BERLIN—Relapse-induced escalation to a highly effective disease-modifying therapy (DMT) is associated with a reduced risk of relapses, according to comprehensive nationwide data from Danish patients with multiple sclerosis (MS). Escalation is associated with a statistically nonsignificant trend toward reduced time to first one-point worsening of Expanded Disability Status Scale (EDSS) score over the short-to-medium term. “Escalation of therapy to a highly effective DMT when patients experience relapses on a moderately effective DMT is recommended to improve control of relapse activity,” said Thor Ameri Chalmer, MD, a doctoral student at Rigshospitalet in Copenhagen, and colleagues at ECTRIMS 2018.
Patients with relapsing-remitting MS who have relapses often switch to a new DMT. Treatment guidelines recommend switching to a highly effective DMT when a patient experiences clinical disease breakthrough. Nevertheless, patients may switch between moderately effective DMTs because of breakthrough disease or adverse effects. Dr. Chalmer and colleagues compared treatment effectiveness between highly effective DMTs and moderately effective DMTs in patients with relapsing-remitting MS who switch therapy because of relapse activity.
In this registry-based cohort study, the investigators retrieved data from the Danish MS Registry on all adults with relapsing-remitting MS. Eligible participants had an EDSS score below 6, experienced a relapse while treated with a moderately effective DMT, and consequently switched to a highly effective DMT or another moderately effective DMT. The groups were compared from treatment initiation until outcome or censoring. Censoring was defined as postbaseline switch between highly effective DMT and moderately effective DMT, cessation of therapy, relocation, or death, whichever occurred first. The primary outcomes were annualized relapse rate (ARR), relapse rate ratio, time to first relapse, and time to first one-point confirmed EDSS worsening. Dr. Chalmer and colleagues used propensity score matching to balance groups, a Cox proportional hazards model to obtain hazard ratios (HR) when modeling time to first relapse and time to first worsening, and negative binomial regression to obtain ARR and relapse rate ratios.
The matched cohort included 814 patients (407 in each group). The median follow-up time was 3.2 years. The group of patients who switched to a highly effective DMT had a 39% lower hazard rate of reaching first relapse (HR, 0.61). ARRs were 0.21 for patients who switched to a highly effective DMT and 0.34 for patients who switched to a moderately effective DMT. Relapse rate ratio for highly effective DMT compared with moderately effective DMT was 0.62. The group who switched to a highly effective DMT had 13% lower hazard rate of one-point EDSS worsening (HR, 0.87).