Trimegestone is a steroidal progestin with potent progesterone receptor affi nity. It was originally developed by Hoechst Marion Roussel back in the mid-1990s. In tablet form, it had reached Phase III trials (in the EU) for postmenopausal osteoporosis by September 1996, and also for postmenopausal syndrome (in the EU and US, respectively), in December 1996 and June 1997.