Purdue Pharma Tries to Salvage 30-Month Stay in OxyContin Case Against Mallinckrodt

Purdue Pharma has been fighting in court for nearly a decade to protect OxyContin--a blockbuster painkiller and by far Purdue's best-selling drug product--from generic competition.  Purdue settled its patent litigation with Endo and Teva last year, and with Impax a few weeks ago.  Recently, Purdue filed complaints against Mallinckrodt and KV Pharma.  Purdue's case against Mallinckrodt is particularly interesting, since it raises some new questions about 30-month stays.

In 2005, Mallinckrodt filed an ANDA for generic OxyContin (oxycodone HCl controlled-release) Tablets with paragraph IV certifications to Purdue's U.S. Patent Nos. 5,508,042; 5,549,912; and 5,656,295.  Purdue received notice of Mallickrodt's ANDA filing on October 4, 2005.  According to Purdue, however, various orders and injunctions in other OxyContin litigation "prevented Purdue from filing suit against Mallinckrodt at that time."  Purdue waited until November 9, 2006 before it sued Mallinckrodt for patent infringement.

In December, Purdue filed a Motion for Order of 30-Month Stay in the district court, asserting "that the 45-day period related to Mallinckrodt's notice of its ANDA filing was equitably tolled until October 17, 2006, and, therefore, that the filing of the complaint on November 9, 2006, within the 45-day period, triggered a 30-month stay of FDA approval of Mallinckrodt's ANDA under the Hatch-Waxman Act."  At the same time, Purdue filed a Petition for Stay of Action with the FDA, asking FDA to stay any approval of Mallinckrodt's ANDA until the district court has ruled on its motion.

Purdue acknowledges that a patent owner or NDA holder is allowed only 45 days after receipt of a paragraph IV notice letter to file a patent infringement suit if it wishes to obtain a 30-month stay.  However, Purdue argues that a January 5, 2004 district court finding of unenforceability in the litigation against Endo, various collateral estoppel orders in related cases against other ANDA applicants, and a June 7, 2005 Federal Circuit opinion affirming the district court's unenforceability opinion, prevented Purdue from filing suit against any other ANDA applicants.

On February 1, 2006, the Federal Circuit withdrew its June 7, 2005 opinion and remanded the case to the district court for further proceedings on inequitable conduct.  Since the February 1, 2006 Federal Circuit opinion, Purdue settled with Endo, Teva, and Impax, and filed proposed stipulated orders vacating the collateral estoppel orders in those cases.  Purdue argues that it was blocked from filing suit against Mallinckrodt until October 17, 2006, when it filed the last remaining proposed stipulated order.

In its Opposition to Purdue's Motion for Order of 30-Month Stay, Mallinckrodt argues first that the statute is "plain and unambiguous": a 30-month stay is available only if suit is filed within 45 days of receiving notice of a paragraph IV certification; the statute simply does not grant a court authority to order a 30-month stay otherwise.  Second, Mallinckrodt argues that the Doctrine of Equitable Tolling does not apply to the 45-day period because the period is not a statute of limitation; and even if the doctrine did apply, "Purdue's repeated failures to take action to protect its interests would bar Purdue from the benefit of the doctrine."

The parties have requested an oral hearing on Purdue's motion for a 30-month stay, although it appears that the court has not yet scheduled a hearing.  In the meantime, Purdue might file a motion for preliminary injunction.  Judge Sidney H. Stein in the Southern District of New York is presiding over the case.