Relapsing MS patients received 300 mg TYSABRI every 28 days (n=627) or placebo (n=315). Patients with PPMS, SPMS, and PRMS were excluded.
83% of patients taking TYSABRI had no sustained disability progression for 12 weeks vs 71% with placebo (primary endpoint: 17% vs 29%; p<0.001)1,2
TYSABRI demonstrated 67% relative reduction in ARR vs placebo (secondary endpoint: 0.22 vs 0.67; p<0.001)1,2
ARR=annualized relapse rate.
In a post hoc analysis of the AFFIRM trial:
Onset of efficacy as early as 2 months and maintained over 2 years
Study description: A post hoc analysis of the AFFIRM pivotal trial was performed to look at time to onset of clinical effects following initiation of TYSABRI. ARR was measured at 3-month intervals.3,a-c
aAnnualized relapse rates per 3-month interval were calculated as the total number of relapses divided by total person-years observed within the interval.
bRelapses were defined as new or recurrent neurologic symptoms not associated with fever or infection that lasted ≥24 hours and were accompanied by new neurologic signs found by the examining neurologist.
cRPost hoc subgroup analysis of data from AFFIRM defined highly active disease as ≥2 relapses in the year before study entry and ≥1 T1 Gd+ MRI lesion at study entry. A total of 209 patients (148 TYSABRI and 61 placebo) in AFFIRM met the criteria for highly active MS.
d58% reduction calculated based on rate of 0.3 with TYSABRI vs 0.71 with placebo: 0.71-0.3=0.41 difference/0.71=0.58 decrease.3
e68% reduction calculated based on rate of 0.3 with TYSABRI vs 0.94 with placebo: 0.94-0.3=0.64 difference/0.94=0.68 decrease.3
This study was funded by Biogen.