Glatiramer Acetate to Fingolimod Switch Might Reduce MS Relapse Rates
VANCOUVER, BC—Patients with relapsing-remitting multiple sclerosis (MS) had fewer relapses after switching from glatiramer acetate to fingolimod vs. remaining on the injectable disease-modifying therapy (DMT), results from a database study reported at the 68th AAN Annual Meeting.
"Given the growing number of DMTs available for relapsing-remitting MS, evidence to inform DMT switch decisions is needed," stated Tara Nazareth, MPH, of Novartis Pharmaceuticals, East Hanover, NJ, and coauthors.
The study's goal was to compare relapse rates among patients who remain on GA vs. those who switched to fingolimod or interferon.
The retrospective longitudinal study used the Truven Health MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases to identify patients with MS treated with glatiramer acetate (GA), fingolimod, or interferon between October 1, 2010, and September 30, 2012.
"All patients were treated with GA in the 12 months prior to prescription of the DMT of interest," she noted.
The study authors defined the index date for the switch from GA to either fingolimod or interferon as the date of the first observed claim for either agent and, for those in the GA-only cohort, "the index date was determined based on the first GA claim within the identification period."
For all cohorts, the pre-index period was defined as the 12-month period preceding the index date, and the post-index period as the 12 months following the index date.
A total of 6,890 patients were included in the study, 6,399 in the GA-only cohort, 363 in the GA switched to fingolimod cohort, and 128 in the GA switched to interferon cohort.
At baseline, significant differences were observed between the GA-only and fingolimod and interferon cohorts in age (P<0.0001 for fingolimod and interferon), MS-related symptoms (P=0.0002 for fingolimod and P=0.0022 for interferon), and adherence (P<0.0001 for fingolimod and interferon) in the pre-index period.
Difference-in-differences analysis found that the cohort switching from GA to fingolimod had a 13.8% reduction in relapses compared to the GA-only cohort, while the interferon cohort had a 4.5% reduction.
Baseline and post-period odds ratios for the fingolimod vs. GA-only cohort group were 2.63 (95% CI: 2.08, 3.33) and 1.22 (95% CI: 0.90, 1.67; P=0.1989) and, for the interferon versus GA-only cohort, 2.31 (95% CI: 1.55, 3.41) and 1.95 (95%: 1.26, 3.02; P=0.0023).
The authors cautioned that "inherent limitations" associated with using administrative claims in a retrospective study include lack of data on a patient's clinical presentation, disease severity, reasons for switching agents, and health plan information.
The study was funded by Novartis.