Glycosylation Pattern and in vitro Bioactivity of Reference Follitropin alfa and Biosimilars

Recombinant follicle-stimulating hormone (FSH) (follitropin alfa) and biosimilar preparations are available for clinical use. They have specific FSH activity and a unique glycosylation profile dependent on source cells. The aim of the study is to compare the originator (reference) follitropin alfa (Gonal-f®)- with biosimilar preparations (Bemfola® and Ovaleap®)-induced cellular responses in vitro. Gonadotropin N-glycosylation profiles were analyzed by ELISA lectin assay, revealing preparation specific-patterns of glycan species (Kruskal-Wallis test; p < 0.05, n = 6) and by glycotope mapping. Increasing concentrations of Gonal-f® or biosimilar (1 × 10^-3-1 × 10³ ng/ml) were used for treating human primary granulosa lutein cells (hGLC) and FSH receptor (FSHR)-transfected HEK293 cells in vitro. Intracellular cAMP production, Ca²⁺ increase and β-arrestin 2 recruitment were evaluated by BRET, CREB, and ERK1/2 phosphorylation by Western blotting. 12-h gene expression, and 8- and 24-h progesterone and estradiol synthesis were measured by real-time PCR and immunoassay, respectively. We found preparation-specific glycosylation patterns by lectin assay (Kruskal-Wallis test; p < 0.001; n = 6), and similar cAMP production and β-arrestin 2 recruitment in FSHR-transfected HEK293 cells (cAMP EC₅₀ range = 12 ± 0.9-24 ± 1.7 ng/ml; β-arrestin 2 EC₅₀ range = 140 ± 14.1-313 ± 18.7 ng/ml; Kruskal-Wallis test; p ≥ 0.05; n = 4). Kinetics analysis revealed that intracellular Ca²⁺ increased upon cell treatment by 4 μg/ml Gonal-f®, while equal concentrations of biosimilars failed to induced a response (Kruskal-Wallis test; p < 0.05; n = 3). All preparations induced both 8 and 24 h-progesterone and estradiol synthesis in hGLC, while no different EC₅₀s were demonstrated (Kruskal-Wallis test; p > 0.05; n = 5). Apart from preparation-specific intracellular Ca²⁺ increases achieved at supra-physiological hormone doses, all compounds induced similar intracellular responses and steroidogenesis, reflecting similar bioactivity, and overall structural homogeneity.

Randomized, active-controlled, comparative phase 3 efficacy and safety equivalence trial of Ovaleap® (recombinant human follicle-stimulating hormone) in infertile women using assisted reproduction technology (ART)

BACKGROUND

Pharmacokinetic studies with XM17 (Ovaleap®), a recombinant human follicle-stimulating hormone (r-hFSH, follitropin alfa), have demonstrated good safety and tolerability in healthy women whose endogenous FSH levels were down-regulated with a long agonist protocol. In these studies, Ovaleap® pharmacokinetics were dose-proportional and bioequivalent to the reference follitropin alfa product (Gonal-f®). The objective of the present study is to determine whether Ovaleap® is equivalent to Gonal-f® with respect to the number of oocytes retrieved in infertile but ovulatory women undergoing assisted reproductive technology (ART) therapy.

METHODS

This multinational, multicenter, randomized (1:1), active-controlled, assessor-blind, comparative study included infertile normally gonadotrophic women 18 to 37 years old with a body mass index of 18 to 29 kg/m(2) and regular menstrual cycles of 21 to 35 days undergoing ART therapy. During a 5-day fixed-dose phase, women received 150 IU/day of Ovaleap® (n = 153) or Gonal-f® (n = 146), followed by an up to 15-day dose-adaptation phase during which doses could be adjusted every 3 to 5 days, up to a maximum of 450 IU/day. Ovaleap® was to be deemed equivalent to Gonal-f® if the two-sided 0.95 confidence interval (CI) for the difference in the number of oocytes retrieved fell within the equivalence range of ±3 oocytes.

RESULTS

Similar numbers of oocytes were retrieved in the 2 treatment groups. The mean ± SD number of oocytes retrieved was 12.2 ± 6.7 in the Ovaleap® group and 12.1 ± 6.7 in the Gonal-f® group (intent-to-treat [ITT] population). Regression analysis estimated a mean difference of 0.03 oocytes between the treatment groups (95 % CI: -0.76-0.82), which was well within the prespecified equivalence range of ±3 oocytes. Ovaleap® and Gonal-f® showed favorable and comparable safety profiles, with no unexpected safety findings.

CONCLUSIONS

Ovaleap® has shown the same efficacy and safety as Gonal-f® for stimulation of follicular development in infertile women (up to 37 years of age) who are undergoing ART therapy.

TRIAL REGISTRATION

EudraCT: 2009-017674-20. Current controlled trials: ISRCTN74772901 . Date of trial registration: 19 March 2010.