High inhibition ratio and transformation index of 2 mg dienogest: further evidence for its use in endometriosis treatment.

Endometriosis is a common, chronic disease with a high burden for women, characterised by the implantation of endometrial cells outside the uterus. Many different treatments have been proposed for this disease, mainly hormonal, with the objective of inducing amenorrhoea and a hypoestrogenic environment. Dienogest (DNG), a fourth-generation progestin, has received approval for the treatment of endometriosis in many countries. Its pharmacological properties make it especially attractive for the treatment of this disease. Several trials demonstrated the clinical efficacy in managing endometriosis-associated pain, preventing symptoms, and reducing lesion recurrence. Its efficacy has been proven both for deep infiltrative endometriosis and ovarian endometriosis, and its long-term safety and tolerability are also well established. Recently, the inhibition ratio and the transformation index for progestins have been proposed. DNG at the used dose of 2 mg/daily, with a transformation index of around 933% and a cyclical inhibition ratio of 200%, appears to have very specific progestin properties, unique among different molecules of the same groups, reinforcing its leading role in the treatment of endometriosis.