Source: Colorado State University

Colorado State University clinical trial found that the antiviral drug molnupiravir is 77% effective in treating feline infectious peritonitis (FIP), a previously almost always fatal disease caused by feline coronavirus. The study, the largest prospective trial of its kind, followed 73 cats treated for 12 weeks, with six months of monitoring. Of the 77% that survived, 12% relapsed but responded to a second treatment round. No severe side effects were reported. 
FIP affects 5% to 10% of cats, especially kittens. Molnupiravir is now the second major antiviral shown effective, alongside GS-441524, which has about 80% efficacy. Having multiple treatments may reduce antiviral resistance and allow combination therapies. Researchers are also studying similarities between FIP and COVID-19, including inflammation and potential long-term effects, as both involve coronaviruses. Ongoing trials are evaluating additional therapies, including Paxlovid, highlighting the potential for feline research to inform human medicine through translational studies.