Patent Baristas

Reliant Pharmaceuticals has filed a lawsuit in the U.S. District Court for the District of Delaware against Par Pharmaceutical for infringement of U.S. Pat. No. 5,681,588. The ‘588 patent, which expires in 2014, relates to Reliant’s Rythmol® SR (propafenone) product.

The ‘588 Patent is listed in the Approved Drug Products with Therapeutic Equivalence Evaluations (“Orange Book“) for Rythmol® SR and claims delayed-release microtablets of beta-phenylpropiophenone derivatives. Propafenone is used to treat heart rhythm abnormalities (antiarrhythmic agent). The primary mechanism of action is blocking channels which transport sodium across cell borders, which prolongs the beginning of the phase during which heart muscle cells become electrically stimulated (action potential). Propafenone slows conduction throughout the heart and is referred to as a type IC antiarrhythmic.

The lawsuit comes in response to Par’s filing of a Paragraph IV Certification in connection with its Abbreviated New Drug Application (an “ANDA”) to the FDA for a generic version of 325mg Rythmol® SR capsules. According to the Notice.

When an ANDA is filed, the applicant must certify to the FDA that for each patent applicable to the brand-name drug, the proposed generic drug would not infringe the patent because either the ANDA filer will not market the generic drug until after the relevant patents expire (21 U.S.C. §355 (j)(2)(A)(vii)(III)) or the patent is believed to be invalid or will not be infringed by the manufacture, use or sale of the drug for which the ANDA applicant seeks approval (21 U.S.C. §355 (j)(2)(A)(vii)(IV)). The certification of invalidity or non-infringement is called a “Paragraph IV Certification.”

The filing of an ANDA with a Paragraph IV Certification seeking approval to begin commercialization of a generic drug before the expiration of relevant patents is defined as an act of patent infringement (35 U.S.C. §271(e)(2)) and gives the pioneer patent owner the right immediately to sue in United States Federal District Court if the owner disagrees with the contentions of invalidity or non-infringement.