Cetrorelix

This prospective randomized phase III European multicentre trial allocated 188 patients to the GnRH antagonist cetrorelix and 85 to the GnRH agonist buserelin during HMG-stimulated IVF/ICSI cycles. Premature LH surges occurred in only 1.6% of cetrorelix-treated patients, and the antagonist arm required significantly fewer HMG ampoules and a shorter duration of stimulation. On the day of hCG, the buserelin group showed more small follicles and higher serum estradiol, while fertilization, cleavage, and clinical pregnancy rates were comparable between arms. The authors concluded the short-duration antagonist approach is advantageous with equivalent efficacy.

In this large European study, women preparing for IVF received either cetrorelix (a newer 'antagonist' drug) or buserelin (an older 'agonist' drug) to stop their bodies from releasing eggs too early. Cetrorelix worked just as well at preventing early ovulation but needed far fewer days of injections and less fertility medication. Pregnancy rates were similar with both approaches, and the shorter, simpler cetrorelix schedule was seen as a practical advantage for patients.

This multicentre randomized controlled trial compared a single 3 mg dose of cetrorelix administered in the late follicular phase (115 patients) with depot triptorelin, a long-protocol GnRH agonist (39 patients), for prevention of premature LH surges in IVF-ET. No LH surge occurred in any patient after cetrorelix administration. Although the cetrorelix group yielded fewer oocytes and embryos, the proportion of mature oocytes, fertilization rates, and clinical pregnancy rates did not differ significantly, while the antagonist protocol required shorter stimulation, fewer hMG ampoules, and had reduced hyperstimulation risk with excellent tolerability.

This study tested whether a single injection of cetrorelix late in the stimulation cycle could reliably prevent eggs from being released prematurely during IVF. It completely prevented early surges in every patient who received it. Compared with the older long-protocol drug, cetrorelix meant fewer injection days and less medication, and although slightly fewer eggs were collected, egg quality, fertilization, and pregnancy rates were comparable, making the single-dose approach an attractive, patient-friendly option.

In this phase III randomized trial, 131 patients undergoing IVF (with or without ICSI) were allocated to a cetrorelix GnRH-antagonist protocol (n=66) or a buserelin GnRH-agonist protocol (n=65). The antagonist protocol produced a significantly shorter stimulation duration (9.5 vs 10.6 days) and a markedly shorter pituitary suppression period (4.6 vs 27.3 days). No significant differences were found in gonadotropin requirements, follicular development, number of oocytes retrieved, fertilization rates, or clinical pregnancy rates, leading the authors to conclude that GnRH antagonists are an effective, safe, and well-tolerated alternative to agonists for controlled ovarian stimulation.

This trial directly compared the antagonist drug cetrorelix with the older agonist drug buserelin in women having IVF. Cetrorelix achieved its effect much faster, cutting the pituitary 'shut-down' phase from about four weeks to less than a week and shortening overall treatment. Importantly, the number of eggs collected, fertilization rates, and pregnancy rates were the same, showing the shorter cetrorelix approach is just as effective and safe while being easier on patients.