SAN FRANCISCO — A revolutionary genetically engineered drug that helps to open clogged arteries in heart attack victims is expected to be approved for sale today by the U.S. Food and Drug Administration, industry and regulatory sources said Thursday.
The decision comes less than six months after an advisory panel of the federal agency provoked a firestorm of criticism by calling for further study before licensing the new Genentech drug, which is known as tissue plasminogen activator or TPA.
Genentech, based in South San Francisco, declined comment, and the FDA would say only that Commissioner Frank E. Young will hold a press conference at 10 a.m. in Washington to discuss heart-attack treatment.
The impending approval "is a vitally important development," said Dr. Eric J. Topol, a University of Michigan Medical Center cardiologist and researcher who has tested the drug on more than 1,000 patients.
Milestone for Biotech
"Over the next couple of years," Topol predicted, "TPA will become the drug of choice" for emergency treatment of heart attacks. About 1.25 million Americans suffer heart attacks every year, and 500,000 of them die.
The FDA action also marks a milestone for the nascent genetic engineering industry, which has excited investors' imaginations but until now has delivered no blockbuster drugs.
Anticipating favorable action by the FDA, investors have been bidding up the stock price of biotech leader Genentech all week. Genentech closed Thursday at $42.75, up $3.25, in over-the-counter trading.
Bullish analysts have estimated that TPA, which Genentech will market under the trade name of Activase, could generate annual sales of $800 million to $1 billion.
Others are more skeptical. "There has been a lot of hype over TPA out of the biotech community--the brokers and underwriters and people like that," said Michael Murphy, editor of the California Technology Stock Letter in San Francisco.
He added: "Most professionals are shorting the stock," or selling borrowed Genentech shares in anticipation of a price decline. "The buying is coming from retail accounts" held by individual shareholders.
To be sure, Activase will face formidable competition. On Nov. 6, the FDA approved the intravenous use of Hoechst-Roussel Pharmaceuticals' clot-dissolving drug, streptokinase, for heart-attack patients. The drug has been available to treat heart attack patients since 1982 but its usefulness previously was limited because it had to be injected using a cardiac catheter, a time-consuming procedure. (TPA is expected to be approved for intravenous use.)
Sales Forces Marshaled
And more than a dozen companies are racing to produce a second generation of anti-clotting agents with more potency and fewer side effects than Genentech's Activase.
Sources said Genentech is marshaling its forces to quickly distribute the drug, which, according to analysts, could cost from $1,500 to $2,500 for a single dose. Genentech's 80 salespeople were flown to San Francisco last week to map strategy.
Heart attacks occur when arteries supplying the heart are blocked by fatty deposits and tiny blood clots. The drug works by activating a protein in the bloodstream known as plasminogen, which in turn dissolves proteins that hold blood clots together.
The FDA panel that recommended against immediate approval of the drug on May 29 acknowledged TPA's effect against blood clots but questioned whether the drug prolonged lives. There are also concerns that TPA can cause excessive internal bleeding in patients.
But the FDA was sharply criticized by doctors, drug company lobbyists--and even the White House--for withholding the potentially lifesaving drug from the market. Already, seven nations--West Germany, South Korea, Austria, France, Brazil, New Zealand and the Philippines--have approved the sale of the Genentech product.