Treating menopausal symptoms with a tissue-selective estrogen complex

Vasomotor symptoms and vulvar-vaginal atrophy are common consequences of menopause, and the only treatment approved by the US Food and Drug Administration is hormone therapy. Because both physicians and women are concerned with the tolerability and safety profile of estrogen and estrogen plus progestin treatments, alternative menopause therapies are needed. An ideal menopause treatment modality would relieve menopausal vasomotor and vulvar-vaginal symptoms, maintain bone mass, and have neutral or beneficial cardiovascular effects, without stimulating the breast or endometrium. The novel tissue-selective estrogen complex (TSEC) agent was paired with a selective estrogen receptor modulator (SERM) with estrogen(s) in an attempt to achieve a more favorable clinical profile based on the blended tissue activities of its components. This article reviews the published reports from Phase III trials of TSEC, which paired bazedoxifene (BZA) and conjugated estrogens (CEs). BZA/CE alleviated menopausal symptoms and prevented postmenopausal bone loss, had an overall good safety profile with an incidence of amenorrhea and breast pain similar to that with placebo, and did not stimulate the endometrium. The largest (N = 3397) and longest (2 years) study of this TSEC containing BZA/CE demonstrated endometrial hyperplasia rates similar to that with placebo and changes in lumbar spine bone mineral density that were significantly better than that with placebo, when a minimum dose of 20 mg of BZA was used with 0.625 or 0.45 mg of CE. Subsequent smaller studies showed that BZA/CE effectively reduced the incidence and frequency of hot flushes and significantly improved signs and symptoms of vaginal atrophy. Longer term safety with regard to cardiovascular and breast effects have not been established. Given the efficacy and safety reported in these Phase III trials, the TSEC of BZA/CE may be a promising new option for the treatment of menopause.