Selective estrogen receptor modulators. Established and new drugs

Selective estrogen receptor modulators (SERMs) are defined as substances that bind with high affinity to the estrogen receptor (ER) without significant binding activity to any other nuclear receptors. In contrast to estrogens themselves, however, they induce "estrogen-agonistic"or"estrogen-antagonistic activities" in various tissues. This can be explained among other things by their interaction with coregulator proteins, which are crucial for the transcriptional activity of the receptor-ligand complex. This interaction is unique for each SERM and leads to its specific profile of tissue-selective actions, which in some cases vary significantly from those of other SERMS. Most SERMs are nonsteroidal molecules. They may take effect in all types of tissue that contain ERs. Differences in the pattern of action of SERMs indicate that each clinical end point must be evaluated individually in appropriate clinical trials. A number of SERMs have been studied to identify their effect on breast cancer; some are still undergoing clinical trials, while others have already been approved. The same is true of recently developed SERMs that have proved highly effective in the prevention and treatment of osteoporosis. Side effects must also be taken into account in the specific profile of action of each SERM.