Enbrel is an extreme example of unintended marketing exclusivity (30 years), a result of our flawed drug patent system. The implementation of the negotiated maximum fair price (MFP) in January 2026 for the Medicare population will at least be a tentative step to obtaining better value for this individual biologic.
We reported back in August on the Colorado Prescription Drug Affordability Board’s (PDAB’s) decision to establish an upper payment limit for Enbrel in the state, effective in 2026. This payment figure reflects an application of the negotiated Medicare MFP with Amgen, a 67% discount on Enbrel’s wholesale acquisition cost (WAC). It is entirely possible that the net US sales of the reference product will be less than $1 billion by the time biosimilar competition by Sandoz and Samsung Bioepis launches at the end of the decade.
Decreasing Enbrel Revenues Because of Lower Net Prices
Amgen continues to see reduced profits from Enbrel. For 2023, Amgen reported, “Full year sales decreased 10% [to $3.6 billion in the US], driven by lower net selling price, lower inventory levels and a 3% impact from unfavorable changes to estimated sales deductions. Year-over-year volume remained flat.” Pretty much the same trend was cited for 2024 full-year sales: “Full year sales decreased 10% [to $3.3 billion in the US], driven by lower net selling price. For 2025, we expect continued declining net selling price and relatively flat volumes.” For the first half of 2025, net US sales were $504 million in Q1 and $597 million in Q2, foretelling a big drop in the final full-year numbers.
Amgen stated the volume of Enbrel sales in the US did not decrease in 2024 and 2023. Consider the broad availability of very-low-cost biosimilar adalimumab, another anti-TNF inhibitor, which treats much the same principal indications and generally as effectively. Both products are subcutaneously injected and mostly covered under the pharmacy benefit. The cost of an adalimumab biosimilar (low-WAC pricing) is about 25% of the negotiated MFP price of Enbrel. Now, that’s relative value!
It should be noted that the list price of etanercept has not dropped; decreased net sales have resulted from greater discounts and rebates from 2023 to 2024, proof that Amgen is aggressively cutting its net price on Enbrel. To what level they’ve cut pricing is unknown. Perhaps Enbrel’s 2025 first-half revenue drop is an unacknowledged result of plans’ encouraged use of the biosimilar. There is little evidence, however, that payers and pharmacy benefits managers are requiring adalimumab use before moving to Enbrel.
This brings us back to the Colorado PDAB’s decision. What level of discounts on Enbrel were payers in Colorado already receiving? One assumes it was not close to 67%, or the move to establish an upper payment limit would be moot.
There is no guarantee that the 2029 launch of only two biosimilar competitors would result in greater discounts than this. So this seems an appropriate way to save money in one state on an agent way overdue for biosimilar competition.
The Association for Accessible Medicines and the Biosimilar Form, both groups advocating for biosimilar manufacturers, are concerned about widespread implementation of upper payment limits on Enbrel and perhaps on other biologics that could be subject to future biosimilar competition. “A competitive market is a better solution to lower costs than the government deciding what it’s going to pay,” said John Murphy III, President and CEO of the Association for Accessible Medicines. This may be generally true, but it is not the direction being taking by states and particularly this federal government.
“It’s About Time” or “It’s Never a Good Time”?
In this particular case, the expanded implementation of MFP pricing to non-Medicare payers may contribute significant savings by 2029, especially if other states follow suit, but also make etanercept biosimilar development less enticing. But in this drug category, the other manufacturers may have already been discouraged by the ludicrous market exclusivity extended to Amgen. No other manufacturer has publicly disclosed an intention to commercialize another etanercept biosimilar, and we cannot even be positive that the approved biosimilars will launch in 2029.
The trade groups’ arguments against the Colorado PDAB’s action seems to reflect an extension of the biosimilar argument against the Inflation Reduction Act and the MFN provision in particular. They make a valid point overall, but the state’s action on Enbrel pricing doesn’t seem to represent a new threat against biosimilar development, especially if applied to this special case.
