(Bloomberg) -- BridgeBio Pharma Inc. jumped the most in 16 months after its drug got US regulators’ nod to treat a rare, deadly form of heart disease, paving the way for head-to-head competition with medications from Pfizer Inc.

The therapy, to be sold under the name Attruby, gained Food and Drug Administration clearance on Friday to treat patients with transthyretin amyloid cardiomyopathy, or ATTR-CM. The list price will be $18,759 for a 28-day supply. 

BridgeBio shares rose as much as 28% at the start of trading Monday in New York, their biggest intraday gain since July, 2023. They had lost 42% this year through Friday’s close. 

The approval pits the small biotech’s drug against Pfizer’s Vyndaqel and Vyndamax, two drugs that use the same active ingredient, tafamidis, to treat the condition. Pfizer’s drugs are priced at the equivalent of about $20,600 for a 28-day supply and generated $3.3 billion in sales last year.

Attruby’s label says it achieves near-complete stabilization of transthyretin, a transport protein that becomes misshapen and loses functionality in ATTR-CM. That may help “convince clinicians that it is best-in-class and differentiated from tafamadis,” according to Danielle Brill, an analyst with Raymond James. 

Once thought to be rare, ATTR-CM is being diagnosed more frequently due to advances in testing, making it an attractive market for drugmakers. More than 300,000 patients globally have the condition. 

BridgeBio had won approval previously for two drugs to treat less-common diseases. ATTR-CM will be the company’s biggest market by far, and investors are waiting to see if the relatively small biotech can compete with Pfizer’s larger sales force.

About 5,000 to 7,000 new cases of the condition are identified in the US annually, researchers estimate. To succeed, BridgeBio will need many doctors to prescribe its drug — a twice-daily pill — ahead of Pfizer’s.

Even more competition is on the horizon. Alnylam Pharmaceuticals Inc. is expected to get approval next year for its drug to treat ATTR-CM. Earlier this month, Intellia Therapeutics published positive results from an early trial of its gene-editing treatment for the condition. Ionis Pharmaceuticals Inc. is also developing a drug for the disease.

(Updates with shares, analyst’s comment starting in third paragraph.)

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