FDA's Preliminary Analysis focuses on a comparison of delta 8,9 DHES to sodium estrone sulfate and sodium equilin sulfate, the estrogens found in Premarin in the largest amounts.
Delta 8,9 DHES satisfies the FDA's criteria for composition, plasma levels and pharmacologic activity and dose response.
The Waxman-Hatch Act governing generic pharmaceuticals requires that the responsibility for demonstrating that a product lacking delta 8,9 DHES is the same as Premarin lies with the generic manufacturer, the applicant for approval.
Wyeth-Ayerst Laboratories filed a Citizen Petition on November 30, 1994, challenging the Food and Drug Administration's potential approval of a generic version of conjugated estrogens that would not be compositionally the same as the innovator product, Premarin, because it failed to contain delta 8,9 DHES.
If one of Premarin's component hormones, such as delta 8,9 DHES
, is eliminated in a generic "copy," there is no way to determine whether the safety and efficacy of the product would be compromised.
On four separate occasions, since the 1991 bio-equivalence guidance was established, Wyeth-Ayerst had the opportunity to demonstrate the importance of delta 8,9 DHES
Ettinger's research clearly refutes Wyeth-Ayerst's arguments regarding the importance of Delta(8,9) DHES in the prevention of osteoporosis.
Yale University Professor of Obstetrics and Gynecology, conducted many scientific experiments that evaluated the effect of Delta(8,9) DHES on human cells.
In an action which would have allowed Wyeth-Ayerst to maintain its drug monopoly, Wyeth- Ayerst filed its Citizen Petition in November, 1994 asking that the FDA refuse to approve any generic conjugated estrogens tablets that do not contain Delta(8,9) DHES.
We believe that the committee understood that there is no need to reclassify delta 8,9 DHES from the impurity status it has held since the FDA's decision in 1991," said Bruce L.
Barr's filing follows current USP specifications and does not contain delta 8,9 DHES.
We believe that the debate over whether delta 8,9 DHES
should be reclassified is scientifically groundless, and intend to make this known in our testimony at the public hearing.