Selecting informative patients for phase 2 progressive trials in MS: Design considerations for phase 2 clinical trials in progressive MS.

While relapsing-remitting multiple sclerosis (MS) has many therapeutic options, progressive forms of MS remain largely untreatable. Phase 2 clinical trials are our main tool to advance new treatments for progressive MS. Given the complexities of progressive MS, it will likely require many phase 2 trials to improve its treatment. To conduct informative and efficient phase 2 trials, it is important that such trials are designed in a way that they can identify a successful treatment as quickly and with as few participants as possible. In this topical review, we discuss cohort selection, outcome selection, cohort enrichment, and dosing selection as strategies to optimize the efficiency of phase 2 clinical trials in progressive MS.

Aging is associated with reduced inflammatory disease activity independent of disease duration in relapsing multiple sclerosis trial populations.

BACKGROUND: Higher age is associated with less inflammatory disease activity in relapsing-remitting multiple sclerosis (RRMS). It is unknown whether age itself or disease duration underlies this association. OBJECTIVES: This study investigated the effects of age, disease duration, and inflammatory disease activity in people with RRMS. METHODS: Individual patient-level data from five large phase III randomized controlled trials (RCTs) was utilized to investigate the association of both age and disease duration with annualized relapse rate (ARR), contrast-enhancing lesions (CELs), and new T2 lesions on magnetic resonance imaging (MRI) at baseline and follow-up. RESULTS: The data set included 5626 participants. Higher age was associated with lower ARRs, lower CEL number on MRI at baseline and follow-up, and lower new T2 lesion numbers at follow-up. This effect was present in all disease duration groups. For example, we found a lower number of new T2 lesions on MRI during follow-up in higher age groups compared to lower age groups, independent of disease duration. CONCLUSION: Aging in RRMS is associated with a lower risk of inflammatory disease activity, across different disease durations. Age should be taken into account when designing clinical trials and future research should investigate how age should be integrated into personalized predictions of treatment response and risk profiling.

Relapse recovery in relapsing-remitting multiple sclerosis: An analysis of the CombiRx dataset.

BACKGROUND: Clinical relapses are the defining feature of relapsing forms of multiple sclerosis (MS), but relatively little is known about the time course of relapse recovery. OBJECTIVE: The aim of this study was to investigate the time course of and patient factors associated with the speed and success of relapse recovery in people with relapsing-remitting MS (RRMS). METHODS: Using data from CombiRx, a large RRMS trial (clinicaltrials.gov identifier NCT00211887), we measured the time to recovery from the first on-trial relapse. We used Kaplan-Meier survival analyses and Cox regression models to investigate the association of patient factors with the time to unconfirmed and confirmed relapse recovery. RESULTS: CombiRx included 1008 participants. We investigated 240 relapses. Median time to relapse recovery was 111 days. Most recovery events took place within 1 year of relapse onset: 202 of 240 (84%) individuals recovered during follow-up, 161 of 202 (80%) by 180 days, and 189 of 202 (94%) by 365 days. Relapse severity was the only factor associated with relapse recovery. CONCLUSION: Recovery from relapses takes place up to approximately 1 year after the event. Relapse severity, but no other patient factors, was associated with the speed of relapse recovery. Our findings inform clinical practice and trial design in RRMS.

Threshold definitions for significant change on the timed 25-foot walk and nine-hole peg test in primary progressive multiple sclerosis.

BACKGROUND AND PURPOSE: The timed 25-foot walk (T25FW) and nine-hole peg test (NHPT) exhibit random variability in the short term. A threshold of ≥20% change from baseline has been used to indicate true disability change, but other threshold definitions may be better suited to exclude false and include true change events. The aim of this study was to use patient-level original trial data to investigate the short-term variation in T25FW and NHPT, and to compare its extent with disability change at 12-month follow-up in people with primary progressive multiple sclerosis (PPMS). METHODS: We used original patient-level data from PROMISE, a large PPMS trial. In this trial, three separate T25FW and NHPT measurements were performed 1 week apart during screening. We used these repeated measures to describe the extent of short-term variation. We used binary logistic regression models to investigate the association between screening characteristics and unacceptable short-term variation. RESULTS: The traditional 20% threshold excluded a reasonable number of false change events, while also yielding a large number of change events at follow-up. Increasing index values on the T25FW and NHPT were associated with higher short-term variation. CONCLUSIONS: The traditional ≥20% change threshold for the T25FW and NHPT represents a reasonable compromise between reducing the number of false change events and achieving the largest number of change events in people with PPMS. Our analyses inform the design of clinical trials in PPMS.

Hydroxychloroquine for Primary Progressive Multiple Sclerosis.

OBJECTIVE: Primary progressive multiple sclerosis (PPMS) does not respond well to immunomodulatory or immunosuppressive treatment. Chronic activation of microglia has been implicated in the pathophysiology of PPMS. The antimalarial drug hydroxychloroquine (HCQ) reduces the activity of human microglia and has neuroprotective effects in vitro. METHODS: We conducted a single-arm, phase II futility trial of 200 mg oral HCQ twice daily for 18 months. In an effort to investigate disability worsening in the absence of overt focal inflammation, we excluded participants with contrast enhancing lesions on a screening magnetic resonance imaging (MRI). The primary end point was ≥20% worsening on the timed 25-foot walk measured between 6 and 18 months of follow-up. RESULTS: Based on original trial data, 40% of the cohort were expected to worsen. We used a Simon 2-stage design to compare a null hypothesis of 40% of the cohort worsening against the one-sided alternative of 20%. Using a 5% type 1 error rate and 80% power, HCQ treatment would be deemed successful if fewer than 10 of 35 participants experienced clinically significant worsening. The study met its primary end point, as only 8 of 35 participants worsened between 6 and 18 months. HCQ was overall well-tolerated, with adverse events in 82% and serious adverse events in 12% of participants. All serious adverse events were unlikely related to HCQ use. INTERPRETATION: HCQ treatment was associated with reduced disability worsening in people with PPMS. HCQ is a promising treatment candidate in PPMS and should be investigated further in randomized controlled clinical trials. ANN NEUROL 2021;90:940-948.

MRI brain volume loss, lesion burden, and clinical outcome in secondary progressive multiple sclerosis.

BACKGROUND: Magnetic resonance imaging (MRI) of brain volume measures are widely used outcomes in secondary progressive multiple sclerosis (SPMS), but it is unclear whether they are associated with physical and cognitive disability. OBJECTIVE: To investigate the association between MRI outcomes and physical and cognitive disability worsening in people with SPMS. METHODS: We used data from ASCEND, a large randomized controlled trial (n = 889). We investigated the association of change in whole brain and gray matter volume, contrast enhancing lesions, and T2 lesions with significant worsening on the Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk (T25FW), Nine-Hole Peg Test (NHPT), and Symbol Digit Modalities Test (SDMT) with logistic regression models. RESULTS: We found no association between MRI measures and EDSS or SDMT worsening. T25FW worsening at 48 and 96 weeks, and NHPT worsening at 96 weeks were associated with cumulative new or newly enlarging T2 lesions at 96 weeks. NHPT worsening at 48 and 96 weeks was associated with normalized brain volume loss at 48 weeks, but not with other MRI outcomes. CONCLUSION: The association of standard MRI outcomes and disability was noticeably weak and inconsistent over 2 years of follow-up. These MRI outcomes may not be useful surrogates of disability measures in SPMS.

The MSIS-29 and SF-36 as outcomes in secondary progressive MS trials.

BACKGROUND: Patient-reported outcome measures (PROMs) are often used in clinical research, but little is known about their performance as longitudinal outcomes. METHODS: We used data from ASCEND, a large SPMS trial (n = 889), to investigate changes on the Short Form Health Survey 36 (SF-36 v2) and the Multiple Sclerosis Impact Scale (MSIS-29) over 2 years of follow-up. RESULTS: PROM scores changed little over the 2 years of follow-up. In contrast to physical disability measures, there was no consistent trend in PROM change: significant worsening occurred about as often as improvement. Using a 6-month confirmation reduced the number of both worsening and improvement events without altering their relative balance. There was no clear difference in worsening events in groups based on population characteristics, nor was there a noticeable effect using different thresholds for clinically significant change. CONCLUSION: We found little consistent change in MSIS-29 and SF-36 over 2 years of follow-up in people with SPMS. Our findings show a disconnect between disability worsening and PROM change in this population. Our findings raise caution about the use of these PROMs as primary outcome measures in SPMS trials and call for a critical reappraisal of the longitudinal use of these measures in SPMS trials.

Early first-line treatment response and subsequent disability worsening in relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: Treatment success in relapsing-remitting multiple sclerosis (RRMS) is generally determined using relapse frequency and magnetic resonance imaging (MRI) activity in the first 6 or 12 months on treatment. The association of these definitions of short-term treatment success with disability worsening and disease activity in the longer term is unclear. In this study, we investigated risk factors associated with early first-line treatment failure in RRMS, and the association of early treatment failure with subsequent disability worsening or "no evidence of disease activity" (NEDA-3) status. METHODS: We used data from CombiRx (clinicaltrials.gov identifier NCT00211887) to investigate risk factors associated with early treatment failure, and the association of early treatment failure at 6 and 12 months with subsequent disability worsening or NEDA-3 at 36 months. RESULTS: CombiRx included 1008 treatment-naïve participants with RRMS, who were randomly assigned to treatment with glatiramer acetate, interferon beta, or the combination of both. Early treatment failure at 6 or 12 months by several definitions was associated with NEDA-3 failure at 36 months, but not with subsequent disability worsening at 36 months. Expanded Disability Status Scale (EDSS) was the only baseline characteristic associated with the risk of disability worsening at 36 months. Approximately 70% of NEDA-3 failures occurred due to MRI activity, and <10% occurred due to EDSS worsening. CONCLUSIONS: Our investigation shows that current definitions of early treatment failure in RRMS are unrelated to patient-relevant disability worsening at 36 months of follow-up. Further research into useful definitions of treatment success and failure in RRMS is needed.

An enrichment strategy for clinical trials in SPMS.

BACKGROUND: We recently compared clinical outcomes in secondary progressive MS (SPMS) clinical trials and found an association of timed 25 foot walk (T25FW) worsening events and baseline disability scores. It is unclear whether disability worsening in clinical trials is comparable to that seen in clinical practice. OBJECTIVE: The objective of this study is to compare disability worsening between the IMPACT and ASCEND data sets and data from the Calgary MS clinic and to characterize the association of baseline T25FW and expanded disability status scale (EDSS) scores with disability worsening. METHODS: We combined the three data sets and investigated the impact of baseline characteristics on disability worsening with a logistic regression model. We calculated T25FW, EDSS, and 'EDSS or T25FW' worsening events as a function of ascending cut-off baseline disability scores. RESULTS: Data source was not associated with T25FW worsening at 12 months. There was a strong association of baseline T25FW and EDSS cut-off scores with T25FW worsening. No such association was present for the EDSS and 'EDSS or T25FW'. CONCLUSION: Our results suggest that it is possible to 'enrich' a trial cohort for expected T25FW worsening events using specific baseline T25FW and EDSS cut-off scores. These analyses inform the selection of inclusion criteria for clinical trials in SPMS.

A comparison of clinical outcomes in PPMS in the INFORMS original trial data set.

BACKGROUND: The expanded disability status scale (EDSS) is the standard clinical outcome measure in primary progressive multiple sclerosis (PPMS), even though the timed 25-foot walk (T25FW), nine-hole peg test (NHPT) or combinations of these measures may be more useful. The paced auditory serial addition test (PASAT) is a widely used cognitive measure in MS, but little is known about change in PASAT scores over time in PPMS. OBJECTIVE: The objective of this study is to compare clinical outcome measures in a large PPMS trial data set. METHODS: We determined significant worsening events on the EDSS, T25FW and NHPT, and PASAT scores over the course of this 3-year trial. We compared unconfirmed, confirmed and sustained disability worsening and contrasted disability worsening with similarly defined improvement. We examined the association of baseline characteristics with the risk of disability worsening at 12, 24 and 36 months with logistic regression models. RESULTS: The EDSS and T25FW showed most worsening events, while only few patients worsened on the NHPT. Adding the NHPT to a combined outcome added only few further worsening events. PASAT scores slightly increased over time, possibly due to a practice effect. CONCLUSION: Both the EDSS and T25FW, but not NHPT or PASAT, appear to be useful outcome measures in PPMS.

Is the Symbol Digit Modalities Test a useful outcome in secondary progressive multiple sclerosis?

BACKGROUND: It is unclear which cognitive outcome measure is the most useful for clinical trials in multiple sclerosis. To investigate the usefulness of the Symbol Digit Modalities Test (SDMT) as a clinical outcome measure in secondary progressive multiple sclerosis (SPMS), we describe the frequency of worsening and improvement events in a large randomized controlled trial (RCT) dataset. METHODS: Using original trial data from the ASCEND trial (n = 889), a recent large RCT in SPMS, we describe worsening and similarly defined improvement with and without 3-month confirmation on the SDMT in the whole trial cohort and unconfirmed worsening and improvement on the Paced Auditory Serial Addition Test (PASAT) in a smaller subset (n = 107). RESULTS: Somewhat unexpectedly, SDMT scores steadily increased throughout the 2 years of follow-up in this trial. There were overall few SDMT worsening events throughout the trial (generally fewer than 10% of participants), but improvement events steadily increased from around 50% of participants with improvement at 12 weeks to more than 70% at 84 weeks and beyond. PASAT scores followed a similar pattern. CONCLUSIONS: In this well-characterized clinical trial cohort, the SDMT does not reflect the steady cognitive decline that patients with SPMS experience. Both SDMT and PASAT scores improve throughout follow-up, possibly due to a practice effect. The SDMT may not be a useful outcome measure of disease progression in 2-year clinical trials in SPMS.

Clinical outcome measures in SPMS trials: An analysis of the IMPACT and ASCEND original trial data sets.

BACKGROUND: Still too little is known about the natural history of clinical outcome measures beyond the Expanded Disability Status Scale (EDSS), such as the timed 25-foot walk (T25FW) and nine-hole peg test (9HPT) in secondary progressive multiple sclerosis (SPMS). OBJECTIVE: To describe progression on the EDSS, T25FW, 9HPT, and their combinations. To investigate the association of the baseline characteristics age, sex, EDSS, T25FW, gadolinium-enhancing lesions, and relapse activity with EDSS and T25FW progression. METHODS: Using original trial data from the placebo arms of the IMPACT and ASCEND randomized controlled trials, we describe disability progression (with and without 3- or 6-month confirmation). We investigated the association of selected baseline characteristics with EDSS and T25FW progression over 2 years using binary logistic regression. RESULTS: T25FW was the single outcome measure with the largest proportion of patients progressing, followed by EDSS and 9HPT. EDSS and T25FW at baseline were associated with EDSS and T25FW progression in both data sets. Age and relapse activity were only mild and inconsistent predictors, while sex and gadolinium enhancement at baseline did not predict disability progression in either data set. CONCLUSION: Our analyses inform the selection of primary outcome measures as well as inclusion criteria for clinical trials in SPMS.

The natural history of early versus late disability accumulation in primary progressive MS.

BACKGROUND: Primary progressive multiple sclerosis (PPMS) is the least common MS disease course and carries the worst prognosis. In relapsing-remitting multiple sclerosis (RRMS) disability accumulation occurs in two distinct phases, but it is unclear whether this is also true for PPMS. Here we investigate factors associated with early and late disability accumulation in PPMS. METHODS: We used Kaplan-Meier survival analyses and Cox regression to investigate the influence of sex, age at disease onset and onset symptoms on time to, and age at, Expanded Disability Status Scale (EDSS) 4 and 6, as well as the time from EDSS 4 to 6 in patients with PPMS. RESULTS: We identified 500 patients with PPMS. The analyses on time to EDSS 4 included 358 patients, and those on time to EDSS 6 included 392 patients. The median times to EDSS 4 and EDSS 6 were 5 and 9 years. The analyses on age at EDSS 4 included 360 patients, and those on age at EDSS 6 included 402 patients. The median ages at EDSS 4 and EDSS 6 were 51 and 55 years. Older age at onset and bilateral motor onset symptoms were independently associated with a shorter time to both EDSS 4 and EDSS 6. Sex and other onset symptoms were not associated with time to, or age at, landmark disability. Only age at onset was significantly associated with the time from EDSS 4 to EDSS 6. CONCLUSIONS: Age at disease onset is the most important predictor of disability accumulation in PPMS. Bilateral motor onset symptoms were associated with quicker disease progression. In contrast to RRMS, we found no evidence for distinct phases of disability accumulation in PPMS. Disability accumulation in PPMS appears to be affected by the same factors throughout its course.

Depression in multiple sclerosis: a long-term longitudinal study.

BACKGROUND: Depression is a common comorbidity in multiple sclerosis (MS), but little is known about its long-term prognosis. Depression in the general population is usually episodic with relatively short-lasting depressive episodes. In this study we investigate the long-term prognosis of depression in MS. METHODS: Using data from a large longitudinal observational study and from the Calgary MS clinic database, we investigated changes in Center for Epidemiological Studies Depression Scale (CESD) scores in MS patients over four years of follow-up. We used logistic regression to investigate the association of the factors sex, age, disease duration, Expanded Disability Status Scale (EDSS), depression at baseline, and antidepressant use with depression at each year of follow-up. RESULTS: CESD scores remained largely stable, or decreased slightly over four years of follow-up, whereas EDSS scores steadily increased. Depression at baseline was the strongest predictor of depression at follow-up; the other factors were not or not consistently associated with depression at follow-up. As expected, antidepressant use was associated with a greater risk of depression at follow-up. Starting and stopping antidepressant treatment during follow-up was not associated with the risk of depression at follow-up or with significant change in CESD scores. CONCLUSION: In contrast to depression in the general population, depression in MS is largely chronic, which suggests a different pathophysiology.

Cerebral white matter blood flow and energy metabolism in multiple sclerosis.

BACKGROUND: Cerebral blood flow (CBF) is reduced in normal-appearing white matter (NAWM) of subjects with multiple sclerosis (MS), but the underlying mechanism is unknown. OBJECTIVE: The objective of this article is to assess the relationship between reduced NAWM CBF and both axonal mitochondrial metabolism and astrocytic phosphocreatine (PCr) metabolism. METHODS: Ten healthy controls and 25 MS subjects were studied with 3 Tesla magnetic resonance imaging. CBF was measured using pseudo-continuous arterial spin labeling. N-acetylaspartate/creatine (NAA/Cr) ratios (axonal mitochondrial metabolism) were obtained using (1)H-MR spectroscopy and PCr/ß-ATP ratios using (31)P-MR spectroscopy. In centrum semiovale NAWM, we assessed correlations between CBF and both NAA/Cr and PCr/ß-ATP ratios. RESULTS: Subjects with MS had a widespread reduction in CBF of NAWM (centrum semiovale, periventricular, frontal and occipital), and gray matter (frontoparietal cortex and thalamus). Compared to controls, NAA/Cr in NAWM of the centrum semiovale of MS subjects was decreased, whereas PCr/ß-ATP was increased. We found no correlations between CBF and PCr/ß-ATP. CBF and NAA/Cr correlated in controls (p = 0.02), but not in MS subjects (p = 0.68). CONCLUSIONS: Our results suggest that in MS patients there is no relationship between reduced CBF in NAWM and impaired axonal mitochondrial metabolism or astrocytic PCr metabolism.

Incidence and prevalence of multiple sclerosis in Europe: a systematic review.

BACKGROUND: Multiple sclerosis (MS) is the most common cause of neurological disability in young adults worldwide and approximately half of those affected are in Europe. The assessment of differential incidence and prevalence across populations can reveal spatial, temporal and demographic patterns which are important for identifying genetic and environmental factors contributing to MS. However, study methodologies vary and the quality of the methods can influence the estimates. This study aimed to systematically review European studies of incidence and prevalence of MS and to provide a quantitative assessment of their methodological quality. METHODS: A comprehensive literature search was performed to obtain all original population-based studies of MS incidence and prevalence in European populations conducted and published between January 1985 and January 2011. Only peer-reviewed full-text articles published in English or French were included. All abstracts were screened for eligibility and two trained reviewers abstracted the data and graded the quality of each study using a tool specifically designed for this study. RESULTS: There were 123 studies that met the inclusion criteria. The study estimates were highly heterogeneous, even within regions or countries. Quality was generally higher in the more recent studies, which also tended to use current diagnostic criteria. Prevalence and incidence estimates tended to be higher in the more recent studies and were higher in the Nordic countries and in northern regions of the British Isles. With rare exceptions, prevalence and incidence estimates were higher in women with ratios as high as 3:1. Few studies examined ethnicity. Epidemiological data at the national level was uncommon and there were marked geographical disparities in available data, with large areas of Europe unrepresented and other regions well-represented in the literature. Only 37% of the studies provided standardized estimates. CONCLUSIONS: Despite the breadth of the literature on the epidemiology of MS in Europe, inter-study comparisons are hampered by the lack of standardization. Further research should focus on regions not yet studied and the evaluation of ethnic differences in MS prevalence and incidence. National-level studies using current diagnostic criteria, validated case definitions and similar age- and sex-standardization would allow better geographical comparisons.

The nine hole peg test as an outcome measure in progressive MS trials.

BACKGROUND: The nine-hole peg test (NHPT) is the outcome measure with the least change in secondary and primary progressive MS (SPMS and PPMS) trials. The Standard NHPT is defined as the average of four measurements, two in each hand. Little is known about the performance of alternative NHPT scoring methods as longitudinal outcome measures in progressive MS. Non-ambulatory people with progressive MS are now generally excluded from clinical trials, and there is little information on longitudinal NHPT change in this patient group. In this investigation, we used patient-level data from two large randomized controlled trials in progressive MS to explore alternative NHPT scoring methods and NHPT change in non-ambulatory people with progressive MS. METHODS: We used patient-level data from the ASCEND (SPMS, n = 889) and PROMISE (PPMS, n = 943) clinical trials to compare significant change on the Standard NHPT with the alternatives dominant hand (DH), non-dominant hand (NDH), and either hand (EH) NHPT in ambulatory and non-ambulatory trial participants. RESULTS: The Standard NHPT changed slowly and showed few worsening events, as did the DH and NDH alternatives. Using the EH NHPT resulted in a substantial increase of worsening events. Non-ambulatory trial participants with PPMS experienced more NHPT worsening than ambulatory participants, especially when using the EH NHPT. CONCLUSION: Using the EH NHPT yielded substantially more worsening events in people with progressive MS. Clinical trials in non-ambulatory people may be possible with the NHPT as the primary outcome measure. More research into the precision of these measures in this patient group is necessary.

Longitudinal Changes in Cognitive Test Scores in Patients With Relapsing-Remitting Multiple Sclerosis: An Analysis of the DECIDE Dataset.

BACKGROUND AND OBJECTIVES: Cognitive impairment is a common and impactful symptom of relapsing-remitting multiple sclerosis (RRMS). Cognitive outcome measures are often used in cross-sectional studies, but their performance as longitudinal outcome measures in clinical trials is not widely researched. In this study, we used data from a large clinical trial to describe change on the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test (PASAT) over up to 144 weeks of follow-up. METHODS: We used the data set from DECIDE (clinicaltrials.gov identifier NCT01064401), a large randomized controlled RRMS trial to describe change on the SDMT and PASAT over 144 weeks of follow-up. We compared change on these cognitive outcomes with change on the timed 25-foot walk (T25FW), a well-established physical outcome measure. We investigated several definitions for clinically meaningful change: any change, 4-point change, 8-point change, and 20% change for the SDMT, any change, 4-point change, and 20% change for the PASAT, and 20% change for the T25FW. RESULTS: DECIDE included 1,814 trial participants. SDMT and PASAT scores steadily improved throughout follow-up: the SDMT from a mean 48.2 (SD, 16.1) points at baseline to 52.6 (SD 15.2) at 144 weeks and the PASAT from 47.0 (SD 11.3) at baseline to 50.0 (SD 10.8) at 144 weeks. This improvement in scores is most likely due to a practice effect. Throughout the trial, participants were more likely to experience improvement than worsening of their SDMT and PASAT performance, whereas the number of worsening events on the T25FW steadily increased. Changing the definition of clinically meaningful change for the SDMT and PASAT or using a 6-month confirmation changed the overall number of worsening or improvement events but did not affect the overall behavior of these measures. DISCUSSION: Our findings suggest that the SDMT and PASAT scores do not accurately reflect the steady cognitive decline that people with RRMS experience. Both outcomes show postbaseline increases in scores, which complicates the interpretation of these outcome measures in clinical trials. More research into the size of these changes is needed before recommending a general threshold for clinically meaningful longitudinal change.

Smoking, obesity, and disability worsening in PPMS: an analysis of the INFORMS original trial dataset.

BACKGROUND: Smoking and obesity are recognized modifiable risk factors associated with a higher MS incidence, but their impact on physical and cognitive disability worsening is less clear. OBJECTIVE: To investigate the impact of smoking and obesity on disability worsening in primary progressive MS (PPMS). METHODS: We used data from INFORMS (clinicaltrials.gov identifier: NCT00731692), a large randomized-controlled trial in PPMS to compare significant worsening on the EDSS, T25FW, NHPT, and PASAT between smokers and non-smokers, and between BMI groups, at 12, 24, and 33 months of follow-up. We investigated the association of smoking and BMI at screening and the risk of disability worsening with logistic regression models. RESULTS: Smokers had significantly higher EDSS scores throughout the trial. EDSS was not significantly different between BMI categories. No other outcome measure was significantly different between smokers and non-smokers and between BMI categories throughout the trial. Neither smoking status nor BMI were associated with significant worsening on any outcome measure at any time point during follow-up. CONCLUSION: Despite the known effects on MS incidence, smoking and BMI were not associated with the risk of physical and cognitive disability worsening over 3 years in this well-characterized PPMS trial cohort.

The timed 25-foot walk is a more sensitive outcome measure than the EDSS for PPMS trials: an analysis of the PROMISE clinical trial dataset.

BACKGROUND: Clinical trials in primary progressive MS (PPMS) generally use the Expanded Disability Status Scale (EDSS) as their primary outcome measure, although different clinical outcomes may be more useful. Disability worsening in PPMS trials may be influenced by baseline factors, such as age, sex, and contrast-enhancing lesions. METHODS: We used the dataset of PROMISE, a large randomized controlled trial of glatiramer acetate (GA) versus placebo, to compare the clinical outcomes EDSS, timed 25-foot walk (T25FW), and nine-hole peg test (NHPT). We used Cox regression analyses to investigate the association of the baseline factors age, sex, treatment arm, contrast-enhancing lesions (CELs), and EDSS on the time to 3-month confirmed disability worsening (3MCDW) on the EDSS and the T25FW. RESULTS: PROMISE included 943 participants. Worsening on the T25FW or EDSS or occurred much more frequently than on the NHPT. Having CELs at baseline was associated with a shorter time to 3MCDW on both the EDSS and T25FW. An additional resampling experiment using the PROMISE dataset showed that increasing representation of participants with CELs at baseline increases the likelihood of having a positive trial result in favor of GA treatment. CONCLUSION: Our investigation suggests that the T25FW may be a more useful primary outcome measure than the EDSS in PPMS trials, and that its use may shorten clinical trials. Our findings on the impact of CELs at baseline on disability outcomes inform the critical appraisal of clinical trials in PPMS.