PF-835231 / Pfizer - LARVOL DELTA

Molecular mechanisms of drug resistance and compensation in SARS-CoV-2 main protease: the interplay between E166 and L50. (PubMed, mBio) - "Here, we investigate the molecular basis of drug resistance conferred by E166A and E166V mutations against nirmatrelvir and the related PF-00835231, individually and in combination with the distal mutation L50F. Our results contribute toward understanding of molecular mechanisms of resistance and combinations of mutations, which pushes toward resistance-thwarting inhibitor design. These principles also apply broadly to many quickly evolving drug targets in infectious diseases."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Discovery of Nirmatrelvir (PF-07321332): A Potent, Orally Active Inhibitor of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS CoV-2) Main Protease. (PubMed, J Med Chem) - "At the outset we focused on modifying PF-00835231 (1) discovered in 2004 as a potent inhibitor of the SARS CoV-1 Mpro with poor systemic exposure. Our effort was focused on modifying 1 with the goal of engineering in oral bioavailability by design, while maintaining cellular potency and low metabolic clearance. Modifications of 1 ultimately led to the invention of nirmatrelvir 14, the Mpro inhibitor component in PAXLOVID."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

PF-00835231 broadly inhibits swine Alpha-coronavirus, including emerging SADS-CoV. (PubMed, J Virol) - "Our study, for the first time, showed that PF-00835231 inhibits swine Alpha-coronavirus infection. At the mechanistic level, we experimentally identified that PF-00835231 inhibits nonstructural protein 5 (Nsp5) protease activity targeting the cleavage at Nsp5-Nsp6 of Alpha-coronaviruses."

Journal • Gastroenterology • Gastrointestinal Disorder • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases • SPECC1

Design of novel and highly selective SARS-CoV-2 main protease inhibitors. (PubMed, Antimicrob Agents Chemother) - "Utilizing a constrained cyclic peptide that locks the conformation between the P3 (Val) and P2 (Leu) residues, we identified a highly selective inhibitor that fills the P2 pocket occupied by the leucine residue sidechain of PF-00835231 and the dimethyl-3-azabicyclo-hexane motif in nirmatrelvir (PF-07321332)...The lead prototype compound 1 (MPro IC50 = 230 ± 18 nM) also inhibits the replication of multiple SARS-CoV-2 variants in vitro, including SARS-CoV-2 variants of concern, and can synergize at lower concentrations with the viral RNA polymerase inhibitor, remdesivir, to inhibit replication...Developing inhibitors against the active site of the main protease (Mpro), which is highly conserved across coronaviruses, is expected to impart a higher genetic barrier to evolving SARS-CoV-2 drug resistance. Drugs that selectively inhibit the viral Mpro are less likely to have off-target effects warranting efforts to improve this therapy."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases • CTSC

Structural basis for the inhibition of coronaviral main proteases by PF-00835231. (PubMed, Acta Biochim Biophys Sin (Shanghai)) - "A detailed analysis of these structures reveals key determinants essential for inhibition and elucidates the binding modes of different coronaviral M pros. Given the importance of the main protease for the treatment of coronaviral infection, structural insights into M pro inhibition by PF-00835231 can accelerate the design of novel antivirals with broad-spectrum efficacy against different human coronaviruses."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Distinct profile of antiviral drugs effects in aortic and pulmonary endothelial cells revealed by high-content microscopy and cell painting assays. (PubMed, Toxicol Appl Pharmacol) - "Here, seven antiviral drugs (remdesivir, PF-00835231, ritonavir, lopinavir, efavirenz, zidovudine and abacavir) were characterized against aortic (HAEC) and pulmonary (hLMVEC) endothelial cells, using high-content microscopy. The effects detected in aortic endothelial cells were not detected in pulmonary endothelial cells. Taken together, high-content microscopy has proven to be a robust and informative method for endothelial drug profiling that may prove useful in predicting the organ-specific endothelial toxicity of various drugs."

Journal • Cardiovascular • Infectious Disease

Safety, Tolerability, and Pharmacokinetics of Single and Multiple Ascending Intravenous Infusions of PF-07304814 (Lufotrelvir) in Participants Hospitalized With COVID-19. (PubMed, Open Forum Infect Dis) - P1b | "PF-07304814-the prodrug (lufotrelvir) and its active moiety (PF-00835231)-is a potent inhibitor of the SARS-CoV-2 3CL protease. Clinical Trials Registration. ClinicalTrials.gov NCT04535167."

Journal • PK/PD data • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

THE METABOLISM OF LUFOTRELVIR, A PRODRUG INVESTIGATED FOR THE TREATMENT OF SARS-COV-2, IN HUMANS FOLLOWING INTRAVENOUS ADMINISTRATION. (PubMed, Drug Metab Dispos) - "Conversion of the phosphate prodrug to the active drug PF-00835231 was complete and the subsequent metabolic clearance of the active drug was largely via amide bond hydrolysis. Substantial drug-related material was not recovered due to loss of the carbon-14 label to endogenous metabolism."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Orthogonal dual reporter-based gain-of-signal assay for probing SARS-CoV-2 3CL protease activity in living cells: inhibitor identification and mutation investigation. (PubMed, Emerg Microbes Infect) - "Except for the approved drug PF-07321332, only five of these inhibit 3CLpro in our assays: GC376; PF-00835231; S-217622; Boceprevir; and Z-FA-FMK. Three mutants were identified as being less susceptible to PF-07321322 (P132H) and S-217622 (G15S, T21I). This assay should greatly facilitate the development of novel 3CLpro-targeted drugs and the monitoring of the susceptibility of emerging SARS-CoV-2 variants to 3CLpro inhibitors."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Crystal Structures of Inhibitor-Bound Main Protease from Delta- and Gamma-Coronaviruses. (PubMed, Viruses) - "A comparison with the apo structure of SW1 M, which is also presented here, enabled the identification of structural arrangements upon inhibitor binding at the active site. The cocrystal structures reveal binding modes and interactions of two covalent inhibitors, PF-00835231 (active form of lufotrelvir) bound to HKU15, and GC376 bound to SW1 M. These structures may be leveraged to target diverse coronaviruses and toward the structure-based design of pan-CoV inhibitors."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases • KEAP1

Electrostatic Embedding of Machine Learning Potentials. (PubMed, J Chem Theory Comput) - "As an example, the scheme is applied to create an embedding model for the QM7 data set using Gaussian Process Regression with only 445 reference atomic environments. The model was tested on the SARS-CoV-2 protease complex with PF-00835231, resulting in a predicted embedding energy RMSE of 2 kcal/mol, compared to explicit DFT/MM calculations."

Journal • Machine learning • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

The Substitutions L50F, E166A, and L167F in SARS-CoV-2 3CLpro Are Selected by a Protease Inhibitor In Vitro and Confer Resistance To Nirmatrelvir. (PubMed, mBio) - "We identified a combination of amino acid substitutions in 3CLpro (L50F E166A L167F) that is associated with a >20× increase in 50% effective concentration (EC) values for ALG-097161, nirmatrelvir (PF-07321332), PF-00835231, and ensitrelvir. The characteristics of in vitro antiviral resistance development may be predictive for the clinical situation. Therefore, our work will be important for the management of COVID-19 with Paxlovid and next-generation SARS-CoV-2 3CLpro inhibitors."

Journal • Preclinical • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

NIRMATRELVIR AND COVID-19DEVELOPMENT, PHARMACOKINETICS, CLINICAL EFFICACY, RESISTANCE, RELAPSES, AND PHARMACOECONOMICS. (PubMed, Int J Antimicrob Agents) - "This finding is of concern when translated to immunocompromised patients, for which N/R efficacy has never been formally investigated in clinical trials. We finally discuss economical sustainability and perspectives for this therapeutic arena."

Clinical • HEOR • Journal • PK/PD data • Review • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Review of preclinical data of PF-07304814 and its active metabolite derivatives against SARS-CoV-2 infection. (PubMed, Front Pharmacol) - "PF-07304814 is a phosphate ester prodrug of PF-00835231 that is rapidly metabolized into the active metabolite PF-00835231 by alkaline phosphatase (ALP) and then suppresses SARS-CoV-2 replication by inhibiting M. PF-07304814 increased the bioavailability of PF-00835231 by enhancing plasma protein binding (PPB). Prodrugs, nanotechnology and salt form drugs may solve this problem. In this review, we focus on the preclinical data of PF-07304814 and its active metabolite derivatives to hopefully provide knowledge for researchers to study SARS-CoV-2 infection."

Journal • Preclinical • Review • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Safety, Tolerability, and Pharmacokinetics of Intravenous Doses of PF-07304814, a Phosphate Prodrug Protease Inhibitor for the Treatment of SARS-CoV-2, in Healthy Adult Participants. (PubMed, Clin Pharmacol Drug Dev) - "Studies on targeted antivirals for treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the ongoing pandemic, are limited. A daily, 24-hour continuous infusion of 270 to 350 mg is expected to maintain PF-00835231 concentration at steady state/above effective antiviral concentrations. Further studies exploring lufotrelvir efficacy in patients with coronavirus disease 2019 are ongoing."

Journal • PK/PD data • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

ADME approaches for the Pfizer oral COVID-19 protease inhibitor program (ACS-Fall 2022) - "The presentation will dwell into the discovery ADME strategies that were adopted for bespoke SARS-CoV-2 3CLpro inhibitor designs that seeked to improve the poor oral absorption characteristics of the previously identified SARS-CoV-1 3CLpro clinical candidate PF-00835231. Finally, a de novo approach that examined human mass balance and disposition of Paxlovid using 19F-NMR spectroscopy (instead of the traditional 14C human ADME) will be outlined. The 19F NMR approach in studying mass balance/disposition has been accepted by regulatory agencies worldwide, and enabled the timely approval of the emergency use authorization."

Infectious Disease • Novel Coronavirus Disease • Pediatrics • Respiratory Diseases

A VSV-based assay quantifies coronavirus Mpro/3CLpro/Nsp5 main protease activity and chemical inhibition. (PubMed, Commun Biol) - "We use SARS-CoV-2 3CLpro in this system to confirm susceptibility to known inhibitors (boceprevir, GC376, PF-00835231, and PF-07321332/nirmatrelvir) and reevaluate other reported inhibitors (baicalein, ebselen, carmofur, ethacridine, ivermectin, masitinib, darunavir, and atazanavir). Moreover, we show that the system can be adapted to report both the function and the chemical inhibition of proteases from different coronavirus species as well as from distantly related viruses. Together with the fact that live cell assays also reflect compound permeability and toxicity, we anticipate that this system will be useful for both identification and optimization of additional coronavirus protease inhibitors."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases • SPECC1

Nirmatrelvir plus ritonavir (Paxlovid) a potent SARS-CoV-2 3CLpro protease inhibitor combination (PubMed, Rev Esp Quimioter) - "During the SARS-COV-1 pandemic, a hydroxymethyl ketone derivative (PF-00835231) was identified with an intense inhibitory activity against the 3CL protease. This antiviral would be effective against current and future viral variants, since 3CL is not modified in them. The FDA approved this antiviral in November 2021 and EMA is in the final evaluation phase."

Journal • Review • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Pre-Steady-State Kinetics of the SARS-CoV-2 Main Protease as a Powerful Tool for Antiviral Drug Discovery. (PubMed, Front Pharmacol) - "The inhibition of M by boceprevir, telaprevir, GC-376, PF-00835231, or thimerosal was investigated. Therefore, our results suggest that even noncovalent inhibitor binding due to a fine conformational fit into the active site is sufficient for efficient inhibition. A structure-based virtual screening and a subsequent detailed assessment of inhibition efficacy allowed us to select two compounds as promising noncovalent inhibitor leads of SARS-CoV-2 M."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Unveiling the Effect of Low pH on the SARS-CoV-2 Main Protease by Molecular Dynamics Simulations. (PubMed, Polymers (Basel)) - "Moreover, we analysed the docking interactions of PF-00835231 from Pfizer in the preclinical phase, which shows excellent affinity with the Mpro at different pHs. (4) Overall, these findings indicate that SARS-CoV-2 Mpro is highly stable at acidic pH conditions, and this inhibitor could have a desirable function at this condition."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Preclinical characterization of an intravenous coronavirus 3CL protease inhibitor for the potential treatment of COVID19. (PubMed, Nat Commun) - "Furthermore, we show that PF-00835231 has additive/synergistic activity in combination with remdesivir. We present the ADME, safety, in vitro, and in vivo antiviral activity data that supports the clinical evaluation of PF-07304814 as a potential COVID-19 treatment."

Journal • Preclinical • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Inhibition Mechanism of SARS-CoV-2 Main Protease with Ketone-Based Inhibitors Unveiled by Multiscale Simulations. Insights for Improved Designs. (PubMed, Angew Chem Int Ed Engl) - "We present the results of classical and QM/MM simulations for the inhibition of SARS-CoV-2 3CL protease by a hydroxymethylketone inhibitor, PF-00835231...This step is followed by the nucleophilic attack of the Sγ atom on the carbonyl carbon atom of the inhibitor and a proton transfer from His41 to the carbonyl oxygen atom mediated by the P1' hydroxyl group. Computational simulations show that the addition of a methylchloride substituent to the P1' group may lower the activation free energy for covalent inhibition."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

"Preclinical data of PF-00835231 SARS-CoV-2 3CLpro inhibitor and its phosphate prodrug PF-07304814 presented by Pfizer. Live from #HatfieldMedChem21 @RSC_BMCS" (@Cortellis)

Preclinical • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Is PF-00835231 a Pan-SARS-CoV-2 Mpro Inhibitor? A Comparative Study. (PubMed, Molecules) - "Various in silico approaches were used to investigate and compare the efficacy of PF-00835231 and five drugs previously documented to inhibit the Mpro. Our study shows that PF-00835231 is not only effective against the wild type but demonstrates a high affinity against the studied mutants as well."

Journal • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases