Ovarian stimulation with HMG: results of a prospective randomized phase III European study comparing the luteinizing hormone-releasing hormone (LHRH)-antagonist cetrorelix and the LHRH-agonist buserelin

In this prospective and randomized study, 188 patients received the luteini zing hormone-releasing hormone (LHRH) antagonist cetrorelix, and 85 patient s the LHRH agonist buserelin to prevent endogenous luteinizing hormone (LH) surges during ovarian stimulation in in-vitro fertilization (IVF)/intracyt oplasmic sperm injection (ICSI) cycles. Ultimately, 181 patients (96.3%) in the cetrorelix group, and 77 190.6%) in the buserelin group, reached the d ay of the hunan chorionic gonadotrophin (HCG) injection. The mean number of human menopausal gonadotrophin (HMG) ampoules administered and the mean nu mber of stimulation days with HMG were significantly less in the cetrorelix group than in the buserelin group (P < 0.01). A rise in LH and progesteron e concentrations was observed in three of the 188 patients (1.6%) who recei ved cetrorelix, On the day of the HCG administration, more follicles of a s mall diameter (11-14 mm) were observed in the buserelin group than in the c etrorelix group (P = 0.02) and the mean serum oestradiol concentration was significantly higher in patients who received buserelin than in those who r eceived cetrorelix (P < 0.01). Similar results were observed in fertilizati on, cleavage and pregnancy rates in the two groups. In conclusion, the use of the LHRH antagonists might be considered more advantageous because of th e short-term application needed to inhibit gonadotrophin secretion, so allo wing a reduction in the treatment time in a clinically significant manner.