Generic drug industry urges approval of Premarin sub

Drug Store News, June 5, 1995

Representatives of the generic drug industry warned Food and Drug Administration (FDA) commissioner David Kessler that the agency would be setting a "dangerous precedent" by ignoring a recommendation from its own expert advisory committee to approve a generic conjugated estrogen product.

That panel's recommendation appeared to open the door to low-cost generic competition for Wyeth-Ayerst's Premarin--a drug that has been off-patent for a generation, yet remains available only as a brand-name product.

But a citizen's petition filed by Wyeth-Ayerst late last year challenged the pharmaceutical equivalence of the new generic version proposed by Duramed Pharmaceuticals.

At issue in the dispute: delta 8,9-dehydroesterone sulfate--an estrogen component that is present in Premarin, but not required in conjugated estrogens under the FDA's standards.

In its petition, Wyeth-Ayerst said some animal studies have questioned the safety and effectiveness of conjugated estrogens lacking delta 8,9-dehydroesterone sulfate, and asked the FDA to delay approval of a generic version until the issue is studied further.

The American Pharmaceutical Association (APhA) quickly jumped in to support Wyeth-Ayerst's petition, contending that pharmacists may have qualms about dispensing a generic conjugated estrogen product lacking all the components of Premarin.

Noting that pharmacies would be under pressure from third-party payors to use the cheaper generic version, APhA told Kessler that "America's pharmacists do not want the FDA to put them in a position where they can only be paid for dispensing a product in which they have little confidence."

Economically, the stakes in the dispute are huge. Currently Premarin, which is the nation's most frequently dispensed drug, is used by more than eight million American women to relieve symptoms associated with menopause and to prevent osteoporosis.

Nevertheless, the cost of Premarin continues to rise. Data released by Medispan indicate that the manufacturer's price for the drug has increased 10 times just since 1988.

Late last month the Generic Pharmaceutical Industry Association entered the controversy, arguing that Wyeth-Ayerst's petition should be rejected because it lacks "appropriate scientific support."

Calling the petition nothing more than "another attempt by Wyeth-Ayerst to delay generic competition" for Premarin, GPIA said the company "never compared their drug to the generic alternative in critical clinical studies on women patients or in comparable animal models."

According to generic drug industry leaders, such a comparison would have established the equivalence of Duramed's version. Delaying a generic version of the nation's most widely prescribed drug on the basis of Wyeth-Ayerst's petition "would set a dangerous precedent for the use of the agency's administrative process solely to preserve a monopoly," GPIA told FDA.