Switching Between MS Therapies Linked to Higher Relapse Risk, Study Finds
A recent real-world study in Canada has highlighted that individuals with multiple sclerosis (MS) who switch between more than two disease-modifying therapies (DMTs) face an increased risk of relapses, irrespective of their adherence to prescribed medications.
The research suggests that a greater number of treatment switches are typically seen in patients with a poor response to various therapies and higher disease activity.
However, among those who switched treatments, individuals transitioning to second-line DMTs experienced a significantly reduced risk of relapses post-switch compared to those who continued with first-line DMTs. This finding implies that higher-efficacy therapies may be more effective at controlling relapses in such patients.
The study reinforces the idea of escalating therapy for those experiencing relapses that require intervention, according to the researchers.
Exploring Treatment Adherence in MS Patients
Over 20 therapies have been approved to date to mitigate disease activity and slow MS progression. Typically, patients are treated according to an escalation strategy, beginning with moderately effective first-line DMTs with established safety profiles. If patients do not respond adequately to this treatment, they can be switched to more potent second-line therapies.
While escalating to more effective treatments is a well-established approach, prior studies have often overlooked treatment adherence when comparing the efficacy of first-line and second-line therapies.
To address this, researchers at the University of Manitoba in Canada assessed how DMT exposure, including adherence and switches between different DMTs, impacted the risk of MS relapses in a real-world clinical context.
Data from two patient registries collected between 1999 and 2015 were examined. One registry, the Manitoba Population Research Data Repository, contains health claims data from 98% of the province’s population, while the other is the Winnipeg MS Clinic Registry, the sole specialty MS clinic in Manitoba.
At the time of the analysis, available first-line therapies included interferon-beta therapies, Copaxone (glatiramer acetate), Tecfidera (dimethyl fumarate), and Aubagio (teriflunomide). Second-line DMTs included Gilenya (fingolimod) and Tysabri (natalizumab).
The primary aim of the study was to determine the time to a first relapse requiring treatment. Such relapses are typically associated with sustained disability progression and serve as a criterion for accessing second-line therapies in Manitoba.
Researchers also explored how switching between DMTs influenced the risk of relapse.
Over 50% Lower Relapse Risk Seen for Patients Switching to Higher-Efficacy DMTs
The analysis included 1,780 patients with relapsing forms of MS, with 1,510 prescribed a DMT and 270 not receiving treatment. Patients who never received a DMT developed MS roughly nine years later than those receiving treatment (47.6 vs. 38.4 years) and had fewer treated relapses (22% vs. 45%).
Among the DMT-prescribed patients, 75.8% showed good adherence to their prescribed treatment, as indicated by a cumulative medication possession ratio (MPR) exceeding 80%. MPR measures the number of days a patient has their medication supply for a given period, assessing their ability to follow the prescription. Lower MPR values indicate poorer adherence.
Additionally, more than half of the treated patients did not switch their prescribed DMT (63.6%), while 26.1% switched once, and 10.3% changed 2-4 times.
Statistical analysis demonstrated that being treated with a DMT was not associated with the time to a first treated relapse. However, among those treated with a DMT, those switching between more than two DMTs faced a significantly increased risk of treated relapses following the switch compared to those who remained on the same treatment.
The reduced risk among patients who never switched treatment was independent of adherence.
The study’s final analysis showed that individuals switching to higher-efficacy DMTs had a 56% lower risk of experiencing treated relapses compared to those who remained on their first-line therapy or switched to another first-line medication.
The research concludes that escalating DMTs effectively reduces the relapse rate among individuals with a history of treated relapses. Further clinical trials are required to assess whether initial treatment with higher-efficacy DMTs is a more suitable approach for treatment-naïve individuals with varying disease activity.
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