Short-Term Relapse Quantitation as a Fully Surrogate Endpoint for Long-Term Sustained Progression of Disability in RRMS Patients Treated with Natalizumab

Table 2

Annualized relapse rate—ITT population—one-year analysis.

	Placebo	Natalizumab	Rate Ratio (95% CI) and 𝑃 value (a)
Number of subjects randomized	315 (100)	627 (100)
Number of subjects with a relapse	135 (43)	132 (21)
Number of relapses^b
0	180 (57)	495 (79)
1	76 (24)	111 (18)
2	42 (13)	17 (3)
3	8 (3)	4 (<1)
≥4	9 (3)	0
Total number of relapses	224	157
Total subject-years followed	320.1	652.6
Unadjusted annualized relapse rate^c	0.700	0.241
Adjusted annualized relapse rate	0.805	0.261	0.325
(95% CI)^a	(0.669, 0.969)	(0.211, 0.323)	(0.256, 0.412)
			<0.001
Subject relapse rate^d
Mean	0.778	0.262
Median	0.000	0.000

Note: the analysis includes relapses and time on the study up to the time that alternative MS medication is added.
^a: From Poisson regression, adjusted for the number of relapses in the one year prior to study entry, baseline EDSS (≤3.5 versus >3.5), presence of Gd lesions (present versus absent), and age (<40 versus ≥40).
^b: Numbers in parentheses are percentages.
^c: The total number of relapses that occurred during the study divided by the total number of subject-years followed in the study.
^d: The number of relapses for each subject divided by the number of years followed in the study for that subject. Mean and median across all subjects are presented.