{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T23:35:10Z","timestamp":1793230510336,"version":"4.5.0"},"reference-count":14,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2022,10,20]],"date-time":"2022-10-20T00:00:00Z","timestamp":1666224000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Feline infectious peritonitis (FIP) is a complex and historically fatal disease, though recent advances in antiviral therapy have uncovered potential treatments. A newer therapeutic option, unlicensed molnupiravir, is being used as a first-line therapy for suspect FIP and as a rescue therapy to treat cats who have persistent or relapsed clinical signs of FIP after GS-441524 and\/or GC376 therapy. Using owner-reported data, treatment protocols for 30 cats were documented. The 26 cats treated with unlicensed molnupiravir as a rescue therapy were treated with an average starting dosage of 12.8 mg\/kg and an average ending dosage of 14.7 mg\/kg twice daily for a median of 12 weeks (IQR = 10\u201315). In total, 24 of 26 cats were still living disease-free at the time of writing. One cat was euthanized after completing treatment due to a prolonged seizure, and the other cat underwent retreatment for relapsed clinical signs. Few adverse effects were reported, with the most notable\u2014folded ears (1), broken whiskers (1), and severe leukopenia (1)\u2014seen at dosages above 23 mg\/kg twice daily. This study provides a proof of principle for the use of molnupiravir in cats and supports the need for future studies to further evaluate molnupiravir as a potentially safe and effective therapy for FIP.<\/jats:p>","DOI":"10.3390\/pathogens11101209","type":"journal-article","created":{"date-parts":[[2022,10,21]],"date-time":"2022-10-21T00:34:30Z","timestamp":1666312470000},"page":"1209","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":47,"title":["Unlicensed Molnupiravir is an Effective Rescue Treatment Following Failure of Unlicensed GS-441524-like Therapy for Cats with Suspected Feline Infectious Peritonitis"],"prefix":"10.3390","volume":"11","author":[{"given":"Meagan","family":"Roy","sequence":"first","affiliation":[{"name":"Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicole","family":"Jacque","sequence":"additional","affiliation":[{"name":"Independent Researcher, San Jose, CA 95123, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wendy","family":"Novicoff","sequence":"additional","affiliation":[{"name":"Departments of Orthopaedic Surgery and Public Health Sciences, School of Medicine, University of Virginia, Charlottesville, VA 22903, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emma","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rosa","family":"Negash","sequence":"additional","affiliation":[{"name":"Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2182-0684","authenticated-orcid":false,"given":"Samantha J. M.","family":"Evans","sequence":"additional","affiliation":[{"name":"Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Felten, S., and Hartmann, K. (2019). Diagnosis of Feline Infectious Peritonitis: A Review of the Current Literature. Viruses, 11.","DOI":"10.3390\/v11111068"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"378","DOI":"10.1177\/1098612X17729626","article-title":"Efficacy of a 3C-like protease inhibitor in treating various forms of acquired feline infectious peritonitis","volume":"20","author":"Pedersen","year":"2018","journal-title":"J. Feline Med. Surg."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1177\/1098612X19825701","article-title":"Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis","volume":"21","author":"Pedersen","year":"2019","journal-title":"J. Feline Med. Surg."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Jones, S., Novicoff, W., Nadeau, J., and Evans, S. (2021). Unlicensed GS-441524-Like Antiviral Therapy Can Be Effective for At-Home Treatment of Feline Infectious Peritonitis. Animals, 11.","DOI":"10.3390\/ani11082257"},{"key":"ref_5","unstructured":"Merck & Co., Inc. (2022, August 26). Authorized for Emergency Use in the Treatment of COVID-19. Lagevrio. Available online: https:\/\/www.lagevrio.com\/patients\/."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"100770","DOI":"10.1016\/j.jbc.2021.100770","article-title":"Molnupiravir promotes SARS-CoV-2 mutagenesis via the RNA template","volume":"297","author":"Gordon","year":"2021","journal-title":"J. Biol. Chem."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"102329","DOI":"10.1016\/j.dsx.2021.102329","article-title":"Molnupiravir in COVID-19: A systematic review of literature","volume":"15","author":"Singh","year":"2021","journal-title":"Diabetes Metab. Syndr. Clin. Res. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"3286","DOI":"10.1093\/jac\/dkab318","article-title":"Optimal dose and safety of molnupiravir in patients with early SARS-CoV-2: A Phase I, open-label, dose-escalating, randomized controlled study","volume":"76","author":"Khoo","year":"2021","journal-title":"J. Antimicrob. Chemother."},{"key":"ref_9","unstructured":"(2022, August 26). FIP Warriors CZ\/SK\u00ae (2022, May 20). Eidd-2801 (Molnupiravir). Available online: https:\/\/www.fipwarriors.eu\/en\/eidd-2801-molnupiravir\/."},{"key":"ref_10","unstructured":"Pedersen, N.C., and Jacque, N. (2022, August 26). Alternative Treatments for Cats with FIP and Natural or Acquired Resistance to GS-441524. Sock it to Fip. Available online: https:\/\/sockfip.org\/https-sockfip-org-wp-content-uploads-2022-03-approaches-to-drug-resistance-in-cats-treated-with-gs-441524-for-fip-v3-pdf\/."},{"key":"ref_11","unstructured":"Pedersen, N.C. (2022, October 08). The Long History of Beta-d-n4-Hydroxycytidine and Its Modern Application to Treatment of COVID-19 in People and FIP in Cats. Sock it to Fip. Available online: https:\/\/sockfip.org\/https-sockfip-org-wp-content-uploads-2022-04-the-long-history-of-beta-d-n4-hydroxycytidine-and-its-modern-application-to-treatment-of-covid-19-in-people-and-fip-in-cats-v2-pdf\/."},{"key":"ref_12","unstructured":"European Medicines Agency (2022, October 08). Committee for Medicinal Products for Human Use (CHMP) Assessment Report: Use of Mol-Nupiravir for the Treatment of COVID-19. Available online: www.ema.europa.eu\/contact."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"104597","DOI":"10.1016\/j.antiviral.2019.104597","article-title":"The prophylactic and therapeutic activity of a broadly active ribonucleoside analog in a murine model of intranasal venezuelan equine encephalitis virus infection","volume":"171","author":"Painter","year":"2019","journal-title":"Antivir. Res."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Fletcher, T., Ah Donovan-Banneld, I., Penrice-Randal, R., Goldswain, H., Rzeszutek, A., Pilgrim, J., Bullock, K., Saunders, G., Northey, J., and Dong, X. (2022). Characterisation of SARS-CoV-2 genomic variations in response to mol-nupiravir treatment in the AGILE Phase IIa clinical trial. Res. Sq.","DOI":"10.1038\/s41467-022-34839-9"}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/11\/10\/1209\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:57:53Z","timestamp":1760144273000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/11\/10\/1209"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,10,20]]},"references-count":14,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2022,10]]}},"alternative-id":["pathogens11101209"],"URL":"https:\/\/doi.org\/10.3390\/pathogens11101209","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,10,20]]}}}