Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system which leads to the formation of focal confluent lesions of primary demyelination in the white and gray matter and to diffuse damage and neurodegeneration in the entire brain. MS is the leading cause of non-traumatic neurological disability in young adults. In the majority of patients multiple sclerosis starts with a relapsing remitting course
(RRMS), which may at later times transform into secondary progressive disease (SPMS).
In about 10% of patients the relapsing remitting disease is skipped and the patients
show progression from the onset, the so called primary progressive MS (PPMS). Despite these distinctions, all clinical forms of MS appear to reflect the same underlying disease process. And although inflammation is typically associated with relapses, and neurodegeneration with progression, it is now recognized that both pathologies are present in essentially all patients across the entire disease continuum.
Siponimod is a selective S1P modulator that is approved for relapsing forms of MS including
active SPMS. Ocrelizumab, cladribine, and ozanimod can also be used for patients with active SPMS. Ocrelizumab is the only approved disease-modifying therapy for the treatment of PPMS.
An increase number of trials and diversity of therapeutic approaches for progressive MS provides hope for future effective therapy.
Assigning Secondary Progressive Multiple Sclerosis (SPMS) course consistently is challenging as it is based on a gradual worsening in neurological disability independent of relapses. Clinical SPMS assignment may therefore vary between registries depending on clinical practice. Consequently, a comparison of SPMS between registries would benefit from an objective definition of SPMS.
To validate three different methods for classifying patients into Relapsing Remitting Multiple Sclerosis (RRMS) or SPMS, compared to the clinical assignment, in five European Multiple Sclerosis (MS) registries.
Data from MS registries in Czech Republic (11,336 patients), Denmark (10,255 patients), Germany (23,185 patients), Sweden (11,247 patients), and the United Kingdom (UK) (5,086 patients) were used. Patients with either RRMS or SPMS, age ≥ 18 years at index date (date with the latest Expanded Disability Status Scale (EDSS) observation) were included. Index period was 01/2017 - 12/2019. Three EDSS centric classification methods were applied; method 1: a modified real world EXPAND criteria (Kappos, L. et al., 2018. The Lancet 391(10127), 2018), method 2: the data-derived definition from Melbourne University but without pyramidal Functional Score (Lorscheider, J. et al., 2016. Brain 139(9)), method 3: the decision tree classifier from Karolinska Institutet (Ramanujam, R. et al., 2020. medRxiv, 2020.07.09.20149674). The classifications were compared to the clinical assignment, where sensitivity (SPMS as true positive), specificity (RRMS as true negative) and accuracy were calculated as similarity measurements.
The overall classification performance (sensitivity, specificity, accuracy) among classifiable patients were; method 1: (0.47, 0.85, 0.79), method 2: (0.77, 0.87, 0.85), method 3: (0.84, 0.83, 0.84). The proportions of unclassifiable patients with each method were; method 1: 20.0%, method 2: 32.2%, method 3: 0%. Methods 2 & 3 provided a high sensitivity, specificity and accuracy, while method 1 provided high specificity but low sensitivity. Method 3 was the only method having no unclassifiable patients.
Our findings suggest that these methods can be used to objectively assign SPMS with a fairly high performance in different registries. The method of choice depends on the research question and to what degree unclassifiable patients are tolerable.
Background: Except for ocrelizumab, treatment options in primary progressive multiple sclerosis (PPMS) are lacking, as randomized clinical trials failed to show efficacy in reducing disability progression in this patient population.
Objective: To investigate the effectiveness of disease-modifying treatment (DMT) on hard disability outcomes (EDSS 6 and 7) in a real-life population of PPMS patients.
Methods: Using the Italian MS Registry, we selected PPMS patients with at least three EDSS evaluations and three years of follow-up. Study baseline was defined as the first EDSS evaluation for untreated patients and the date of the first DMT initiation for treated patients. The impact of DMT on the risk of reaching EDSS 6 and 7 was assessed as a dichotomous variable (yes versus no) and as a time-dependent covariate through multivariable Cox regression models (adjusted for age at baseline, sex, first EDSS score, symptoms at onset, annualized visit rate, annualized relapse rate). We compared outcomes with an as-treated analysis and used propensity-score matching (PSM) to select cohorts with comparable baseline characteristics. DMT-exposure was also evaluated in terms of quartiles of exposure.
Results: Of the 1214 patients we included 671 females, mean ± Standard Deviation baseline age 48.7 ± 11.1 years, mean EDSS score 4.1 ± 1.8, 790 (65%) received a DMT during the follow-up (57% platform and 43% highly active treatments). In the whole sample, after a mean follow-up of 11.6 ± 6.3 years, 994 (82%) patients reached EDSS 6 and 539 (44%) EDSS 7. In the multivariable Cox regression models, the use of DMT analyzed as a dichotomous variable did not influence the risk of reaching EDSS 6 (aHR=1.1, 95% CI 0.95-1.28, p=0.181) and EDSS 7 (aHR = 0.93, 95% CI 0.77-1.12. p = 0.454). However, longer DMT exposure significantly reduced the risk of reaching EDSS 7 (aHR = 0.73, 95% CI 0.56-0.95, p =0.021). Of note, patients in the upper quartile of DMT exposure compared with those with shorter DMT exposure were younger at baseline (mean age 44.1 ± 10.6 years; p < 0.001) and received the first DMT closer to the disease onset (mean time to first DMT 6.8 years ± 6.1 ; p=0.002). All these findings were confirmed in the PSM analysis.
Conclusion: Our results suggest that longer exposure to DMT may delay time to wheelchair in PPMS patients. Moreover, treating younger patients and reducing the delay to treatment initiation may improve the patients’ long-term disability outcomes. To optimize treatment decision-making in PPMS further profiling of the best candidates to treatment is needed.
Until recently, disease modifying treatment options for MS patients with a secondary progressive course (SPMS) were limited, leading to the common practice of off-label treatment with drugs approved for relapsing-remitting MS. We previously showed that applying objective algorithms tend to increase the proportion of SPMS in MS registries, suggesting that SPMS is under-diagnosed in clinical practice, possibly related to available treatment options.
To compare characteristics of patients clinically assigned an RRMS course that are re-classified when an algorithm-based SPMS assignment method is applied.
Data from MS registries in the Czech Republic (11,336 patients), Denmark (10,255 patients), Germany (23,185 patients), Sweden (11,247 patients) and the United Kingdom (5,086 patients) were used. Inclusion criteria were patients with relapsing remitting (RR)MS or SPMS with age ≥ 18 years at the beginning of the study period (1 January 2017 – 31 December 2019). In addition to clinically assigned SPMS a data-driven assignment method was applied in the form of a decision tree classifier based on age and last EDSS (Ramanujam, R. et al., 2020. medRxiv, 2020.07.09.20149674).
Across the five registries 8,372 RRMS patients were re-assigned as SPMS (Denmark: n=1,566, Czech Republic: n=1,958, Germany: n=2,906, Sweden: n=648, United Kingdom: n=1,294) increasing the overall SPMS proportion from 17% to 31%. Re-assigned patients tended be younger, were older at onset and had experienced a quicker progression to SPMS. The overall proportion of clinically assigned SPMS patients on disease modifying treatments (DMTs) was 36% but varied greatly between registries (Czech Republic: 18%, Denmark: 35%, Germany: 50%, Sweden: 40%, and the United Kingdom: 12%) whereas a higher proportion of 69% (OR=4.0, P<0.00004) were on DMTs among RRMS patients re-assigned as SPMS (Czech Republic: 71%, Denmark: 68%, Germany: 78%, Sweden: 80%, and the United Kingdom 40%).
SPMS patients on DMTs may be clinically mis-classified as RRMS, most likely by not being re-assigned to SPMS after conversion has occurred. This challenges the use of time to SPMS conversion as an outcome in comparative effectiveness studies using real world evidence data and argues for the use of objective classification tools in the analysis of MS patient populations.