DANBURY’s SUCCESSFUL PATENT CHALLENGE OF ICI’s TENORMIN HYPERTENSION CLAIM

DANBURY's SUCCESSFUL PATENT CHALLENGE OF ICI's TENORMIN HYPERTENSION CLAIM on June 12 will give the generic manufacturer ANDA exclusivity for use of both the hypertension claim in generic atenolol labeling and for a generic atenolol/chlorthalidone combination until Jan. 20, 1993, Danbury's parent Schein Pharmaceutical said in a June 24 release. Danbury won the initial round of the patent challenge in Delaware federal court last October. A federal circuit court ruling on June 12 upheld the lower court's decision in favor of the generic firm. Danbury has marketed a generic atenolol indicated solely for the treatment of angina since winning ANDA approval from FDA in late December. The appellate court decision clears the way for the company to add the hypertension claim to its atenolol labeling and to promote the product for that use pending FDA approval. Schein said that a supplement for the hypertension claim has been filed with the agency. The successful patent challenge also makes Danbury the only generic manufacturer that can market an atenolol/chlorthalidone combination product (ICI's Tenoretic) until Jan. 20, 1993, the expiration date of the atenolol use patent for the treatment of hypertension. Tenoretic's sole protection from generic competition since the expiration of the atenolol composition patent in September 1991 has been the use patent for hypertension. Danbury has an ANDA pending at FDA for an atenolol/chlorthalidone product. Schein said it "anticipates completion of the FDA review process for atenolol/chlorthalidone in the near future."