P-594 Retrospective comparative study of follitropin delta vs follitropin alfa in progestin-primed ovarian stimulation (PPOS) protocol in IVF
Authors: Enatsu Y , Fukagawa D , Otsuka M , Yoshioka N , Kuramoto K , Kuramoto T 
Published: July 2024

Abstract

Study question
Could the individualized fixed-dose algorithm with follitropin delta show a similar pregnancy rate to conventional dosing with follitropin alfa in PPOS protocol?

Summary answer
Individualized fixed-dose algorithm with follitropin delta showed a similar pregnancy rate to follitropin alfa In PPOS protocol.

What is known already
Follitropin delta (REKOVELLE, Ferring Pharmaceuticals, Switzerland) is the first human cell line driven recombinant follicle-stimulating hormone (FSH) with an individualized fixed-dose algorithm based on serum AMH level and body weight. Follitropin alfa is a Chinese hamster ovarian cell driven recombinant FSH and its dosing is adjusted according to follicular response during the stimulation period. There was no significant difference between follitropin delta and follitropin alfa in terms of pregnancy rate under GnRH antagonist protocol.

Study design, size, duration
A retrospective analysis of 355 patients aged under 40 years who underwent ovarian stimulation in PPOS protocol using follitropin delta or follitropin alfa and on whom frozen-thawed single blastocyst transfer was conducted between August 2021 and November 2023 was performed.

Participants/materials, setting, methods
193 cycles of women who used follitropin delta were compared to 162 cycles of women who used follitropin alfa. The following clinical outcomes on each treatment group were analyzed: chemical pregnancy rate (serum β hCG), clinical pregnancy rate (gestational sac), ongoing pregnancy rate(gestational sac and fetal heartbeat), serum E2 level at trigger day, cycle proportion of ≥ 10 oocytes retrieval, blastocyst formation rate, cycle proportion of ≥ 5 blastocysts and cycle proportion of ≥ 2 good quality blastocysts.

Main results and the role of chance
Baseline demographics in the follitropin delta group and the follitropin alfa group were not significantly different: age, 33.9 ± 3.5 years vs 34.5 ± 3.2 years; body weight, 53.5 ± 8.3 kg vs 53.8 ± 5.9 kg; number of previous IVF cycles, 0.2 ± 0.6 vs 0.3 ± 0.7; serum AMH level, 5.5 ± 2.9 ng/mL vs 5.3 ± 3.8 ng/mL, respectively. The chemical pregnancy rate (69.9% vs. 64.8%, P = 0.308), clinical pregnancy rate (58.0% vs. 56.2%, P = 0.748) and ongoing pregnancy rate (51.8% vs. 46.3%, P = 0.338) were comparable between the follitropin delta group and the follitropin alfa group. The individualized follitropin delta treatment resulted in a smaller cycle proportion of ≥ 10 oocytes retrieval (77.7% vs. 90.8%, P &lt; 0.001) with lower serum E2 level at trigger day (3273 ± 1577 pg/mL vs. 3927 ± 1732 pg/mL, p &lt; 0.001). However, the blastocyst formation rate was significantly higher in the follitropin delta group (75.5% vs. 68.7%, p &lt; 0.001). Moreover, the cycle proportion of ≥ 5 blastocysts (71.0% vs. 76.4%, P = 0.286) and the cycle proportion of ≥ 2 good quality blastocysts (51.8% vs. 60.3%, P = 0.115) were comparable between the groups.

Limitations, reasons for caution
This is a non-controlled, retrospective study.

Wider implications of the findings
Follitropin delta in its individualized fixed-dose regimen could have the potential to decrease the risk of OHSS by minimizing excessive ovarian response, whereas a similar pregnancy rate to conventional dosing regimen could be expected due to the number of good quality blastocysts secured.

Trial registration number
not applicable