Ninety percent of the expensive, widely used biologic drugs facing patent expiration by 2034 have no lower-cost alternatives in development, according to a new report by the Association for Accessible Medicines, a trade group representing generic drugmakers.

This means Americans could miss out on nearly $200 billion in healthcare savings over the next decade with 118 popular biologic drugs going off patent, according to the association's estimates. These drugs are highly complex medicines manufactured inside living cells and often end up being multibillion-dollar blockbusters for drug companies.

Market uptake for newly launched biosimilars-lower-cost copycat versions-has suffered a steep decline in recent years, dimming companies' excitement about developing them. The rate at which available biosimilars are actually dispensed to patients over brand-name counterparts fell to 23% in 2025, down from about 40% in 2024. That is partly because pharmacy-benefit managers, the middlemen that decide which drugs people are steered to through their insurance plans, often place brand-name drugs over cheaper biosimilars, AAM said.

PBMs receive rebates calculated as a percentage of a drug's list price, meaning higher-priced brand drugs yield larger payments.

AAM said brand-name drugmakers exploit this system by offering PBMs massive rebates on high-price original drugs. Drugmakers can use that leverage to discourage coverage of cheaper biosimilar competitors. "The payment and reimbursement systems out there are built to favor higher-priced brand products," said Alex Keeton, executive director of the AAM's biosimilars division. "That lack of predictability leaves a biosimilar manufacturer asking: 'I can bring value, but is that market going to be there?'"

A spokesman for the Pharmaceutical Care Management Association, which represents PBMs, said that drugmakers' "abuse of the patent system far too often blocks biosimilars from the market," adding that PBMs are working to make biosimilars the primary option for patients.

A spokesman for the Pharmaceutical Research and Manufacturers of America, which represents drugmakers, said the lack of biosimilars under development is the fault of PBMs. "If policymakers want lower costs and faster competition, they should focus on insurer-PBM conglomerates-not the IP system that has delivered more than 900 new medicines since 2000," he said. Used to treat serious conditions such as cancer, rheumatoid arthritis and diabetes, biologic drugs account for a growing portion of U.S. drug spending.

Several big drugmakers, including Pfizer and Amgen, are also large biosimilar manufacturers.

Bringing a biosimilar to market requires immense capital, costing at times hundreds of millions of dollars, much more than a standard generic pill. Manufacturers that invest those sums then encounter "patent thickets," where brand-name drugmakers pile up dozens or hundreds of overlapping patents to delay competition and launch legal attacks.

Drugmakers facing biosimilar competition have increasingly turned to reformulating their own drugs into modified versions filed as newly branded biologics rather than biosimilars, which builds a fresh estate of patents around a new formulation. AAM is lobbying Congress on several bills that it said aim to speed up biosimilar development and curb the brand-name patent practices its report criticizes.