Background

Our current understanding of demographic and clinical modifiers of the effectiveness of multiple sclerosis (MS) therapies is limited.

Objectives

To assess whether patients’ response to disease modifying therapies (DMT) in MS varies by disease activity (annualised relapse rate, presence of new MRI lesions), disability, age, MS duration or disease phenotype.

Methods

Using the international MSBase registry, we selected patients with MS followed for ≥1 year, with ≥3 visits, ≥1 visit per year. Marginal structural models (MSMs) were used to compare the hazard ratios (HR) of 6-month confirmed worsening and improvement of disability (EDSS), and the incidence of relapses between treated and untreated periods. MSMs were continuously re-adjusted for patient age, sex, pregnancy, date, time from first symptom, prior relapse history, disability and MRI activity.

Results

Among 23 687 patients with relapsing MS, those on DMT experienced 20% greater chance of disability improvement [HR 1.20 (95% CI 1.0-1.5)], 47% lower risk of disability worsening [HR 0.53 (0.39-0.71)] and 51% reduction in relapses [HR 0.49 (0.43-0.55)]. The effect of DMT on relapses and EDSS worsening was attenuated with longer MS duration and higher prior relapse rate. The effect of DMT on EDSS improvement and relapses was more evident in low EDSS categories. DMT was associated with 51% EDSS improvement in patients without new MRI lesions [HR 1.51 (1.00-2.28)] compared to 4% in those with MRI activity [HR 1.04 (0.88-1.24)]. Among 26329 participants with relapsing or progressive MS, DMT was associated with 25% reduction in EDSS worsening and 42% reduction in relapses in patients with relapsing MS [HR 0.75 (0.65-0.86) and HR 0.58 (CI 0.54-62), respectively], while evidence for such beneficial effects of treatment in patients with progressive MS was not found [HR 1.11 (0.91-1.46) and HR 1.16 (0.91-1.46), respectively].

Conclusions

DMTs are associated with reduction in relapse frequency, progression of disability, and increased chance of recovery from disability. In general, the effectiveness of DMTs was most pronounced in subgroups with shorter MS duration, lower EDSS, lower relapse rate and relapsing MS phenotype.

Background

Ponesimod (PON), an orally active, highly selective and reversible modulator of sphingosine-1-phosphate receptor 1, reduces circulating lymphocytes by sequestration in lymphoid organs. In the phase-3 OPTIMUM study (NCT02425644), PON showed superior efficacy vs teriflunomide (TER) in patients with relapsing multiple sclerosis (RMS).

Objectives

To evaluate prespecified MRI-based endpoints and no evidence of disease activity (NEDA) status in patients with RMS.

Methods

Patients (18-55 years) with RMS (expanded disability status scale scores: 0-5.5) were randomized (1:1) to receive PON 20 mg or TER 14 mg for 108 weeks. MRI endpoints included: percentage change from baseline to week 108 in brain volume (SIENA, Structural Image Evaluation, using Normalization of Atrophy), mean number of new gadolinium-enhancing (Gd+) T1 lesions and volume/count of new/enlarging T2-weighted (T2) lesions. NEDA-3 (absence of confirmed relapse, 12-week confirmed disability accumulation, Gd+T1 and new/enlarging T2 lesions on annual MRIs) and NEDA-4 status (NEDA-3 and no average annual brain volume decrease ≥0.4%) were evaluated from baseline to week 108.

Results

985/1133 (86.9%) randomized patients completed the study. MRI findings for PON vs TER from baseline to week 108, respectively, were: least square (LS) mean percent change from baseline in brain volume: −0.91% vs −1.25% (difference: 0.34%, 95% CLs: 0.17;0.50, p<0.0001); LS mean difference (PON−TER) in change from baseline in total T2 lesion load: −399.2 mm³ (95% CLs: −651.5;−146.8, p=0.002); mean number of new/enlarging T2 lesions per year: 1.40 vs 3.16 (rate ratio [RR]: 0.44, 95% CLs: 0.36;0.54, p<0.0001); PON vs TER odds ratio (OR [95% CL]) for absence of new/enlarging T2 lesions: 1.71 (1.30;2.25, p=0.0001); mean number of new Gd+T1 lesions per scan: 0.18 vs 0.43 (RR: 0.42, 95% CLs: 0.31;0.56, p<0.0001); PON vs TER (OR [95% CL]) for absence of new Gd+T1 lesions: 2.18 (1.61;2.95, p<0.0001). At week 108, 28.2% (159/564) PON vs 18.3% (102/558) TER patients (OR: 1.70, 95% CLs: 1.27;2.28, p=0.0004) achieved NEDA-3; 15.0% (79/526) PON vs 8.5% (45/532) TER patients (OR: 1.85, 95% CLs: 1.24;2.76, p=0.0026) achieved NEDA-4. The most common reason for not achieving NEDA-3 or NEDA-4 status was presence of new/enlarging T2 lesions.

Conclusions

PON showed benefit vs TER for all MRI outcomes including brain volume loss and a significantly higher proportion of patients achieved NEDA-3 and NEDA-4 status, supporting the effects observed on clinical endpoints.

Background

Ponesimod, an orally active, selective sphingosine 1-phosphate receptor-1 (S1P) modulator, showed benefits in clinical and MRI outcomes in a double-blind, placebo controlled, phase 2b Core Study (NCT01006265). Patients rolled-over into an ongoing Extension Study (NCT01093326).

Objectives

Evaluate the long-term efficacy and safety of ponesimod in patients with relapsing-remitting multiple sclerosis (RRMS).

Methods

A total of 435 patients with RRMS received ≥1 dose of ponesimod (10, 20, or 40-mg/day) during the Core and/or Extension Study. The 40 and 10-mg doses were subsequently discontinued during Treatment Period 1 (TP1) and TP2 of the Extension Study. All patients received 10 or 20-mg during TP2, followed by open-label 20-mg in TP3. Key efficacy parameters: annualized relapse rate (ARR), 6-month confirmed disability accumulation (CDA), and MRI outcomes. Safety parameters: frequencies of adverse events (AEs) and serious AEs (SAEs). Results of combined analyses of Core and Extension studies are presented.

Results

As of 31 March 2019, 214 patients were still on ponesimod treatment; median exposure in 20-mg group was 8.02 years; Cumulative exposure across all doses was 2372.47 patients-years. In 20-mg group, ARR (95% CI) for confirmed relapses was 0.154 (0.111‒0.214); 64.1% patients remained free of confirmed relapse; Kaplan-Meier estimate of 6- month CDA at Week 432 was 20.4% (13.7‒29.7); Mean number of T1 gadolinium enhancing lesions per patient per scan was 0.448 (0.305‒0.657); Mean number of new or enlarging T2 lesions per year was 0.718 (0.523‒0.985). In ponesimod-treated patients, the most common treatment-emergent AEs were nasopharyngitis (30%), headache (24%) and upper respiratory tract infection (21%). Most SAEs were reported in a single patient, no SAE was reported at an incidence of >1%.

Conclusions

Long-term treatment with ponesimod 20 mg showed consistently low levels of disease activity across relevant clinical and MRI outcomes in patients with RRMS. No new safety signals were identified.

Background

The rapidly evolving therapeutic landscape of multiple sclerosis (MS) can make treatment decisions challenging. Novel tools using artificial intelligence (AI) can provide estimations of MS disease progression, which may aid MS therapeutic decisions. However, whether neurologists are willing to utilize information provided by AI-based models when making therapeutic decisions is unknown.

Objectives

To assess whether neurologists rely on clinical judgment (CJ) or quantitative/ qualitative estimations of disease progression provided by hypothetical AI-based models (assuming these models can reliably identify patients at high vs. low risk of disease progression) in simulated MS case scenarios.

Methods

Overall, 231 neurologists with expertise in MS from 20 countries were randomized to receive qualitative (high/low) or quantitative (85-90% vs. 15-20%) information regarding the likelihood of disease progression. Participants were presented with simulated MS case scenarios, and initially made 7 treatment decisions based on the clinical information using CJ. After randomization, participants made 10 treatment decisions using CJ and estimations of disease progression provided by AI models. We evaluated concordance and discordance of therapeutic decisions based on CJ and AI. The primary outcome was the proportion of “optimal” treatment decisions defined as treatment escalation when there was evidence of disease progression or continuing the same treatment when clinically stable. Mixed models were used to determine the effect of randomization group, case risk level, and CJ/AI. Clinicaltrials.gov #NCT04035720

Results

Of 300 neurologists invited to participate, 231 (77.0%) completed the study. Study participants had a mean age (SD) of 44 (±10) years. Of 2310 responses, 1702 (73.7%) were classified as optimal. Optimal decisions were more common for the high-risk vs. low-risk CJ group (84.5% vs 57.6%; p<0.001). There were no differences in the estimated odds of optimal responses between the quantitative vs. qualitative groups (OR 1.09; 95%CI 0.86, 1.39) after adjustment for pre-intervention responses. The estimated odds of optimal decisions for the high-risk vs low-risk CJ group was 2.96 (95%CI: 2.47, 3.56 ) after adjusting for group, pre-intervention responses, and AI-based estimations. For low-risk CJ cases, additional input by AI-based estimations was associated with a lower likelihood of optimal responses; being worse for high-risk vs. low-risk AI estimations (OR 0.235; 95%CI: 0.16, 0.340) adjusting for covariables.

Conclusions

Neurologists were more likely to make optimal treatment choices for high-risk simulated scenarios. The addition of hypothetical information provided by AI-based models- did not improve treatment decisions for low-risk cases. These results provide a framework for understanding therapeutic decision-making in MS neurologists, who are more reliant on their own CJ over AI-based tools.

Background

Therapeutic inertia (TI) is a worldwide phenomenon affecting physicians who manage patients with chronic conditions. Previous studies in Multiple Sclerosis (MS) showed TI affects 60 to 90% of neurologists and up to 25% of daily treatment decisions.

Objectives

To determine the most important factors and levels of attributes associated with treatment escalation in an international sample of neurologists with expertise in the management of patients with MS.

Methods

We conducted an international study comprised of 300 neurologists with expertise in MS from 20 countries (Europe: 59.4%, Asia/Australia: 18.3%, America: 22.3%). Participants were presented with 12 pairs of simulated MS patient profiles reflective of case scenarios encountered in clinical practice. Patient profiles included information on age, sex, previous MS history of relapses, MRI findings, desire for pregnancy, and other relevant details. We used disaggregated discrete choice experiments (a conjoint analysis), which is a standard technique used in economic research to estimate the weight of factors and attributes (e.g. categories) affecting physicians’ decisions when considering treatment selection by asking respondents to choose between pairs of options. In our study, participants were asked to select the ideal candidate (Patient A, B or neither) for treatment escalation (from first-line to second-line therapies- eg. Fingolimod, Cladribine, Monoclonal antibodies).

Results

Of 300 neurologists invited to participate, 229 (76.3%) completed the study. The mean age (SD) of study participants was 44 (±10) years. The mean (SD) number of MS patients seen per week by each neurologist was 18 (±16).

The top 3 factors (relative importance) associated with treatment escalation were: previous relapses (20%), EDSS (18%), and MRI activity (13%). Patient demographics and desire for pregnancy had a modest influence (<3%) in treatment escalation.

Participants were 13% less likely to escalate treatment for patients with EDSS >7.0 (compared to EDSS <6.0), whereas symptom severity during most recent relapse and higher number of MRI lesions at 1 year were each associated with 6% higher likelihood of treatment escalation.

We observed differences in the weight of factors associated with treatment escalation between MS specialists and non-specialists and participants practicing in European vs. non-European countries.

Conclusions

This is the first study applying a conjoint design to assess factors associated with treatment escalation and therapeutic inertia in neurologists caring for people living with MS. Our results provide critical information on factors influencing neurologists’ treatment decisions and should be applied to continuing medical education strategies.

Background

Regional brain atrophy is a sensitive disability marker for MS patients. A previous study has shown that atrophy of the corpus callosum is an early marker for disease progression. However, the relationship between diffuse pathology in specific brain regions and the course of regional atrophy development remains poorly understood.

Objectives

To investigate quantitative T1 maps and entropy (amount of T1 inhomogeneity) in regional brain structures from diagnostic MRI (performed at disease onset) of MS patients and compare these findings with healthy controls (HC).

Methods

Fifty MS patients and 102 HC were examined on a 3T MRI scanner (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The MRI protocol comprised 3D MP2RAGE, 3D MPRAGE, 3D FLAIR and 3D DIR. The calculation of T1 maps, brain structure segmentations and brain volume measurements were obtained from a single MP2RAGE scan. Lesion segmentation masks were obtained using the LeManPV prototype software (Siemens Healthcare, Erlangen, Germany). We evaluated T1 maps from normal-appearing white matter (excluding lesions) in the corpus callosum, the brain lobes, brainstem and cerebellum, as well as from normal-appearing gray matter (excluding lesions) in the thalami, basal ganglia, and cortical gray matter. We calculated median regional T1 relaxation times, T1 entropy and volume for the above-mentioned structures for the early-MS group and 50 age- and sex-matched HC subjects. Statistical comparison was performed using t-tests.

Results

The median T1 of the corpus callosum in the early MS group was 838 ms (SD 38.5), with entropy 8.42 (SD 0.24); compared to 810 ms (SD 25.2) and 8.23 (SD 0.13) in the HC group. Statistically significant differences were found in T1 times and entropy between the groups (p<0.001); volumes were, however, not statistically different. Smaller but also statistically significant differences in T1 maps and entropy were found for white matter of the brain lobes (p<0.001). Thalami volumes showed statistically significant differences between groups, but not median T1 times (MS group 1055 ms, SD 32.6 vs. HC 1049 ms, SD 21.2).

Conclusions

Pathology of the normal-appearing white matter in T1 relaxometry can already be detected at MS disease onset. In particular, corpus callosum T1 times were considerably higher at clinical onset of MS compared to HC. We hypothesize that early microstructural changes detected at disease onset lead to evolution of regional brain atrophy.

Background

SC pathology occurs early in the course of MS. However, few studies have investigated the relationship between lesions, diffuse changes and mean upper cervical cord area (MUCCA) in MS patients with different levels of disability in detail.

Objectives

To explore spinal cord (SC) pathology in multiple sclerosis (MS) patients with different levels of disability and MS phenotypes.

Methods

638 MS patients with different degrees of disability and 102 healthy controls (HC) underwent MRI on a 3T (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The MRI protocol comprised transversal 3D-T2WI for MUCCA, sagittal T2WI-Fat-Sat and PDWI for SC pathology, and 3D-MPRAGE for regional brain volume (BV). MUCCA was measured automatically between the C3 and C4 vertebra (ScanView.cz). Global and regional BVs were estimated by the fully automated MorphoBox prototype (Siemens Healthcare, Erlangen, Germany). Diffuse changes, number and location of SC lesions were assessed manually. Patients and HC were matched by sex and age using propensity scores. MUCCA, regional BVs and SC pathology were compared among matched subgroups of: 54 patients with mild disability (EDSS=<1.5), 54 patients with mild-to-moderate disability (EDSS 2-3.5), 54 patients with severe disability (EDSS 4-4.5), 54 patients with very severe disability (EDSS>=5), 18 primary progressive (PP) patients, and 54 controls from the HC group. ANOVA test was used for between-group comparison.

Results

There was a trend of lower MUCCA with higher disability level. Mean MUCCA was 76.5±10.8 mm² invery severe, 80.1±9.6 mm² in severe, 85.7±8.0 mm² in moderate, 85.6±8.5 mm² in mild disability, and 90±7.7 mm² in HC groups. There was a significant difference in MUCCA between HC and mild disability group (p<0.001). SC pathology was prominent in 64.1% of the patients with mild disability, compared to 90.4% patients with very severe disability. The percentage of diffuse changes varied greatly between the groups, with prevalence increasing almost four times between patients with mild and very severe disability.

Conclusions

SC pathology is present in all disability MS groups. MUCCA differentiated between patients with mild disability and healthy controls, suggesting that it may be promising for the implementation in diagnostic protocols. The evaluation of diffuse changes can help to predict disability. Low MUCCA together with prominent diffuse changes could help differentiate PP MS from other MS phenotypes.

Background

Some cohort studies have reported similar onset age and disability accrual in primary and secondary progressive MS (PPMS, SPMS); others have reported later onset and faster disability accrual in SPMS. Comparisons are complicated by differences in baseline disability and exposure to disease-modifying therapies (DMT), and by lack of a standardized definition of SPMS.

Objectives

We compared hazards of disability accrual in PPMS and SPMS patients from the MSBase cohort using multivariable Cox models, applying validated diagnostic criteria for SPMS (Lorscheider et al., Brain 2016).

Methods

Inclusion required adult-onset progressive MS; ≥ 3 recorded Expanded Disability Status Scale (EDSS) scores; and, for SPMS, initial records with EDSS ≤ 3 to allow objective identification of SPMS conversion. Phenotypes were subgrouped as active (PPMS-A, SPMS-A) if ≥ 1 progressive-phase relapse was recorded, and inactive (PPMS-N, SPMS-N) otherwise. Disability accrual was defined by sustained EDSS increases confirmed over ≥ 6 months. Hazard ratios (HR) for disability accrual were obtained using Andersen-Gill Cox models, adjusted for sex and time-varying age, disability, visit frequency, and proportion of time on DMT or immunosuppressive therapy. Sensitivity analyses were performed using (1) PPMS and SPMS diagnosed since 1995, and (2) physician-diagnosed SPMS. Cumulative probability of reaching EDSS ≥ 7 (wheelchair required) was assessed (Kaplan-Meier).

Results

5461 patients were included (1257 PPMS-N; 1308 PPMS-A; 1731 SPMS-N; 1165 SPMS-A). Age at progression onset was older in SPMS than PPMS (47.2 ± 10.2, vs. 41.5 ± 10.7 [mean ± SD]), and in the inactive subgroups of each phenotype. Hazard of disability accrual was decreased in SPMS relative to PPMS (HR 0.85; 95% CI 0.78–0.92); decreased by proportion of time on DMT (HR 0.99 per 10% increment; 0.98–0.99); and higher in males (1.18; 1.12–1.25). Relative to PPMS-N, hazard was decreased in SPMS-A (0.79; 0.71–0.87) but similar for PPMS-A (1.01; 0.93–1.10) and SPMS-N (0.94; 0.85–1.05). Sensitivity analyses corroborated these results. However, patients with SPMS-A reached EDSS ≥ 7 at younger ages (cumulative probability 30% by 57, vs. 64–66 for SPMS-N, PPMS-A, PPMS-N).

Conclusions

Progressive phase onset is later in SPMS than PPMS. Hazard of disability accrual during the progressive phase is lower in SPMS than PPMS. However, patients with SPMS-A reach wheelchair requirement younger than other progressive phenotypes, reflecting earlier progression onset versus SPMS-N, and greater disability at onset versus PPMS

Background

In secondary progressive multiple sclerosis (SPMS), reduction in the rates of disability accrual after starting disease modifying therapy (DMT) has largely been limited to patients with ongoing inflammatory activity. A delayed treatment effect, termed therapeutic lag, may obscure therapeutic benefits in SPMS.

Objectives

To compare the effect of high and low efficacy DMT on disability outcomes in patients with recently active and inactive SPMS after accounting for therapeutic lag.

Methods

Using data from MSBase, a multinational MS registry, and OFSEP, the French MS registry, we identified patients with SPMS as per a previously validated objective definition. We identified patients treated with high- (natalizumab, alemtuzumab, mitoxantrone, ocrelizumab, rituximab, cladribine, fingolimod) or low-efficacy (interferons, glatiramer acetate, teriflunomide) DMT after SPMS onset. Based on our previous work, an individualised estimate of duration of therapeutic lag was calculated for each patient. Only events that occurred after the estimated therapeutic lag period were included in the analysis. Propensity score matching was used to select groups with comparable baseline characteristics. Disability and relapse outcomes were compared in paired, pairwise-censored analyses adjusted for visit density.

Results

Of 7359 patients with SPMS, 1000 patients fulfilled the criteria for study inclusion (510 active SPMS, 490 inactive SPMS). For the relapse outcomes, patients with active SPMS treated with high-efficacy DMTs experienced lower probabilities of relapses than low-efficacy DMTs (hazard ratio [HR] 0.7 [95%CI 0.5-0.9], p=0.006). Patients with inactive SPMS had similar probabilities of relapses in the high and low efficacy DMT groups (0.8 [0.6-1.2], p=0.39). No difference in the risk of 6-month sustained disability accumulation, or proportion of patients reaching EDSS>=7, was observed between groups when accounting for therapeutic lag.

Conclusions

The risk of disability accumulation in SPMS seems to be comparable in patients treated with high- and low- efficacy DMT. High efficacy DMT is superior to low efficacy therapy in reducing relapse activity in patients with active SPMS, but not those with inactive SPMS. Pre-treatment inflammatory activity, clinical or radiological, is a treatable target in SPMS which may benefit from higher-efficacy anti-inflammatory therapies.

Background

Multiple sclerosis (MS), a chronic disabling disease requiring long-term treatment and regular monitoring, is associated with negative effects on health-related quality of life (HRQoL). CLARIFY-MS (NCT03369665) aims to assess the impact of cladribine tablets (CT) 10 mg (3.5 mg/kg cumulative dose over 2 years; CT3.5) on HRQoL and treatment satisfaction in patients with highly-active relapsing MS (RMS).

Objectives

To present an interim analysis of CLARIFY-MS at 6 months after initiating treatment with CT, assessing treatment satisfaction through the Treatment Satisfaction Questionnaire for Medication (TSQM) v1.4 and safety through the collection of safety assessments in highly-active RMS patients.

Methods

CLARIFY-MS is an ongoing phase IV, open label, single arm, multicenter, 2-year study. Patients with RMS received CT3.5, with 2 weeks of active treatment per course (week 1 and 5 of each year). TSQM v1.4 was used to assess patient-reported treatment satisfaction (a score of 100 is the best possible rating). The TSQM measures 14 items across four domains: effectiveness (three items), side effects (five items), convenience (three items), and global satisfaction (three items).Treatment-emergent adverse events (TEAEs), serious adverse events (AEs), and lymphocyte counts were recorded.

Results

Treatment satisfaction: Of 554 patients screened, 482 received CT. The age and Expanded Disability Status Scale adjusted global treatment satisfaction score (95% confidence interval) at Month 6 was 70.0 (66.6–73.5). Treatment-experienced patients (prior treatment with disease-modifying drugs [DMDs]) reported similar treatment satisfaction scores to DMD-naïve patients (70.2 vs 68.7). At Month 6, >75% of patients rated the TSQM side effects score with 100. The mean side effects score was 91.9, mean convenience 86.6. Safety: 275 patients (57.1%) experienced ≥1 TEAE after drug initiation, most commonly headache and lymphopenia. Most post-baseline lymphopenias were of grade 1-2; 33 patients (6.8%) experienced grade 3 lymphopenia and no grade 4 lymphopenia was observed.

Conclusions

This interim analysis of CLARIFY-MS found that at 6 months, patients were generally satisfied with CT treatment. The convenience of CT treatment and side effect profile were especially important to patients. Safety results at 6 months post-treatment are consistent with the known safety profile, with no new emerging safety signal; most lymphopenias were grade 1-2.

Background

Disease activity has been investigated in pregnant women with RRMS treated with low-efficacy or no therapy. How newer, more efficacious therapies affect relapse and disability progression risk after pregnancy remains understudied.

Objectives

To describe disease activity in a modern pregnancy cohort contrasted with historical cohorts. To determine the predictors of postpartum relapse and the predictors of six-month confirmed disability progression events in a contemporary pregnancy cohort.

Methods

Data were obtained from the MSBase Registry. Term/preterm pregnancies conceived from 2011-2019 (modern cohort) were compared with those conceived between 2005-2010 and pre-2005. Annualised relapse rates (ARR) were calculated for each pregnancy trimester and 12 months either side. Predictors of time-to-relapse postpartum (1^st 3 months) and time to 6-month confirmed disability progression event were determined with clustered Cox regression analyses. Breastfeeding duration and time to DMT reinitiation were modelled as time-varying covariates.

Results

We included 1640 pregnancies from 1452 women (modern cohort). Disease-modifying therapy (DMT) used in the year before conception included interferon-beta (n=597), natalizumab (n=219) and fingolimod (n=147). Continuation of DMT up to conception increased over time (31% pre-2005 vs 54% modern cohort). Preconception ARR decreased across epochs (pre-2005: 0·58 [95% CI 0·49-0·70]; 2005-2010: 0·40 [95% CI 0·36-0·45]; modern: 0·29 [95% CI 0·27-0·32]). In all epochs, ARR decreased during pregnancy to reach similar troughs in the 3^rd trimester, and rebounded in the 1^st 3-months postpartum. Preconception use of high-efficacy DMT predicted early postpartum relapse (hazard ratio (HR) 2.1 [1.4-3.1]); although those on no DMT were also at risk of postpartum relapse, relative to women on low-efficacy DMT (HR 2.7 [1.2-5.9]). Conception EDSS ≥2, higher preconception and in-pregnancy ARR were also risk factors. DMT reinitiation, particularly of high-efficacy DMT (HR 0.17 [0.07-0.38]), was protective against postpartum relapse. Women who breastfed were less likely to relapse (HR 0.63 [0.42-0.94]). 4.5% of modern pregnancies had confirmed disability progression after delivery. This was predicted by higher pregnancy and postpartum ARR, with postpartum ARR remaining independently predictive in multivariable analysis (HR 1.5 [1.2-2.0]).

Conclusions

The early postpartum period remains a period of vulnerability for disease rebound in women with MS in the modern era. Early DMT reinitiation, particularly with high-efficacy treatment, is protective against postpartum relapse. Confirmed disability progression events after pregnnacy are uncommon in the modern era. Relapse activity is the key driver of these events.