The National Institutes of Health plans to independently explore whether a Gilead Sciences (GILD) compound, which some academics maintain is highly similar to remdesivir, but which the company has deemphasized in its efforts, may be useful in combating Covid-19.
The compound, called GS-441524, works in the same way as remdesivir to inhibit viruses, according to research that was conducted partly by the company (more here). But the compound has not been tested in humans and, for the past few months, a pair of researchers at the University of Texas MD Anderson Cancer Center has argued publicly that Gilead ought to run tests.
Now, the NIH’s National Center for Advancing Translational Sciences is curious. Scientists at the institute have “reviewed the literature and agree that this compound merits further exploration,” according to an Aug. 20 letter sent to MD Anderson researchers and the advocacy group Public Citizen, which recently wrote to the NIH and the Food and Drug Administration in hopes of pressuring Gilead to conduct studies.
“We are planning to independently test the therapeutic hypothesis for GS-441524 in treating SARS-CoV-2, [which causes Covid-19], and have informed our colleagues at [the National Institute of Allergy and Infectious Diseases] about our plans for preclinical studies. We expect to conduct these studies quickly and make the results available to the research community for further consideration,” the agency said in the letter.
The compound actually made headlines for a different reason earlier this year. GS-441524 has been sold on black markets to repel feline infectious peritonitis, a disease in cats caused by a different coronavirus than the virus that causes Covid-19.
Lab tests have suggested GS-441524 is active against SARS-CoV-2, and it is apparently similar or superior to the effects of remdesivir at levels that do not cause much toxicity, according to the Anderson researchers, who want to run their own tests. They also maintain the compound is more easily synthesized than remdesivir, so it should be easier to create oral versions and make higher doses.
Earlier this month, the drug maker explained there were several reasons for pursuing remdesivir instead. These include evidence indicating remdesivir is more effective in test tubes and animal models than GS-441524 in blocking viral replication, and was also more active in lab tests against multiple coronaviruses, include SARS-CoV-2.
The company and the researchers sparred over such issues as toxicology findings in both remdesivir and GS-441524. So far, though, the drug maker has not offered to cooperate in their research. A Gilead spokesman recently noted that additional preclinical studies to further compare remdesivir and GS-441524 have begun. [UPDATE: The following day, the spokesman wrote us to say the company has shared available preclinical data with the NIH.]
One of the Anderson researchers, Victoria Yan, a graduate research assistant specializing in phosphate chemistry, wrote us that she is “really excited” by the NCATS decision. But she added the researchers are still seeking permission from Gilead to use data on the compound that is on file with the FDA. She is hopeful any data generated by NCATS can support their own investigational drug application to the FDA.