Drug May Alleviate a Form of Infertility

A drug commonly used to treat circulatory disorders may prove to be an effective new therapy for infertility caused by endometriosis, an often painful condition suffered by millions of women worldwide, researchers announced Thursday.

In a study directed by Dr. Alex Steinleitner of Mt. Sinai Medical Center in Miami, researchers induced endometriosis in hamsters. All hamsters subsequently given the drug pentoxifylline became fertile, and none of the untreated animals became pregnant, said Steinleitner, who is co-director of Mt. Sinai’s in-vitro fertilization program.

The findings were presented Thursday at a meeting here of the American Fertility Society.

Steinleitner said that he expects to begin studies in women shortly. If the results in humans parallel those in animals, he predicted that the drug would become “a revolutionary treatment” for infertility caused by the disease.

Endometriosis results when normal endometrial tissue--the lining of the uterus--grows in abnormal locations, such as the ovaries, Fallopian tubes, outer surface of the uterus, bowel and abdominal cavity. It often afflicts women in their 30s and 40s who have delayed childbearing.

Steinleitner said that up to 40% of women who are infertile suffer from endometriosis.

The usual treatments for the condition are surgery or doses of danazol, a male hormone that produces unpleasant side effects similar to those associated with menopause.

Also, both of those treatments frequently cause only a temporary disappearance of endometriosis and do not always have an impact on infertility.

Dr. Alan Decherney, an expert on endometriosis and professor of obstetrics and gynecology at Yale University, described the drug as a “unique approach” and said that the findings offer “significant promise.” But he cautioned that infertility is caused by many factors. “Many women have endometriosis and are perfectly fertile, so there’s more to it than meets the eye,” he said.

The researchers emphasized that the animal results must be duplicated in human studies before the drug is used to treat infertility associated with endometriosis. Steinleitner found that animals treated for four days each month with the drug became fertile.

He believes that the drug influences the activities of macrophages, white blood cells that are a part of the immune system. These cells act within the female reproductive system each month to prevent infection and clean up tissue and other debris from menstruation, he said. He said researchers believe that, in women with endometriosis, these cells become “hyperactive” and interfere with fertility and the growth of a healthy embryo.

The drug deactivates macrophage activity during ovulation and prevents the cells from interfering with fertility, he said.

The drug does not cure the endometriosis but seems to reverse the infertility caused by the disease, he said.

He said that the only known side effect of the drug is that it causes “mild” stomach upsets in up to 5% of those who take it for its currently approved uses.

Human studies on women with endometriosis who are trying to become pregnant are scheduled to begin by January, he said. For six months, women will either be given a placebo or the drug, which they will take for four days during ovulation. During the study, the women will be artificially inseminated to maximize their chances of pregnancy, he said.