The nafarelin also produced "a high level of hot flashes," as did the danazol, but no patients discontinued the treatment with the new drug because of them, he said. Patients were so pleased with relief from the pain of endometriosis that the hot flashes "seemed to be a reasonable trade-off," [Scott E. Moore] said.

Researchers divided the endometriosis sufferers who volunteered for the study into three groups, treating one with danazol and the remaining two with different doses of nafarelin, he said. The patients' severity of endometriosis was measured before the study and six months after treatment. The progress of the disease was arrested in all three groups, but women who were treated with nafarelin experienced fewer and less severe symptoms, Moore said.

In addition, 26 patients who had been infertile became pregnant after the study, and 19 of these had been treated with nafarelin. However, Moore said, it is not known how many of the women were trying to conceive at the time of the study, and it is premature to conclude that nafarelin was more effective in combatting infertility.