(Reuters) – Veru Inc said on Monday a higher dose of its experimental drug reduced hot flashes in men with advanced prostate cancer after six weeks of treatment, in a mid-stage study.

The drug, zuclomiphene citrate, is a synthetic estrogen that aims to reduce the frequency of hot flashes, an unintended effect of androgen deprivation therapy which is a commonly used treatment for prostate cancer.

There are currently no FDA-approved treatments on the market for hot flashes in men.

Patients taking a 50 mg dosage of the oral treatment had reduced hot flashes after six weeks compared to placebo and the 10 mg dosage. The trial, which includes 93 patients, will continue for a total of 12 weeks.

Veru expects to begin a late-stage trial for the drug in the first half of 2020, pending discussions with the U.S. Food and Drug Administration, Chief Executive Officer Mitchell Steiner told Reuters.

There were no serious side-effects related to the drug, including those commonly seen in men such as breast enlargement, breast pain, blood clots in legs or lungs, or strokes from taking off-label estrogens.

Oppenheimer analyst Leland Gershell estimates U.S. sales of $163 million in 2026 from the drug.

Androgen deprivation therapy, or “chemical castration”, is one of the most common treatments to put prostate cancer into remission. Testosterone feeds prostate cancer, and androgen deprivation therapy eliminates the hormone.

However, men undergoing androgen deprivation therapy often experience hot flashes, the rapid heating up of their body sometimes accompanied by sweating.

The condition, which usually occurs in postmenopausal women, happens as suppressing testosterone in men also lowers estrogen.

(Reporting by Ruhi Soni and Vishwadha Chander; Editing by Shinjini Ganguli)