Comparison of B-cell depletion versus natalizumab for treatment of multiple sclerosis: A semi-supervised causal analysis
Authors: DiSanto Dominic , Tang Weijing , Zhu Wen , Morris Michele , Visweswaran Shyam , Cai Tianxi , Xia Zongqi 
Published: January 2025

Background

B-cell depletion (BCD) therapies (e.g.,ocrelizumab, ofatumumab, rituximab) and natalizumab (NTZ) are highly effective disease-modifying therapies (DMTs) for multiple sclerosis (MS). However, no randomized clinical trial and only limited observational studies compared the two DMT classes.

Objective

We compared BCD and NTZ in managing MS patient-reported disability progression using registry-linked electronic healthcare record (EHR) data.

Methods

The study population of an EHR cohort of MS patients included a subset enrolled in a clinic-based MS registry that provided gold-standard outcome labels. To estimate average treatment effects, we applied a doubly-robust semi-supervised approach to analyze all (not only registry) patients and comprehensively adjusted for confounders that included not onlya prioristandard features but also knowledge graph-derived EHR features. While gold-standard disability outcomes were available in registry patients, we imputed the baseline pre-treatment and post-treatment disability status for non-registry patients. We categorized patient-reported disability progression status as “sustained worsening”, “sustained improvement”, or “no sustained change” based on 3 or more observations or imputations of Patient Determined Disease Steps (PDDS) scores within 3 years after target treatment initiation as the primary endpoint.

Results

In this MS cohort (n=1,738, Age=46±13 years, Non-Hispanic White=86.71%), there was no significant difference between BCD (n=1,245, 71.63%) and NTZ (n=495, 28.37%) in mitigating sustained worsening (ATE=0.012, 95% CI [-0.123, 0.102], p=.803) or promoting sustained improvement (ATE=-0.0823, 95% CI [-0.194, 0.022], p=.172) of patient-reported disability. Sensitivity analyses using a 2-year window after treatment initiation confirmed no difference in sustained worsening (ATE=-0.0141, 95% CI [-0.107, 0.080], p=.895) or sustained improvement (ATE=-0.0713, 95% CI [-0.263, 0.026], p=.245) between BCD and NTZ. In power analysis, the semi-supervised approach increased statistical power compared to the standard approach of using gold-standard data alone.

Conclusion

This real-world comparative effectiveness analysis based on a novel doubly- robust semi-supervised approach found no difference between BCD and NTZ in managing MS disability progression.

Key Messages

The scarcity of patient-reported disability outcomes in routine clinical care hinders analysis based on real-world patient-reported outcomes, while evaluation of sustained disability accumulation requires long-term follow-up in clinical trials.

Using a large registry-linked electronic healthcare record cohort and a novel semi- supervised, doubly-robust method, we conducted a causal inference study to compare sustained change in patient-reported disability in people with MS.

The semi-supervised approach effectively leverages additional data from patients without observed outcome information and increases the statistical power of the comparative effectiveness study while retaining robustness properties in the causal analysis.

There was no statistically significant difference between B-cell depletion therapy and natalizumab in sustained patient-reported disability outcomes up to 3-years after treatment initiation.