Remdesivir vs GS441524
Remdesivir is the prodrug of GS441524. When given Remdesivir, it is broken down
to GS4412524, the ultimate active ingredient that stops the replication of FIPV.
Dosage required
The molecular weight of Remdesivir is 603 g/mol, while the molecular weight of
GS-441524 is 291 g/mol. This suggests that cats being treated with Remdesivir will
require approximately twice the dose compared to GS441524. This means that the cat will need to endure twice the pain of the injection during the 84 days of treatment for FIP. Preparation of treatment Remdesivir treatment needs to be prepared with saline, stored in the refrigerator and must be used within 5 days. GS441524 injection vials are ready-to-use and the treatment can be given directly via subcutaneous injection. The shelf life of GS441524 is up to 2 years when kept in ambient temperature, away from direct sunlight. GS441524 is also available in capsules, which can be given to FIP cats that have improved greatly (active, good appetite and have no diarrhoea & vomiting problems to ensure optimal absorption).
Possible toxicity
Clinical trial of GS441524 in the treatment of FIP in cats has shown that there is no
adverse side effect after 84 days of treatment. Pedersen noted the “impressive”
safety profile of GS441524, with no systemic signs of toxicity observed when
administered subcutaneously up to the dose of 10 mg/kg (to treat neurological
manifestations of FIP). Even at these higher doses, they found that GS441524
treatment resulted in the long term resolution of neurological FIP with an excellent
safety profile: minimal dose-related toxicities were observed.
On the other hand, not only is there very limited study of Remdesivir in FIP
treatment, but mild signs of liver and kidney toxicity have been observed with
Remdesivir in humans Covid treatment. Adverse events of Remdesivir therapy
include mild-to-moderate degrees of nausea and vomiting, headache, fatigue, renal
dysfunction, serum aminotransferase elevations and rash. Rare instances of
hypersensitivity reactions, acute renal dysfunction and liver injury have also been
reported.