P-656 Comparative clinical outcome following individualized follitropin delta dosing in Japanese women undergoing progestin-primed ovarian stimulation for in vitro fertilization /intracytoplasmic sperm injection
Authors: Miyazaki K , Kamoshita K 
Published: July 2024

Study question

Is ovarian stimulation with follitropin delta (FD) in its individualized regimen as efficacious as follitropin alfa and human menopausal gonadotropin (FAHMG)?

Summary answer

Ovarian stimulation with individualized FD dosing resulted in a significantly higher fertilization rate and number of blastocysts with good quality compared to conventional FAHMG dosing.

What is known already

Previous randomized controlled trials conducted in Japan, China, Europe, and both North and South America have demonstrated that ovarian stimulation using the individualized FD dosing regimen, which is based on serum anti-Müllerian hormone (AMH) levels and body weight, effectively modulated the ovarian response without compromising pregnancy and live birth rates.

Study design, size, duration

A retrospective study was conducted by reviewing the medical records of 1,720 IVF/ICSI cycles in 1,272 Japanese patients. The primary endpoint of the study was the ongoing pregnancy rate, assessed at 8 weeks of gestation, in the frozen-thawed embryo transfer.

Participants/materials, setting, methods

The FD treatment consisted of a fixed daily dose individualized according to each patient’s initial AMH level and body weight (AMH &lt;2.04 ng/ml: 12 μg; AMH ≥2.04 ng/ml: 0.19 to 0.10 μg/kg; min-max 6–12 μg). The FAHMG dose was determined by the antral follicle count (AFC), with the following protocol: for AFC &lt;25, 300 IU/day; for 40&gt; AFC ≥25, 225 IU/day; and for AFC ≥40: 150 IU/day). A progestin-primed ovarian stimulation (PPOS) protocol was applied.

Main results and the role of chance

Multiple regression analyses (MRA) showed that the use of FD was negatively correlated with the number of oocytes retrieved (NOR) (P = 0.001), and positively correlated with the fertilization rate (FR) (P = 0.02). NOR was comparable between FD and FAHMG (10.9 ± 6.4 versus 11.8 ± 7.8) when the Mann-Whitney test (MW) was applied (P = 0.111), but significantly higher in FAHMG when the patient is younger than 40 years old with AMH ≥2 ng/ml (P &lt; 0.01). The total gonadotropin use was significantly (P &lt; 0.001) reduced from an average of 167.1 ± 46.9 μg (2789.9 ± 782.9 IU) FAHMG to 102.6 ± 31.6 μg FD. FR was significantly higher in FD compared with FAHMG (78.7% versus 74.1%, P &lt; 0.05) on MW. Additionally, MW indicated a significantly higher number of good-quality blastocysts in FD (2.9±2.6) versus with FAHMG (2.4±2.5) (P &lt; 0.05). The blastocysts obtained from FD also showed a significantly higher implantation rate (50.1% versus 39.7%, P &lt; 0.01) and a comparable ongoing pregnancy rate (28.7% versus 25.7%, P = 0.292) compared to those from FAHMG as determined by chi-square test. The higher implantation rate in FD may be attributed to the greater number of good-quality blastocysts obtained compared with FAHMG.

Limitations, reasons for caution

This study only covered the clinical outcome of women undergoing PPOS protocol with frozen-thawed blastocyst transfers.

Wider implications of the findings

The present study shows that FD in its individualized fixed-dose regimen has the potential to improve the success rate in frozen-thawed embryo transfer across all ages and with a lower gonadotropin consumption compared to conventional FAHMG dosing.

Trial registration number

not applicable