Follicle-stimulating hormone (FSH), a
glycoprotein produced by the anterior pituitary gland, plays an important role in the regulation of fertility in both men and women. FSH is used clinically to treat women with anovulatory
infertility, for controlled ovarian stimulation in women being treated with assisted reproductive technologies (ART), and in the treatment of male hypogonadotrophic
hypogonadism. Urine-derived
gonadotropin preparations containing variable amounts of FSH together with urinary
proteins have been available for many years. More recently, FSH preparations produced using
recombinant DNA technology have become available. Recombinant FSH has a high specific activity, high purity, and guaranteed consistency among batches. Two recombinant FSH preparations have been available for clinical use for some years:
follitropin-alpha and
follitropin-beta. The continuing development of recombinant FSH has recently resulted in a new presentation (
follitropin-alpha filled by mass [FbM]). This product can be filled by mass (microg) with an activity (IU), reflecting exceptional consistency as a result of refinement and improvement in the manufacturing process, allowing the clinician to deliver a guaranteed dose of FSH. Experience with recombinant FSH in the treatment of male hypogonadotrophic
hypogonadism is limited, but the available data suggest that recombinant FSH has a similar efficacy to urine-derived preparations (
urofollitropin). In patients with WHO group I anovulatory
infertility, the use of recombinant FSH to stimulate follicular development is effective and well tolerated. In patients with WHO group II
anovulation, protocols based on recombinant FSH are more effective than conventional protocols using
urofollitropin. Comparative studies and a meta-analysis have shown that recombinant FSH is more effective than
urofollitropin for controlled ovarian stimulation in women undergoing ART. Pharmacoeconomic modeling indicates that
follitropin-alpha is more cost effective than
urofollitropin in a range of different healthcare systems. The available evidence from comparative studies of the two recombinant FSH preparations suggests that
follitropin-alpha may have an advantage over
follitropin-beta in terms of efficacy.
Follitropin-alpha is superior to
follitropin-beta in terms of local tolerability. Recent preliminary studies suggest an efficacy advantage for
follitropin-alpha FbM compared with standard
follitropin-alpha. The FbM presentation appears to represent an advance on standard preparations of recombinant FSH in terms of consistency and clinical efficacy.