The US patent trial for Sanofi-aventis' Plavix is postponed to June 12, 2006 from the previously scheduled date of April 3, 2006.

Generic drug makers Apotex and Dr. Reddy's Laboratories have been challenging the patent since 2002, hoping they can sell cheaper copycat versions of the drug, known chemically as clopidogrel bisulfate in the United States.

At the request of Apotex and Dr. Reddy's Laboratories, which invoked a conflict of dates of their lawyers in other legal procedures, the Plavix trial has been rescheduled, claims the company release.

The court indicated that the date would be further postponed depending on the duration of the trial of another earlier case.

Apotex and Dr. Reddy's Laboratories are expected to argue that the Plavix patent, which expires in 2011 in the United States, is not truly new and inventive.