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Alnylam decides to ‘pause’ drug trial, citing new federal pricing law

The Cambridge biotech is concerned about the impact on what it could charge for a medicine to treat a rare eye disease.

Alnylam CEO Yvonne Greenstreet says the company is "pressing the pause button" on Amvuttra as a treatment for Stargardt disease, an inherited disorder that causes vision loss in children and young adults.Suzanne Kreiter/Globe Staff

Alnylam Pharmaceuticals said Thursday that it won’t begin a clinical trial for a treatment for a rare genetic eye disease this year because of a new drug-pricing law signed by President Biden that could limit what the Cambridge-based firm could charge for the medication.

Alnylam said it will not start its scheduled late-stage trial of Amvuttra for Stargardt disease, an inherited disorder that causes vision loss in children and young adults, as the company “continues to evaluate the impact of the Inflation Reduction Act.”

“We’re pressing the pause button,” Yvonne Greenstreet, Alnylam’s chief executive, said in an interview after the company disclosed the decision in its third-quarter earnings report. “We really are just in the process of evaluating the best way to serve the needs of these patients.”


Under the new law, the federal government will be able to negotiate prices for a small number of drugs prescribed to Medicare recipients. The law focuses on medicines that the federal program spends the most money on and have been marketed for years. Some drug firms, including Alnylam, have argued that the law may deter investment in new medicines.

Amvuttra was approved in June to treat a rare disease called transthyretin-mediated amyloidosis, and Alnylam was going to study whether it might have a second use, for Stargardt disease. The drug costs $463,500 a year per patient. In its first full quarter on the market, the company said, it generated $25 million in revenue.

The drug-pricing law exempts medications with only one rare-disease indication from price negotiations. If Amvuttra worked for Stargardt and the Food and Drug Administration approved it for a second disease, it might not be exempted. The list of medicines subject to negotiations is reserved for the 50 that Medicare spends the most on by 2029, and it’s unclear whether Amvuttra would be among them.


“We are very supportive of the cap on patients’ out-of-pocket costs,” Greenstreet said. Nonetheless, she said, Alnylam and other drug companies worry that the law may serve as a “disincentive for companies to progress medicines for more than one orphan-disease indication.”

Alnylam executives, she said, haven’t decided whether they will launch the trial later. It’s possible that the company may pivot to developing another drug for Stargardt.

Paul Matteis, an analyst with Stifel in Boston, said Alnylam’s decision was reasonable because of the many unanswered questions about the drug-pricing law, including whether Congress might change it after the upcoming elections. Matteis said he had no reason to think it had anything to do with the potential viability of the drug. He also said that Alnylam has been so successful at developing cutting-edge medicines in recent years that it could develop another treatment for Stargardt.

Founded in 2002, Alnylam develops drugs that rely on RNA interference, a Nobel Prize-winning scientific innovation that “silences” disease-causing genes. RNAi represents one of the most promising frontiers in drug development, and Alnylam has used it to win five US drug approvals since 2018.

Jonathan Saltzman can be reached at