AstraZeneca has submitted to FDA three additional patents covering its proton pump inhibitor Prilosec for listing in the "Orange Book."

The U.S. Patent & Trademark Office recently issued omeprazole process and composition patents Nos. 6,166,213 and 6,147,103, as well as patent No. 6,150,380, which describes a crystalline form of omeprazole.

While the three late-listed patents do not appear in the current "Orange Book," AstraZeneca said it submitted the '103 and '380 patents for listing on Dec. 8 and the '213 patent on Jan. 16.

AstraZeneca alerted the litigants in its pending Prilosec patent cases about the listing of the three patents March 14 after realizing that an administrative error had failed to include them in the published version of the "Orange Book."

One of the Prilosec litigants, the generic drug firm Andrx, said it has notified the Federal Trade Commission "of this most recent listing abuse."

Andrx said it intends to "pursue its rights to enable FDA to approve the marketing of its generic version of Prilosec, as originally planned; following the expiration of the patent protection (April 5, 2001) and possible pediatric exclusivity accorded omeprazole."

ANDA applicants must certify that their applications do not violate patents listed in the "Orange Book." The filing of a lawsuit triggers a 30-month stay on FDA approval of any applications, unless a court ruling comes sooner, as was the case in the Bristol Buspar patent dispute (¹ Also see "Mylan Buspirone Launch Awaits Bristol Appeal Of BuSpar Patent Order" - Pink Sheet, 19 March, 2001.).

Ongoing Prilosec patent litigation between AstraZeneca and four generic applicants (Andrx, Genpharm, Schwarz Pharma and Cheminor) has been consolidated in Manhattan federal court.

In the cases, AstraZeneca is claiming that the applicants' generic omeprazole would infringe six different patents. AstraZeneca is also seeking to add process patent No. 6,013,281, issued Jan. 11, 2000, to the pending suit (² Also see "Prilosec Case Could Go To Trial After Decision On Inclusion Of Process Patent" - Pink Sheet, 8 January, 2001.). In a Feb. 26 order, Judge Barbara Jones said she would make a decision on whether to include the patent within 60 days.

The expected trial date for Genpharm is May 28, a court order states. Under a settlement over a dispute regarding which firm was first to file, Genpharm will receive 15% of Andrx' initial profits from the generic.

Under the latest Prilosec patents, generic versions of Prilosec could be barred from market entry until 2019.

AstraZeneca said crystalline patent '380 (filed Nov. 10, 1998 and issued to Astra Aktiebolag Nov. 21) will expire Nov. 10, 2018. FDA has issued AstraZeneca a written request for pediatric studies with omeprazole, which would result in an additional six months of pediatric exclusivity, blocking generics from the market until May 2019.

Patent '103 was filed Oct. 9, 1998 and issued to Merck Nov. 14. Merck shares revenues on Prilosec under the breakup agreement for the Astra-Merck joint venture in June 1998. The '213 patent, filed Oct. 9, 1998, was issued to Merck Dec. 26. AstraZeneca said both process patents will expire Oct. 9, 2018.

The '103 and '213 patents describe "an improved process for the preparation, isolation, and purification of the anti-ulcer agent omeprazole."

The patents also claim "compositions of omeprazole containing no chromatographically detectable levels of residual non-alcoholic organic reaction solvent." Composition of matter claims may be more difficult for generic companies to challenge.

As it looks to extend its Prilosec exclusivity through additional patent listings, AstraZeneca also hopes to capitalize on switching patients to the Prilosec successor Nexium (esomeprazole). The single isomer version of the active ingredient in Prilosec was approved Feb. 20 and is being introduced at a discount to its predecessor (³ Also see "AstraZeneca Nexium Relying On Healing Rate, Symptom Maintenance" - Pink Sheet, 26 February, 2001.).

AstraZeneca also hopes to prolong its Prilosec exclusivity by filing an NDA for use of omeprazole as an over-the-counter product. In October, FDA's Nonprescription and Gastrointestinal Drugs Advisory Committees decided that while gastroesophageal reflux disease is appropriate for OTC treatment, the Prilosec switch NDA was not approvable (⁴ Also see "Prilosec GERD Indication Suitability For OTC Use Debated By Advisory Cmte." - Pink Sheet, 23 October, 2000.).

AstraZeneca Awaits "Orange Book" Listing For Three Prilosec Patents

More from Archive

More from Pink Sheet