Introduction of Biosimilars Led to More Rebates on Humira

In the first year on the market, the uptake of biosimilars for Humira (adalimumab) was low but there was lower net spending and prices on adalimumab, which was likely because of rebates from AbbVie, Humira’s manufacturer, according to a new analysis published today in JAMA Health Forum.

Benjamin N. Rome, M.D., M.P.H.

“The fact that AbbVie offered higher rebates for Humira to maintain formulary position likely led to lower healthcare spending, and these rebates often offset premiums for patients,” Benjamin N. Rome, M.D., M.P.H., one of the researchers involved in the study, told Formulary Watch. “But rebates are generally not passed along directly to patients who use medications, which means patients who used Humira may not have noticed any change in their out-of-pocket costs due to the rebates.”

Rome is an assistant professor of Medicine, at Harvard Medical School and a faculty member of the division of Pharmacoepidemiology and Pharmacoeconomics at Brigham and Women’s Hospital.

Researchers, led by Rome and his colleagues — Aaron S. Kesselheim, M.D., J.D., M.P.H., and Anushka Bhasker, M.Phil., both also with the division of Pharmacoepidemiology and Pharmacoeconomics at Brigham and Women’s Hospital — examined the use and spending on Humira and nine biosimilars.

They assessed the four quarters before and after the launch of the first biosimilar in January 2023. Amgen’s Amjevita (adalimumab-atto), launched in Janaury 2023, was the first Humira to come on the market. It was joined by eight others in 2023 and another, Simlandi (adalimumab-ryvk), in May 2024.

They measured the number of prescriptions dispensed using the IQVIA National Prescription Drug Audit. Sales data, net of rebates and discounts, were assessed from manufacturer financial filing. But sales data were only available for Humira and three biosimilars. Researchers calculated the net price and compared with Humira’s list price.

What they found was that the proportion of biosimilars increased from 0.03% in the first quarter of 2023 to 1.35% in the fourth quarter of 2023. Net sales for adalimumab were $5 billion in the fourth quarter of 2022 and decreased by 45% to $2.8 billion in the fourth quarter of 2023.

Net price per prescription declined by 43% from $5,007 in the fourth quarter of 2022 to $2,837 in the fourth quarter of 2023. In the fourth quarter of 2023, the net price per prescription for Humira was $2,798 and was lower than the biosimilars, which ranged from $3,452 to $4,793.

“Lower healthcare spending is a goal of biosimilar introduction, but low uptake raises concerns that manufacturers may withdraw from the market or avoid developing future biosimilars,” the authors wrote.

Rome said that in 2024 the three largest pharmacy benefit managers, starting with CVS Caremark, announced deals in which they co-branded their own biosimilar version with one of the biosimilar makers and started to prefer this version on their formulary.

“Thus, biosimilar uptake has increased in 2024 (after our study) but the effects on spending and out-of-pocket costs for patients are not yet clear,” he said. “It’s hard to predict, but it seems like the PBM co-branded biosimilars are the current approach by PBMs and payers and I'd expect that to continue.”

The Humira biosimilars, with now 10 available on the market, have been seen as a crucial test of biosimilar market because Humira had the top selling prescription brand-name drug for years. Humira and its biosimilars are used to treat several immune conditions, including rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, psoriasis, ulcerative colitis and Crohn’s disease.

“Humira is one of the first self-administered retail pharmacy biologics to face biosimilar competition,” Rome said. “So all of the concerns we’ve seen with the roll-out of Humira biosimilars are definitely warning signs for what we might see with future biosimilars, including Stelara.”

Stelara (ustekinumab), developed by Janssen, a Johnson & Johnson company, is a high-cost drug with a list price of $13,836 for one month’s supply. It generated $10.86 billion in revenue globally in 2023 compared with $6.4 billion the previous year.

Biosimilars of Stelara are expected to be launched in 2025. So far, six biosimilars have been approved, which treat patients with plaque psoriasis and psoriatic arthritis, as well as ulcerative colitis and Crohn’s disease.

Additionally, Evernorth has already indicated that it will offer a private-label biosimilar of Stelara. The interchangeable biosimilar will be produced for Evernorth’s affiliate private-label distributor, Quallent Pharmaceuticals, and will have a price that is more than 80% lower than the list price of Stelara.