A comparison between follitropin alpha filled by mass and follitropin alpha filled by bioassay in the same egg donors.

This study assessed the ovarian stimulation characteristics of recombinant follitropin alpha filled by mass (rFSH-fbm) versus recombinant follitropin alpha filled by conventional bioassay (rFSH-bio) in the same egg donor patients. Eleven egg donors, who had two ovarian stimulation cycles for oocyte retrieval (total of 23 cycles), one with rFSH-bio (Gonal-f Multidose) and the second one with rFSH-fbm (Gonal-f RFF), were evaluated. The protocol of ovarian stimulation was exactly the same in both cycles, consisting of GnRH suppression (luteal phase) followed by exclusive stimulation with rFSH. Despite no differences in the number of days of rFSH treatment and in the total dosage of rFSH administered, the number of follicles >14 mm and the number of oocytes retrieved were significantly higher in the rFSH-fbm group (P = 0.01 and 0.04 respectively). The mean oestradiol peak values showed a trend in favour of rFSH-fbm (3123 versus 2405 pg/ml respectively). These results suggest that the consistency in dosing provided by follitropin alpha filled by mass as opposed to follitropin alpha filled by bioassay offers added value for the ovarian stimulation of oocyte donor patients.