PIKfyve-specific inhibitors restrict replication of multiple coronaviruses in vitro but not in a murine model of COVID-19

The ongoing COVID-19 pandemic has claimed more than 6 million lives and continues to test the world economy and healthcare systems. To combat this pandemic, the biological research community has shifted efforts to the development of medical countermeasures, including vaccines and therapeutics. However, to date, the only small molecules approved for the treatment of COVID-19 in the United States are the nucleoside analogue Remdesivir and the protease inhibitor Paxlovid, though multiple compounds have received Emergency Use Authorization and many more are currently being tested in human efficacy trials. One such compound, Apilimod, is being considered as a COVID-19 therapeutic in a Phase II efficacy trial. However, at the time of writing, there are no published efficacy data in human trials or animal COVID-19 models. Here we show that, while Apilimod and other PIKfyve inhibitors have potent antiviral activity in various cell lines against multiple human coronaviruses, these compounds worsen disease in a COVID-19 murine model when given prophylactically or therapeutically.

Corneal topography and photokeratoscopy

A keratometer measures the radius of curvature of the two principal meridians that correspond to the steepest and flattest meridians, by projecting an illuminated circle onto the corneal surface from a fixed distance. A photokeratoscope allows a permanent record to be made and further evaluated. It takes a picture primarily of the intermediate zone of the cornea. By measuring the distance between reflected rings and comparing them to the actual distance between the rings on the instrument, the curvature of the cornea can be ascertained at any given point.