Interferon beta assessment in non-Chinese and Chinese subjects: pharmacokinetics and pharmacodynamic activity of an endogenous cytokine are not race dependent.

Interferon beta-1a (IFNß-1a) is a first-line therapy for relapsing multiple sclerosis when administered as 30 mcg intramuscularly (IM) once weekly. This endogenous cytokine displays pharmacokinetic (PK) attributes consistent with a glycoprotein of 20-kDa molecular weight that is administered IM. In this study, 24 healthy Chinese subjects (11 male, 13 female) each received 4 once-weekly 60-mcg IM doses of IFNß-1a. Serial blood samples were drawn for PK and pharmacodynamic (PD) assessments following the first and last dose of drug. Results were compared with historical data from a recent PK/PD assessment conducted in non-Chinese subjects. Noncompartmental analysis revealed that no meaningful differences in either IFNß-1a exposure or response were apparent between the Chinese and non-Chinese populations. Thus, it was concluded that no adjustment in dose regimen is warranted for future assessments of safety and efficacy in multiple sclerosis patients of Chinese origin.