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Multiple SclerosisJuly 2022Summary reviewed August 2026

Spacing Out MS Infusions Showed More Brain Changes Than Monthly Dosing

Patients with relapsing-remitting multiple sclerosis who switched from monthly natalizumab infusions to one every six weeks had more new brain lesions on MRI scans than those who stayed on the monthly schedule. The six-week schedule is sometimes used to lower the risk of a rare brain infection, but this study found it may be less effective at controlling disease activity.

What the trial was testing

The NOVA enrolled 585 patients with multiple sclerosis. The study was sponsored by Biogen and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

Patients on the six-week schedule had about five times more new brain lesions than those on the monthly schedule.

The Lancet. Neurology · 2022 · NCT03689972

These findings — that patients on six-week dosing vs. monthly dosing — were published in the The Lancet. Neurology and represent the headline result of the study.

Researchers tracked outcomes across 585 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with multiple sclerosis, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

If you're on natalizumab for MS, this study suggests that spacing infusions to every six weeks instead of every four may lead to more disease activity. The six-week option is sometimes chosen to reduce the risk of a rare brain infection, but it may not control MS as well. Talk with your neurologist about the right schedule for you based on your individual risk factors. Natalizumab is FDA-approved for relapsing MS.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.