FDA approves drug to ease breathing of hospitalized heart failure patients

Published Tuesday, August 14, 2001

WASHINGTON (AP) _ The government has approved the first new therapy in over a decade to help hospital patients with congestive heart failure who are gasping for breath _ something that happens to about a million Americans a year.

The drug Natrecor is a genetically engineered version of the hormone these patients' hearts churn out naturally to ease their breathing. The idea: Give them more of that hormone, and they'll improve without having to try riskier medications.

Natrecor should make treating these patients "much simpler," said Dr. James Young, heart failure chief at the Cleveland Clinic Foundation, who led manufacturer Scios Inc.'s main study of the drug.

But it does carry one serious risk _ blood pressure that drops dangerously low, warned Dr. Douglas Throckmorton, the Food and Drug Administration's deputy director of cardiorenal drugs. That side effect may not appear for four or five hours after treatment, and can take longer to clear up than hypotension caused by a competing treatment, he said.

That will mean a change in habit for doctors used to treating heart failure with today's standard drug, nitroglycerin. "You need to watch them longer," Throckmorton warned physicians.

Almost 5 million Americans have congestive heart failure, where their hearts gradually lose the ability to pump blood. About 1 million a year suffer flare-ups where fluid fills the lungs and they need hospitalization to ease their breathing.

Natrecor, known chemically as nesiritide, is novel: It's a bioengineered version of "B-type natriuretic peptide," or BNP, a hormone the heart uses to try to heal itself.

BNP dilates blood vessels around the heart, helping the weakened organ get blood moving. In a heart failure flare-up, fluid also builds up in the lungs _ hence the gasping _ and BNP also helps the kidneys flush out fluids, Young explained.

Two years ago, the FDA rejected approval of Natrecor because between 8 percent and 14 percent of patients using the bioengineered form of BNP suffered dangerously low blood pressure.

So Scios tested a much smaller dose in another study of 498 patients. It did help patients breathe better as blood circulation and lung congestion improved. And this time, hypotension struck only about 4 percent, similar to the side effect rate of nitroglycerin _ so the FDA announced Monday it had approved the lower Natrecor dose.

But is Natrecor any better than that old standby nitroglycerin? Throckmorton warned that the Scios study was not designed to tell that, and notes that nitroglycerin also dilates blood vessels.

But the study did show that the peak Natrecor effect occurred after about 15 minutes of treatment, versus two hours for nitroglycerin. Natrecor also has the beneficial effect on kidneys, Young said, and _ aside from requiring doctors to wait several hours to see if the patient's blood pressure drops _ it's actually a little easier to use than nitroglycerin.

More importantly, Young said, "it gives us another alternative to turn to before" trying stronger medications known as inotropes that carry the risk of a worse side effect _ irregular heartbeat.

California-based Scios said Natrecor will begin shipping to hospitals this week; each vial, a day's treatment, will cost $380.

On the Net:

Scios: http://www.sciosinc.com/index.php

Food and Drug Administration: http://www.fda.gov/