Recombinant human follicular stimulating hormone and recombinant human luteinizing hormone in a 2:1 ratio combination. Pharmacological characteristics and clinical applications

Importance of the field: A new fixed combination of recombinant human follicle stimulating hormone (r-hFSH) and recombinant human luteinizing hormone (r-hLH) at a 2:1 ratio has been recently developed to induce ovulation in patients with hypogonadotrophic hypogonadism. Whether or not this compound is useful for controlled ovarian stimulation for in vitro fertilization is still a matter of debate.Areas covered in this review: Description of pharmacological and clinical aspects of this new product, through the analysis of the Phase I, II and II trials and post-marketing clinical randomized trials, performed since the initial assays in 1998 to nowadays.What the reader will gain: After reading this review the reader will understand the pharmacological aspects of this new compound, in terms of efficacy and safety, and will have an update of the potential role of r-LH administration in controlled ovarian stimulation for in vitro fertilization.Take home message: The 2:1 combination of r-hFSH and r-hLH has been seen as an optimum preparation in terms of safety and clinical efficacy in hypogonatrophic hypogonadism patients. Its use in ovarian stimulation for IVF remains controversial, as the target population that may receive a benefit of it is not well defined.