Posted on by L. M.

2024 – Dr. Pedersen – Winter News

Original article: 2024 – Dr. Pedersen's 2024 Winter Update

2024 has been a remarkable year for FIP treatment and research. Although many thousands of cats have been cured of FIP in the past 5 years, antiviral drugs such as GS-441524 and molnupiravir have until now only been available on the unapproved market. Fortunately, both drugs are now available legally in many countries at a price comparable to unapproved sources. The full approval of Remdesivir, Molnupirvir, and Paxlovid for human use against COVID-19 has allowed veterinarians to prescribe them to cats with FIP, but at the price of a human prescription. The price of the unapproved and approved drug GS-441524 has also dropped significantly over the past few years, making it much more affordable for cat owners, cat rescue groups, catteries, and shelters.

SOCK FIP Friends continued their long-term support of FIP research at the University of California, Davis (UCD) School of Veterinary Medicine (SVM), and the ongoing studies were quite diverse. Clinical trials of the treatment, led by Dr. Krystle Reagan, included GS-441524 by oral and subcutaneous routes (equally effective); GS-441524 vs. Molnupiravir (equally effective); GS-441524 vs. Remdesivir (also equally effective); 1, 2 and Paxlovid (very promising preliminary results). Ongoing studies in owned cats have also served as a crucial source for other types of studies. Approximately 20 % cats with FIP die within the first few days of treatment, and the causes of these deaths have been investigated by Dr. Brian Murphy and his team.3 In addition to the typical lesions of severe FIP, cats that died early often had signs of secondary bacterial sepsis (supporting pneumonia, hepatitis) and severe heart disease (myodegeneration, myocarditis/pericarditis). Immune cell phenotypes from blood and lymph nodes and levels of various cytokines in body fluids were analyzed by Dr. Amir Kol and colleagues to determine how the immune system responds to infection. Preliminary results show that immunity is much more complex than previously thought, and that lymph node enlargement and cellular changes persist for a very long time after recovery. A third research team, led by Drs. Patty Pesavento and Teresa Brostoff, set out to investigate how vaccines could help prevent FIP, which, if effective, would be a desirable adjunct to treatment. A messenger RNA vaccine against the core protein of feline coronavirus was developed and has been shown to be highly immunogenic in mice. 4 and these studies will now be extended to laboratory and field cats.

Discovery of an effective treatment for FIP, as first announced in 2018 (GC376)5 and 2019 (GS-441524)6 , has led to a renaissance of clinical knowledge and interest in FIP research. FIP research has also intensified significantly in many countries outside the United States, such as China, Japan, and countries in Southeast Asia and Europe. Recently, the severity of FIP in Mediterranean countries, particularly in feral and rescue cat populations, has been documented, leading to a renewed focus on cats in this region of the world. The ability to effectively treat FIP with antiviral drugs has also stimulated not only knowledge of FIP but also interest in feline medicine among veterinarians worldwide. SVM UC Davis is proud of our contribution to this renewed interest in FIP, and we hope that SOCK FIP contributors are equally proud of the support they have provided to this effort.

On behalf of the entire SOCK FIP board, I would like to wish our supporters happy holidays and a happy and productive year 2025. We look forward to an even more productive year 2025.

–Niels C. Pedersen

References

  1. Cosaro, E.; Pires, J.; Castillo, D.; Murphy, BG; Reagan, KL Efficacy of Oral Remdesivir Compared to GS-441524 for Treatment of Cats with Naturally Occurring Effusive Feline Infectious Peritonitis: A Blinded, Non-Inferiority Study. Viruses2023, 15, 1680. https://doi.org/10.3390/v15081680
  2. Reagan KL, Brostoff T, Pires J, Rose A, Castillo D, Murphy BG. Open label clinical trial of orally administered Molnupiravir as a first-line treatment for naturally occurring effusive feline infectious peritonitis. J Vet Intern Med. 2024; 38(6), 3087. https://doi.org/10.1111/jvim.17187
  3. Murphy, BG; Castillo, D.; Neely, NE; Kol, A.; Brostoff, T.; Grant, CK; Reagan, KL Serologic, Virologic and Pathologic Features of Cats with Naturally Occurring Feline Infectious Peritonitis Enrolled in Antiviral Clinical Trials. Viruses2024, 16, 462. https://doi.org/10.3390/v16030462
  4. Brostoff, T.; Savage, HP; Jackson, KA; Dutra, JC; Fontaine, JH; Hartigan-O'Connor, DJ; Carney, RP; Pesavento, PA Feline Infectious Peritonitis mRNA Vaccine Elicits Both Humoral and Cellular Immune Responses in Mice. Vaccines2024, 12, 705. https://doi.org/10.3390/vaccines12070705
  5. Pedersen NC, Kim Y, Liu H, Galasiti Kankanamalage AC, Eckstrand C, Groutas WC, Bannasch M, Meadows JM, Chang KO. Efficacy of a 3C-like protease inhibitor in treating various forms of acquired feline infectious peritonitis. J Feline Med Surg. 2018 20, 378. https://doi.org/10.1177/1098612X17729626.
  6. Pedersen NC, Perron M, Bannasch M, Montgomery E, Murakami E, Liepnieks M, Liu H. Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis. J Feline Med Surg. 2019 Apr;21(4):271-281. https://doi.org/10.1177/1098612X19825701.
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