PFIZER NIFEDIPINE PATENTS FOR TABLET FORMULATIONS

PFIZER NIFEDIPINE PATENTS FOR TABLET FORMULATIONS cover the same active ingredient in Procardia (nifedipine liquid capsules) and, therefore, should be accepted by FDA for filing under provisions of the Waxman/Hatch law, Pfizer outside counsel Peter Barton Hutt (Covington & Burling) argued in a Dec. 22 petition to the agency. The petition asks FDA to (1) "declare that information on patents claiming nifedipine in tablet formulations for which approval has not been sought may be filed with FDA pursuant to section 505 (b) (1) and (c) (2) of the FD&C Act"; and (2) "accept for filing under section 505 (c) (2)" Pfizer's two patents "covering nifedipine-containing solid compositions."

The firm's petition asks that the patents be listed so that patent challenge procedures under the Waxman/Hatch law will apply if an ANDA is filed for a tablet formulation of infedipine. The petition follows an Oct. 6 ANDA suitability petition filed by Par asking the agency to allow submission of ANDAs for nifedipine in 10 and 20 mg tablets. FDA approved the ANDA suitability petition on Dec. 11.

By pursuing an ANDA for nifedipine tablets, Par could get a two-year jump on entry into the nifedipine market. Pfizer has a patent on the capsule formulation of nifedipine that lasts until Jan. 8, 1991; however, the firm's patent on the pharmaceutical composition of nifedipine expires on Feb. 22, 1989.

Under the Waxman Hatch law, if patent information is filed with FDA on a product, an ANDA sponsor must certify that its proposed product does not infringe the innovator's patent; the sponsor also must notify the patent holder of the ANDA submission and the company with information supporting the noninfringement claim. If the patent holder believes that its patent would be infringed and litigates, FDA is barred from approving the application for 30 months or until the litigation is settled, whichever comes first.

Pfizer's petition argues that the company should be entitled to the same 30 month protection and rights of notification because it holds patents on tablet formulations of nifedipine. In 1985, Pfizer submitted one of the tablet patents to FDA for filing. FDA, according to the petition, "refused to file information submitted by Pfizer on the nifedipine solid dosage form patent, because the Pfizer NDA for this drug covered only a capsule form." FDA has maintained that the only patents it is required to file under the Waxman/Hatch law are those which specifically refer to the version of the drug which is the subject of the NDA.

Although Pfizer doesn't market tablet formulations of nifedipine, the company has patents on two tablet formulations: one which expires in 2000, and one which expires in 2003. One of the patents covers a tablet formulation of nifedipine marketed in Europe by Pfizer's licensor, Bayer AG.

Pfizer's petition argues that both the intent and the language of the Waxman/Hatch law support filing of any patents which cover the active ingredient of an NDAed product. "FDA's current narrow reading of the filing provision enables generic manufacturers to file ANDAs proposing formulations not presently marketed by innovators but for which an innovator may hold a valid patent," the petition states. "The nub of the problem," the petition points out, "is that a suitability petition may be approved for a version of the drug covered by a patent, while FDA has not permitted the relevant information to be filed."