Progressive Multiple Sclerosis Trials Research Articles

Investigating the Prevalence of Comorbidity in Multiple Sclerosis Clinical Trial Populations.

Comorbidity is common in multiple sclerosis (MS) with the most prevalent conditions being depression, anxiety, hypertension, and hyperlipidemia. Limited information regarding the representation of comorbidity status is available from phase III clinical trials in MS leading to concern about the potential underrepresentation of individuals with comorbidity in clinical trials. The objective was to estimate the prevalence of comorbidities in MS clinical trial populations. Individual-level data from multiple sponsors were requested for a 2-stage meta-analysis of phase III clinical trials of MS disease-modifying therapies. To ensure consistency of our approach across trials, we followed the Maelstrom retrospective harmonization guidelines. Chronic comorbidities at clinical trial enrollment recommended by the International Advisory Committee on Clinical Trials in MS were considered (depression, anxiety, hypertension, hyperlipidemia, migraine, diabetes, chronic lung disease). Additional comorbidities were also classified. Classification was based on medical history data. Individual comorbidities were summed and categorized as 0, 1, 2, or ≥3. We report the pooled prevalence (95% confidence interval [95% CI]) of comorbidity. The pooled prevalence and prevalence ratios across age, sex, race, disability level, and treatment were also reported. Heterogeneity was assessed using the I2 statistic. Seventeen trials involving 17,926 participants were included. Fourteen trials enrolled participants with relapsing MS (RMS) while 3 enrolled participants with progressive MS (PMS). The distributions of sex, age, and disability level were generally consistent within RMS and PMS trials. When pooled, almost half of trial participants (46.5%) had ≥1 comorbidity (1: 25.0%, 95% CI 23.0-27.0, I2 = 89.9; 2: 11.4% [9.3-14.0], I2 = 96.3; ≥3: 6.0% [4.2-8.4], I2 = 97.7). Depression (16.45% [12.96-20.88], I2 = 98.3) was the most prevalent comorbidity reported, followed by hypertension (10.16% [8.61-11.98], I2 = 93.2). Heterogeneity was high across trials. Older age and female participants were associated with increased number of comorbidities. Older individuals and male participants had a higher prevalence of hyperlipidemia, while older individuals and female participants had a higher prevalence of depression and anxiety. Individuals with comorbidities are included in clinical trials, although they may still be underrepresented compared with the general MS population. Given the comorbidity prevalence in the trial populations and studies suggesting an association of comorbidities with disease activity, comorbidity may influence outcomes in clinical trials.

Recurrent disability progression endpoints in multiple sclerosis clinical trials

Background: The current standard endpoint to assess disability accumulation in multiple sclerosis (MS) clinical trials is the time to the first confirmed disability progression, which excludes subsequent progression events. Including recurrent progression events may permit a more comprehensive assessment of treatment effects on disability progression. Objective: To propose a definition of recurrent disability progression events and to compare time-to-first and recurrent event analysis. Methods: Recurrent disability progression events were defined by expanding the recommended first event definition. Marginal recurrent event methods (negative binomial model, Lin–Wei–Yang–Ying model) were compared with Cox regression in data from three randomized controlled trials in relapsing multiple sclerosis (RMS) and primary progressive multiple sclerosis (PPMS), and in simulated randomized controlled trial data. Results: The recurrent event analyses included a substantially larger number of progression events compared with the time-to-first-event analyses (+7.5% and +9.9% in the RMS trials and +22.7% in the PPMS trial). The increase in the number of events resulted in more precise treatment effect estimates and a corresponding gain in statistical power. Conclusion: Our results support the use of recurrent event data analysis, especially in progressive MS trials, to improve estimates of treatment effects, increase statistical power, and better capture the clinically meaningful long-term disability progression experience.

N-Acetyl Cysteine as a Neuroprotective Agent in Progressive Multiple Sclerosis (NACPMS) trial: Study protocol for a randomized, double-blind, placebo-controlled add-on phase 2 trial

IntroductionPatients with progressive multiple sclerosis (PMS) experience relentless disability worsening. Current approved therapies have very modest effects on disability progression and purely focus on immunomodulation. While some inflammatory processes exist in non-active PMS, other biological processes such as neuronal injury from oxidative stress are likely more critical. N-acetyl cysteine (NAC) directly scavenges free radicals and restores neuronal glutathione, a major endogenous antioxidant. Our group has recently evaluated the safety of high dose NAC in a pilot trial in PMS with no tolerability concerns. We aim now to assess the safety, tolerability, and effect of NAC on progression of several MRI, clinical and biological markers in PMS patients. MethodsThe NACPMS trial is a multi-site, randomized, double-blind, parallel-group, placebo-controlled add-on phase 2 trial. Ninety-eight PMS patients with EDSS 3.0–7.0 and aged 40–70 years will be randomized to NAC 1200 mg TID or matching placebo (1:1) as an add-on to the standard of care stratified by site and disease type during a 15-month intervention period. It is hypothesized that a reduction in oxidative stress injury will lessen brain atrophy estimated by MRI. The primary outcome analysis will compare the percent change over 12 months (Month 15 vs Month 3) between treatment and control arms using multivariable linear regression adjusted by age, sex, and disease duration. EthicsThis study was approved by the Institutional Review Board at the University of California, San Francisco (IRB21–34143), and an Investigational New Drug approval was obtained from the FDA (IND127184).Trial registration: NCT05122559.

Designing Multi-arm Multistage Adaptive Trials for Neuroprotection in Progressive Multiple Sclerosis.

There are few treatments shown to slow disability progression in progressive multiple sclerosis (PMS). One challenge has been efficiently testing the pipeline of candidate therapies from preclinical studies in clinical trials. Multi-arm multistage (MAMS) platform trials may accelerate evaluation of new therapies compared to traditional sequential clinical trials. We describe a MAMS design in PMS focusing on selection of interim and final outcome measures, sample size, and statistical considerations. The UK MS Society Expert Consortium for Progression in MS Clinical Trials reviewed recent phase II and III PMS trials to inform interim and final outcome selection and design measures. Simulations were performed to evaluate trial operating characteristics under different treatment effect, recruitment rate, and sample size assumptions. People with MS formed a patient and public involvement group and contributed to the trial design, ensuring it would meet the needs of the MS community. The proposed design evaluates 3 experimental arms compared to a common standard of care arm in 2 stages. Stage 1 (interim) outcome will be whole brain atrophy on MRI at 18 months, assessed for 123 participants per arm. Treatments with sufficient evidence for slowing brain atrophy will continue to the second stage. The stage 2 (final) outcome will be time to 6-month confirmed disability progression, based on a composite clinical score comprising the Expanded Disability Status Scale, Timed 25-Foot Walk test, and 9-Hole Peg Test. To detect a hazard ratio of 0.75 for this primary final outcome with 90% power, 600 participants per arm are required. Assuming one treatment progresses to stage 2, the trial will recruit ≈1,900 participants and last ≈6 years. This is approximately two-thirds the size and half the time of separate 2-arm phase II and III trials. The proposed MAMS trial design will substantially reduce duration and sample size compared to traditional clinical trials, accelerating discovery of effective treatments for PMS. The design was well-received by people with multiple sclerosis. The practical and statistical principles of MAMS trial design may be applicable to other neurodegenerative conditions to facilitate efficient testing of new therapies.

Spatial patterns of brain lesions assessed through covariance estimations of lesional voxels in multiple Sclerosis: The SPACE-MS technique

Predicting disability in progressive multiple sclerosis (MS) is extremely challenging. Although there is some evidence that the spatial distribution of white matter (WM) lesions may play a role in disability accumulation, the lack of well-established quantitative metrics that characterise these aspects of MS pathology makes it difficult to assess their relevance for clinical progression. This study introduces a novel approach, called SPACE-MS, to quantitatively characterise spatial distributional features of brain MS lesions, so that these can be assessed as predictors of disability accumulation. In SPACE-MS, the covariance matrix of the spatial positions of each patient’s lesional voxels is computed and its eigenvalues extracted. These are combined to derive rotationally-invariant metrics known to be common and robust descriptors of ellipsoid shape such as anisotropy, planarity and sphericity. Additionally, SPACE-MS metrics include a neuraxis caudality index, which we defined for the whole-brain lesion mask as well as for the most caudal brain lesion. These indicate how distant from the supplementary motor cortex (along the neuraxis) the whole-brain mask or the most caudal brain lesions are.We applied SPACE-MS to data from 515 patients involved in three studies: the MS-SMART (NCT01910259) and MS-STAT1 (NCT00647348) secondary progressive MS trials, and an observational study of primary and secondary progressive MS. Patients were assessed on motor and cognitive disability scales and underwent structural brain MRI (1.5/3.0 T), at baseline and after 2 years. The MRI protocol included 3DT1-weighted (1x1x1mm3) and 2DT2-weighted (1x1x3mm3) anatomical imaging. WM lesions were semiautomatically segmented on the T2-weighted scans, deriving whole-brain lesion masks. After co-registering the masks to the T1 images, SPACE-MS metrics were calculated and analysed through a series of multiple linear regression models, which were built to assess the ability of spatial distributional metrics to explain concurrent and future disability after adjusting for confounders.Patients whose WM lesions laid more caudally along the neuraxis or were more isotropically distributed in the brain (i.e. with whole-brain lesion masks displaying a high sphericity index) at baseline had greater motor and/or cognitive disability at baseline and over time, independently of brain lesion load and atrophy measures. In conclusion, here we introduced the SPACE-MS approach, which we showed is able to capture clinically relevant spatial distributional features of MS lesions independently of the sheer amount of lesions and brain tissue loss. Location of lesions in lower parts of the brain, where neurite density is particularly high, such as in the cerebellum and brainstem, and greater spatial spreading of lesions (i.e. more isotropic whole-brain lesion masks), possibly reflecting a higher number of WM tracts involved, are associated with clinical deterioration in progressive MS. The usefulness of the SPACE-MS approach, here demonstrated in MS, may be explored in other conditions also characterised by the presence of brain WM lesions.

Measuring Treatment Response in Progressive Multiple Sclerosis-Considerations for Adapting to an Era of Multiple Treatment Options.

Disability in multiple sclerosis accrues predominantly in the progressive forms of the disease. While disease-modifying treatment of relapsing MS has drastically evolved over the last quarter-century, the development of efficient drugs for preventing or at least delaying disability in progressive MS has proven more challenging. In that way, many drugs (especially disease-modifying treatments) have been researched in the aspect of delaying disability progression in patients with a progressive course of the disease. While there are some disease-modifying treatments approved for progressive multiple sclerosis, their effect is moderate and limited mostly to patients with clinical and/or radiological signs of disease activity. Several phase III trials have used different primary outcomes with different time frames to define disease progression and to evaluate the efficacy of a disease-modifying treatment. The lack of sufficiently sensitive outcome measures could be a possible explanation for the negative clinical trials in progressive multiple sclerosis. On the other hand, even with a potential outcome measure that would be sensitive enough to determine disease progression and, thus, the efficacy or failure of a disease-modifying treatment, the question of clinical relevance remains unanswered. In this systematic review, we analyzed outcome measures and definitions of disease progression in phase III clinical trials in primary and secondary progressive multiple sclerosis. We discuss advantages and disadvantages of clinical and paraclinical outcome measures aiming for practical ways of combining them to detect disability progression more sensitively both in future clinical trials and current clinical routine.

Association of Age With Contrast-Enhancing Lesions Across the Multiple Sclerosis Disease Spectrum.

To investigate the association of age and the presence of contrast-enhancing lesions (CELs) on cranial MRI scans in different disease courses of multiple sclerosis (MS), we describe the frequency of CELs as a function of age in 4 large randomized controlled trial (RCT) datasets. Using original trial data from CombiRx (Combination Therapy in Patients With Relapsing-Remitting Multiple Sclerosis; clinicaltrials.gov identifier NCT00211887), a trial in relapsing-remitting MS; ASCEND (A Clinical Study of the Efficacy of Natalizumab on Reducing Disability Progression in Participants With Secondary Progressive Multiple Sclerosis; clinicaltrials.gov identifier NCT01416181), a trial in secondary progressive MS; and the 2 primary progressive MS trials PROMISE and INFORMS; clinicaltrials.gov identifier NCT00731692), we describe the occurrence of CELs per age group at baseline for the entire trial cohort and at 1 year follow-up in the treatment arms. CombiRx included 1,008, ASCEND 889, PROMISE 943, and INFORMS 970 participants. At baseline, CEL frequency differed between datasets according to disease course: 39.6% of CombiRx, 23.9% of ASCEND, 14.0% of PROMISE, and 12.3% of INFORMS participants had CELs. This distribution by disease course was largely preserved within each age group. In all datasets, there was an almost linear decrease of the percentage of participants with CELs with advancing age. After 1 year of experimental treatment, CEL occurrence was reduced in all trial datasets, and almost absent in ASCEND. The decrease of CEL occurrence with advancing age was preserved in CombiRx, PROMISE, and INFORMS after 1 year of treatment. We investigated the association of the baseline factors age, disease duration, sex, and EDSS with having CELs at baseline with multivariable binary logistic regression models. Age was the only characteristic associated with the risk of CELs at baseline in all datasets, with higher age associated with a lower risk of CELs (odds ratios for having CELs at baseline per year increase in age: CombiRx: 0.96, 95% confidence interval [CI] 0.95-0.98; ASCEND: 0.94, 95% CI 0.92-0.97; PROMISE: 0.94, 95% CI 0.91-0.96; INFORMS: 0.97, 95% CI 0.94-0.99). Our analysis of 4 large, well-characterized RCT datasets shows that the association of age and CEL occurrence is a general phenomenon across the spectrum of MS disease courses. Our findings should be replicated in real-world MS datasets.

Patient-Centered Approach Might Effectively Tackle Progression In Chronic Neurological Diseases: Results From the EmBioProMS Trial in Progressive Multiple Sclerosis (1129)

Patient-Centered Approach Might Effectively Tackle Progression In Chronic Neurological Diseases: Results From the EmBioProMS Trial in Progressive Multiple Sclerosis (1129)

Influence of equipment changes on MRI measures of brain atrophy and brain microstructure in a placebo-controlled trial of ibudilast in progressive multiple sclerosis.

BackgroundHardware changes can be an unavoidable confound in imaging trials. Understanding the impact of such changes may play an important role in the analysis of imaging data.ObjectiveTo characterize the effect of equipment changes in a longitudinal, multi-site multiple sclerosis trial.MethodsUsing data from a clinical trial in progressive multiple sclerosis, we explored how major changes in imaging hardware affected data. We analyzed the extent to which these changes affected imaging biomarkers and the estimated treatment effects by including such changes as a time-dependent covariate.ResultsSignificant differences whole brain atrophy (brain parenchymal fraction, BPF) and microstructure (transverse diffusivity, TD) between scans with and without changes were found and depended on the type of hardware change. A switch from GE HDxt to Siemens Skyra led to significant shifts in BPF (p < 0.04) and TD (p < 0.0001). However, we could not detect the influence of hardware changes on overall trial outcomes– differences between placebo and treatment arms in change over time of BPF and TD (p > 0.5).ConclusionsThe results suggest that differences among hardware types should be considered when planning and analyzing brain atrophy and diffusivity in a longitudinal clinical trial.

Optical coherence tomography outcomes from SPRINT-MS, a multicenter, randomized, double-blind trial of ibudilast in progressive multiple sclerosis

Background: The SPRINT-MS trial demonstrated benefit of ibudilast on brain atrophy over 96 weeks in progressive multiple sclerosis (MS). Optical coherence tomography (OCT) was performed in all trial participants. Objective: Report the OCT results of the SPRINT-MS trial. Methods: OCT was obtained at baseline and every 6 months using spectral domain OCT and analyzed by an OCT reading center. Change in each OCT outcome measure by treatment group was estimated using linear mixed models. Results: Change in pRNFL thickness was +0.0424 uM/year (95% confidence interval (CI): −0.3091 to 0.3939) for ibudilast versus −0.2630 uM (95% CI: −0.5973 to 0.0714) for placebo (n = 244, p = 0.22). Macular volume change was −0.00503 mm3/year (−0.02693 to 0.01688) with ibudilast versus −0.03659 mm3/year (−0.05824 to −0.01494) for placebo in the Spectralis cohort (n = 61, p = 0.044). For the Cirrus cohort, macular volume change was −0.00040 mm3/year (−0.02167, 0.020866) with ibudilast compared to −0.02083 mm3/year (−0.04134 to −0.00033) for placebo (n = 183, p = 0.1734). Ganglion cell-inner plexiform layer thickness change, available from Cirrus, was −0.4893 uM/year (−0.9132, −0.0654) with ibudilast versus −0.9587 uM/year (−1.3677, −0.5498) with placebo (n = 183, p = 0.12). Conclusion: Retinal thinning in MS may be attenuated by ibudilast. Sample size estimates suggest OCT can be a viable outcome measure in progressive MS trials if a therapy has a large treatment effect. Trial registration: NN102/SPRINT-MS ClinicalTrials.gov number, NCT01982942.

Novel Imaging Techniques in Detection of Progressive Multiple Sclerosis

Conventional brain imaging is increasingly used to support clinicians in diagnosing and monitoring the progression of multiple sclerosis (MS). Nevertheless, the correlation between a patient's clinical manifestation and conventional magnetic resonance imaging (MRI) measures is often weak, especially in patients with progressive MS (PMS). Imaging markers for monitoring disease progression in progressive multiple sclerosis (PMS) are scarce, thereby limiting the possibility to monitor disease evolution and to test effective treatments in clinical trials. Advanced imaging techniques that have the advantage of metrics with increased sensitivity to short-term tissue changes and increased specificity to the structural abnormalities characteristic of PMS have recently been applied in clinical trials of PMS. This study conducted on 200 Egyptian patients coming to MS clinic at Al-azhar university hospitals (120 female and 80 male) diagnosed as clinically definite multiple sclerosis according to 2017McDonald criteria for Multiple Sclerosis.The survey was conducted from May 2017 till May 2019. MS patients underwent baseline and 2-year follow-up scans. All patients underwent an examination by MS specialist neurologist including evaluation of the Expanded Disability Status Scale (EDSS) score and timed 25-foot walk (T25FW). All patients received disease-modifying immunotherapy during the observation period, as was selected and prescribed by their treating physician according to routine clinical care. The data came from the combination of computational tools of image processing and neuroimaging acquired in a 1.5 Tesla scanner using different techniques: Diffusion, T2,T1, FLAIR and Structural Morphometry. Data from more than 25 brain regions of 25 healthy individuals and 200 MS patients were collected. This study assessed MRI lesions from 200 clinically well-documented MS with a mean disease duration of 5 years, of whom 10 patients were diagnosed with primary progressive MS (PPMS), 15 with secondary progressive MS (SPMS), and175 with relapsing–remitting MS (RRMS). Twelve of them had an undetermined clinical course. We analysed the heterogeneity of lesion activity and its relationship to the disease course and severity. Compared with patients who had RRMS, those with progressive MS had a higher lesion load and a higher proportion of mixed active–inactive lesions, which helped to explain their greater disease severity (a shorter time to reach an EDSS score of 6). The study demonstrated that extensive cortical damage at disease onset and during the first 2 years of disease monitoring, as assessed by the number and volume of cortical lesions and cortical atrophy, was associated with a higher relapse rate during the study and more rapid onset of a progressive phase. Most importantly, a high cortical lesion count at disease onset predicted conversion to SPMS, and the number of lesions correlated with the speed of conversion (on average 4 years earlier in patients with ≥7 cortical lesions than in those with 1–3 lesions). None of the patients without cortical lesions at baseline evolved to SPMS. Combined with data from patients with clinically isolated syndrome, which suggest that cortical lesions are specific to MS and are associated with the accrual of more severe disability, these findings support the development of standardized MRI sequences for the assessment of cortical lesions in clinical practice. The importance of grey matter involvement for long-term prognosis was also confirmed by follow-up study of 49 patients with RRMS. An MRI model that included diffusion tensor measures of grey matter damage at baseline and measures of neurodegeneration — namely, formation of new T1-hypointense lesions and changes in brain volume — during the first 15 months of follow-up allowed the prediction of long-term disability in 77.6% of the patients. In contrast to previous studies of PPMS with a shorter follow-up (2 years), spinal cord atrophy was not associated with clinical deterioration, suggesting that the processes leading to accrual of disability evolve over time. Conventional and modern magnetic-resonance-based techniques to the study of MS has improved our ability to diagnose and monitor MS, as well as our understanding of disease pathophysiology. New techniques need to be refined and validated before they can be properly integrated into clinical research and practice. New schemes and analysis procedures require standardisation and optimisation so that they can be used in multi-site settings, both in natural history studies and treatment trials. From the data available, it is evident that the combining of different magnetic resonance methods, which are sensitive to different aspects of MS pathology, is a promising way to increase further our understanding of the mechanisms underlying the accumulation of irreversible disability.

Multiple sclerosis: clinical trial design 2019.

Recent years have seen the approval of more than 15 disease-modifying drugs for multiple sclerosis (MS), mainly for its relapsing-remitting form (RRMS). The focus of the MS clinical trials is moving toward clinical trials aimed at progressive patients or based on putatively neuroprotective compounds. Here we reviewed the challenges of this paradigm shift. Progressive MS and neuroprotective drugs trials will both need a change in patients' enrollment criteria, outcome selection, and clinical trials design. Published ocrelizumab Primary Progressive MS data, as well as translational neuroimaging and clinical research suggest that MRI markers of inflammation could be used to enrich progressive MS trials population, albeit with the risk of overestimating the relevance of antiinflammatory therapeutic effects in this population and that conventional MRI-based metrics need to be complemented with volumetric and multiparametric approaches to disease severity quantification. Lastly, regarding statistical design, Bayesian approaches are at last making their way from oncology to neurology improving our ability to evaluate multiple treatments in the same trials' population. Adequate clinical trials design was one of the key factors in the RRMS treatment success story. Multidisciplinary collaborations are needed to adequately plan the progressive MS and restorative therapies trials that lay ahead in the near future.

Over three decades study populations in progressive multiple sclerosis have become older and more disabled, but have lower on-trial progression rates: A systematic review and meta-analysis of 43 randomised placebo-controlled trials

Background: Progression is the major driver of disability and cost in multiple sclerosis (MS). However, the search for treatments in progressive multiple sclerosis (PMS) has not mirrored the success in relapsing MS. Objectives: To assess changes in PMS trials over time. Methods: PubMed, MEDLINE and Embase were searched to identify randomised, double-blind, placebo-controlled trials in PMS. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used, study quality was assessed and trends were examined by regression. Results: Placebo groups of 43 studies published between 1988 and 2018 were included. The mean age at trial entry increased by 9.8 years per decade (95% confidence interval (CI): [2.7; 4.9]; p < 0.001). Mean baseline Expanded Disability Status Scale (EDSS) scores increased by 0.36 points (95% CI: [0.09; 0.62]; p = 0.009) and disease durations at baseline were prolonged by 1.8 years (95% CI: [0.7; 2.9]; p = 0.003) per decade. The trials became larger, specifically placebo groups increased by about 222 patients (95% CI: [36; 409]; p = 0.021) and 88 patients (95% CI: [12; 165]; p = 0.025) per decade for primary progressive multiple sclerosis (PPMS) and secondary progressive multiple sclerosis (SPMS), respectively. The proportion of patients on placebo experiencing disability progression within 24 months decreased by 7.6 percentage points (95% CI: [1.2; 14.1]; p = 0.022) per year. Conclusion: Over three decades, PMS trial populations changed and are now older, with a longer disease duration and more disability, with lower on-trial progression rates.

Monitoring Progressive Multiple Sclerosis with Novel Imaging Techniques.

Imaging markers for monitoring disease progression in progressive multiple sclerosis (PMS) are scarce, thereby limiting the possibility to monitor disease evolution and to test effective treatments in clinical trials. Advanced imaging techniques that have the advantage of metrics with increased sensitivity to short-term tissue changes and increased specificity to the structural abnormalities characteristic of PMS have recently been applied in clinical trials of PMS. In this review, we (1) provide an overview of the pathological features of PMS, (2) summarize the findings of research and clinical trials conducted in PMS which have applied conventional and advanced magnetic resonance imaging techniques and (3) discuss recent advancements and future perspectives in monitoring PMS with imaging techniques.

Imaging outcome measures for progressive multiple sclerosis trials

Imaging markers that are reliable, reproducible and sensitive to neurodegenerative changes in progressive multiple sclerosis (MS) can enhance the development of new medications with a neuroprotective mode-of-action. Accordingly, in recent years, a considerable number of imaging biomarkers have been included in phase 2 and 3 clinical trials in primary and secondary progressive MS. Brain lesion count and volume are markers of inflammation and demyelination and are important outcomes even in progressive MS trials. Brain and, more recently, spinal cord atrophy are gaining relevance, considering their strong association with disability accrual; ongoing improvements in analysis methods will enhance their applicability in clinical trials, especially for cord atrophy. Advanced magnetic resonance imaging (MRI) techniques (e.g. magnetization transfer ratio (MTR), diffusion tensor imaging (DTI), spectroscopy) have been included in few trials so far and hold promise for the future, as they can reflect specific pathological changes targeted by neuroprotective treatments. Position emission tomography (PET) and optical coherence tomography have yet to be included. Applications, limitations and future perspectives of these techniques in clinical trials in progressive MS are discussed, with emphasis on measurement sensitivity, reliability and sample size calculation.

Advancing trial design in progressive multiple sclerosis

The failure of a majority of clinical trials in progressive multiple sclerosis (MS) has highlighted the need to reconsider how these trials are designed and conducted, and many areas deserve focus. Basic scientists are reconceptualising the pathophysiology of progressive MS into three broad areas: systemic inflammation, compartmentalized inflammation and non-inflammatory neurodegeneration, with the latter two becoming predominant as the disease progresses. This framework will guide the choice of experimental therapies. Previous clinical trials have highlighted how participant selection can have a significant impact on study outcome. Phase 2 biomarkers which are biologically stable, dynamically changing over time, and easy to assess in multi-centre studies are greatly needed. Shortcomings inherent in the Expanded Disability Status Scale are prompting the development and validation of better clinical measures. The standard two-arm, fixed-duration trial paradigm has been challenged with new, innovative approaches that can test more therapies efficiently. International collaboratives such as the Progressive MS Alliance will support increased dialogue with regulators, industry and other funding agencies. Better engagement with people living with progressive MS will transform them from simply being the recipient of MS therapies to partners in the search for new treatments. Focused, targeted action will drive further development of effective therapies for progressive MS.

Progressive MS trials: Lessons learned

Up to very recently, no treatments had proved effective in progressive multiple sclerosis (MS). In 2016, four drugs, two tested in phase 3 and two in phase 2 trials, showed a beneficial effect in primary or secondary progressive MS. Although this could indicate a turning point in progressive MS treatment, most of these successes have been modest and mainly restricted to patients with active inflammation, in the context of trials with powerful anti-inflammatory agents. This paper summarises these reasons, particularly focusing on the main lessons learned for the design of future trials. First, a drug’s mechanism of action should tackle the specific pathogenic mechanisms that characterise progressive MS. Second, trial populations where new drugs are to be tested should be carefully chosen, possibly including younger patients with shorter disease durations, which have greater chances of showing active deterioration during the trial, therefore increasing the power to detect treatment effects. Third, outcome measures used in future phase 2 and phase 3 trials should be highly sensitive and be accompanied by smart trial designs.

Clinical trial design for progressive MS trials

The design of clinical trials is a key aspect to maximizing the possibility to detect a treatment effect. This fact is particularly challenging in progressive multiple sclerosis (PMS) studies due to the uncertainty about the right target and/or outcome in phase-2 studies. The aim of this review is to evaluate the current challenges facing the design of clinical trials for PMS. The selection of patients, the instrumental and clinical outcomes that can be used in PMS trials, and issues in their design will be covered in this report.

Clinical outcome measures for progressive MS trials

Treatment options for progressive multiple sclerosis remain the main unmet need of the field. As the understanding of multiple sclerosis (MS) pathogenesis improves, new pathways and molecules will be tested for potential reparative, remyelinating, or neuroprotective effects. The clinical outcomes used will determine successful demonstration of beneficial treatment effects to regulatory agencies, clinicians, and persons with MS. This review focuses on clinical outcome measures including the Expanded Disability Status Scale, Multiple Sclerosis Functional Composite, and novel composite measures of disability. The paper also covers cognitive outcomes and screening tests for use in clinical trials. The growing importance of patient-reported outcomes and their suitability for clinical trials is also presented. The review aims to create consensus in regard to these topics and suggestions for future research.

Fluid biomarker and electrophysiological outcome measures for progressive MS trials

Progressive multiple sclerosis (MS) is characterized by insidious clinical worsening that is difficult to accurately quantify and predict. Biofluid markers and electrophysiological measures are potential candidate outcome measures in clinical trials, allowing the quantification of nervous damage occurring in the disease. Neurofilaments are highly specific neuronal proteins. They may have come closest to such applications by their higher concentrations repeatedly demonstrated in cerebrospinal fluid (CSF) in all stages of MS, during relapses, their responsiveness to disease-modifying treatments in relapsing and progressive MS and their associations with measures of inflammatory and degenerative magnetic resonance imaging (MRI) outcomes. Digital single-molecule array (Simoa) technology improves accuracy of bioassays in the quantification of neurofilament light chain (NfL) in serum and plasma. NfL seems to mark a common final path of neuroaxonal injury independent of specific causal pathways. CSF and blood levels of NfL are highly correlated across various diseases including MS, suggesting that blood measurements may be useful in assessing response to treatment and predicting future disease activity. Other biomarkers like matrix metalloproteinases, chemokines, or neurotrophic factors have not been studied to a similar extent. Such measures, especially in blood, need further validation to enter the trial arena or clinical practice. The broadening armamentarium of highly sensitive assay technologies in the future may shed even more light on patient heterogeneity and mechanisms leading to disability in MS. Evoked potentials (EPs) are used in clinical practice to measure central conduction of central sensorimotor pathways. They correlate with and predict the severity of clinical involvement of their corresponding function. Their validation for use in multicenter studies is still lacking, with the exception of visual EPs. If further validated, EPs and fluid biomarkers would represent useful outcome measures for clinical trials, being related to specific mechanisms of the ongoing pathologic changes.