Restoration of spermatogenesis in a male with prolactinoma-induced hypogonadotropic hypogonadism using follitropin delta and recombinant choriogonadotropin alfa: a case report.

BACKGROUND: Follitropin delta is a recombinant human follicle-stimulating hormone (FSH) produced in the human PER.C6 cell line, approved exclusively for controlled ovarian stimulation in women. Its unique glycosylation profile confers distinct pharmacokinetic advantages over Chinese hamster ovary-derived follitropin alfa. To date, no published report exists on the use of follitropin delta in males. The present case describes the first successful off-label use of follitropin delta in combination with recombinant choriogonadotropin alfa (hCG) to restore spermatogenesis in a male patient with prolactinoma-induced hypogonadotropic hypogonadism and exogenous testosterone-associated azoospermia.

CASE REPORT: A 30-year-old male with a 6-cm pituitary prolactinoma diagnosed at age 18, managed with cabergoline, presented with azoospermia following 2 years of testosterone undecanoate replacement therapy. There was confirmed suppression of gonadotropins (luteinizing hormone 0.3 mIU/mL and FSH 0.3 mIU/mL) and prolactin of 100 ng/mL. Hormonal stimulation was initiated with follitropin delta 10 µg twice weekly and hCG alfa (~ 125 µg every 4-5 days), alongside continued cabergoline. After 4 months of therapy, semen analysis revealed sperm concentration of 3.5 million/mL (total sperm count 4.9 million/ejaculate). Testosterone levels normalized, with marked clinical improvement.

CONCLUSION: This case provides the first evidence that follitropin delta can successfully replace conventional FSH preparations in male gonadotropin stimulation protocols. Spermatogenesis was restored within a favorable timeframe, enabling access to assisted reproductive technology (IVF/ICSI). Nevertheless, these findings are limited to a single case report and require confirmation in larger studies.