Cost-effectiveness of disease-modifying therapy for multiple sclerosis: a population-based study.

OBJECTIVE: To evaluate the cost-effectiveness of disease-modifying therapies (DMTs) in the United States compared to basic supportive therapy without DMT for patients with relapsing multiple sclerosis (MS). METHODS: Using data from a longitudinal MS survey, we generated 10-year disease progression paths for an MS cohort. We used first-order annual Markov models to estimate transitional probabilities. Costs associated with losses of employment were obtained from the Bureau of Labor Statistics. Medical costs were estimated using the Centers for Medicare and Medicaid Services reimbursement rates and other sources. Outcomes were measured as gains in quality-adjusted life-years (QALY) and relapse-free years. Monte Carlo simulations, resampling methods, and sensitivity analyses were conducted to evaluate model uncertainty. RESULTS: Using DMT for 10 years resulted in modest health gains for all DMTs compared to treatment without DMT (0.082 QALY or <1 quality-adjusted month gain for glatiramer acetate, and 0.126-0.192 QALY gain for interferons). The cost-effectiveness of all DMTs far exceeded $800,000/QALY. Reducing the cost of DMTs had by far the greatest impact on the cost-effectiveness of these treatments (e.g., cost reduction by 67% would improve the probability of Avonex being cost-effective at $164,000/QALY to 50%). Compared to treating patients with all levels of disease, starting DMT earlier was associated with a lower (more favorable) incremental cost-effectiveness ratio compared to initiating treatment at any disease state. CONCLUSION: Use of DMT in MS results in health gains that come at a very high cost.

Multicenter randomized clinical trial of donepezil for memory impairment in multiple sclerosis.

OBJECTIVES: The goal of this study was to determine if memory would be improved by donepezil as compared to placebo in a multicenter, double-blind, randomized clinical trial (RCT). METHODS: Donepezil 10 mg daily was compared to placebo to treat memory impairment. Eligibility criteria included the following: age 18-59 years, clinically definite multiple sclerosis (MS), and performance ≤ ½ SD below published norms on the Rey Auditory Verbal Learning Test (RAVLT). Neuropsychological assessments were performed at baseline and 24 weeks. Primary outcomes were change on the Selective Reminding Test (SRT) of verbal memory and the participant's impression of memory change. Secondary outcomes included changes on other neuropsychological tests and the evaluating clinician's impression of memory change. RESULTS: A total of 120 participants were enrolled and randomized to either donepezil or placebo. No significant treatment effects were found between groups on either primary outcome of memory or any secondary cognitive outcomes. A trend was noted for the clinician's impression of memory change in favor of donepezil (37.7%) vs placebo (23.7%) (p = 0.097). No serious or unanticipated adverse events attributed to study medication developed. CONCLUSIONS: Donepezil did not improve memory as compared to placebo on either of the primary outcomes in this study. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence which does not support the hypothesis that 10 mg of donepezil daily for 24 weeks is superior to placebo in improving cognition as measured by the SRT in people with MS whose baseline RAVLT score was 0.5 SD or more below average.

Assessing disability progression with the Multiple Sclerosis Functional Composite.

BACKGROUND: The initial Multiple Sclerosis Functional Composite (MSFC) proposal was a three-part composite of quantitative measures of ambulation, upper extremity function, and cognitive function expressed as a single composite Z-score. However, the clinical meaning of an MSFC Z-score change is not obvious. This study instead used MSFC component data to define a patient-specific disease progression event. OBJECTIVE: Evaluate a new method for analyzing disability progression using the MSFC. METHODS: MSFC progression was defined as worsening from baseline on scores of at least one MSFC component by 20% (MSFC Progression-20) or 15% (MSFC Progression-15), sustained for >or=3 months. Progression rates were determined using data from natalizumab clinical studies (Natalizumab Safety and Efficacy in Relapsing Remitting Multiple Sclerosis [AFFIRM] and Safety and Efficacy of Natalizumab in Combination With Interferon Beta-1a in Patients With Relapsing Remitting Multiple Sclerosis [SENTINEL]). Correlations between MSFC progression and other clinical measures were determined, as was sensitivity to treatment effects. RESULTS: Substantial numbers of patients met MSFC progression criteria, with MSFC Progression-15 being more sensitive than MSFC Progression-20, at both 1 and 2 years. MSFC Progression-20 and MSFC Progression-15 were related significantly to Expanded Disability Status Scale (EDSS) score change, relapse rate, and the SF-36 Physical Component Summary (PCS) score change. MSFC Progression-20 and MSFC Progression-15 at 1 year were predictive of EDSS progression at 2 years. Both MSFC progression end points demonstrated treatment effects in AFFIRM, and results were replicated in SENTINEL. CONCLUSION: MSFC Progression-20 and MSFC Progression-15 are sensitive measures of disability progression; correlate with EDSS, relapse rates, and SF-36 PCS; and are capable of demonstrating therapeutic effects in randomized, controlled clinical studies.

Proof of concept studies for tissue-protective agents in multiple sclerosis.

BACKGROUND: There is considerable interest in tissue-protective treatments for multiple sclerosis (MS). METHODS AND OBJECTIVES: We convened a group of MS clinical trialists and related researchers to discuss designs for proof of concept studies utilizing currently available data and assessment methods. RESULTS: Our favored design was a randomized, double-blind, parallel-group study of active treatment versus placebo focusing on changes in brain volume from a post-baseline scan (3-6 months after starting treatment) to the final visit 1 year later. Study designs aimed at reducing residual deficits following acute exacerbations are less straightforward, depending greatly on the anticipated rapidity of treatment effect onset. CONCLUSIONS: The next step would be to perform one or more studies of potential tissue-protective agents with these designs in mind, creating the longitudinal data necessary to refine endpoint selection, eligibility criteria, and sample size estimates for future trials.

Dose comparison trial of sustained-release fampridine in multiple sclerosis.

OBJECTIVE: To examine the efficacy and safety of three different doses of sustained-release fampridine in people with multiple sclerosis (MS). METHOD: This multicenter, randomized, double-blind, placebo-controlled, parallel-group study recruited 206 participants at 24 centers in the United States and Canada. After a single-blind, 2-week placebo run-in, participants were randomly assigned to receive fampridine (10, 15, or 20 mg twice daily) or placebo for 15 weeks. The primary efficacy variable was percent change in walking speed based on the timed 25-foot walk. RESULTS: Trends for increased walking speed were consistent across dose groups vs placebo, but not significant, on the prospective analysis. An increase from baseline in lower extremity strength during the 12-week stable-dose period was seen in the groups receiving 10- and 15-mg doses, compared with placebo (p = 0.018 and 0.003). There were no significant changes in other secondary assessments. Post hoc analysis revealed subsets of participants in each dose group with walking speeds during the treatment period that were consistently faster than during the nontreatment period. There were significantly more "consistent responders" in the drug-treated groups than in the placebo group (36.7% compared with 8.5%). Consistent responders showed significantly greater improvement in self-assessed ambulation on the 12-Item MS Walking Scale than did nonresponders. Fampridine was generally well tolerated. Severe and serious adverse events were more frequent at the highest dose. CONCLUSIONS: This phase 2 study suggests that a subgroup of patients, when treated with fampridine, experiences a clinically relevant improvement in walking ability, which is sustained for at least 14 weeks.

Quantitative risk-benefit analysis of natalizumab.

OBJECTIVE: To model the long-term risks and benefits of natalizumab in individuals with relapsing multiple sclerosis (MS). METHODS: We created a Markov model to evaluate treatment effects on reducing relapses and slowing disease progression using published natural history data and clinical trial results. Health changes, measured in quality-adjusted life-years (QALYs), were based on patient health preferences. Patient cohorts treated with no disease-modifying treatment, natalizumab, subcutaneous interferon beta-1a, and a theoretical "perfect" MS treatment were modeled. Sensitivity analysis was used to explore model uncertainty, including varying risks of developing progressive multifocal leukoencephalopathy (PML). RESULTS: Treatment with natalizumab resulted in 9.50 QALYs over a 20-year time horizon, a gain of 0.80 QALYs over the untreated cohort and 0.38 QALYs over interferon beta-1a. The health loss due to PML was small (-0.06 QALYs). To offset natalizumab's incremental health gain over interferon beta-1a, the risk had to increase from 1 to 7.6 PML per 1,000 patients treated over 17.9 months. The "perfect" MS treatment accumulated 10.59 QALYs over the 20-year time horizon, 1.89 QALYs above the untreated cohort. Interferon beta-1a resulted in greater QALY gains compared with natalizumab if natalizumab's relative relapse reduction was reduced from 68% to 35% or if interferon beta-1a's relative reduction was increased from 32% to 65%. CONCLUSIONS: A more than sevenfold increase in actual risk of progressive multifocal leukoencephalopathy was required to decrease natalizumab's health gain below that of interferon beta-1a, and there remains considerable room for additional gains in health (>50%) beyond those already achieved with current therapies.

Ethics of placebo-controlled clinical trials in multiple sclerosis: a reassessment.

The increasing number of established effective therapies for relapsing multiple sclerosis (MS) and emerging consensus for early treatment raise practical concerns and ethical dilemmas for placebo-controlled clinical trials in this disease. An international group of clinicians, ethicists, statisticians, regulators, and representatives from the pharmaceutical industry convened to reconsider prior recommendations regarding the ethics of placebo-controlled trials in MS. The group concluded that placebo-controlled trials can still be done ethically, with restrictions. For patients with relapsing MS for which established effective therapies exist, placebo-controlled trials should only be offered with rigorous informed consent if the subjects refuse to use these treatments, have not responded to them, or if these treatments are not available to them for other reasons (e.g., economics). Suggestions are provided to protect subject autonomy and improve informed consent procedures. Recommendations are tighter than previously suggested for placebo-controlled trials in "resource-restricted" environments where established therapies may not be available. Guidance is also provided on the ethics of alternative trial designs and the balance between study subject burden and risk, scientific rationale and interpretability of trial outcomes.

Quantifying the risks and benefits of natalizumab in relapsing multiple sclerosis.

Using published data, we quantified the risk and benefits of natalizumab in relapsing multiple sclerosis using quality-adjusted life years (QALYs) as a metric. Over the first 2 years of therapy, the negative health effects from progressive multifocal leukoencephalopathy were small (loss of 0.001 QALYs) relative to the positive effects on relapses and disability resulting in 0.033 QALYs (12 quality-adjusted days) gained. For context, we performed an analogous calculation for interferon beta-1a, which also had a net health benefit of 0.033 QALYs (12 quality-adjusted days).

Safety of rasagiline in elderly patients with Parkinson disease.

The authors examined age effects on adverse events from two randomized, controlled trials of rasagiline, comparing younger (younger than 70 years) and older (70 years and older) subjects. Older patients were more prone to serious adverse effects than younger patients, but there was no statistical interaction between age and rasagiline exposure. This absence of an age-rasagiline interaction suggests that rasagiline does not require special safety precautions for elderly subjects with Parkinson disease.

Quantitative functional measures in MS: what is a reliable change?

As a first step toward understanding which changes should be considered as meaningful, the authors assessed the reliability of quantitative functional tests on 5 consecutive days in 63 patients with MS, determining the range of measurement variability present when patients are clinically stable. Time to walk 25 feet (T25FW) and the 9-hole peg test (9HPT) varied by <20% of individual mean scores on repeated testing. Therefore, a 20% change on these tests can be considered to be the threshold that reliably indicates a true change in function for an individual.

Are quantitative functional measures more sensitive to worsening MS than traditional measures?

The authors used data collected prospectively during a multicenter trial in 133 patients with secondary progressive MS to assess the relative sensitivity of quantitative functional tests and traditional measures, including the Expanded Disability Status Scale (EDSS) and Ambulation Index. Quantitative functional measures worsened in 69% of patients during an average of 6 months of observation, whereas the Clinical Global Impression of Change worsened in 33% and the EDSS worsened in 25% of patients. These changes should be interpreted in the context of the test-retest reliability for each measure.

Quantitative assessment of motor fatigue and strength in MS.

OBJECTIVE: To determine the test-retest reliability of strength and fatigue measurements in patients with MS and in healthy control subjects, and to examine associations among motor fatigue, strength, and ambulatory impairment in MS patients. BACKGROUND: Motor fatigue, defined as the loss of the maximal capacity to generate force during exercise, and weakness are common in patients with MS. METHOD: Twenty ambulatory MS patients and 20 age- and sex-matched healthy control subjects participated in the study. Test-retest reliability was assessed in two identical testing sessions, separated by 3 to 5 days. Maximal voluntary isometric strength was determined by fixed myometry of seven muscle groups on each side. Motor fatigue was assessed using three exercise protocols: sustained maximal contractions (static fatigue), repetitive maximal contractions, and walking as far as 500 m. Four analysis models for static fatigue were examined for their test-retest reliability and their ability to discriminate between normal fatigue and pathologic fatigue from MS. RESULTS: Test-retest reliability in MS patients was excellent for isometric strength and very good for static fatigue. Test-retest reliability was lower for exercise protocols that involved repetitive contractions or ambulation. Compared with healthy control subjects, MS patients were weak in lower extremity muscles, but upper extremity strength was relatively preserved. Fatigue was greater in MS patients, even in muscles that were not clearly weak. There were no significant associations between strength and fatigue in any of the muscles tested. A fatigue analysis model based on the area under the force-versus-time curve gave the best combination of reliability and sensitivity to detect differences between MS patients and healthy control subjects. CONCLUSIONS: Strength and motor fatigue can be measured reliably in patients with MS. MS patients experience more fatigue than healthy control subjects during sustained contractions, repetitive contractions, and ambulation. Motor fatigue appears to be distinct from weakness because the degree of fatigue was not associated with the degree of weakness in individual muscles. Quantitative assessment of strength and fatigue may be useful to monitor changes in motor function over time in MS patients.

Therapy of relapsing multiple sclerosis. Treatment approaches for nonresponders.

There is increasing impetus to begin disease-modifying therapy for relapsing multiple (R-MS) early, before the development of irreversible tissue damage and resultant permanent disability. However, all of the currently-approved therapies for relapsing multiple sclerosis are only partially effective for patients as a group. Treatment failure can be due to noncompliance with therapy, intolerable adverse effects, the development of neutralizing antibodies, or non-responsive disease. Neurologists managing patients on disease-modifying therapy for R-MS must remain vigilant for these issues and take appropriate action when necessary.

Neuropsychologic status in multiple sclerosis after treatment with glatiramer.

BACKGROUND: Glatiramer acetate (Copaxone) therapy reduces clinical disease activity in relapsing-remitting multiple sclerosis (MS). OBJECTIVE: To study the effect of glatiramer therapy on neuropsychologic function as part of a randomized, placebo-controlled, multicenter trial. METHODS: Two hundred forty-eight patients with relapsing-remitting MS and mild to moderate disability (Expanded Disability Status Scale score, <5.0) were tested before and 12 and 24 months after randomization to administration of glatiramer acetate, 20 mg/d, or matching placebo. Neuropsychologic tests examined 5 cognitive domains most often disrupted in patients with MS: sustained attention, perceptual processing, verbal and visuospatial memory, and semantic retrieval. RESULTS: Baseline neuropsychologic test performance was similar in both treatment groups and was within normal range, except for impaired semantic retrieval. Mean neuropsychologic test scores were higher at 12 and 24 months than at baseline, and no differences were detected between treatment groups over time. No significant interactions were detected between treatment and either time or baseline impairment. CONCLUSIONS: Our 2-year longitudinal study showed no effect of glatiramer therapy on cognitive function in relapsing-remitting MS. Although it is possible that glatiramer therapy has no effect on cognitive function, the lack of measurable decline in cognitive function in both patient groups for 2 years limits the opportunity for glatiramer to demonstrate a therapeutic effect by minimizing such decline. Emerging treatments for MS should continue to be examined for their effect on cognitive impairment because it can be a critical determinant of disability. A greater understanding of the natural history of cognitive decline in MS is essential for a rational design of these drug trials.

The measurement of ambulatory impairment in multiple sclerosis.

The objective of this study was to examine the relationships between continuous measures of ambulatory impairment in MS patients and their ordinal counterparts. Much of the disability caused by MS is due to ambulatory impairment. The Expanded Disability Severity Scale (EDSS) and the Ambulation Index (AI) are ordinal measures of MS severity based largely on the maximal distance subjects can walk (Dmax) and the time to walk 8 m (T8), respectively. At EDSS levels 6.0 to 7.0 and AI levels 3 to 6, scores are defined more by the use of ambulatory aids, rather than by Dmax or T8. We determined Dmax (up to 500 m), T8, the EDSS score, and the AI in 237 ambulatory MS patients. The maximal distance subjects could walk and T8 were strongly related to their ordinal counterparts (Spearman r = 0.65 and 0.91, respectively), but the continuous measures showed considerable variability within EDSS and AI levels that the ordinal scales did not reflect. Most of the variability occurred at EDSS levels 6.0 to 7.0 and AI levels 3 to 6. Because the use of an aid did not clearly predict Dmax or T8, many patients in these ranges had better ambulatory function based on the continuous measures than those with less disability according to the ordinal scales. We found that Dmax and T8 provide more precise information about ambulatory impairment in MS than do the EDSS and AI, allowing better discrimination of differences between patients and potentially greater sensitivity to detect therapeutic effects in clinical trials.

Autoimmune hyperthyroidism in patients with multiple sclerosis treated with interferon beta-1b.

OBJECTIVE: To report symptomatic autoimmune hyperthyroidism developing in patients with multiple sclerosis (MS) treated with interferon beta-1b (IFN-beta-1b). REPORT OF CASES: A 44-year-old woman experienced gradually worsening fatigue, depression, and motor function several months after beginning therapy with IFN-beta-1b for MS. Graves disease associated with episodic palpitations, shortness of breath, hair loss, increased appetite, weight loss, and insomnia was confirmed with endocrinologic studies. Increased fatigue and weakness developed in a 52-year-old woman several months after starting IFN-beta-1b therapy. She also noted sweats, heat intolerance, palpitations, increased appetite, and irritability, and endocrinologic evaluation supported a diagnosis of Graves disease. CONCLUSIONS: To our knowledge, this is the first report of autoimmune thyroid disease associated with IFN-beta-1b treatment in patients with MS. Psoriasis has also been reported during interferon therapy for MS, and similar phenomena occur during interferon therapy for hepatitis C. Since some symptoms of thyroid dysfunction may be difficult to distinguish from typical MS-related symptoms, thyroid hormone levels should be checked when unexplained constitutional symptoms occur during IFN-beta-1b therapy.

Quantitative assessment of sustained-release 4-aminopyridine for symptomatic treatment of multiple sclerosis.

OBJECTIVE: To evaluate the efficacy of 4-aminopyridine sustained release (4AP SR) (fampridine, EL-970) using quantitative measures of motor function in multiple sclerosis (MS) patients. BACKGROUND: In vitro, 4AP improves conduction through demyelinated axons. A previous multicenter trial of 4AP SR using the Expanded Disability Status Scale (EDSS) as the primary outcome was unable to establish clinical efficacy. DESIGN/METHODS: Ten MS patients with stable motor deficits (EDSS 6.0-7.5) were given 4AP SR 17.5 mg bid and placebo for 1 week each in a double-blind, placebo-controlled, crossover trial. Time to walk 8 meters, time to climb four stairs, maximum voluntary isometric contraction measured quantitatively (MVICT), manual muscle testing (MMT), grip strength, EDSS, and the patient's global impression were measured. RESULTS: Timed gait was improved on 4AP SR compared with placebo in 9 of 10 subjects (p = 0.02). Timed stair climbing, MVICT, MMT, grip strength, and EDSS showed nonsignificant improvements on 4AP SR. Based on their global impressions, seven subjects preferred 4AP SR over placebo; only one preferred placebo. There were no serious side effects. CONCLUSION: 4AP SR improved motor function in MS patients. The quantitative outcomes used in this study permit more sensitive evaluation of the therapeutic effect and promise to be useful in future trials of symptomatic treatments for MS.