ELAN EXPECTS NIFELAN ONCE-DAILY NIFEDIPINE APPROVAL SOON

ELAN EXPECTS NIFELAN ONCE-DAILY NIFEDIPINE APPROVAL SOON following a preapproval inspection of the company's manufacturing facilities, Elan said. The Athlone, Ireland-based company said that no FDA queries have yet resulted from that inspection. Elan noted that the completion of the mid-February inspection is a positive precursor to getting approval for Nifelan. As of April 1, the company had not received an "approvable" letter for the product. Elan filed an NDA in July 1989 for Nifelan, which employs the firm's INDAS (Insoluble Drug Absorption System) once- daily tablet technology ("The Pink Sheet" Jan. 14, 1991, T&G-5). Elan's U.S. licensee, Miles, will market its own extended- release nifedipine as well as Nifelan. Miles' NDA for nifedipine extended-release 30, 60, and 90 mg tablets has been "approvable" since Jan. 29. Miles said it recently had a preapproval inspection for its once-daily nifedipine product and expects approval "shortly". Elan has run into two attempts by Pfizer to prevent FDA approval of Nifelan. Pfizer markets the brand name immediate- release nifedipine Procardia and once-daily product Procardia XL, developed by Alza. Pfizer filed a lawsuit against Elan in July alleging that Nifelan would infringe a patent licensed in the U.S. to Pfizer by Miles' parent firm Bayer AG, the nifedipine ingredient innovator ("The Pink Sheet" July 20, 1992, p. 10). Procardia XL has patent protection until Sept. 16, 2003. A Delaware Federal District Court dismissed the law suit and denied Pfizer's request for a preliminary injunction against FDA approval of Nifelan ("The Pink Sheet" Feb. 15, In Brief). On March 16, the D.C. law firm Williams & Connolly submitted a citizen petition, on Pfizer's behalf, requesting that FDA deny Elan's application for its extended-release nifedipine "if such approval would depend, in any material respect, on data or information in Pfizer's applications, or on data or information from Pfizer's applications that is included in the nifedipine application of Miles, Inc., and more generally, unless and until all legal requirements for approval of it have been met." The petition points out that since nifedipine is a chronic use drug, "an NDA must include chronic animal toxicology studies (i.e., long-term animal bioassays)." Williams & Connolly stated: "It appears very unlikely that the application submitted by Elan contains reports of the long-term animal bioassays necessary for approval of a chronic use drug such as nifedipine." The petition states that in June 1986, Pfizer entered into an agreement with Elan, under which Pfizer was to fund Elan's development of a sustained-release nifedipine, and that "the agreement was terminated in June 1987." The petition states: "It appears from public documents that Elan's application was submitted to FDA in July or August 1989. Even if Elan commenced long-term animal bioassays immediately after the June 1987 termination of the agreement, it appears impossible for Elan to have completed the conduct, analysis, and write up of those studies by July-August 1989." The petition adds that Pfizer asked Bayer about the studies used by Elan and, in response, Bayer said that "Elan confirms that their NDA was prepared and filed on the basis of safety and efficacy established by Elan's own clinical trials on the formulation and was not based on any confidential data received from Bayer." Also, Pfizer's contract with Bayer "precludes Miles from giving to any third party any right of reference or use with respect to" data in the NDA of Miles' immediate-release nifedipine Adalat. The petition adds that "Elan has not received from Pfizer any right of reference or use with respect to such studies in Pfizer's NDAs." Elan said that it did not need to refer to Pfizer's studies since the information is in the public domain. Elan pointed out that any company is free to use such information since immediate- release nifedipine is off patent. Pfizer met with FDA Office of Generic Drugs in early February for what some FDAers characterized as "a marathon meeting." Pfizer said it did not meet with the agency to discuss Elan's extended- release nifedipine. The meeting may have focused on a more direct threat to Pfizer's Procardia XL franchise: a generic application seeking an AB (therapeutically equivalent) rating.