(Adds safety details, share price)
By Michael Erman
NEW YORK, May 6 (Reuters) - The U.S. Food and Drug Administration on Monday approved Pfizer Inc's oral drug, tafamidis, to treat a rare and fatal heart disease called transthyretin amyloid cardiomyopathy, the U.S drugmaker said.
Pfizer, which has touted tafamidis as a potential blockbuster product, set a list price of $225,000 a year for the medicine, which would be sold under the brand name Vyndaqel. It is the first approved medicine for the disease in the United States.
Analysts are forecasting annual sales to exceed $1 billion in 2024, according to Refinitiv data.
The FDA also approved another oral formulation of tafamidis under the brand name Vyndamax, with a recommended dose of either Vyndaqel 80 mg once-daily, taken as four 20 mg capsules or Vyndamax 61 mg once-daily, taken as a single capsule.
"There were three factors we took into consideration on this price: the transformative nature of this compound, the population ... and the third would be our capacity to ramp up diagnosis over time," Paul Levesque, head of rare disease at Pfizer, said in a phone interview.
Quickly reaching more than 30 percent of a rare disease population with a new drug is very rare, Levesque said.
Pfizer believes there are about 100,000 people in the United States with the condition, the vast majority undiagnosed. Only about 2,000 to 5,000 patients are currently diagnosed with the progressive heart disease globally.
The company has been in talks with insurers and is confident the drug will be reimbursed at the $225,000 price, he said.
The drug, which received FDA breakthrough status in May, reduced the risk of death for patients with the disease by 30 percent when compared with placebo in clinical trials.
In 2012, tafamidis was rejected by the FDA as treatment for a rare, progressive and fatal neurodegenerative disease called familial amyloid polyneuropathy (FAP). But it is approved in 40 other countries for that disease.
Vyndaqel currently sells for about $100,000 a year outside the United States as a treatment for FAP. It was approved in Japan for transthyretin amyloid cardiomyopathy in May at a price of around $750,000 a year that was set by a government body, Pfizer said.
As the disease primarily affects an older population, a significant percentage of U.S. patients will likely be on the government's Medicare program.
For those Medicare patients unable to afford potentially high copays on the medicine, Pfizer said it will have a program to make Vyndaqel available through patient assistance programs.
Pfizer believes there could be 400,000 to 500,000 patients in developed markets around the world and said the current rate of those diagnosed may be as low as 0.5 percent to 1 percent.
Pfizer said that the frequency of adverse of effects in patients treated with the drug was similar to those on placebo.
Both Alnylam Pharmaceuticals and Ionis Pharmaceuticals Inc have approved medicines that treat a similar disease called hereditary TTR amyloidosis, also caused by a buildup of transthyretin protein in the body. Those drugs cost around $450,000 a year.
Pfizer has touted tafamidis as one of its "15 in 5" - 15 experimental treatments in development, each with at least $1 billion annual sales potential that the drugmaker hopes to launch over a five-year period.
Shares of Pfizer were flat at $41.39 on Monday morning. (Reporting by Michael Erman, additional reporting by Manas Mishra in Bengaluru; Editing by Bill Berkrot, Arun Koyyur and Susan Thomas)