Pharmaceutical US clinical-stage biotech Enanta Pharmaceuticals yesterday announced that it has filed suit in US District Court for the District of Massachusetts against pharma giant Pfizer seeking damages for infringement of US Patent No. 11,358,953 (the '953 Patent) in the manufacture, use and sale of Pfizer's COVID-19 antiviral, Paxlovid (nirmatrelvir tablets; ritonavir tablets). 22 June 2022