Background: Human follicle-stimulating hormone (hFSH; follitropin alfa) can be employed therapeutically to induce ovarian follicular development in assisted reproduction treatments. Current recombinant hFSH (r-hFSH) preparations available for clinical use are labeled either in terms of the bioactivity expressed in international units (IU) or in mass (microg). Several clinical trials have tried to assess the clinical implications of the physicochemical improvements in the dosing of follitropin alfa filled by mass (FbM). The aim of this study was to perform a meta-analysis of previous studies in order to assess the efficacy and safety of ovarian stimulation using follitropin alfa FbM compared with follitropin alfa filled by international units (FbIU).
Methods: A literature search was carried out in scientific databases to find published articles and abstracts comparing both hormone preparations. A fixed effects model meta-analysis was performed. The variables studied include the average dose (IU), days of treatment, estradiol peak, follicles >14 mm, number of extracted oocytes, number of embryos obtained, number of cases of ovarian hyperstimulation syndrome (OHSS), and clinical pregnancies.
Results: A total of six studies met the stated criteria and were included in the meta-analysis. In these studies, the average r-hFSH dose per patient was 230.29 IU less with administration of follitropin alfa FbM compared with FbIU, and the number of days of treatment was reduced by 0.48. In addition, a significantly greater number of oocytes (0.84) were extracted, more embryos (0.88) were obtained, and a higher peak level of estradiol (613.08 pmol/L) was achieved in the patients undergoing ovarian stimulation with follitropin alfa FbM. However, no statistically significant differences were observed in the number of follicles >14 mm, clinical pregnancies, or OHSS cases.
Conclusion: Follitropin alfa FbM, a technologically modified formulation of r-hFSH, is as safe as follitropin alfa FbIU but requires a smaller dose over a shorter period to produce more oocytes and final embryos.