Drug Effective in Tests on Disease That Causes Infertility
A research drug in the form of a nasal spray appears to significantly reduce the severity of endometriosis, a painful female affliction that is a major cause of infertility, a UC San Francisco scientist said Thursday.
Dr. Scott E. Moore, an associate professor of obstetrics and gynecology, said 141 women who volunteered for a UCSF study to test the drug nafarelin “generally experienced a remarkable improvement” within one month of treatment.
Endometriosis, which afflicts from 4 million to 10 million American women, is a condition in which tissue from the lining of the uterus spreads to other parts of the pelvic cavity.
The most common symptom is severe pain with menstruation and intercourse, and the only treatment currently available, a drug called danazol, produces undesirable side effects such as weight gain, acne, facial hair growth and depression. The side effects are so distressing that “a significant number of women will discontinue the treatment,” Moore said.
Moore made the remarks in an interview at the international meeting of the Endocrine Society at the Anaheim Convention Center. The UCSF scientific paper was presented there by principal researcher Dr. Milan Henzl.
Moore said the most distressing side effect of nafarelin was a moderate loss of bone tissue, the result of decreased levels of estrogen.
“There is concern over bone loss, but it appears to reverse itself” when the nafarelin is stopped, he said. Further studies are planned to determine how nafarelin can be given “at a level so that bone loss is not a danger,” or whether bone-building calcium supplements can correct the problem, he said.
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,” Moore said.
He added that the nafarelin did not have any effect on pre-existing scar tissue caused by endometriosis, which can cause nodules to grow on the walls of the reproductive organs, but was effective in stopping new scar tissue from forming.
“It does not appear to be a cure, but a way of controlling the disease,” 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.
‘Window’ for Conception
However, the results suggest that nafarelin might be best for early treatment for endometriosis, before large amounts of irreversible scar tissue form, he said.
It also could be used to arrest the progress of the disease long enough to create “a window of time for conception,” Moore said. Even for those women who have no desire to become pregnant or whose disease is well advanced, the drug still offers relief from the painful symptoms, he said.
Nafarelin works by mimicking a hormone released from the brain that regulates pituitary and ovarian functions, Moore said. The drug is administered as a nasal spray because it can be absorbed through the mucous membranes, he added, explaining that it cannot be taken in pill form because, as a protein, it is destroyed in the digestive tract.
