District Court Denies Motion for Judgment in Patent Infringement Lawsuit Under Hatch-Waxman Act

In a patent infringement lawsuit brought under the Hatch-Waxman Act, the district court in the Northern District of West Virginia recently denied Plaintiffs Bausch Health Ireland Limited and Salix Pharmaceuticals, Inc.’s motion for judgment on the pleadings as to Defendant Mylan’s infringement of the patents-in-suit. See Bausch Health Ireland Limited et al v. Mylan Laboratories Limited et al, 1-22-cv-00020 (NDWV Mar. 30, 2023). This decision highlights a distinct and important procedural aspect of lawsuits brought under the Hatch-Waxman Act for infringement allegations of patents covering an FDA-approved drug for which the defendant is seeking approval to market a generic equivalent.

Under the Hatch-Waxman Act, prior to litigation a generic drug applicant is required to certify to the FDA that the patents associated with the brand name drug are “invalid or will not be infringed by the manufacture, use, or sale of the new drug for which the application is submitted.” 21 U.S.C. § 355(j)(2)(A)(vii). The generic applicant must also send a “Paragraph IV notice letter” to the patent holder that includes “a detailed statement of the factual and legal basis of the opinion of the applicant that the patent is invalid or will not be infringed.” Id. at § 355(j)(2)(B)(iv)(II). The question raised by the Plaintiffs in this case is whether a defendant in an ensuing Hatch-Waxman litigation is limited to the invalidity and non-infringement theories raised in their Paragraph IV notice letter.

In this case, the Plaintiffs alleged that Mylan has infringed the patents-in-suit by filing its Abbreviated New Drug Application and seeking approval to sell generic forms of the drug Trulance®. Mylan denied all infringement allegations in its Answer. Nonetheless, Plaintiffs argued that judgment on the pleadings was appropriate because Mylan’s Paragraph IV notice letter did not include non-infringement arguments for every asserted claim of the patents-in-suit, and Mylan cannot deviate from the defenses asserted in its notice letter. Mylan argued that they are not limited to the defenses in their notice letter. 

The court agreed with Mylan, citing Federal Circuit case law and decisions from other district courts. The court held that “it possesses no authority to penalize any perceived deficiencies in Mylan’s Paragraph IV notice letter under the Hatch-Waxman Act, [and, therefore,] it will not limit Mylan to the theories raised in therein.” In reaching its decision, the court cited Federal Circuit precedent that the Paragraph IV notice requirement “cannot be enforced by a private party in a patent infringement action.” See Minnesota Mining & Mfg. Co v. Barr Labs., Inc., 289 F.3d 775, 777 (Fed. Cir. 2002). The court also noted that its decision aligns with other district courts that have considered this issue and likewise found that generic drug applicants are not limited to the theories raised in their Paragraph IV letters.  See Abbott Lab'ys v. Lupin Ltd., 2011 WL 1897322, at *7 (D. Del. May 19, 2011); Abbott Lab'ys, Inc. v. Apotex Inc., 725 F. Supp. 2d 724, 728 (N.D. Ill. 2010).

This decision is a useful reminder of the interplay between the statutory requirements of the Hatch-Waxman Act and procedural requirements of district court litigation. On this particular issue of defenses raised in a Paragraph IV notice letter, district courts continue to hold that defendants in Hatch-Waxman litigations are not limited to the theories raised in their notice letter.