Testosterone-Reducing Therapy May Aid Against Virus, Study Shows

(Bloomberg) -- Therapy to reduce testosterone and other hormones in men with prostate cancer may have a protective effect against the new coronavirus, a study of thousands of Italian patients showed.

Men with the disease who got hormone therapy had a fourfold lower risk of virus infection than patients who didn't get such treatment, the study showed. The difference was even more pronounced when the research team compared prostate cancer patients on hormone therapy with people who had any other type of cancer.

The results don't mean that virus patients should start taking hormone therapy, cautioned Fabrice Andre, director of research at the Institut Gustave Roussy in Paris and editor-in-chief of Annals of Oncology, where the results were published. But the data show that it would be worth studying the therapy in infected people, Andre said.

“This is really a new piece in the puzzle,” said Andrea Alimonti, a professor of oncology at the Universita della Svizzera Italiana and ETH Zurich in Switzerland. Researchers are preparing a follow-up study in which high-risk virus patients would be randomly assigned to take the hormone treatment, and plan to be ready to start if there's a second wave of infections later this year, Alimonti said.

Reducing testosterone might help because a receptor for male hormones also regulates a protein called TMPRSS2, shown in other research to help Covid-19 infect healthy cells. Therapies that suppress male hormones can also decrease TMPRSS2 -- not just in the prostate, but in other tissues in the body, Alimonti said.

The study looked at 4,532 men infected with Covid-19 in Italy's Veneto region, finding that about 10% had cancer, while 2.6% had prostate cancer. Cancer patients had nearly twice the risk of getting the virus compared with the male population as a whole, and got sicker once they were infected. However, among the 5,273 men on hormone therapy for prostate cancer in Veneto, just four got the coronavirus, and none died.

One confounding factor could have been that cancer patients on hormone therapy are treated at home instead of going to a hospital, making them better able to stick to social distancing, Alimonti said.