FDA Panel Backs Merck's Aggrastat For Platelet Inhibition ReoPro Could Soon Face Big Pharma Competition

FDA Panel Backs Merck's Aggrastat For Platelet Inhibition

By Lisa Seachrist

Washington Editor

WASHINGTON — Following the 9-1 recommendation of an FDA advisory panel on Friday, Merck & Co. stands ready to enter the competition for the anti-platelet market currently controlled by Centocor Inc. and estimated to be worth potentially $1 billion a year.

The Cardiovascular and Renal Drugs Advisory Committee overwhelmingly endorsed Whitehouse Station, N.J.-based Merck's Aggrastat as a treatment for patients with acute coronary syndromes — unstable angina and non-Q-wave myocardial infarction (MI), which is a mild heart attack that can serve as the prelude to a serious event.

"We are very excited by the recommendation and will be ready should the agency approve Aggrastat," said Christine Fanelle, Merck's manager of public relations. "This is really a new way of treating heart disease. The clinical community is very enthusiastic about having a way to treat unstable angina."

Aggrastat is a non-peptide inhibitor of platelet aggregation based on a component of the venom of the saw-scaled viper snake. Like Centocor's ReoPro and COR Therapeutics Inc.'s Integrilin, Aggrastat blocks the GPIIb-GPIIIa receptor, which binds fibrinogen and mediates platelet aggregation.

In clinical trials, the drug when added to standard heparin and aspirin therapy, reduced the risk of heart attack, death and refractory ischemia in patients suffering from angina and non-Q-wave MI by 32 percent in the first seven days and 22 percent at 30 days.

In issuing its recommendation, the committee endorsed the drug's use in acute coronary syndromes, but refused to support the company's quest to get labeling for use in patients scheduled to have angioplasty and stent placement and did not vote on whether the drug could be used in patients who are likely to undergo those procedures.

Label claims could eventually determine which drug dominates the market. ReoPro is approved for patients about to undergo percutaneous coronary intervention (PCI) and unstable angina patients who are slated to undergo PCI within 24 hours. However, Centocor of Malvern, Pa., has continued clinical trials and that label could be expanded further in the future.

Three months ago, the same advisory panel voted to recommend South San Francisco-based COR's Integrilin for angioplasty only. However, three weeks ago the FDA announced that it was ignoring the panel's advice and planning to approve the drug for use in acute coronary syndromes and as an adjunct to angioplasty and atherectomy.

The agency has until April 30 to decide whether Merck will get such a favorable label.

Competition Could Boost ReoPro

Anthony Butler, senior vice president at Lehman Brothers, in New York, said that in the end all three drugs are likely to have the same label, leaving the decision up to the clinical community, which he suggests will choose the more efficacious product, ReoPro.

"In the acute care setting, we have yet to see a less efficacious drug win out," Butler said. "In fact, I wouldn't be surprised to find that the other drugs may raise the visibility of this class of drugs and lead to physicians using ReoPro off label."

Some analysts have contended that ReoPro, which is a monoclonal antibody, is such an expensive drug that less-costly drugs may have an edge.

Butler said cost "does play a role" and that the addition of new anti-platelet products may offer "a learning experience." However, so far, "we haven't seen cost seriously affect the acute coronary care setting. This is a life and death situation."

The agency is not bound by the decisions of its advisory panel but typically follows them.

Fanelle told BioWorld Today the company stands ready to aggressively market the drug as soon as it receives clearance from FDA. COR is relying on the expertise of marketing partner Schering-Plough Corp., of Madison, N.J.

Merck's stock (NYSE:MRK) closed Monday at $125.25, down $1. Centocor's stock (NASDAQ: CNTO) was up $0.437 to $41.187. COR's stock (NASDAQ:CORR) ended the day off $0.937 at $19.375. *