22 MARKET NEWS Zantac ® faces patent challenge from a different angle

Glaxo's Zantac® [ranitidine] is facing yet another challenge from generics. Geneva, the US generic division of Ciba, has filed an abbreviated NDA with the FDA to market a generic version of ranitidine based on Form I of Glaxo's patent, when that patent expires in Dec 1995.

Zantac® is based on the Form 2 patent, which expires in 2002, and Glaxo has never marketed a Form 1 version of ranitidine. Apparently, Form 1 and 2 ranitidine have different crystalline structures, but are identical in solution.

For regulatory approval, Geneva will need to demonstrate to the FDA that the generic product is bioequivalent to Zantac ili. Moreover, Form 1 is difficult to manufacture, and Glaxo has warned that it may take legal action against Geneva if its

manufacturing process utilises any part of the Form 2 patent, or produces Form 2 ranitidine at any time.

Other generic companies are also challenging Zantac~)os patent, but these companies are claiming that the Form 2 patent is invalid because the product is not a distinct entity from that produced by the Form 1 patent.

In 1993, Zantac® was the world's topselling drug . ...,,,,..

9 Apr 1994 INPHARMA- 0156·2703l94/0932·00022l$1.ocf Adl. Internatlon.1 Limited 1994. All right. reHrVed