Impact of methodological choices in comparative effectiveness studies: application in natalizumab versus fingolimod comparison among patients with multiple sclerosis.

BACKGROUND: Natalizumab and fingolimod are used as high-efficacy treatments in relapsing-remitting multiple sclerosis. Several observational studies comparing these two drugs have shown variable results, using different methods to control treatment indication bias and manage censoring. The objective of this empirical study was to elucidate the impact of methods of causal inference on the results of comparative effectiveness studies. METHODS: Data from three observational multiple sclerosis registries (MSBase, the Danish MS Registry and French OFSEP registry) were combined. Four clinical outcomes were studied. Propensity scores were used to match or weigh the compared groups, allowing for estimating average treatment effect for treated or average treatment effect for the entire population. Analyses were conducted both in intention-to-treat and per-protocol frameworks. The impact of the positivity assumption was also assessed. RESULTS: Overall, 5,148 relapsing-remitting multiple sclerosis patients were included. In this well-powered sample, the 95% confidence intervals of the estimates overlapped widely. Propensity scores weighting and propensity scores matching procedures led to consistent results. Some differences were observed between average treatment effect for the entire population and average treatment effect for treated estimates. Intention-to-treat analyses were more conservative than per-protocol analyses. The most pronounced irregularities in outcomes and propensity scores were introduced by violation of the positivity assumption. CONCLUSIONS: This applied study elucidates the influence of methodological decisions on the results of comparative effectiveness studies of treatments for multiple sclerosis. According to our results, there are no material differences between conclusions obtained with propensity scores matching or propensity scores weighting given that a study is sufficiently powered, models are correctly specified and positivity assumption is fulfilled.

Cost-utility of oral methylprednisolone in the treatment of multiple sclerosis relapses: Results from the COPOUSEP trial.

BACKGROUND: Studies have shown that oral high-dose methylprednisolone (MP) is non-inferior to intravenous MP in treating multiple sclerosis relapses in terms of effectiveness and tolerance. In order to assist with resource allocation and decision-making, its cost-effectiveness must also be assessed. Our objective was to evaluate the cost-utility of per os high-dose MP as well as the cost-savings associated with implementing the strategy. METHODS: A cost-utility analysis at 28 days was carried out using data from the French COPOUSEP multicenter, double-blind randomized controlled non-inferiority trial and the statutory health insurance reimbursement database. Costs were calculated using a societal perspective, including both direct and indirect costs. An incremental cost-effectiveness ratio was calculated and bootstrapping methods assessed the uncertainty surrounding the results. An alternative scenario analysis in which MP was administered at home was also carried out. A budgetary impact analysis was carried at five years. RESULTS: In the conditions of the trial (hospitalized patients), there was no significant difference in utilities and costs at 28 days. The incremental cost-effectiveness ratio was €15,360 per quality-adjusted life-year gained. If multiple sclerosis relapses were treated at home, oral MP would be more effective, less costly and associated with annual savings up to 25 million euros for the French healthcare system. CONCLUSIONS: Oral MP is cost-effective in the treatment of multiple sclerosis relapses and associated with major savings.

SMILE: a predictive model for Scoring the severity of relapses in MultIple scLErosis.

BACKGROUND: In relapsing-remitting multiple sclerosis (RRMS), relapse severity and residual disability are difficult to predict. Nevertheless, this information is crucial both for guiding relapse treatment strategies and for informing patients. OBJECTIVE: We, therefore, developed and validated a clinical-based model for predicting the risk of residual disability at 6 months post-relapse in MS. METHODS: We used the data of 186 patients with RRMS collected during the COPOUSEP multicentre trial. The outcome was an increase of ≥ 1 EDSS point 6 months post-relapse treatment. We used logistic regression with LASSO penalization to construct the model, and bootstrap cross-validation to internally validate it. The model was externally validated with an independent retrospective French single-centre cohort of 175 patients. RESULTS: The predictive factors contained in the model were age > 40 years, shorter disease duration, EDSS increase ≥ 1.5 points at time of relapse, EDSS = 0 before relapse, proprioceptive ataxia, and absence of subjective sensory disorders. Discriminative accuracy was acceptable in both the internal (AUC 0.82, 95% CI [0.73, 0.91]) and external (AUC 0.71, 95% CI [0.62, 0.80]) validations. CONCLUSION: The predictive model we developed should prove useful for adapting therapeutic strategy of relapse and follow-up to individual patients.

Inaugural tumor-like multiple sclerosis: clinical presentation and medium-term outcome in 87 patients.

BACKGROUND: Tumefactive demyelinating lesions of the central nervous system can be the initial presentation in various pathological entities [multiple sclerosis (the most common), Balo's concentric sclerosis, Schilder's disease and acute disseminated encephalomyelitis] with overlapping clinical presentation. The aim of our study was to better characterize these patients. METHODS: Eighty-seven patients (62 women and 25 men) from different MS centers in France were studied retrospectively. Inclusion criteria were (1) a first clinical event (2) MRI showing one or more large demyelinating lesions (20 mm or more in diameter) with mass-like features. Patients with a previous demyelinating event (i.e. confirmed multiple sclerosis) were excluded. RESULTS: Mean age at onset was 26 years. The most common initial symptoms (67% of the patients) were hemiparesis or hemiplegia. Aphasia, headache and cognitive disturbances (i.e. atypical symptoms for demyelinating diseases) were observed in 15, 18 and 15% of patients, respectively. The mean largest diameter of the tumefactive lesions was 26.9 mm, with gadolinium enhancement in 66 patients (81%). Twenty-one patients (24%) had a single tumefactive lesion. During follow-up (median time 5.7 years) 4 patients died, 70 patients improved or remained stable and 12 worsened. 86% of patients received initial corticosteroid treatment, and 73% received disease-modifying therapy subsequently. EDSS at the end of the follow-up was 2.4 ± 2.6 (mean ± SD). CONCLUSION: This study provides further evidence that the clinical course of MS presenting with large focal tumor-like lesions does not differ from that of classical relapsing-remitting MS, once the noisy first relapsing occurred.

Decrease of blood anti-α1,3 Galactose Abs levels in multiple sclerosis (MS) and clinically isolated syndrome (CIS) patients.

The etiology of multiple sclerosis (MS) remains elusive. Among the possible causes, the increase of anti-Neu5Gc antibodies during EBV primo-infection of Infectious mononucleosis (IMN) may damage the integrity of the blood-brain barrier facilitating the transfer of EBV-infected B cells and anti-EBV T cell clones in the brain. We investigated the change in titers of anti-Neu5Gc and anti-α1,3 Galactose antibodies in 49 IMN, in 76 MS, and 73 clinically isolated syndrome (CIS) patients, as well as age/gender-matched healthy individuals. Anti-Gal and anti-Neu5Gc are significantly increased during IMN (p=0.02 and p<1.10-4 respectively), but not in acute CMV primo-infection. We show that, whereas there was no change in anti-Neu5Gc in MS/CIS, the two populations exhibit a significant decrease in anti-Gal (combined p=2.7.10-3), in contrast with patients with non-MS/CIS central nervous system pathologies. Since anti-Gal result from an immunization against α1,3 Gal, lacking in humans but produced in the gut, our data suggest that CIS and MS patients have an altered microbiota or an altered response to this microbiotic epitope.

Unique B cell differentiation profile in tolerant kidney transplant patients.

Operationally tolerant patients (TOL) display a higher number of blood B cells and transcriptional B cell signature. As they rarely develop an allo-immune response, they could display an abnormal B cell differentiation. We used an in vitro culture system to explore T-dependent differentiation of B cells into plasma cells. B cell phenotype, apoptosis, proliferation, cytokine, immunoglobulin production and markers of differentiation were followed in blood of these patients. Tolerant recipients show a higher frequency of CD20(+) CD24(hi) CD38(hi) transitional and CD20(+) CD38(lo) CD24(lo) naïve B cells compared to patients with stable graft function, correlating with a decreased frequency of CD20(-) CD38(+) CD138(+) differentiated plasma cells, suggestive of abnormal B cell differentiation. B cells from TOL proliferate normally but produce more IL-10. In addition, B cells from tolerant recipients exhibit a defective expression of factors of the end step of differentiation into plasma cells and show a higher propensity for cell death apoptosis compared to patients with stable graft function. This in vitro profile is consistent with down-regulation of B cell differentiation genes and anti-apoptotic B cell genes in these patients in vivo. These data suggest that a balance between B cells producing IL-10 and a deficiency in plasma cells may encourage an environment favorable to the tolerance maintenance.

Mycophenolate mofetil in multiple sclerosis: a multicentre retrospective study on 344 patients.

OBJECTIVES: Mycophenolate mofetil (MMF) is an immunosuppressive agent, sometimes used as a disease-modifying therapy for multiple sclerosis (MS). Several studies have reported the relative safety of this treatment but, to date, its efficacy has rarely been described. We performed a retrospective study to assess the safety and efficacy of MMF in patients with MS. METHODOLOGY: Three French MS centres included all of their patients treated by MMF. The main outcome criterion was annualised relapse rate (ARR) in the 1 year period after onset of MMF compared with the 1 year control period. Treatment with another immunosuppressive drug, such as mitoxantrone or cyclophosphamide, in the 2 years preceding initiation of MMF was included in a subgroup analysis. MMF safety and progression of the Expanded Disability Status Scale (EDSS) score were also assessed. RESULTS: 344 patients were included; 149 patients were previously treated with another immunosuppressant (IS group). Mean MMF treatment duration was 25.3±1.1 months. During the 1 year control period, ARR was 1.11±0.08, and for the 1 year treatment period, ARR was reduced significantly to 0.35±0.05 (p<0.0001, Wilcoxon paired test). Adverse events (occurring in 11% of patients) were mainly digestive disorders, benign infections, asthenia and transitory lymphopenia. Concerning the progression of disability, in the subgroup of patients without previous immunosuppressant treatment, EDSS remained stable between initiation and 1 year after the beginning of MMF. INTERPRETATION: Our results suggest that MMF can improve or stabilise MS patients and can be used as an alternative therapy.

[Adaptative immunity and pathophysiology of multiple sclerosis]. / Immunité adaptative et physiopathologie de la sclérose en plaques.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). The appearance of demyelinating patches in the CNS of patients with MS is associated with an inflammatory infiltrate mainly composed of macrophages and T lymphocytes. In this review, we focus on the evidence linking the development of the disease and the cell populations of the adaptative immune system. This evidence arises from anatomopathological, genetical and immunological studies, both on human and the animal model of the disease. Hence, we detail the implication of the effector lymphocytes, i.e. CD4(+) and CD8(+) T lymphocytes, but also B lymphocytes, in the disease. The implication of the regulatory T and B lymphocytes is also approached. Finally, the main hypotheses proposing an explanation to the development of MS are presented.

[Increased risk of relapse in multiple sclerosis patients after ovarian stimulation for in vitro fertilization]. / Augmentation du risque de poussée de sclérose en plaques après stimulation ovarienne pour fécondation in vitro.

In this preliminary study we analysed the impact of ovarian stimulations and the different protocols used for in vitro fertilizations (IVF) on the clinical activity of multiple sclerosis (MS). By matching the databases on MS and IVF of the past 10 years at the university hospital of Nantes, six patients have been found and, for five of them MS relapse rate seemed to be increased in the three-month period following IVF as compared to the previous three months and to two other control periods of three months (P<0.05, Friedman test). The increased relapse rate mainly concerned patients treated by GnRH agonists but not the patients treated by GnRH antagonists. This preliminary work suggests a possible impact of the treatments used for IVF on MS relapse rate. Further studies are now underway to validate these results on a larger scale, by including all cases reported in France.