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Alnylam says heart disease drug meets goal in clinical trial, stock rises

Yvonne Greenstreet, CEO of Alnylam Pharmaceuticals.Suzanne Kreiter/Globe Staff

(Bloomberg) -- Alnylam Pharmaceuticals Inc. vaulted in premarket trading after Onpattro, the company’s drug for a nerve condition, met the main goal of a late-stage trial in patients with a form of heart disease, paving the way for the company to seek wider approval from US regulators.

The shares rose as much as 48% before US markets opened.

The drug is already cleared to treat nerve disease caused by transthyretin amyloidosis, a disorder where misfolded protein accumulates in certain tissues. Cambridge-based Alnylam is now seeking to use the drug in people whose hearts can’t function properly because of deposits of the harmful material.


“What this means is we’ll be able to speak with regulators and hopefully be able to expand the label for Onpattro to treat these patients who continue to progress and need alternative treatments,” Alnylam Chief Executive Officer Yvonne Greenstreet said in an interview, calling the results “really, really, really good data.”

Study participants who received Onpattro showed a statistically significant improvement in a test of walking ability a year later compared to those who received a placebo, Alnylam said Wednesday. The company didn’t disclose details showing exactly how the drug performed in its statement, saying those will be forthcoming at a medical meeting next month. The test, which measures how far a person can walk in six minutes, is used as a proxy for heart health and function, said Emanuel Finet, a cardiologist at the Cleveland Clinic.

The study, called Apollo-B, became one of the year’s most closely watched news events in the biotech industry after BridgeBio Pharma Inc.’s competing experimental treatment failed in a late-stage trial last December. BridgeBio’s drug didn’t appear much better than placebo when comparing results of the six-minute walk test. Because Alnylam’s trial used the same metric, investors worried it would face the same problem.


Drugmakers are racing to introduce new drugs for the heart effects of transthyretin amyloidosis, which can be inherited or develop with age. Once considered rare, the conditition has turned out to be more common, affecting upwards of an estimated 200,000 people. Cambridge, Massachusetts-based Alnylam is one of a handful of companies trying to unseat Pfizer Inc., whose Vyndaqel and Vyndamax were approved in 2019 and dominate the market for transthyretin amyloidosis with $2 billion in sales last year.

Alnylam’s Onpattro, also known as patisiran, uses Nobel Prize-winning technology called RNA interference to decrease production of the disease-causing protein. The drug also met its goal on quality of life measures. However, the treatment didn’t definitively decrease deaths and the number of heart issues people experienced. The company said the study wasn’t designed to show whether it would.

Side effects were similar among recipients of the drug and placebo, Alnylam said, although infusion-related reactions, joint stiffness and muscle spasms were reported more often in people who got the drug.

Alnylam said it will present full results from the trial at a medical meeting in Germany on September 8 and plans to file for US approval later this year.

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