A biological, immunological and physico-chemical comparison of the currentclinical batches of the recombinant FSH preparations Gonal-F and Puregon

The immunopotency and in-vitro biopotency of clinical batches of Gonal-F (R ) and Puregon (R) (recombinant human follicle stimulating hormones) were co mpared and their carbohydrate chains investigated for charge heterogeneity and internal carbohydrate complexity. Immunopotency (IU/pmol) for both Gona l-F and Puregon was 0.35 +/- 0.01 and biopotency (ED50, pmol/l) was similar , being 7.3 +/- 0.6 and 5.4 +/- 0.2 respectively, Charge distributions were essentially the same with no difference either in median isoelectric point (pI) (between 4.26 and 4.50), or in the bulk of material fractionated betw een pi 4 and 5 (66.0 +/- 1.8% Gonal-F and 72.0 +/- 1.8% Puregon), However, there were minor differences in charge at extremes of pi, Gonal-F being sli ghtly more acidic: 18.2% Gonal-F versus 9.8% Puregon at pi 3.5-4.0 (P = 0.0 3) and 6.7% Gonal-F versus 10.7% Puregon at pi 5.0-5.5 (P = 0.03), Carbohyd rate complexity was the same: 9.3 versus 10.9 (complex), 76.6 versus 78.6 ( intermediate) and 14.1 versus 10.5% (simple), In summary, Gonal-F and Pureg on have similar immunopotency, in-vitro biopotency and internal carbohydrat e complexity, differing slightly in charge heterogeneity, Gonal-F having mo re acidic glycoforms, We conclude them to be intrinsically very similar, ex pecting no difference in clinical efficacy on the basis of respective struc ture.