MF-101, an estrogen receptor beta agonist for the treatment of vasomotor symptoms in peri- and postmenopausal women.

During peri- and postmenopausal stages, the majority of women experience moderate-to-severe vasomotor symptoms, such as hot flashes and night sweats, that interfere with sleep and reduce quality of life. Estrogen alone or in combination with a progestagen has been the standard therapy for such vasomotor symptoms; however, this therapeutic regimen is associated with severe side effects, such as breast cancer or cardiovascular events. To provide a better treatment option for menopausal women, Bionovo Inc is developing the estrogen receptor (ER)beta-selective agonist MF-101. Selective ER agonists can stimulate either ERalpha or ERbeta and induce tissue-specific estrogen-like effects, thus providing a safer alternative to conventional hormone therapy. MF-101 is derived from 22 herbs that are traditionally used in Chinese medicine for the treatment of menopausal symptoms. MF-101 did not promote the growth of breast cancer cells or stimulate uterine growth in preclinical studies and, in a phase II trial, was demonstrated to be safe and more effective in reducing the frequency and severity of hot flashes in postmenopausal women compared with placebo. To confirm the safety and efficacy of MF-101, larger phase III trials were planned for 2009. Although MF-101 appears to be a promising therapeutic, the herbal composition of the drug may be a disadvantage, because of the increased risk of causing allergic reactions in the general population. Studies with the MF-101-isolated active compounds liquiritigen and chalcone demonstrated selectivity for ERbeta, with no induction of proliferative events. If these isolates were demonstrated to be as effective and safe in clinical trials as preliminary data suggest regarding MF-101, these compounds could change the way clinicians treat menopause-associated symptoms.