FDA Ordered To Rescind Barr's 180-Day Exclusivity For Generic Tamoxifen

FDA is ordered to reverse its March 1999 decision to grant Barr's tamoxifen 180-day exclusivity by Washington, D.C. federal court on the grounds that Barr lost its first ANDA filer status when it dropped its patent challenge in a settlement with tamoxifen innovator AstraZeneca.

Washington D.C. federal court Judge Ricardo Urbina ruled that a March 2, 1999 letter from FDA giving exclusivity to Barr should be vacated because it violates the language and the purpose of Waxman/Hatch legislation.

The letter had granted Barr's request for a stay of approval of any generic tamoxifen until 180 days after the expiration of AstraZeneca's Nolvadex patent on Aug. 20, 2002. Barr claimed the 180 days as the first to file an ANDA with paragraph IV certification challenging the Nolvadex patent, No. 4,536,516.

Barr had received 180-day exclusivity on top of the seven years of only-generic status it has had as a result of a 1993 agreement to settle patent litigation on AstraZeneca's Nolvadex.

Although it was the first generic applicant to file a paragraph IV ANDA for tamoxifen, in September 1987, Barr amended its application in March 1993 to paragraph III - abandoning its challenge to the patent -as a provision of the settlement with Zeneca.

The settlement provided that Barr amend its tamoxifen ANDA to drop the patent challenge and Zeneca abandon its appeal of a July 1992 New York City federal court decision invalidating the patent. Barr received $21 mil. and a license to market an "authorized" version of tamoxifen. The firms vacated the 1992 court decision, leaving patent in force.

Mylan filed suit against FDA in April 1999, asking the court to grant exclusivity for its ANDA for tamoxifen, which was submitted with paragraph IV certification in June 1996. Pharmachemie amended its tamoxifen ANDA to include a paragraph IV certification in August 1994, and filed suit against FDA March 30, 1999, also seeking to overturn FDA's decision, but not requesting exclusivity.

The decision grants Mylan and Pharmachemie declaratory relief, ruling that Barr's 180-day exclusivity period expired in January 1993, after being triggered by the July 1992 New York City federal court ruling.

Urbina declined to order FDA to grant Mylan's request for injunctive relief, explaining that the court has not concluded that the company is entitled to exclusivity.

The decision remands the case to FDA for development of a "permissible interpretation of the statute," but does not give FDA clear guidelines on how it should provide 180-day exclusivity for tamoxifen generics.

However, the judge states that "it appears from the statute that Barr's 180-day exclusivity period was triggered by the [NYC federal court] decision in Barr's favor" concerning the Zeneca patent.

Urbina pointed to the recent Washington D.C. federal court decision in Mylan v. Shalala, which states that exclusivity should be triggered by the first court decision declaring a patent invalid (¹ (Also see "Mylan Wins Argument In Exclusivity Case, But Not Terazosin Approval" - Pink Sheet, 17 Jan, 2000.)).

FDA previously interpreted the court trigger to be initiated by the final decision of an appeals court, but issued a revised interpretation March 30 in light of the Mylan decision (² (Also see "Ivax Generic Zoloft Exclusivity Will Be Unaffected By New FDA Guidance" - Pink Sheet, 3 Apr, 2000.)).

Urbina said that FDA's decision to grant Barr's exclusivity request had disregarded "the fact that first-filer Barr's application had not contained a paragraph IV certification since 1993," when the company settled with Zeneca and amended its ANDA.

The decision emphasizes that FDA's decision to grant exclusivity to Barr also "conflicts with the purposes" of the Waxman/Hatch Act in that it "excessively favors Barr and [AstraZeneca's] anticompetitive hold over tamoxifen." AstraZeneca had Nolvadex sales of $573 mil. in 1999.

The Department of Justice has expressed interest in the Barr/AstraZeneca tamoxifen settlement, and requested documents from the 1992 patent suit.

The decision clears the way for approval of Mylan and Pharmachemie's tamoxifen ANDAs since the Waxman/Hatch 30-month stay of approval expired for the companies in 1998.