Efficacy of nafarelin in assisted reproductive technology: a meta-analysis

A systematic review identified nine randomized, controlled trials (both published and unpublished) which assessed the efficacy of nafarelin during IVF compared with other gonadotrophin-releasing hormone (GnRH) agonists. The trials included 1,014 women (nafarelin n = 597) in protocols employing three different dosage regimens, long and short stimulation protocols, and three comparative GnRH agonists (buserelin n = 348; triptorelin n = 14, and leuprolide n = 55). The meta-analysis of the data showed that pregnancy rates per embryo transfer with nafarelin were equivalent to those obtained with other GnRH agonists. Nafarelin and other agonists were also comparable in terms of several intermediate IVF outcomes, including fertilization rates, number of oocytes retrieved, peak oestradiol concentrations, and cycle cancellations. Women treated with nafarelin required fewer ampoules of human menopausal gonadotrophin (HMG)/FSH for ovarian stimulation and fewer days of stimulation. Safety results from both the meta-analysis and a qualitative analysis of 12 additional reports suggested that adverse effects were within the accepted tolerance range; the most frequent adverse effects were hypo-oestrogenic symptoms. In conclusion, the overall efficacy of nafarelin was equivalent to that of other GnRH agonists. The possibility that the reduced gonadotrophin requirements in women taking nafarelin will translate into cost savings per IVF treatment cycle requires further study.