Pilot Trial to Individualize the Dose of Follitropin Delta in Oocyte Donors: REKO15

<b>Objectives:</b> This research aimed to study the effect of 15mcg/day of follitropin delta on normo-responding women. <b>Methods</b>: A single-center, open-label, matched case-control pilot trial was carried out from September 2021 to June 2022. In this trial, normo-responding oocyte donors were given 15 mcg/day of follitropin delta or 225 IU/day of follitropin alfa, as well as medroxyprogesterone acetate for pituitary suppression during the cycle. The main outcome measured was the number of oocytes retrieved. <b>Results</b>: A fixed dose of 15 mcg/day of follitropin delta for ovarian stimulation in normo-responders achieved an average of 17 oocytes retrieved. No differences were observed vs. 225 IU/day of follitropin alfa in the number of oocytes [17.8 ± 7.8 vs. 18.5 ± 7.7, respectively, <i>p</i> = 0.156], the number of metaphase II oocytes [13.5 ± 6.9 vs. 15 ± 6.3, <i>p</i> = 0.105], the fertilization rates (71.1% vs. 72.9%, <i>p</i> = 0.523), the number of usable blastocysts (4.9 ± 2.4 vs. 4.5 ± 2.5, <i>p</i> = 0.466), and the implantation rate (64% vs. 57%, <i>p</i> = 0.575). In the follitropin delta group, the duration of the stimulation was significantly shorter (9.4 ± 1.2 vs. 10.9 ± 1.2, <i>p</i> < 0.01), and the overall gonadotropin intake was lower. There were no clinically relevant differences between treatment groups regarding the safety profile. Global patient satisfaction with the follitropin delta ovarian stimulation was very high (7.7 ± 2.2). <b>Conclusions</b>: A daily dose of 15 mcg of follitropin delta may provide a similar ovarian response to 225 IU/day of follitropin alfa; aiming to retrieve 17 oocytes in normo-responders undergoing progestin-primed ovarian stimulation, it could reduce gonadotropin intake by reducing the duration of the stimulation cycle, with a possible high patient satisfaction level.