ESTROGEN INDICATION FOR PREVENTION OF OSTEOPOROSIS

ESTROGEN INDICATION FOR PREVENTION OF OSTEOPOROSIS should be included in physician labeling, FDA's Fertility & Maternal Health Drugs Advisory Cmte. unanimously recommended at an April 27 meeting. Cmte. consultant William Andrews, MD, Eastern Virginia Medical College, said there is "good, consistent evidence that estrogen will retard bone loss" and decrease the risk of bone fracture. The cmte. said it concurred with the conclusion of the Natl. Institutes of Health Consensus Development Conference on osteoporosis. In its consensus statement, the conference panel stated that "estrogen replacement therapy is the most effective single modality for the prevention of osteoporosis in women" ("The Pink Sheet" April 9, p. 9). The panel also noted that physicians and patients may want to limit prophylaxis use to high risk patients, such as those with premature menopause, until more data on benefits and risks are available. FDA presented to the cmte. a draft revision of estrogen labeling, which excluded the prophylaxis claim. The agency's proposed revision stated: "Estrogens are indicated for postmenopausal patients with evidence of loss of bone mass, e.g. radiographic findings of osteoporotic bone fractures . . . It is not clear that the benefits outweigh the risks of giving estrogens to postmenopausal women prior to the development of overt signs of osteoporosis." Explaining the Metabolism & Endocrine Div.'s position, division Director Solomon Sobel, MD, asserted that a prophylaxis claim "opens the door" for too wide a use of postmenopausal estrogen. He said epidemiological studies for such an indication are lacking and the evidence of efficacy is mostly anecdotal. The cmte. also recommended the labeling include a statement on the reported benefits of adding progestin to estrogen therapy. Andrews suggested the labeling state: "Studies of the addition of progestin for seven or more days to the cycle of estrogen administration have reported a lower incidence of endometrial cancer." FDA had proposed a statement that "current evidence is insufficient to determine . . . if the the addition of a progestin during each month of treatment with estrogen lessens the risk of endometrial cancer." The cmte. agreed the labeling should include a boxed warning which states "estrogens have been reported to increase the risk of endometrial carcinoma in post-menopausal women." The labeling cites five case control studies which "reported that the risk of endometrial cancer in estrogen users was about four to 20 times or more greater than in non-users." It adds that "the risk appears to depend on both duration of treatment and on estrogen dose." With regard to the risk of breast cancer, the draft labeling agreed to by the cmte. states that "at the present time there is insufficient evidence that estrogens given to postmenopausal women increase the risk of cancer of the breast, although a recent long-term follow-up of a single physician's practice has raised this possibility and suggested that the risk was especially high in women in whom benign breast disease developed after they had started taking estrogens." Andrews suggested the warning be restated as follows: "Some studies have suggested a possible increased incidence of breast cancer . . . The majority of studies, however, have not shown an association at doses used in estrogen replacement therapy."