ABSTRACT
The worldwide outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. Alongside vaccines, antiviral therapeutics are an important part of the healthcare response to countering the ongoing threat presented by COVID-19. Here, we report the discovery and characterization of PF-07321332, an orally bioavailable SARS-CoV-2 main protease inhibitor with in vitro pan-human coronavirus antiviral activity and excellent off-target selectivity and in vivo safety profiles. PF-07321332 has demonstrated oral activity in a mouse-adapted SARS-CoV-2 model and has achieved oral plasma concentrations exceeding the in vitro antiviral cell potency in a phase 1 clinical trial in healthy human participants.
Subject(s)
COVID-19 Drug Treatment , Lactams/pharmacology , Lactams/therapeutic use , Leucine/pharmacology , Leucine/therapeutic use , Nitriles/pharmacology , Nitriles/therapeutic use , Proline/pharmacology , Proline/therapeutic use , SARS-CoV-2/drug effects , Viral Protease Inhibitors/pharmacology , Viral Protease Inhibitors/therapeutic use , Administration, Oral , Animals , COVID-19/virology , Clinical Trials, Phase I as Topic , Coronavirus/drug effects , Disease Models, Animal , Drug Therapy, Combination , Humans , Lactams/administration & dosage , Lactams/pharmacokinetics , Leucine/administration & dosage , Leucine/pharmacokinetics , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , Nitriles/administration & dosage , Nitriles/pharmacokinetics , Proline/administration & dosage , Proline/pharmacokinetics , Randomized Controlled Trials as Topic , Ritonavir/administration & dosage , Ritonavir/therapeutic use , SARS-CoV-2/physiology , Viral Protease Inhibitors/administration & dosage , Viral Protease Inhibitors/pharmacokinetics , Virus Replication/drug effectsABSTRACT
Analogues related to dirlotapide (1), a gut-selective inhibitor of microsomal triglyceride transfer protein (MTP) were prepared with the goal of further reducing the potential for unwanted liver MTP inhibition and associated side-effects. Compounds were designed to decrease active metabolite load: reducing MTP activity of likely human metabolites and increasing metabolite clearance to reduce exposure. Introduction of 4'-alkyl and 4'-alkoxy substituents afforded compounds exhibiting improved therapeutic index in rats with respect to liver triglyceride accumulation and enzyme elevation. Likely human metabolites of select compounds were prepared and characterized for their potential to inhibit MTP in vivo. Based on preclinical efficacy and safety data and its potential for producing short-lived, weakly active metabolites, compound 13 (PF-02575799) advanced into phase 1 clinical studies.