to date, no consensus exists on how aggressively and timely treat relapsing-remitting multiple sclerosis (RRMS) patients.
To evaluate disability trajectories in a cohort of RRMS patients stratified according to two different disease modifying therapy (DMT) strategies, early intensive treatment (EIT) or moderate-efficacy treatment followed by escalation to higher-efficacy DMT (ESC).
RRMS patients with ≥5-year follow-up and ≥3 visits after start DMT, and a first visit within 3 years from disease onset were selected from the Italian MS Registry. EIT group included patients who received, as first DMT, fingolimod, natalizumab, mitoxantrone, alemtuzumab, ocrelizumab, cladribine. ESC group included those who received the high efficacy DMT after ≥1 year of glatiramer acetate, interferons, azathioprine, teriflunomide or dimethylfumarate treatment. Patients were 1:1 propensity score(PS)-matched for characteristics at the first DMT. The follow-up time from the first DMT start has been segmented into 12-month periods. The disability trajectories were evaluated by applying a longitudinal model for repeated measures with an autoregressive variance-covariance structure. The effect of early versus late start of high-efficacy DMT was assessed by the mean annual EDSS changes compared to baseline values (delta-EDSS) in EIT and ESC groups.
The study cohort included 2,652 RRMS patients from 62 Italian MS centers. The PS matching procedure produced 365 pairs. The median (IQR) follow-up after the first DMT start was 8.5 (6.5–11.7) years. All of the ESC patients escalated to a higher-efficacy DMT after a median time of 5.1 (3.1–8.4) years. The estimated baseline EDSS with relative confidence interval (95% CI) value was 2.52 (2.33-2.71) in the ESC group and 2.45 (2.26-2.64) in the EIT group. Mean delta-EDSS at each 12 month period were all significantly (p<0.02) higher in the ESC group compared to the EIT group. In particular, the mean delta-EDSS differences between the two groups tend to increase from 0.1 (0.01-0.19, p=0.03) at 1 year to 0.30 (0.07-0.53, p=0.009) at 5 years and to 0.67 (0.31-1.03, p=0.0003) at 10 years.
Our results indicate that EIT strategy is more effective than ESC strategy in controlling disability progression and the effect tends to increase over time despite patients in the ESC group escalated to a higher-efficacy DMT.