A drug used to treat advanced breast and lung cancers has been found to prolong the lives of men with advanced prostate cancer whose tumors don’t respond to hormone therapy, according to two studies published on Wednesday.

But treatment with docetaxel, sold by Aventis under the brand name Taxotere, is not a cure. The men who received it only lived two months longer than patients who received the Amgen drug mitoxantrone.

The lead author of one of the studies, Daniel Petrylak of Columbia University, said the research shows “Taxotere is a new standard for the treatment of men with advanced prostate cancer” and the first drug to increase survival when hormone therapy doesn’t work.

Prostate cancer kills about 29,900 men each year in the United States and more than 230,000 are diagnosed with it each year, according to the American Cancer Society.

Both studies were funded by Aventis, which is part of the Sanofi-Aventis Group, and published in the New England Journal of Medicine.

In one study, led by Ian Tannock of the University of Toronto, 335 volunteers given docetaxel every three weeks survived for an average of 18.9 months, compared to 337 recipients who lived for an average of 16.5 months after receiving standard care with mitoxantrone every three weeks.

Although the docetaxel recipients experienced more side effects, such as fatigue, hair loss, diarrhea and stomach problems, they also reported a better quality of life, the study said.

A third group of men who received weekly injections of docetaxel did not fare any better than those who got it every three weeks.

In Petrylak’s study, which injected patients with docetaxel every three weeks, researchers also found the drug prolonged the lives of the men by about two months.

The 336 who got mitoxantrone lived an average of 15.6 months; the 338 who received docetaxel survived for 17.5 months. Both drugs did a comparable job of relieving pain, according to the Petrylak study, but the extra months came at a price - the docetaxel patients had more nausea and vomiting and more heart problems.