Follicle-stimulating hormone in clinical practice: an update.

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.