The presence of anti-natalizumab antibodies was correlated with a reduction in serum natalizumab levels. In Study MS1, the Week 12 pre-infusion mean natalizumab serum concentration in antibody-negative patients was 15 mcg/mL compared to mcg/mL in antibody-positive patients. Persistent antibody-positivity resulted in a substantial decrease in the effectiveness of TYSABRI. The risk of increased disability and the annualized relapse rate were similar in persistently antibody-positive TYSABRI-treated patients and patients who received placebo. A similar phenomenon was also observed in Study MS2.
The plant will provide 400 potential new jobs to the Hillerød municipality. However, the geographical situation of the facility site in Medicon Valley (on the border of Denmark and Sweden, connected by the 16km Oresund Bridge) has led Biogen Idec to estimate that half the new workforce will come from Denmark with the remainder from Sweden. The new plant will increase Biogen Idec's employment worldwide by more than 20%. There will also be an influx of Dutch workers as the packaging and quality functions are being transferred to Hillerød.