22 MARKET NEWS Wyeth-Ayerst to characterise composition of 'Premarin'

The US FDA will not approve any new drug applications for a generic form of the conjugated estrogen product 'Premarin' [Wyeth-Ayerst] until its composition has been characterised, reports the Pink Sheet.

Dr Janet Woodcock, Director of the Center for Drug Evaluation and Research stated that 'the active ingredient of Premarin cannot now be definitively identified' and that until this is done, a synthetic generic product cannot be approved.

Significance of DHES Controversy has surrounded the question of

whether the estrogen delta-8,-9 dehydroestrone sulfate (DRES) can or cannot be considered an active ingredient of 'Premarin', as its presence is not controlled by the manufacturing process. DHES is present in 'Premarin', and the FDA has stated that DHES must also be present in any generic forms of the drug, unless it is proved that the effect of DHES has no clinical impact.

The FDA concedes that approval for generic forms of 'Premarin' might be given if the drugs originated from the same source material as 'Premarin' (i.e. from the urine of pregnant mares). Wyeth-Ayerst commits to characterization of Premarin. FDA says; generic conjugated estrogens may not be approved until Premarin is characterized. FDC Reports - Pink Sheet - Prescription Phannaceuticals and Biotechnology 59: 3-5, 12 May 1997 """"'12

Inphanna- 24 May 1997 No.1 088 1173-8324197/1088-000221$01.00° Adi. Internatlonel Limited 1997. All right. reserved