Table 2.

Reasons for natalizumab treatment discontinuation.

Reason for discontinuationa	Total cohort (n = 642)
	n	%
Anti-John Cunningham virus (JCV) antibody positivity	306	48
Disease activity	76	12
Adverse events	72	11
Other	70	11
Patient's own decision	57	9
Pregnancy	39	6
Alteration of disease course	36	6
Drug antibodies	32	5
Missing – discontinued without specified reason	32	5

^a Individual patients may have more than one reason for discontinuation.