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  • Writer's pictureMichael Goettler

The Battle for Market Share: Why Biosimilars Struggle to Capture the Market


Humira biosimilars began entering the market in January 2023, with 10 now FDA-approved. Three have the coveted interchangeability status, allowing pharmacists to substitute them for Humira without a doctor’s permission, a huge achievement and market advantage for these manufacturers. In spite of these options, and biosimilar prices being discounted up to 87% of the wholesale acquisition cost (WAC), Humira is still not collapsing. As of February 2024, the US market share of adalimumab (Humira) biosimilars was only 4%. Why?

The answer is complicated but resolving it could save the healthcare industry $6 billion.

First, doctors don’t always have an incentive to prescribe them to patients. When someone is already on Humira and it’s working well for them, the patient likely won’t want to switch.

If Humira is working, why risk changing the treatment, even for a drug that should behave the same way?

The easier time to make that switch is when a patient needs the initial treatment. The biosimilar is also a great option when there’s a financial incentive to prescribe it. The financial incentive could be the patient’s, in the form of lower co-pays or deductibles. And it could be for the doctor if the health system prioritizes biosimilars over brand names.

But there’s a more fundamental reason that biosimilar adoption hasn’t caught on: pharmacy benefit managers (PBMs) are making it difficult to adopt from a cost perspective. PBMs have their own incentives to keep patients on the brand name biologic drugs. Costs reach upwards of $84,000 a year, and PBMs make money off negotiated rebates and other fees. With lower-cost biosimilars, those profits decline.

There’s no easy answer for how to ensure continued pharmaceutical innovation, for brand name manufacturers and those producing biosimilars. Once we can better align the healthcare system’s incentives, we have a better shot at lowering costs and improving access, while continuing to develop life-changing medications.



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