A prospective, randomized, assessor-blind, multicentre study comparing recombinant and urinary follicle stimulating hormone (Puregon versus Metrodin) in in-vitro fertilization.

Urinary follicle stimulating hormone (FSH) is being used for the treatment of human infertility. Recently, FSH manufactured by means of recombinant DNA technology with a much higher purity (> 99%) has become available. A prospective, randomized, assessor-blind, multicentre (n = 18) study was conducted in infertile women undergoing in-vitro fertilization comparing recombinant FSH (Org 32489, Puregon) and urinary FSH (Metrodin). Eligible subjects were randomized (recombinant versus urinary FSH = 3:2) and pretreated with buserelin for pituitary suppression. FSH was given until three or more follicles with a diameter of at least 17 mm were seen. After oocyte retrieval, fertilization routines were applied according to local procedures. No more than three embryos were replaced. In all, 585 subjects received recombinant FSH and 396 urinary FSH. Significantly more oocytes were retrieved after recombinant FSH treatment (mean adjusted for centre 10.84 versus 8.95, P < 0.0001). Ongoing pregnancy rates per attempt and transfer in the recombinant FSH group were 22.17 and 25.97% respectively, and in the urinary FSH group, 18.22 and 22.02% respectively (not significant). Ongoing pregnancy rates including pregnancies resulting from frozen-thawed embryo cycles were 25.7% for recombinant and 20.4% for urinary FSH (P = 0.05). Compared to urinary FSH, the total dose of FSH was significantly lower with recombinant FSH (2138 versus 2385 IU, P < 0.0001) in a significantly shorter treatment period (10.7 versus 11.3 days, P < 0.0001). No clinically relevant differences between recombinant and urinary FSH were seen with respect to safety variables. It is concluded that recombinant FSH (Puregon) is more effective than urinary FSH in inducing multifollicular development and achieving an ongoing pregnancy.