While the primary efficacy of currently available GnRH antagonists is assessed in the same way (i.e. proportion of responders with ≤80ml uterine blood loss per cycle and at least a 50% reduction in menstrual blood loss at week 24), the patient population used in the phase 3 trials may be different1,2 Importantly, pharmacokinetic parameters can vary when looking at certain populations – including racial and body weight differences. The study patient demographics will be available in the respective Summary of Product Characteristics. 1,2