Alnylam's drug cuts risk of death, heart issues in key study, shares jump

By Bhanvi Satija

(Reuters) -Alnylam Pharmaceuticals said its drug vutrisiran reduced deaths and cardiovascular events by a third in a study involving patients with a rare heart disease, sending the drugmaker's shares surging 38% on Monday.

Vutrisiran helped reduce the number of deaths and heart issue-related hospitalizations by 33% in the study, which enrolled 655 patients who either received the drug or a placebo.

The study tested adults with transthyretin amyloid cardiomyopathy (ATTR-CM), where function of the heart muscles is restricted due to the accumulation of irregular proteins.

Analysts said the study data likely opens the door to a much larger market for vutrisiran, which is already approved to treat nerve damage, or polyneuropathy, in patients with a related heart condition.

An expanded approval will unlock substantial revenue growth, Alnylam CEO Yvonne Greenstreet said.

"This is a market that's 10 times the size of the polyneuropathy market," Greenstreet said, adding that an expanded approval could come by next year.

Vutrisiran is expected to bring in peak sales of $3.7 billion by 2032 following an approval for ATTR-CM, William Blair analyst Myles Minter said.

Alnylam estimates ATTR-CM affects about 200,000 to 300,000 people worldwide, a majority of whom are not diagnosed.

Current treatment options include Pfizer's tafamidis, sold as Vyndaqel and Vyndamax, which works by stabilizing production of the protein transthyretin.

Vutrisiran, on the other hand, works by "switching off" or "silencing" the irregular production of transthyretin.

Some patients in the study had previously been treated with tafamidis. Including those patients, Alnylam's drug reduced deaths and hospitalizations by 28%.

Treatment with vutrisiran also helped increase the distance patients could walk in six minutes - a key measure of disease progression.

Alnylam's shares were trading at $228.16.

Shares of BridgeBio, which is developing a rival drug, fell 17%. Ionis Pharmaceuticals and Intellia, which are developing drugs belonging to the same class as vutrisiran, rose 1% and 6.4%, respectively.

(Reporting by Bhanvi Satija in Bengaluru; Editing by Sonia Cheema and Shounak Dasgupta)