WEST PALM BEACH, FLA. – About a third of patients with multiple sclerosis (MS) switch to a more potent disease-modifying therapy (DMT) within 1 year of disease activity being detected on MRI, according to a study of prescribing practices. The number of T2 lesions on MRI may be associated with the likelihood of switching DMTs, said Ryan Canissario, MD, a neurology resident at University of Rochester (New York) Medical Center, and colleagues.

The researchers had hypothesized that “the majority of patients would undergo a change in DMT in response to MRI activity,” they said. Delays in follow-up or therapy start times may partly explain the relatively low rates of switching during the first few months. “We speculate that other reasons ... include clinician or patient risk tolerance, patient age, prior longstanding stability on existing therapy, recent therapy change prior to MRI, or high baseline DMT potency,” the researchers said. Future studies will try to clarify the findings and assess outcomes related to prescribing practices.

Preventing new lesions on MRI is a primary treatment target in MS. “Following this principle, change in [DMT] should be considered in the setting of MRI evidence of disease activity,” but prescribing practices have not been well characterized, Dr. Canissario and colleagues said.

To identify and characterize patients who underwent a DMT change after the detection of brain MRI disease activity, Dr. Canissario and colleagues analyzed data from more than 1,300 patients in MS PATHS (MS Partners Advancing Technology and Health Solutions), a research network of 10 health care institutions. The investigators presented their results at ACTRIMS Forum 2020, the meeting held by the Americas Committee for Treatment and Research in Multiple Sclerosis.

By consensus, the investigators classified DMTs as low potency (for example, interferons, immunoglobulin G, glatiramer acetate, and teriflunomide), medium potency (azathioprine, cladribine, daclizumab, dimethyl fumarate, fingolimod, methotrexate, and mycophenolate mofetil), or high potency (alemtuzumab, cyclophosphamide, mitoxantrone, natalizumab, ocrelizumab, ofatumumab, and rituximab).

The researchers reviewed available imaging data from Apr. 2015 to Aug. 2019 to identify patients with new T2 or gadolinium-enhancing lesions. They determined whether these patients had an escalation in DMT potency or a lateral switch at 3, 6, 9, and 12 months after a radiologist reviewed the MRI.

The number of patients with MRI evidence of disease activity and complete DMT data ranged from 1,364 at 3 months to 952 at 12 months. The proportion of patients who had an escalation in therapy was 17.4% at 3 months, 25.5% at 6 months, 30.4% at 9 months, and 34.3% at 12 months. The proportion with a lateral change was 2% at 3 months, 3.4% at 6 months, 4.3% at 9 months, and 6% at 12 months.

The percentage of patients with DMT escalation or lateral change at 9 months increased with an increasing number of new T2 lesions. About 27% of patients with one new lesion switched therapy, compared with 43.5% of those with more than three new lesions.

Dr. Canissario had no disclosures. Coauthors disclosed research support from and consulting for pharmaceutical companies. MS PATHS is funded by Biogen.

jremaly@mdedge.com

SOURCE: Canissario R et al. ACTRIMS Forum 2020. Abstract P112.

How often do neurologists escalate MS therapy after detecting MRI activity?