September 9, 2019
Dear owner of a cat with FIP: I am receiving many emails and phone calls regarding cats that are either being treated with GS-441524 with or without help from veterinarians or from owners that intend to start treatment with GS from Chinese black-market sources and need advice. It is essential that owners have access to a personal veterinarian that is knowledgeable about FIP, that the cat is confirmed to suffer from FIP and not another disease, and that veterinarians assist with the treatment to assure proper administration of the drug and correct monitoring for a response. I cannot replace a personal veterinarian in these cases.
All of the information that owners and veterinarians require for treating cats with GS-441524 is covered in the April 2019 issue of Journal of Feline Medicine and Surgery, which describes the drug, how it is administered and how the treatment should be monitored. A copy of the paper can be downloaded free of cost by owners or veterinarians at: journals.sagepub.com.
I must also warn owners seeking GS-441524 treatment that it is expensive, stressful for owners and cats, requires proper monitoring and is not always successful. Cats with neurological FIP are the most difficult to treat and often require an even higher dosage. I also cannot offer advice on the best sources of GS-441524, as it is currently only available from the Chinese black-market and has no official approval for veterinary use.
Veterinarians will be rightfully resistant to purchase and resale of black-market drugs and will either refuse to help with treatment or only assist if owners take responsibility for the purchase and the unapproved veterinary use of GS-441524 for treatment of FIP. It should also be noted that these black-market suppliers have been given a cease and desist order by the patent holder, Gilead Sciences, Inc., and that this unapproved source of GS-441524 cannot be assured in the future.
Many cat lovers see the advent of GS376 and GS-441524 treatment as a final solution to the problem of FIP. This is far from the case, as there is need to find even more effective drugs. Drugs that can more efficiently penetrate into the central nervous system and eyes are needed. Diluents that will maintain the stability of a drug but not cause injection site reactions need to be researched. Oral forms of injectable drugs need to be developed and tested in field trials. Treatments that help stimulate the immune system during anti-viral drug treatment need to be studied, as successful treatment of FIP, as with hepatitis C in people, may depend ultimately on establishment of a protective immune response. We need to discover how the FIP virus abrogates protective immunity so that treatments can be found that will negate this effect. An understanding of FIP virus immunity may also lead someday to effective vaccines. Finally, we need a much better understanding of the environmental factors in high density cat populations that foster FIP. The ultimate goal of FIP research should be a total prevention. An effective treatment for FIP will not prevent FIP from occurring, but it is an important tool in this ultimate goal. Please keep supporting FIP research and researchers around the world.