Recombinant human follicle-stimulating hormone: a scientific step to clinical improvement

Urinary-derived follicle-stimulating hormone (FSH) preparations have been used clinically for many years. Although effective, these have a number of disadvantages, not least of which is their variable composition. The availability of recombinant human FSH (r-hFSH), produced from CHO cells, with its constant composition and exceptionally high purity, has, therefore, aroused great interest. This review focuses on the use of r-hFSH for ovarian stimulation in assisted reproduction technology protocols and the treatment of World Health Organization Group I and II anovulation. The use of r-hFSH has been shown to lead to improvements in efficacy over urinary-derived preparations, particularly in assisted reproductive treatment, and a recent meta-analysis has shown higher ongoing pregnancy rates with the recombinant product. Although the two available recombinant products from CHO cells (follitropin alpha [Gonal-F((R))] and beta [Puregon((R))]) are similar from a physicochemical perspective, some minor advantages have been reported for follitropin alpha in relation to pregnancy rates and better local tolerance to injections. The apparent higher bioactivity of r-hFSH has led to reduced total FSH consumption over shorter treatment periods compared with conventional preparations, thus reducing overall exposure for patients. This is likely to confer not only safety benefits, but also cost-effectiveness as demonstrated through pharmaco-economic modelling.