The disease that vutrisiran targets is called transthyretin amyloid cardiomyopathy (ATTR-CM), which is estimated to affect about 100,000 people in the United States and 500,000 people worldwide, most of whom are men. It often leads to heart failure and may require a heart transplant.
“I, [trial] “This suggests that butrisiran has the potential to be a breakthrough treatment for patients with ATTR amyloidosis with cardiomyopathy,” Alnylam CEO Yvonne Greenstreet said in a statement.
He said that if the drug receives Food and Drug Administration approval, “it has the potential to become a new standard of care for treating this disease and drive Alnylam’s next major period of growth.”
Vutriciran is already approved to treat another rare, related disorder that affects the heart, other organs, and peripheral nerves. Alnylam markets it under the name Amvtra. Like Alnylam’s other approved drugs, it uses RNA interference (RNAi), a Nobel Prize-winning technique that silences disease-causing genes. And like all Alnylam drugs, it’s very expensive, costing about $475,000 per patient per year, according to the company.
The study enrolled 655 patients and followed them for up to three years, with the goal of using butrisiran to reduce death and hospitalization rates in patients taking a drug called tafamidis, made by the pharmaceutical company Pfizer, and in patients not taking the Pfizer drug.
Alnylam said butrisiran reduced deaths and cardiac-related hospitalizations in the two groups by 28% and 33%, respectively.
Tafamidis, taken as a daily pill, is the only drug approved for ATTR-CM, and analysts expect sales of the drug, sold as Vyndamax, to exceed $4 billion this year.
William Blair & Co. analyst Miles Minter called Alnylam’s findings “a clear home run.” In a pre-trading note to investors, he predicted Alnylam’s stock price could rise 45%.
Mani Foroohar, another Leerink Partners analyst, said he wasn’t surprised by the surge in Alnylam shares, but he expects the company to present more detailed data at the European Society of Cardiology conference in London in late August to fully gauge the treatment’s potential.
Alnylam’s chief medical officer, Dr. Pushkar Garg, said the company is “moving with urgency” to win FDA approval, and the company plans to begin filing applications with regulators around the world later this year.
The trial results mark a dramatic turn of fortunes for Alnylam: In October, the FDA rejected the biotech’s application for another infusion drug, sold as Onpattro, for patients with ATTR-CM. Regulators argued there was insufficient evidence that the treatment significantly improved patients’ lives.
Alnylam is one of the state’s most valuable biotech companies, with its stock price at The company’s market capitalization on Monday was about $28 billion. Its shares closed at $222.90 a share, up $57.20.
Jonathan Saltzman can be contacted at jonathan.saltzman@globe.com.