Prilosec OTC Patent Extension Submission Pending At PTO
This article was originally published in The Tan Sheet
Executive Summary
AstraZeneca appears to be building its case to ward off eventual private label competition for Prilosec OTC upon expiration of Hatch/Waxman exclusivity
|
AstraZeneca appears to be building its case to ward off eventual private label competition for Prilosec OTC upon expiration of Hatch/Waxman exclusivity. Although the proton pump inhibitor's marketing exclusivity extends until mid-2006, the drug's licensor may be setting up an argument for why Prilosec OTC marketed by Procter & Gamble, is protected by composition patents. At the heart of the firm's argument is the active ingredient - omeprazole magnesium (20 mg) - which AstraZeneca contends had not been approved for marketing in the U.S. prior to FDA's clearance of Prilosec OTC on June 20, 2003 (1 (Also see "Prilosec OTC Approved In 28-, 42-Count Multiple Regimen Sizes" - Pink Sheet, 23 Jun, 2003.), p. 3). In a patent term extension application filed with the Patent & Trademark Office in August 2003, the company maintains that "omeprazole magnesium is a different active ingredient than omeprazole, which is marketed as Prilosec...for which a patent term extension has previously been granted." As part of PTO's review of the application, the office recently requested confirmation from FDA regarding the approval dates listed in the request. Thus far, PTO's evaluation indicates "the subject patent would be eligible for extension of the patent term...if the active ingredient is omeprazole magnesium, not omeprazole," according to the July 19 letter to FDA. AstraZeneca is seeking a 623-day extension of patent #5,817,338, which is set to expire on Oct. 6, 2015. If granted, the patent would terminate on June 20, 2017. However, the 623 additional days may be secondary in significance to the possibility of PTO recognizing omeprazole magnesium as an active ingredient and '338 as a key composition and method patent. FDA's Orange Book lists 11 patents that apply to Prilosec OTC, with expiration dates ranging from April 10, 2005 to Nov. 15, 2019. Three-year Hatch/Waxman exclusivity awarded following OTC approval expires June 20, 2006. The extension application for '338 was filed Aug. 19, 2003, 60 days after approval. PTO has not yet responded to AstraZeneca, nor is there a timeframe within which the agency must answer, according to White & Case, the New York law firm that submitted the application. The '338 patent states that the tablets comprise "enteric coating layered units containing an acidic susceptible substance in the form of omeprazole or one of its single enantiomers or an alkaline salt thereof [that] can be manufactured by compressing said unity into tablets without significantly affecting the properties of the enteric coating layer." "The enteric coating layer(s) covering the individual units of active substance has properties such that the compression of the units to a tablet does not significantly affect the acid resistance of the individually coated layered units," the patent states. The product is formed so that each layer of the tablet contains the active ingredient wrapped in an enteric coat, which provides long-term stability. If AstraZeneca is awarded the extension and in turn uses patent '338 as a defense against generic competition, the firm's success in court nevertheless would hinge on the strength of the patent. A strong patent could protect the product, while a weak one - even with an extension - likely would not prevent generic firms from successfully challenging the patent. Schwarz, Mylan, Novartis (Lek) and Apotex offer generic Rx omeprazole. In the meantime, omeprazole magnesium has been the focal point of ongoing claims litigation involving Prilosec OTC. In a suit filed in December, Mylan Labs contends that P&G should be enjoined from making statements that the Rx and OTC versions of Prilosec are equivalent, since the active ingredient in the prescription form is omeprazole sodium, while the OTC product contains the magnesium salt of omeprazole (2 (Also see "Mylan Seeks Halt Of “Misleading” Prilosec OTC Ad Claims In Suit" - Pink Sheet, 19 Jan, 2004.), p. 5). P&G acknowledges that the two formulations are not bioequivalent - while contending it never suggested that they were - and argues the fact is irrelevant to the product's OTC status and marketing (3 (Also see "Prilosec OTC Bioequivalence To Rx Version “Has No Impact” – P&G" - Pink Sheet, 3 May, 2004.), p. 7). |