Recommendation for the collection and analysis of endometrial biopsies for hormone therapies

The assessment of endometrial safety is one of the key requirements for the clinical development of new products for hormone therapy (HT) to treat menopausal symptoms in women who have a uterus. Both the Food and Drug Administration (FDA) in the United States and the European Medicines Agency (EMA) provide detailed guidance on the requirements for the evaluation of biopsies to prove endometrial safety. However, there are some discrepancies between the European and the US requirements, making it difficult to fulfil both guidelines simultaneously. In order to facilitate multinational clinical trials performed within clinical programs to develop novel HT products, we developed an approach considering both guidance documents as far as possible and proposed solutions for issues that are inconsistently described in these guidelines. A table with the required sample sizes is given. Our recommendation for a unified approach for the estimation of the hyperplasia rate for hormone therapies fulfils the intent of the recommendations of both the FDA and the EMA and thus leads to a globally harmonized drug development for hormone therapies.