BACKGROUND: Multiple sclerosis
(MS) registry data, primarily from Europe, suggest that treatment with
natalizumab delays time to relapse compared with platform therapy
(interferon beta/glatiramer acetate).
OBJECTIVE:This
study uses US administrative claims data and propensity score matching
(PSM) to compare relapse rates and time to relapse among patients with
MS using either platform therapy or natalizumab.
METHODS:Adults
with MS receiving either platform therapy or natalizumab between
January 1, 2009 and April 1, 2012 were identified in the Truven Health
MarketScan® Research Databases. Patients were included if
they had 12 months of continuous enrollment both before and after the
index date (the first claim for either drug cohort) and had 12 months of
claims data suggesting consistent treatment adherence during the
follow-up period. Characteristics used in PSM included demographics,
selected comorbidities and concomitant medications, MS severity,
baseline relapse rates, and expenditures. A relapse was defined as an
MS-related hospitalization or corticosteroid use.
RESULTS:A
total of 882 patients were matched. Relapse occurred among
significantly fewer patients in the natalizumab group (26.5 %) than
platform therapy (35.5 %, p < 0.001) (hazard ratio 0.69; 95 % CI
0.59-0.82). Relapses were also significantly later for those on
natalizumab (308 vs 283 days without relapse, p < 0.001).
CONCLUSION:Treatment
with natalizumab was associated with a significantly lower risk and
rate of MS relapse and longer MS relapse-free time compared with
platform therapies.
Probability of no relapse: natalizumab vs. platform therapy