Benefit-Risk of Therapies for Relapsing-Remitting Multiple Sclerosis: Testing the Number Needed to Treat to Benefit (NNTB), Number Needed to Treat to Harm (NNTH) and the Likelihood to be Helped or Harmed (LHH): A Systematic Review and Meta-Analysis

Cost-utility analysis of teriflunomide in naïve vs. previously treated patients with relapsing–remitting multiple sclerosis in Italy

Background

Multiple sclerosis (MS) accounts for 176 cases per 100,000 inhabitants (female/male ratio = 2:1) in Italy. For most of the patients (67%), the disease course is relapsing–remitting MS (RRMS).

Objective

To compare the costs and quality-adjusted life years (QALYs) of teriflunomide in RRMS naïve patients vs. RRMS patients previously treated (experienced) with other disease-modifying therapies in Italy.

Methods

A four health states Markov model-supported cost-utility analysis (CUA) covering a 7-year timespan through annual cycles was developed, following the healthcare sector and the societal viewpoints. Part of the parameters that populated the Markov model was obtained from a questionnaire administered to four primary Italian MS centres. Costs of healthcare and non-healthcare resources, expressed in euro (€) 2019, and QALYs were discounted at 3% real social discount rate. One-way, scenario and probabilistic sensitivity analyses tested the uncertainty of the baseline findings.

Results

Baseline CUA shows that teriflunomide in RRMS naïve patients is strongly dominant vs. experienced patients (healthcare sector perspective: − €1042.68 and + 0.480 QALYs; societal perspective: − €6782.81 and + 0.480 QALYs). Sensitivity analyses confirmed the robustness of the baseline results.

Conclusion

Teriflunomide in RRMS naïve vs. experienced patients is cost-effective and possibly strongly dominant from both the healthcare sector and the society viewpoints in Italy. Our findings need further confirmation from real-world studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10072-022-06022-x.

Methodological standards for conducting and reporting meta-analyses: Ensuring the replicability of meta-analyses of pharmacist-led medication review

BACKGROUND

Meta-analyses of clinical pharmacy services are frequently criticized for restricted data transparency and reproducibility.

OBJECTIVES

To describe the methodological characteristics of meta-analyses of pharmacist-led medication reviews, to identify the elements that limit their replicability and robustness, and to propose recommendations for an appropriate conduction and reporting.

METHODS

A meta-research study was conducted. Systematic searches of the PubMed, Scopus, and Web of Science databases were performed to identify meta-analyses of pharmacist services. Meta-analyses assessing the effect of pharmacist-led medication reviews were selected for data extraction, analysis and replication. Two replication exercises were performed for the two most common outcomes: (i) considering the data provided by authors to construct the meta-analysis and (ii) considering the raw data available in the primary studies included. Prediction intervals (PI), fragility index (FI), and number needed to treat (NNT) were also calculated for each replicated meta-analysis.

RESULTS

Nine studies reporting meta-analyses about pharmacist-led medication review were found comprising 30 different outcomes. Eleven meta-analyses, including six for hospital admission and five for mortality, were replicated. In five meta-analyses, the pooled effect sizes of the replicated meta-analyses differed from the original ones. Only four meta-analyses mentioned the statistical method used. Other meta-analytic parameters (e.g., q-value, tau2) were omitted in all studies. In nine meta-analyses, the data from primary studies had been incorrectly extracted for at least one variable. The PI demonstrated that the uncertainty intervals of the effect sizes were always underestimated by the authors. NNTs showed wide intervals, ranging from benefit to harm, in almost all meta-analyses. Nine recommendations to facilitate the replication of a meta-analysis were proposed: providing all original data needed to build the analysis; informing about the imputed data or data obtained from different sources; performing sensitivity analyses for imputed or unpublished data; inform about all the statistical methods used; providing all statistical results; and reporting the PI, FI and NNT.

CONCLUSION

Errors in data extraction and poor reporting of meta-analytic parameters are common in the pharmacy literature. We proposed nine recommendations to enhance data reproducibility and interpretability. Journal editors and peer reviewers should ensure that authors strictly comply with minimum standards for conduction and reporting of meta-analyses.

Effect of renin-angiotensin-aldosterone system inhibitors on all-cause mortality and major cardiovascular events in patients with diabetes: A meta-analysis focusing on the number needed to treat and minimal clinical effect

AIMS

To assess the effectiveness of renin-angiotensin-aldosterone system (RAAS) inhibitors, angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) separately to prevent all-cause mortality, myocardial infarction (MI), stroke and heart failure (HF) in patients with diabetes considering the number needed to treat (NNT) and minimal clinical effect (MCE).

METHODS

Data from 17 morbidity-mortality trials in patients with diabetes were used to calculate NNTs and evaluate MCE to prevent all-cause mortality, myocardial infarction, stroke, and heart failure.

RESULTS

A total of 17 trials involving 42,037 patients were included in this meta-analysis. Mean follow-up was 3.7 years. ACEIs significantly reduced the risk of all-cause mortality, MI and HF; the corresponding mean NNTBs were 48, 62 and 78, respectively, but ARBs were only associated with a reduction in heart failure. The clinical significance assessment of the included trials indicated that most of the statistically significant trial results had no definitive clinical significance, and only some of them had possible clinical significance.

CONCLUSIONS

Among patients with diabetes, ACEIs reduced all-cause mortality, MI and HF, whereas ARBs could only prevent HF. However, none of the results of these trials had clear clinical significance, and most had only possible clinical significance.

Persistence, adherence, healthcare resource utilisation and costs for interferon Beta in multiple sclerosis: a population-based study in the Campania region (southern Italy)

Background

To differentiate five formulations of Interferon Beta for the treatment of multiple sclerosis (MS) in clinical practice, by analysing persistence, adherence, healthcare resource utilisation and costs at population level.

Methods

In this population-based study, we included individuals with MS living in the Campania Region of Italy from 2015 to 2017, on treatment with intramuscular Interferon Beta-1a (Avonex® = 618), subcutaneous pegylated Interferon Beta-1a (Plegridy® = 259), subcutaneous Interferon Beta-1a (Rebif® = 1220), and subcutaneous Interferon Beta-1b (Betaferon® = 348; and Extavia® = 69). We recorded healthcare resource utilisation from administrative databases (hospital discharges, drug prescriptions, MS-related outpatients), and derived costs from the Regional formulary. We classified hospital admissions into MS-related and non-MS-related. Persistence (time to switch to other disease modifying treatments (DMTs)), and adherence (medication possession ratio (MPR) = medication supply obtained/medication supply expected during follow-up period) were calculated.

Results

Patients treated with Rebif® were younger, when compared with other Interferon Beta formulations (p < 0.01). The probability of switching to other DMTs was 60% higher for Betaferon®, 90% higher for Extavia®, and 110% higher for Plegridy®, when compared with Rebif® (p < 0.01). Plegridy® presented with 7% higher adherence (p < 0.01), and Betaferon® with 3% lower adherence (p = 0.03), when compared with Rebif®. The probability of MS-related hospital admissions was 40% higher in Avonex® (p = 0.03), 400% higher in Betaferon® (p < 0.01), and 60% higher in Plegridy® (p = 0.04), resulting into higher non-DMT-related costs, when compared with Rebif®.

Discussion

Interferon Beta formulations presented with different prescription patterns, persistence, adherence, healthcare resource utilisation and costs, with Rebif® being used in younger patients and with less MS-related hospital admissions.

Retrospectively acquired cohort study to evaluate the long-term impact of two different treatment strategies on disability outcomes in patients with relapsing multiple sclerosis (RE.LO.DI.MS): data from the Italian MS Register

BACKGROUND

The increase in disease-modifying drugs (DMDs) allows individualization of treatment in relapsing multiple sclerosis (RMS); however, the long-term impact of different treatment sequences is not well established. This is particularly relevant for MS patients who may need to postpone more aggressive DMD strategies.

OBJECTIVE

To evaluate different therapeutic strategies and their long-term outcomes, measured as relapses and confirmed disability progression (CDP), in MS 'real-world' settings.

METHODS

Multicentre, observational, retrospectively acquired cohort study evaluating the long-term impact of different treatment strategies on disability outcomes in patients with RMS in the Italian MS Register.

RESULTS

We evaluated 1152 RMS-naïve patients after propensity-score adjustment. Patients included were receiving: interferon beta-1a (IFN-β1a) 44 µg switching to fingolimod (FTY; IFN-switchers; n = 97); FTY only (FTY-stayers; n = 157); IFN-β1a only (IFN-stayers; n = 849). CDP and relapses did not differ between FTY-stayers and IFN-switchers [HR (95% CI) 0.99 (0.48-2.04), p = 0.98 and 0.81 (0.42-1.58), p = 0.55, respectively]. However, IFN-stayers showed increased risk of relapses compared with FTY-stayers [HR (95% CI) 1.46 (1.00-2.12), p = 0.05].

CONCLUSION

The ideal treatment option for MS is becoming increasingly complex, with the need to balance benefit and risks. Our results suggest that starting with FTY affects the long-term disease outcome similarly to escalating from IFN-β1a to FTY.

Utility of the number needed to treat in paediatric haematological cancer randomised controlled treatment trials: a systematic review

OBJECTIVES

The primary objective was to assess the utility of the number needed to treat (NNT) to inform decision-making in the context of paediatric oncology and to calculate the NNT in all superiority, parallel, paediatric haematological cancer, randomised controlled trials (RCTs), with a comparison to the threshold NNT as a measure of clinical significance.

DESIGN

Systematic review DATA SOURCES: MEDLINE, EMBASE and the Cochrane Childhood Cancer Group Specialized Register through CENTRAL from inception to August 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Superiority, parallel RCTs of haematological malignancy treatments in paediatric patients that assessed an outcome related to survival, relapse or remission; reported a sample size calculation with a delta value to allow for calculation of the threshold NNT, and that included parameters required to calculate the NNT and associated CI.

RESULTS

A total of 43 RCTs were included, representing 45 randomised questions, of which none reported the NNT. Among acute lymphoblastic leukaemia (ALL) RCTs, 29.2% (7/24) of randomised questions were found to have a NNT corresponding to benefit, in comparison to acute myeloid leukaemia (ALM) RCTs with 50% (3/6), and none in lymphoma RCTs (0/13). Only 28.6% (2/7) and 33.3% (1/3) had a NNT that was less than the threshold NNT for ALL and AML, respectively. Of these, 100% (2/2 ALL and 1/1 AML) were determined to be possibly clinically significant.

CONCLUSIONS

We recommend that decision-makers in paediatric oncology use the NNT and associated confidence limits as a supportive tool to evaluate evidence from RCTs while placing careful attention to the inherent limitations of this measure.

Enduring Clinical Value of Copaxone® (Glatiramer Acetate) in Multiple Sclerosis after 20 Years of Use

Multiple sclerosis (MS) is a chronic progressive neurodegenerative demyelinating disease affecting the central nervous system. Glatiramer acetate (GA; Copaxone®) was the first disease-modifying treatment (DMT) for MS successfully tested in humans (1977) and was approved by the US Food and Drug Administration in December 1996. Since then, there have been numerous developments in the MS field: advances in neuroimaging allowing more rapid and accurate diagnosis; the availability of a range of DMTs including immunosuppressant monoclonal antibodies and oral agents; a more holistic approach to treatment by multidisciplinary teams; and an improved awareness of the need to consider a patient's preferences and patient-reported outcomes such as quality of life. The use of GA has endured throughout these advances. The purpose of this article is to provide an overview of the important developments in the MS field during the 20 years since GA was approved and to review clinical data for GA in MS, with the aim of understanding the continued and widespread use of GA. Both drug-related (efficacy versus side-effect profile and monitoring requirements) and patient factors (preferences regarding mode of administration and possible pregnancy) will be explored.

The Effect of Disease Modifying Therapies on Disability Progression in Multiple Sclerosis: A Systematic Overview of Meta-Analyses

Background: Disease modifying therapy (DMT) efficacy trials make an essential contribution to the development of evidence-based clinical treatments and practices for people with multiple sclerosis (MS). Meta-analysis is a critical part of this process and provides a powerful tool to assess the effects of DMT on MS progression. However, although there have been several meta-analyses on the effect of DMT on MS disease progression, they often do not reach the same conclusions.

Objective: Our aim was to better understand and contextualize the results of meta-analyses evaluating DMT, identify differences in methodology that might explain their differing conclusions, and highlight areas for future research that will improve our ability to develop clinical recommendations.

Methods: We conducted an overview of systematic reviews with meta-analyses assessing the efficacy of DMT on disability progression in people with MS in PubMed (Medline) and the Cochrane Database of Systematic Reviews.

Results: We included 22 meta-analyses in this overview: eight general (on >3 DMT), 11 specific (on ≤3 DMT), 2 that evaluated subsets, and 1 that evaluated long-term effects. We found that there is good evidence that DMT improve short-term (≤2–3 years) disability progression outcomes relative to placebo in people with relapsing-remitting MS. However, results varied substantially between meta-analyses, and there is little evidence of their efficacy in other populations or over longer periods. The relative effects of individual DMT also remain unclear. The variance in results between meta-analyses may be related to the substantial differences in inclusion criteria, which was reflected in the limited overlap in included studies, as well as the year of meta-analysis publication. Of the 123 total unique studies included in the general meta-analyses, 77 (62.6%) were included in only one meta-analysis. This incongruence was also evident in the included DMT. Six of the 16 (37.5%) DMT evaluated in the general meta-analyses were only included in one meta-analysis.

Conclusions: Translating DMT efficacy studies into evidence-based clinical practice requires greater methodological consistency in meta-analyses, more data on the relative effects of DMT through head-to-head clinical trials, and better reporting of adverse events.

Oral Disease-Modifying Treatments for Relapsing Multiple Sclerosis: A Likelihood to Achieve No Evidence of Disease Activity or Harm Analysis

BACKGROUND

The likelihood to help or harm (LHH) is an absolute measure of the benefit versus risk profile of a medication, which can be used to assess the potential for benefit versus harm of different disease-modifying treatments (DMTs) for relapsing multiple sclerosis (R-MS) and facilitate clinical decision-making.

OBJECTIVE

The objective of this study was to assess absolute differences in benefit:risk ratios of oral DMTs for R-MS, using LHH analysis with no evidence of disease activity (NEDA) as beneficial outcome.

DESIGN/METHODS

The number needed to treat for a paient to achieve NEDA (NNTB_NEDA) was used as an effect size metric of efficacy and the number needed to treat for a patient  to experience  an adverse event (NNTH_AE), a serious adverse event (NNTH_SAE), or treatment discontinuation due to an adverse event (NNTH_AE-D) were used as measures of risk. The LHH-which is the ratio of NNTH:NNTB-values were calculated from published phase III trial data for oral DMTs.

RESULTS

The values for likelihood to achieve NEDA than experience any AE ratio (LHH_(AE/NEDA)) were 3.5, 6.8, 12.5 and 2.6, the likelihood to achieve NEDA than experience a SAE ratio (LHH_(SAE/NEDA)) values were 13.0, 3.5, 23.5 and 2.7, and the likelihood to achieve NEDA versus discontinue treatment (LHH_(AE-D/NEDA)) values were 17.7, 6.5, 4.6 and 3.0 for cladribine, dimethyl-fumarate, fingolimod, and teriflunomide, respectively.

CONCLUSIONS

With all of the oral DMTs examined, R-MS patients are more likely to achieve NEDA than experience any adverse event.

Benefit-risk assessment of erenumab and current migraine prophylactic treatments using the likelihood of being helped or harmed

Objective

This study evaluated the benefit-risk profile of erenumab relative to other therapies approved for migraine prophylaxis and available in the majority of European countries.

Methods

Trials were identified via a published systematic literature review updated to December 2017 using MEDLINE. Erenumab’s pivotal trials study reports were also included (NCT02066415, NCT02456740). From these sources, ≥ 50% responder rates and discontinuations due to adverse events were extracted to generate numbers needed to treat and harm and likelihood of being helped or harmed, a quantitative benefit-risk measure.

Results

Eleven articles (nine randomized clinical trials) met the inclusion/exclusion criteria. Low numbers needed to treat (range: 4–13) were observed for most treatments, while numbers needed to harm showed substantial differences (erenumab’s higher numbers needed to harm indicating better tolerability). In chronic and episodic migraine, likelihoods of being helped or harmed for erenumab 70 mg were 143 and 167, and 42 and 167 for erenumab 140 mg. Likelihoods of being helped or harmed in chronic migraine were 2 and 3 for topiramate (two studies) and 4 for onabotulinumtoxinA. In episodic migraine, likelihoods of being helped or harmed were 2 for topiramate and 2 for propranolol.

Conclusions

While all prophylactic treatments were more likely to help than harm (likelihood of being helped or harmed > 1), erenumab showed a likelihood of being helped or harmed of high magnitude, supporting its favorable benefit-risk profile across the entire migraine frequency spectrum, in contrast with other prophylactic treatments.

Alemtuzumab-Induced Thyroid Dysfunction Exhibits Distinctive Clinical and Immunological Features

CONTEXT

Alemtuzumab, a highly effective treatment for multiple sclerosis (MS), predisposes to Graves disease (GD), with a reportedly indolent course.

OBJECTIVE

To determine the type, frequency, and course of thyroid dysfunction (TD) in a cohort of alemtuzumab-treated patients with MS in the United Kingdom.

DESIGN

Case records of alemtuzumab-treated patients who developed TD were reviewed.

RESULTS

A total of 41.1% (102 out of 248; 80 female and 22 male) of patients developed TD, principally GD (71.6%). Median onset was 17 months (range 2 to 107) following the last dose, with the majority (89%) within 3 years. Follow-up data (range 6 to 251 months) were available in 71 case subjects, of whom 52 (73.2%) developed GD: 10 of these (19.2%) had fluctuating TD. All 52 patients with GD commenced antithyroid drugs (ATDs): 3 required radioiodine (RAI) due to ATD side effects, and drug therapy is ongoing in 2; of those who completed a course, 16 are in remission, 1 developed spontaneous hypothyroidism, and 30 (64%) required definitive or long-term treatment (RAI, n = 17; thyroidectomy, n = 5; and long-term ATDs, n = 8). Three cases of thyroiditis and 16 cases of hypothyroidism were documented: 5 with antithyroid peroxidase antibody positivity only, 10 with positive TSH receptor antibody (TRAb), and 1 of uncertain etiology. Bioassay confirmed both stimulating and blocking TRAb in a subset of fluctuating GD cases.

CONCLUSIONS

Contrary to published literature, we recorded frequent occurrence of GD that required definitive or prolonged ATD treatment. Furthermore, fluctuating thyroid status in GD and unexpectedly high frequency of TRAb-positive hypothyroidism suggested changing activity of TRAb in this clinical context; we have documented the existence of both blocking and stimulating TRAb in these patients.

Systematic literature review and network meta-analysis of cladribine tablets versus alternative disease-modifying treatments for relapsing-remitting multiple sclerosis

OBJECTIVE

To assess the comparative efficacy and safety of cladribine tablets versus alternative disease modifying treatments (DMTs) in patients with active relapsing-remitting multiple sclerosis (RRMS), and in a subgroup with high disease activity (HRA + DAT), using systematic literature review (SLR) and network meta-analysis (NMA).

METHODS

MEDLINE, Embase, MEDLINE In-Process and CENTRAL databases were systematically searched to identify English-language publications of relevant studies of approved DMTs for RRMS. Searches were conducted from database inception to January 2017. Conference websites and trial registries were also searched. NMA considered the effects of DMTs on annualized relapse rate (ARR), confirmed disease progression (CDP), no evidence of disease activity (NEDA) and safety.

RESULTS

Of 10,825 articles retrieved and screened, 44 studies assessing 12 DMTs contributed to the NMA. In patients with active RRMS, cladribine tablets were associated with a significant 58% reduction in ARR versus placebo (p < .05); cladribine tablets were similar or significantly better than other DMT regimens and ranked fourth among DMTs, behind alemtuzumab, natalizumab and ocrelizumab. For CDP for 6 months and NEDA, improvements with cladribine tablets were significantly greater than those of placebo (p < .05), with no comparator DMT demonstrating significantly better results. Similar findings were reported in the HRA + DAT population. Overall adverse event risk for cladribine tablets did not differ significantly from that of placebo and most alternative DMTs.

CONCLUSION

In this first NMA to consider cladribine tablets, ocrelizumab and daclizumab for treatment of RRMS, cladribine tablets are a comparatively effective and safe alternative to other DMTs in both active RRMS and HRA + DAT populations.

A 8-year retrospective cohort study comparing Interferon-β formulations for relapsing-remitting multiple sclerosis

BACKGROUND

Interferon-β has been approved for the treatment of relapsing-remitting (RR) multiple sclerosis (MS), whereas its efficacy in preventing long-term disability and conversion to secondary progressive (SP) MS is still debated. We aim to compare long-term clinical evolution of newly-diagnosed RRMS patients treated with different Interferon-β formulations.

METHODS

507 patients were included in the analysis and followed-up for 8.5 ± 3.9 years. 37.6% were treated with subcutaneous Interferon-β1a 44mcg, 33.4% with intramuscular Interferon-β1a 30mcg, and 29.0% with subcutaneous Interferon-β1b 250mcg. Relapse occurrence, 1-point EDSS progression, reaching of EDSS 4.0 and conversion to SP were recorded as outcome measures. To reduce the selection bias, we calculated the propensity score of receiving the specific treatment considering age (32.7 ± 8.3 years), gender (female 63.1%), disease duration (2.7 ± 2.8 years), and baseline EDSS (1.5, range 1.0-3.5). Propensity score and covariates (age, gender, disease duration and EDSS) were included in the statistical models.

RESULTS

At Cox regression models, the reaching of EDSS 4.0 was not-significantly higher for Interferon-β1b 250mcg (HR = 1.207; p = 0.063) and for Interferon-β1a 30mcg (HR = 1.363; p = 0.095), when compared with Interferon-β1a 44mcg. The rate of SP conversion was higher for Interferon-β1b 250mcg (HR = 2.054; p = 0.042), and not-significantly higher for Interferon-β1a 30mcg (HR = 1.884; p = 0.081), when compared with Interferon-β1a 44mcg.

CONCLUSIONS

Patients treated with Interferon-β1a 44mcg presented with a marginally reduced risk of disability accrual in the long-term, when compared with Interferon-β1b 250mcg and, at least in part, with Interferon-β1a 30mcg. Formulation, frequency of administration and dose of Interferon-β might affect the long-term clinical evolution of RRMS.

Number needed to treat (NNT) in clinical literature: an appraisal

BACKGROUND

The number needed to treat (NNT) is an absolute effect measure that has been used to assess beneficial and harmful effects of medical interventions. Several methods can be used to calculate NNTs, and they should be applied depending on the different study characteristics, such as the design and type of variable used to measure outcomes. Whether or not the most recommended methods have been applied to calculate NNTs in studies published in the medical literature is yet to be determined. The aim of this study is to assess whether the methods used to calculate NNTs in studies published in medical journals are in line with basic methodological recommendations.

METHODS

The top 25 high-impact factor journals in the "General and/or Internal Medicine" category were screened to identify studies assessing pharmacological interventions and reporting NNTs. Studies were categorized according to their design and the type of variables. NNTs were assessed for completeness (baseline risk, time horizon, and confidence intervals [CIs]). The methods used for calculating NNTs in selected studies were compared to basic methodological recommendations published in the literature. Data were analyzed using descriptive statistics.

RESULTS

The search returned 138 citations, of which 51 were selected. Most were meta-analyses (n = 23, 45.1%), followed by clinical trials (n = 17, 33.3%), cohort (n = 9, 17.6%), and case-control studies (n = 2, 3.9%). Binary variables were more common (n = 41, 80.4%) than time-to-event (n = 10, 19.6%) outcomes. Twenty-six studies (51.0%) reported only NNT to benefit (NNTB), 14 (27.5%) reported both NNTB and NNT to harm (NNTH), and 11 (21.6%) reported only NNTH. Baseline risk (n = 37, 72.5%), time horizon (n = 38, 74.5%), and CI (n = 32, 62.7%) for NNTs were not always reported. Basic methodological recommendations to calculate NNTs were not followed in 15 studies (29.4%). The proportion of studies applying non-recommended methods was particularly high for meta-analyses (n = 13, 56.5%).

CONCLUSIONS

A considerable proportion of studies, particularly meta-analyses, applied methods that are not in line with basic methodological recommendations. Despite their usefulness in assisting clinical decisions, NNTs are uninterpretable if incompletely reported, and they may be misleading if calculating methods are inadequate to study designs and variables under evaluation. Further research is needed to confirm the present findings.

Number Needed to Treat in Multiple Sclerosis Clinical Trials

Clinicians are expected to select a therapy based on their appraisal of evidence on benefit-to-risk profiles of therapies. In the management of relapsing-remitting multiple sclerosis (RRMS), evidence is typically expressed in terms of risk (proportion) of event, risk reduction, relative and hazard rate reduction, or relative reduction in the mean number of magnetic resonance imaging lesions. Interpreting treatment effect using these measures from a RRMS clinical trial is fairly reliable; however, this might not be the case when treatment effect is expressed in terms of the number needed to treat (NNT). The objective of this review is to discuss the utility of NNT in RRMS trials. This article presents an overview of the methodological definition and characteristics of NNT as well as the relative merit of NNT use in RRMS controlled clinical trials, where endpoints are typically time-to-event and frequency of recurrent events. The authors caution against using NNT in multiple sclerosis, a clinically heterogeneous disease that can change course and severity unpredictably. The authors also caution against the use of NNT to interpret results in comparative trials where the absolute risk difference is not statistically significant, computing NNT using the time-to-event endpoint at intermediate time points, computing NNT using the annualized relapse rate, and comparing NNT across trials.

Interdisciplinary Risk Management in the Treatment of Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) is the most common autoimmune disease of the central nervous system. There are at least 150 000 persons with MS in Germany. Recent years have seen the approval of new drugs against.

METHODS

This article is based on pertinent literature retrieved by a selective search in PubMed as well as on documentation of relevant risks and adverse effects in "red hand letters" (information bulletins from pharmaceutical companies to physicians about adverse drug effects) and elsewhere, along with data provided by the German Multiple Sclerosis Competence Network.

RESULTS

In recent years, there have been major advances enabling better, more individualized treatment of patients with MS. Physicians must, however, give due consideration to potentially severe or even life-threatening adverse drug effects. These can include, for example, transaminase elevation (hepatotoxicity), cardio- and nephrotoxicity, or lympho- and leukopenia with a variable risk of infection. Among patients taking natalizumab, the cumulative risk of developing progressive multifocal leukencephalopathy (PML) may be 1:100 or higher, depending on the individual risk profile. Rare cases of PML have also been seen under treatment with fingolimod and dimethyl fumarate. Moreover, any type of immunosuppressive treatment can, at least theoretically, increase the risk of malignant disease. Secondary autoimmune diseases can arise as well: approximately 35% of patients treated with alemtuzumab develop autoimmune thyroid disease within two years, and 2% of patients who take daclizumab have severe autoimmune dermatological side effects. Teriflunomide, fingolimod, natalizumab, mitoxantrone, interferon β1-a/b, and daclizumab can all damage the liver. There are also psychiatric, reproductive, and vaccineassociated risks and side effects that must be considered.

CONCLUSION

Newer drugs for MS have enabled more effective treatment, but are also associated with a higher risk of side effects. Interdisciplinary risk management is needed.