This In Focus provides an overview of the complex procedures governing pharmaceutical patent disputes. FDA Regulation of Drugs and Biologics.Learn strategies to effectively handle patent infringement issues in the pharmaceutical industry and safeguard your innovations. On January 25, 2008, Endo and Penwest filed a patent infringement lawsuit against. Patent litigation is the process through which one party sues another for making allegedly unlawful claims upon their patented invention. The patent infringement claims from case 18-cv-664 were stayed pending IPRs. Consistently support competition in the prescription drug industry.