An experimental prostate cancer drug improved the survival of hospitalised COVID-19 patients in Brazil in a clinical trial, researchers reported on Tuesday on medRxiv ahead of peer review.
The drug, proxalutamide being developed by Kintor Pharmaceuticals, blocks the effects of androgen hormones by inactivating their "receptors" on cell surfaces.
Before the spikes on the surface of the coronavirus can break into cells and infect them, they must be "primed" by a protein called TMPRSS2, which is regulated by androgen receptors, explained study co-author John McCoy of Applied Biology Inc.
In the Brazil trial, 645 hospitalised COVID-19 patients who were breathing on their own received either proxalutamide for 14 days or a placebo, plus standard care. After two weeks, recovery rates were 81.4% for the proxalutamide group versus 35.7% for those who got a placebo. After four weeks, 49.4% in the placebo group had died, versus 11% with proxalutamide. Benefits were similar across genders, even though women might not be expected to respond to drugs that block male hormones, McCoy said.
The study was done during a COVID-19 surge in a Brazilian state where the Gamma variant, formerly known as P1 and first discovered in Brazil, was dominant. The mortality reduction could be even higher in other settings where infection rates are lower and that variant is not predominant, said coauthor Dr. Carlos Gustavo Wambier of the Alpert Medical School of Brown University. "We still don't know," he said. "Someone has to initiate an investigation there."
