Decisions to change multiple sclerosis treatments soon after starting them appear to be driven more by MRI findings

ORLANDO — Decisions to change multiple sclerosis treatments soon after starting them appear to be driven more by MRI findings of increasing disease activity than worsened clinical symptoms, a researcher said here.

In a retrospective analysis of 606 patients showing suboptimal responses to an initial disease-modifying therapy, the factor showing the strongest association with a change in treatment was increased disease activity seen in MRI scans (odds ratio 6.3 compared with a single relapse alone, 95% CI 3.1-12.9), reported Barbara Teter, PhD, MPH, of the State University of New York at Buffalo.

Oddly, though, the patients least likely to change treatments were those showing relapses plus either worsened disability or increased MRI lesions, according to Teter. She and her colleagues had no firm explanation for this finding, but their hypothesis is that such patients are psychologically resistant to seeking other treatments, she told MedPage Today.

Other factors associated with increased or decreased likelihood of changing treatments after a suboptimal initial response included multiple relapses, disability progression, patient age, and time elapsed from diagnosis to initiation of disease-modifying treatment.

Teter and colleagues reviewed data from 1,448 patients in a New York state registry of MS patients from 1996 to 2009, comprising 14 MS clinics and neurology practices. Records were complete for 606 patients who had started treatment with either interferon-beta (Rebif, Avonex, Betaseron) or glatiramer acetate (Copaxone) and subsequently suffered an MS “event.”

An event was defined as a clinical relapse, disability worsening as measured on the Expanded Disability Status Score (EDSS) system, increases in MRI lesion volumes or counts, or any combination of these noted at a single clinic visit. Patients who changed treatments after a second MS event separated in time from the first were not included in the analysis.

Patient demographics and clinical characteristics were reflective of the general MS population starting on disease-modifying drugs during the study period. About 75% were women, they were in their early 30s on average at symptom onset, and they started their first disease-modifying treatment a mean of about 8 years later. Mean EDSS score at initiation of disease-modifying therapy was 2.3 (SD 1.6).

Of the 606 patients in the analysis, 214 changed to another disease-modifying treatment within 6 months of an event, whereas the other 392 remained on their initial therapy. Switchers changed treatments a mean of 3.4 years (SD 2.7) after starting the first therapy.

The most common event in the overall sample was EDSS worsening alone, seen in 25% of patients, followed by relapse alone (22%), MRI worsening alone (16%), and relapse combined with EDSS worsening (16%). Other combinations were seen in less than 10% of patients.

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