Background: Prospective database studies can provide useful information regarding 'real-world' outcomes and drug efficacy.
Objective: To determine the early predictors of suboptimal treatment responses at two and three years under injectable Disease Modifying Therapy (DMT).
Methods: This was a multi-centre prospective database study. Adult patients who started injectable DMTs between January 2008 and June 2013 were included. The follow-up continued until July 2014. Suboptimal treatment responses were defined as: the presence of clinical relapse and/or Expanded Disability Status Score (EDSS) progression and/or newly emerging T2 lesions or/and gadolinium enhancing lesions on magnetic resonance imaging (MRI). The parameters were assessed up to 24 months prior to, and every 12 months during, the treatment.
Results: Analysis included 297 MS (multiple sclerosis) patients followed for a mean time of 2.3 ± 1.3 years (range 1-5). Within the three years of observation, the persistence and efficacy with injectable DMTs was high. With increased disability, defined by EDSS ≥ 3, the risk of treatment failure increased up to seven times, OR 7.33 in the second year radiological analysis (CI 95% : 1.69-29.2) p < 0.01, similar to over two times in the second year clinical analysis, with the baseline symptomatic hemiparesis OR 2.75 (CI 95% : 1.06-7.06) p 0.034. A high relapse rate one year prior to treatment adversely influenced the treatment success at three years, OR 3.04 (CI 95% : 1.49-8.43) p < 0.01.
Conclusions: Injectable DMTs should not be chosen for treatment initiation in motoric disabled patients (EDSS ≥ 3) with a high grade of clinical activity. These drugs are effective in less active relapsing-remitting (RR) MS patients.
Keywords: Expanded Disability Status Score; RIO score; annualised relapse rate; disease modifying treatment; efficacy; magnetic resonance imaging; multiple sclerosis.