17 beta-Hydroxysteroid dehydrogenase inhibitors: a patent review

Importance of the field: 17 beta-Hydroxysteroid dehydrogenases (17 beta-HSDs) mainly catalyze the reduction of C17-ketosteroids to their corresponding hydroxylated forms as well as the reverse reaction (oxidation). Able to convert inactive or less active steroid hormones into more potent ones and vice versa, certain 17 beta-HSDs play a key role, especially in the regulation of estrogen and androgen levels. The therapeutic potential of this enzyme family, especially for the treatment of breast cancer, prostate cancer, acne and osteoporosis, then stimulated the development of inhibitors of 17 beta-HSDs and important progress was achieved over the last years. Areas covered in this review: This review article reports all patent applications related to the inhibitors of 17 beta-HSD5, including some articles needed to complement the information presented. What the reader will gain: Readers will be informed about the role and function of 17 beta-HSDs in the first section and about the history of inhibitor development in the second section. Furthermore, in the third and main section, the readers will learn about the structures of patented inhibitors originating from different companies and academic groups. Take home message: The increase in the number of 17 beta-HSD inhibitors reported in the last years augurs well for the future. The challenge is now to translate these results into clinical studies to allow determination of the therapeutic usefulness of 17 beta-HSD inhibitors.