A U.S. Appeals Court ruling late last month will prevent generic manufacturer Dr. Reddy's Laboratories from launching an alternative salt version of Pfizer's hypertension treatment Norvasc

Drug Store News, March 22, 2004 by James Frederick

A U.S. Appeals Court ruling late last month will prevent generic manufacturer Dr. Reddy's Laboratories from launching an alternative salt version of Pfizer's hypertension treatment Norvasc, the company's No. 2 best-selling drug.

Norvasc will continue to have marketing, exclusivity through September 2007, when Pfizer's besy-late salt patent expires, the company stated. The first Norvasc patent expiration, according to the FDA's Orange Book, will be reached in July 2006, however.

Dr. Reddy developed a chemical cousin to Norvasc, called AmVaz, and argued that the new formulation did not violate Pfizer's patent. AmVaz was approved for sale in October.

Norvasc posted 2003 U.S. sales of $1.9 billion, according to Pfizer. Last month, the FDA approved Pfizer's combination therapy Caduet, which combines Norvasc and Lipitor. Analysts suggest that Pfizer hopes to convert its Norvasc patients to Caduet before the patent protecting Norvasc expires.