarily by the introduction of ustekinumab biosimilars (referencing Stelara) and the ongoing dynamics of the adalimumab biosimilar market (referencing Humira). The following roundup highlights the top 5 news stories detailing these developments, focusing on regulatory milestones, market challenges, and real-world clinical outcomes for inflammatory bowel disease (IBD) and related gastrointestinal conditions.
5. High Acceptance Levels After Switching to an Adalimumab Biosimilar for IBD
Positive real-world data emerged regarding patient willingness and clinical outcomes following a switch to an adalimumab biosimilar. A French observational study focused on patients with IBD, which includes Crohn disease and ulcerative colitis, who were offered a switch from the reference adalimumab product. The study found "high acceptance levels" among patients with IBD who received education and personalized guidance regarding the switch.
Specifically, 92% of patients accepted the switch, and a notable 71% remained on a biosimilar after 12 months. Clinical outcomes were strong: 85% of switched patients remained in clinical remission at the 12-month mark, suggesting that the switch had no negative impact on disease control. The high cost of biologics, including adalimumab, makes these biosimilar alternatives crucial for treating the estimated 7 million people with IBD around the world.
While the majority reported a positive experience (66%), the most frequent reason for discontinuing the biosimilar was injection site pain (25%). Researchers concluded that most patients with IBD were receptive to switching to a biosimilar and achieved good outcomes, emphasizing that continuous patient education and addressing individual concerns are "crucial for improving overall satisfaction with biosimilars."
4. FDA Approves Starjemza as New Stelara Biosimilar
The momentum in the ustekinumab space continued with the FDA approval of Starjemza (ustekinumab-hmny) in May 2025, marking the eighth ustekinumab biosimilar to receive regulatory clearance. Starjemza, developed through a partnership between Hikma Pharmaceuticals and Bio-Thera Solutions, is approved for treating several rheumatic and gastrointestinal conditions.
The approval further enhances the treatment landscape for patients, following the approval of Steqeyma in late 2024. The FDA’s decision was based on data from 2 clinical studies, including a phase 3 trial in patients with moderate to severe plaque psoriasis, which confirmed that Starjemza maintained comparable efficacy, safety, and immunogenicity to the reference product, Stelara. At the time of this approval, 6 ustekinumab biosimilars were already available on the US market, some of which—like Wezlana—are available exclusively through private label distributors.
3. Skyrizi Overtakes Humira: “Product Hopping” Leaves Biosimilar Market in Limbo
In a significant market shift concerning biologics used to treat conditions like Crohn disease and ulcerative colitis, AbbVie’s Skyrizi (risankizumab-rzaa) officially surpassed Humira (reference adalimumab) as the company’s leading sales driver in the third quarter of 2024. The change can be attributed to the practice of "product hopping," where originator companies strategically shift patient demand from an innovator drug facing biosimilar competition (Humira) to a newer, patented product (Skyrizi or Rinvoq) that treats the same indications.
This market maneuver has complicated the sustainability of the US adalimumab biosimilar space. While 10 adalimumab biosimilars have launched since January 2023, the combined market shares only reached 22% by October 2024, a notable improvement from the 2% share after the first year. However, the growth of Skyrizi and Rinvoq has led to a "large drop in total adalimumab volume," effectively shrinking the overall market size, meaning biosimilars are gaining share in a diminishing pie.
Experts attending the GRx+Biosims conference emphasized that policy reforms, such as fair access fees and better formulary placement, are necessary to ensure a transparent and competitive market for biosimilars to thrive against product hopping practices.
2. 3 Ustekinumab Biosimilars Launch on US Market
The ustekinumab market heated up quickly following Wezlana's launch, as 3 additional biosimilars entered the US market in February 2025. These competitors—Pyzchiva (ustekinumab-ttwe) from Samsung Bioepis/Sandoz, Yesintek (ustekinumab-kfce) from Biocon Biologics, and Selarsdi (ustekinumab-aekn) from Teva/Alvotech—expand patient access to more affordable options referencing the blockbuster drug Stelara. Stelara generated $10.4 billion in sales in 2024 alone.
All 7 FDA-approved ustekinumab biosimilars are indicated for the treatment of plaque psoriasis, psoriatic arthritis, Crohn disease, and ulcerative colitis. Inflammatory bowel disease, encompassing Crohn disease and ulcerative colitis, is estimated to impact between 2.4 million and 3.1 million Americans. The Crohn's and Colitis Foundation's chief education, support, and advocacy officer commented that this influx of options represents a "meaningful advancement" for eligible patients with chronic disease. The competition is particularly important because Wezlana's initial access is restricted by its exclusive agreement with Nuvaila. Although Pyzchiva has been provisionally designated as interchangeable, it must wait for the lapse of Wezlana's one-year exclusivity for being the first interchangeable ustekinumab biosimilar before the full designation can be granted.
1. Welcome Wezlana: The First Stelara Biosimilar to Launch in the US
January 1, 2025, marked a significant moment for gastroenterology patients with the launch of the first ustekinumab biosimilar in the US: Amgen’s Wezlana (ustekinumab-auub). Ustekinumab products, which are interleukin (IL)-12 and IL-23 antagonists, are crucial for treating conditions like Crohn disease and ulcerative colitis, in addition to plaque psoriasis and psoriatic arthritis. The arrival of Wezlana, delayed from a projected 2023 launch due to a settlement with Johnson & Johnson, ushers in a new class of lower-cost biologics for Americans with these gastrointestinal and rheumatic conditions.
Wezlana was the first ustekinumab biosimilar to receive FDA approval and possesses an interchangeability designation. This designation is key for patient access and convenience, as it allows the biosimilar to be substituted for the reference product, Stelara, at the pharmacy level without requiring prior provider approval. However, the initial launch has been partially limited: the biosimilar is exclusively available through Nuvaila, Optum Rx's biosimilar procurement business. This launch is being closely watched to see if it follows the path of adalimumab biosimilars, especially concerning the risk of "product hopping," where the originator company might shift patients to a newer product, such as Tremfya (gusekumab), to limit the uptake of biosimilars. Wezlana’s approval was supported by a phase 3 trial confirming comparable safety and efficacy profiles to Stelara.
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