Recombinant human interferon-beta-1a (Rebif (R)) vs recombinant interferon-beta-1b (Betaseron (R)) in healthy volunteers - A pharmacodynamic and tolerability study

Objectives: This study compared the pharmacodynamics and tolerability of su bcutaneous 6MU (22 mu g) interferon (IFN)-beta-1a (Rebif(R)) and 8MU (250 m u g) IFN-beta-1b(Betaserono(R)). Participants and Methods: Twelve healthy volunteers received a single injec tion of each treatment in this randomised crossover study. Vital signs and treatment tolerability were monitored and blood samples taken for assay of the serum markers of immune activation, beta(2)-microglobulin and neopterin . Results: Both treatments produced similar increases in beta(2)-microglobuli n and neapterin with areas under the concentration-time curves (AUC(0-168h) ) of 2177 +/- 669 mu g/ml.h for IFN-beta-1a and 2323 +/- 649 mu g/ml.h for IFN-beta-lb. Headache was the mast common adverse event in both treatment g roups, with 15 episodes in the IFN-beta-1a group and 11 episodes in the IFN -beta-1b group. Both treatments produced increases in body temperature, and mild fever was a common adverse event associated with the treatments. Howe ver, 10 volunteers in the IFN-beta-1b group experienced fever at WHO grade 2 compared with one in the IFN-beta-1a group. Overall, IFN-beta-1a had a mo re favourable adverse-event profile and produced a lower incidence of fever and a smaller increase in body temperature than IFN-beta-1b. Conclusions: Both treatments had equivalent pharmacodynamic effects, but IF N-beta-1a may be better tolerated.