Breaking the assumption: Disease-modifying therapy efficacy and relapse severity in relapsing-remitting multiple...

The severity of relapses is lower in patients treated with DMTs compared to untreated patients. Although Disease-modifying treatments (DMTs) differ considerably in their efficacy for relapse prevention, the specific impact of different DMTs on relapse severity has not yet been thoroughly investigated.

To study the relationship between DMT use, relapse severity and recovery outcomes in relapsing-remitting multiple sclerosis (RRMS).

A restrospective cohort study analyzed 85 RRMS patients treated with either moderate-efficacy DMTs (interferons, glatiramer acetate, teriflunomide, dimethyl fumarate; n = 48) or high-efficacy DMTs (fingolimod, natalizumab, ocrelizumab, alemtuzumab, cladribine; n = 37). Regular EDSS assessments were used to evaluate relapse severity and subsequent recovery.

Although patients on high-efficacy DMTs tended to experience less severe relapses (ΔEDSS = 0.49 ± 0.59 vs 0.71 ± 0.68 with moderate-efficacy DMTs; p = 0.12), multivariable analysis did not confirm a significant influence of high-efficacy treatment on relapse severity (OR = 0.46; 95 % CI: 0.13-1.61; p = 0.22). Relapse recovery showed a similar gradual improvement in both groups, with a slightly lower increase in disability among patients on high-efficacy DMTs at 6 months (0.26 ± 0.89 vs 0.39 ± 0.73; p = 0.46) and 12 months (0.27 ± 0.83 vs 0.31 ± 0.78; p = 0.98), though without statistically significant differences. Baseline EDSS emerged as the main determinant of relapse severity (OR=0.40; 95 % CI: 0.21-0.77; p = 0.006).

These findings indicate that, among the DMTs analyzed (both moderate- and high-efficacy), the level of preventive efficacy does not substantially modify relapse severity or recovery once a relapse occurs.