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

Treatment De-escalation in Relapsing-Remitting Multiple Sclerosis: An Observational Study

BACKGROUND

In relapsing-remitting multiple sclerosis (RRMS), extended exposure to high-efficacy disease modifying therapy may increase the risk of side effects, compromise treatment adherence, and inflate medical costs. Treatment de-escalation, here defined as a switch to a lower efficacy therapy, is often considered by patients and physicians, but evidence to guide such decisions is scarce. In this study, we aimed to compare clinical outcomes between patients who de-escalated therapy versus those who continued their therapy.

METHODS

In this retrospective analysis of data from an observational, longitudinal cohort of 87,239 patients with multiple sclerosis (MS) from 186 centers across 43 countries, we matched treatment episodes of adult patients with RRMS who underwent treatment de-escalation from either high- to medium-, high- to low-, or medium- to low-efficacy therapy with counterparts that continued their treatment, using propensity score matching and incorporating 11 variables. Relapses and 6-month confirmed disability worsening were assessed using proportional and cumulative hazard models.

RESULTS

Matching resulted in 876 pairs (de-escalators: 73% females, median [interquartile range], age 40.2 years [33.6, 48.8], Expanded Disability Status Scale [EDSS] 2.5 [1.5, 4.0]; non-de-escalators: 73% females, age 40.8 years [35.5, 47.9], and EDSS 2.5 [1.5, 4.0]), with a median follow-up of 4.8 years (IQR 3.0, 6.8). Patients who underwent de-escalation faced an increased hazard of future relapses (hazard ratio 2.36 and 95% confidence intervals [CI] [1.79-3.11], p < 0.001), which was confirmed when considering recurrent relapses (2.43 [1.97-3.00], p < 0.001). It was also consistent across subgroups stratified by age, sex, disability, disease duration, and time since last relapse.

CONCLUSIONS

On the basis of this observational analysis, de-escalation may not be recommended as a universal treatment strategy in RRMS. The decision to de-escalate should be considered on an individual basis, as its safety is not clearly guided by specific patient or disease characteristics evaluated in this study.

Five-year efficacy outcomes of ocrelizumab in relapsing multiple sclerosis: A propensity-matched comparison of the OPERA studies with other disease-modifying therapies in real-world lines of treatments

Background

Clinical trials comparing the efficacy of ocrelizumab (OCR) with other disease-modifying therapies (DMTs) other than interferon (IFN) β-1a in relapsing multiple sclerosis (RMS) are lacking.

Objectives

To compare the treatment effect of OCR vs six DMTs' (IFN β-1a, glatiramer acetate, fingolimod, dimethyl fumarate, teriflunomide, natalizumab) treatment pathways used in clinical practice by combining clinical trial and real-world data.

Methods

Patient-level data from OPERA trials and open-label extension phase, and from the German NeuroTransData (NTD) MS registry, were used to build 1:1 propensity score-matched (PSM) cohorts controlling for seven baseline covariates, including brain imaging activity. Efficacy outcomes were time to first relapse and time to 24-week confirmed disability progression over 5.5 years of follow-up. Intention-to-treat analysis using all outcome data irrespective of treatment switch was applied.

Results

The analyses included 611 OPERA patients and 7141 NTD patients. We built 12 paired-matched cohorts (six for each outcome, two for each DMT) to compare efficacy of OCR in OPERA with each DMT treatment pathway in NTD. Post-matching, baseline covariates and PS were well balanced (standardized mean difference <.2 for all cohorts). Over 5.5 years, patients treated with OCR showed a statistically significant reduction in the risk of relapse (hazard ratios [HRs] .30 to .54) and disability progression (HRs .51 to .67) compared with all index therapies and their treatment switching pathways in NTD. Treatment switch and/or discontinuation occurred frequently in NTD cohorts.

Conclusion

OCR demonstrates superiority in controlling relapses and disability progression in RMS compared with real-world treatment pathways over a 5.5-year period. These analyses suggest that high-efficacy DMTs and high treatment persistence are critical to achieve greatest clinical benefit in RMS.

Registration

OPERA I (NCT01247324), OPERA II (NCT01412333).

Comparative efficacy of ofatumumab versus oral therapies for relapsing multiple sclerosis patients using propensity score analyses and simulated treatment comparisons

Background

Evidence from network meta-analyses (NMAs) and real-world propensity score (PS) analyses suggest monoclonal antibodies (mAbs) offer a therapeutic advantage over currently available oral therapies and, therefore, warrant consideration as a distinct group of high-efficacy disease-modifying therapies (DMTs) for patients with relapsing multiple sclerosis (RMS). This is counter to the current perception of these therapies by some stakeholders, including payers.

Objectives

A multifaceted indirect treatment comparison (ITC) approach was undertaken to clarify the relative efficacy of mAbs and oral therapies.

Design

Two ITC methods that use individual patient data (IPD) to adjust for between-trial differences, PS analyses and simulated treatment comparisons (STCs), were used to compare the mAb ofatumumab versus the oral therapies cladribine, fingolimod, and ozanimod.

Data sources and methods

As IPD were available for trials of ofatumumab and fingolimod, PS analyses were conducted. Given summary-level data were available for cladribine, fingolimod, and ozanimod trials, STCs were conducted between ofatumumab and each of these oral therapies. Three efficacy outcomes were compared: annualized relapse rate (ARR), 3-month confirmed disability progression (3mCDP), and 6-month CDP (6mCDP).

Results

The PS analyses demonstrated ofatumumab was statistically superior to fingolimod for ARR and time to 3mCDP but not time to 6mCDP. In STCs, ofatumumab was statistically superior in reducing ARR and decreasing the proportion of patients with 3mCDP compared with cladribine, fingolimod, and ozanimod and in decreasing the proportion with 6mCP compared with fingolimod and ozanimod. These findings were largely consistent with recently published NMAs that identified mAb therapies as the most efficacious DMTs for RMS.

Conclusion

Complementary ITC methods showed ofatumumab was superior to cladribine, fingolimod, and ozanimod in lowering relapse rates and delaying disability progression among patients with RMS. Our study supports the therapeutic superiority of mAbs over currently available oral DMTs for RMS and the delineation of mAbs as high-efficacy therapies.

Observational studies of treatment effectiveness in neurology

The capacity and power of data from cohorts, registries and randomized trials to provide answers to contemporary clinical questions in neurology has increased considerably over the past two decades. Novel sophisticated statistical methods are enabling us to harness these data to guide treatment decisions, but their complexity is making appraisal of clinical evidence increasingly demanding. In this review, we discuss several methodological aspects of contemporary research of treatment effectiveness in observational data in neurology, aimed at academic neurologists and analysts specializing in outcomes research. The review discusses specifics of the sources of observational data and their key features. It focuses on the limitations of observational data and study design, as well as statistical approaches aimed to overcome these limitations. Among the examples of leading clinical themes typically studied with analyses of observational data, the review discusses methodological approaches to comparative treatment effectiveness, development of diagnostic criteria and definitions of clinical outcomes. Finally, this review provides a brief summary of key points that will help clinical audience critically evaluate design and analytical aspects of studies of disease outcomes using observational data.

Switching to natalizumab or fingolimod in multiple sclerosis: Comparative effectiveness and effect of pre-switch disease activity

BACKGROUND

Patients with relapsing-remitting multiple sclerosis (RRMS) who experience relapses on a first-line therapy (interferon, glatiramer acetate, dimethyl fumarate, or teriflunomide; collectively, "BRACETD") often switch to another therapy, including natalizumab or fingolimod. Here we compare the effectiveness of switching from a first-line therapy to natalizumab or fingolimod after ≥1 relapse.

METHODS

Data collected prospectively in the MSBase Registry, a global, longitudinal, observational registry, were extracted on February 6, 2018. Included patients were adults with RRMS with ≥1 relapse on BRACETD therapy in the year before switching to natalizumab or fingolimod. Included patients received natalizumab or fingolimod for ≥3 months after the switch.

RESULTS

Following 1:1 propensity score matching, 1000 natalizumab patients were matched to 1000 fingolimod patients. Mean (standard deviation) follow-up time was 3.02 (2.06) years after switching to natalizumab and 2.58 (1.64) years after switching to fingolimod. Natalizumab recipients had significantly lower annualized relapse rate (relative risk=0.66; 95% confidence interval [CI], 0.59-0.74), lower risk of first relapse (hazard ratio [HR]=0.69; 95% CI, 0.60-0.80), and higher confirmed disability improvement (HR=1.27; 95% CI, 1.03-1.57) than fingolimod recipients. No difference in confirmed disability worsening was observed.

CONCLUSIONS

Patients with RRMS switching from BRACETD demonstrated better outcomes with natalizumab than with fingolimod.