Background

There are currently two immune-reconstitution therapies (IRTs) licensed for relapsing multiple sclerosis (MS) - alemtuzumab (ALZ), an anti-CD52 monoclonal infusion, and cladribine (CdA), a short-course oral, T- and B-cell depletor.

Objectives

To review real world data of characteristics and disease-modifying treatment (DMT) history among EU and US patients switched to IRTs.

Methods

In 2019, 276 EU neurologists contributed online chart reviews for a retrospective audit of 1,266 MS patients who switched to a new DMT (ALZ: 77; CdA: 47) within the prior 3 months. In 2020, 204 US neurologists contributed 1,009 chart reviews (ALZ: 35; CdA: 21). Conducted at the .05 alpha level, independent samples t-test was used to test differences in means, and z-test (with Bonferroni correction) in proportions, between DMTs.

Results

Overall, IRT use was low, with slightly more patients switched to ALZ (EU: 6.1%; US: 3.5% of switch charts) than CdA (EU: 3.7%; US: 2.1%), except in Germany. While age, gender, recent relapse, and lesion counts did not differ by therapy or region, US patients treated with ALZ trended towards being diagnosed more recently compared to CdA-treated patients (mean: 30 vs. 68 months; p=0.058).

In the US, CdA was more likely than ALZ to be prescribed to patients with relapsing-remitting MS (RRMS) (86% vs. 60%; p=0.043) and trended towards being used less in RRMS patients with perceived risk for transition to secondary progressive MS transition (CdA: 17% vs. ALZ: 43%; p=0.077).

In both regions, most IRT switches were first DMT switches. In the EU, patients switched to CdA were more likely to have switched from an interferon (CdA: 28% vs. ALZ: 23%). In the US, glatiramer acetate more frequently preceded CdA (CdA: 38% vs. ALZ: 23%), while an anti-CD20 monoclonal antibody was more likely to have preceded ALZ (ALZ: 29% vs. CdA: 5%; p=0.030).

Conclusions

IRT treatment patterns in the EU and US are similar, with the exception of known differences in preceding injectable DMT use. In the US, patients are more likely to have been treated with anti-CD20 therapy before switching to ALZ than CdA, perhaps due to perceived differences in IRT efficacy profiles. ALZ is also more likely than CdA to be used among US patients diagnosed with, or at risk of transitioning to, progressive MS. Conversely, in the EU, the two IRTs are prescribed to very similar patient types.