The Mandelbear's Musings

My originally planned Episode 11 has gotten postponed again. At this rate... Anyway. I saw a report earlier today about a mutant form of the SARS-CoV-2 coronavirus that appears to be more contagious than the original. A few hours later I made a connection between that and another mutant coronavirus: the mutant form of Feline coronavirus (FCoV) that causes Feline infectious peritonitis (FIP). If you've been following my DW for a while you'll remember that as the disease that killed poor Curio -- the cat in the userpic -- with symptoms alarmingly like those of severe COVID-19. So I duck-duck-went with it, as one does.

Sure enough, there it was: the connection between FIP and Covid19. A few years back (but too late for Curio), a drug was found that promised to be practically a miracle cure for FIP, called GS-441524. And wouldn't you know, it's closely related to Remdesivir. In fact, it's one of the intermediate steps in synthesizing Remdesivir, and it's also what Remdesivir metabolizes into once it gets into a cell, before being phosphorylated into the active triphosphate form. Turns out Gilead Sciences owns the patents for both of them.

I'd been wondering why GS-441524 didn't become available -- veterinary drugs don't need nearly as arduous an approval process as human drugs. It turns out that Gilead was afraid that getting GS-441524 approved for cats might interfere with their attempt to get Remdesivir approved for humans. Why would that be? Maybe because GS-441524 is much less expensive to make? (A less cynical person might also point out that Remdesivir has superior ability to transport the active compound into cells. One wonders, however, which is the more cost-effective.)

I note in passing that GS-441524 is available from China on the black market; cat owners can easily find it these days. It may become harder to come by if Remdesivir production ramps up.

( Notes & links )