To investigate the effect of disease-modifying treatment on short-term disability outcomes in secondary progressive multiple sclerosis (SPMS).
Methods:
Using MSBase, an international cohort study, we previously validated a highly accurate definition of SPMS. Here, we identified patients in MSBase who were either untreated or treated with a disease-modifying drug when meeting this definition. Propensity score matching was used to select subpopulations with comparable baseline characteristics. Disability outcomes were compared in paired, pairwise-censored analyses adjusted for treatment persistence, visit density, and relapse rates.
Results:
Of the 2,381 included patients, 1,378 patients were matchable (treated n = 689, untreated n = 689). Median pairwise-censored follow-up was 2.1 years (quartiles 1.2–3.8 years). No difference in the risk of 6-month sustained disability progression was observed between the groups (hazard ratio [HR] 0.9, 95% confidence interval [CI] 0.7–1.1, p = 0.27). We also did not find differences in any of the secondary endpoints: risk of reaching Expanded Disability Status Scale (EDSS) score ≥7 (HR 0.6, 95% CI 0.4–1.1, p = 0.10), sustained disability reduction (HR 1.0, 95% CI 0.8–1.3, p = 0.79), or change in disability burden (area under the EDSS-time curve, β = −0.05, p = 0.09). Secondary and sensitivity analyses confirmed the results.
Conclusions:
Our pooled analysis of the currently available disease-modifying agents used after conversion to SPMS suggests that, on average, these therapies have no substantial effect on relapse-unrelated disability outcomes measured by the EDSS up to 4 years.
Classification of evidence:
This study provides Class IV evidence that for patients with SPMS, disease-modifying treatment has no beneficial effect on short-term disability progression.
Within 2 decades of onset, 80% of untreated patients with relapsing-remitting multiple sclerosis (MS) convert to a phase of irreversible disability accrual termed secondary progressive MS. The association between disease-modifying treatments (DMTs), and this conversion has rarely been studied and never using a validated definition.
Objective
To determine the association between the use, the type of, and the timing of DMTs with the risk of conversion to secondary progressive MS diagnosed with a validated definition.
Design, Setting, and Participants
Cohort study with prospective data from 68 neurology centers in 21 countries examining patients with relapsing-remitting MS commencing DMTs (or clinical monitoring) between 1988-2012 with minimum 4 years’ follow-up.
Exposures
The use, type, and timing of the following DMTs: interferon beta, glatiramer acetate, fingolimod, natalizumab, or alemtuzumab. After propensity-score matching, 1555 patients were included (last follow-up, February 14, 2017).
Main Outcome and Measure
Conversion to objectively defined secondary progressive MS.
Results
Of the 1555 patients, 1123 were female (mean baseline age, 35 years [SD, 10]). Patients initially treated with glatiramer acetate or interferon beta had a lower hazard of conversion to secondary progressive MS than matched untreated patients (HR, 0.71; 95% CI, 0.61-0.81;P < .001; 5-year absolute risk, 12% [49 of 407] vs 27% [58 of 213]; median follow-up, 7.6 years [IQR, 5.8-9.6]), as did fingolimod (HR, 0.37; 95% CI, 0.22-0.62;P < .001; 5-year absolute risk, 7% [6 of 85] vs 32% [56 of 174]; median follow-up, 4.5 years [IQR, 4.3-5.1]); natalizumab (HR, 0.61; 95% CI, 0.43-0.86;P = .005; 5-year absolute risk, 19% [16 of 82] vs 38% [62 of 164]; median follow-up, 4.9 years [IQR, 4.4-5.8]); and alemtuzumab (HR, 0.52; 95% CI, 0.32-0.85;P = .009; 5-year absolute risk, 10% [4 of 44] vs 25% [23 of 92]; median follow-up, 7.4 years [IQR, 6.0-8.6]). Initial treatment with fingolimod, alemtuzumab, or natalizumab was associated with a lower risk of conversion than initial treatment with glatiramer acetate or interferon beta (HR, 0.66; 95% CI, 0.44-0.99;P = .046); 5-year absolute risk, 7% [16 of 235] vs 12% [46 of 380]; median follow-up, 5.8 years [IQR, 4.7-8.0]). The probability of conversion was lower when glatiramer acetate or interferon beta was started within 5 years of disease onset vs later (HR, 0.77; 95% CI, 0.61-0.98;P = .03; 5-year absolute risk, 3% [4 of 120] vs 6% [2 of 38]; median follow-up, 13.4 years [IQR, 11-18.1]). When glatiramer acetate or interferon beta were escalated to fingolimod, alemtuzumab, or natalizumab within 5 years vs later, the HR was 0.76 (95% CI, 0.66-0.88;P < .001; 5-year absolute risk, 8% [25 of 307] vs 14% [46 of 331], median follow-up, 5.3 years [IQR], 4.6-6.1).
Conclusions and Relevance
Among patients with relapsing-remitting MS, initial treatment with fingolimod, alemtuzumab, or natalizumab was associated with a lower risk of conversion to secondary progressive MS vs initial treatment with glatiramer acetate or interferon beta. These findings, considered along with these therapies’ risks, may help inform decisions about DMT selection.
Disability progression is a key milestone in the disease evolution of people with multiple sclerosis (PwMS). Prediction models of the probability of disability progression have not yet reached the level of trust needed to be adopted in the clinic. A common benchmark to assess model development in multiple sclerosis is also currently lacking.
It is unclear whether relapses and disease-modifying therapies are associated with the rate of disability accumulation in patients with secondary progressive multiple sclerosis (SPMS).To examine the association of relapses with the rate of disability accumulation in patients with SPMS and to assess whether treatment before or during the secondary progressive phase can slow the progression of disability accumulation.In this observational cohort study, patient data were prospectively collected from the MSBase international registry between January 1, 1995, and February 1, 2018. Among 53 680 patients in the MSBase registry, 4997 patients with SPMS (using the Lorscheider definition) were identified. Of those, 1621 patients were eligible for study inclusion based on sufficient follow-up before and after the onset of SPMS. Data were analyzed from November 15, 2017, to January 13, 2020.The association between disability accumulation and several clinical and demographic variables, including relapses and exposure to immunotherapy, was evaluated.Two outcomes were analyzed as measures of disability accumulation during SPMS: the rate of disability accumulation during the secondary progressive phase (change relative to the reference population of patients with MS and absolute change) and the risk of becoming wheelchair dependent. A third outcome, the cumulative risk of experiencing confirmed disability progression events, was used for a secondary analysis. Outcomes were evaluated using multivariable mixed models (ie, linear and Cox models).Of 1621 patients eligible for inclusion, 1103 patients (68.0%) were female, with a mean (SD) age at MS onset of 33.9 (10.6) years. A total of 661 patients (40.8%) experienced superimposed relapses during SPMS. Therapy receipt and relapses during early relapsing-remitting MS were not associated with disability accumulation during the secondary progressive phase. Higher relapse rates during the secondary progressive disease stage were associated with an increased risk of becoming wheelchair dependent (hazard ratio [HR], 1.87; 95% CI, 1.17-3.00; P = .009). Among patients who experienced superimposed relapses during SPMS, greater receipt of disease-modifying therapies was significantly associated with a reduced rate of disability progression and a lower risk of becoming wheelchair dependent.In this study, the rate of disability progression after the onset of SPMS was not associated with the early disease course and treatment decisions. Relapses during SPMS were associated with accelerated disability progression and represent an accessible treatment target. Disease-modifying therapy was associated with improvements in disability outcomes among patients with active relapses during SPMS. The study's results suggest that inflammatory disease activity remains a substantial yet modifiable component of SPMS.