Estetrol

Naturally or synthetically produced steroid estrogens have a wide range of pharmaceutical uses ranging from hormonal contraception to the treatment of menopausal symptoms. Estetrol (E4) is a native estrogen occurring naturally during pregnancy, but can be synthesized from a plant source and used for contraception. It is more potent and is safer than the synthetic estrogen ethinylestradiol (EE2) found in 97% of oral contraceptive pills, reducing the environmental accumulation of unwanted endocrine disrupting chemicals (EDCs) that often lead to harmful epigenetic effects.

On April 15 2021, Mayne Pharma Group Limited and Mithra Pharmaceuticals were granted FDA approval for the oral contraceptive Estelle/Nextstellis, a combination of drospirenone and estetrol. Estetrol is the first new estrogen introduced to the USA in over 50 years and is the first approved estetrol product in the world. The combination of drospirenone and estetrol offers a new choice with a favourable safety profile for women seeking contraceptive therapy. In Canada, Nextstellis was approved for use in March 2021; it was developed by Mithra and is marketed by Searchlight Pharma.