By Michael Erman

NEW YORK (Reuters) – Pfizer Inc said on Monday that its drug tafamidis reduced the risk of death for patients with a rare and fatal heart disease by around 30 percent, boosting the prospects of what could be a billion-dollar-a-year drug.

The study showed that tafamidis reduced all-cause mortality over a 30-month period in patients with transthyretin amyloid cardiomyopathy to 29.5 percent, versus 42.9 percent in patients who received a placebo. It also reduced the rate of cardiovascular-related hospitalization by around 32 percent, Pfizer said.

The data was presented at the European Society of Cardiology Congress in Munich.

“The result is really, phenomenally encouraging and gives fantastic hope for patients with this devastating illness,” said Dr. Brenda Cooperstone, chief development officer of rare disease at Pfizer. “It’s a uniformly fatal disease.”

Tafamidis is one of 15 potential blockbuster treatments Pfizer is trying to develop. The company’s chief executive officer, Ian Read, has touted Pfizer’s pipeline, arguing that the growth potential from these drugs makes undertaking a large transaction unnecessary.

There are currently no approved medications in the United States for transthyretin cardiomyopathy. The number of patients currently diagnosed with the progressive disease is exceedingly small — somewhere in the range of 2,000 to 5,000 patients globally.

But Pfizer believes the disease is underdiagnosed and that there could be 400,000 to 500,000 patients in developed markets around the world. Cooperstone said the current diagnosis rate is only around 0.5 percent to 1 percent.

“Part of that is driven by the fact that today there is no therapy – there’s no reason to actually make the diagnosis,” she said, noting that a real treatment should significantly help improve the diagnosis rate.

The U.S. Food and Drug Administration gave the drug breakthrough status in May after Pfizer released topline results from the study, which could accelerate the drug’s approval.

Cooperstone said Pfizer expects to complete the submission of its application for tafamidis to the FDA in the fourth quarter. The agency has committed to reviewing it as fast as possible, she said, but declined to lay out a timeline for approval.

Until then, Pfizer has established an expanded access program to make the drug available to patients prior to regulatory approval.

SunTrust Robinson Humphrey analyst John Boris said in a research note last week that a second-half submission to regulators suggests approval and launch of the drug in 2019. He said that at an annual price of $150,000 to $300,000, the drug could bring in $600 million to $1.2 billion globally.

The study had around 440 patients enrolled.

Tafamidis was previously rejected by the FDA as treatment for a rare neurodegenerative disease. But it is currently approved, under the brand name Vyndaqel, in 40 other countries as a treatment for familial amyloid polyneuropathy, a rare, progressive and fatal neurodegenerative disease.

While the drug would not currently have any competition, Alnylam Pharmaceuticals and Ionis Pharmaceuticals Inc are developing drugs for a similar disease – hereditary TTR amyloidosis – also caused by a buildup of transthyretin protein in the body.

(Reporting by Michael Erman; Editing by Leslie Adler)