MS Activity Returns Soon After Stopping Natalizumab (Tysabri)

AMSTERDAM – Significant percentages of patients with relapsing-remitting multiple sclerosis who discontinue natalizumab but start another medication experience a return of disease activity within 12 weeks, according to the results of the RESTORE study.

The risk of return of disease activity during treatment interruption was “notable” even with the use of interferon beta-1a (IFNB-1a, Avonex); glatiramer acetate (Copaxone); or methylprednisolone in place of natalizumab in the study of 175 patients, Dr. Robert Fox said during a late-breaking trials session at the joint triennial congress of the European and Americas Committees for Treatment and Research in Multiple Sclerosis.

The risk of temporarily stopping natalizumab generally appeared to outweigh its benefits in this exploratory study, said Dr. Fox, the lead investigator of the study and medical director at the Mellen Center for Multiple Sclerosis at the Cleveland Clinic in Ohio.

Interrupting treatment with natalizumab has been proposed as a possible way to reduce the risk of progressive multifocal leukoencephalopathy, a rare and potentially fatal opportunistic disease caused by the JC virus. It has been associated with prolonged natalizumab therapy.

In RESTORE, all patients had been treated for 1 year or longer and were relapse free before treatment with natalizumab (given at 300 mg IV once every 4 weeks) was interrupted for 24 weeks. The investigators randomized patients to continue natalizumab treatment (n = 45), stop natalizumab and receive IV placebo (n = 42), or stop natalizumab and receive 1,000 mg IV methylprednisolone every 4 weeks (n = 54), 30 mg intramuscular IFNB-1a once per week (n = 17), or 20 mg subcutaneous glatiramer acetate once daily (n = 17) for 24 weeks, followed by re-instatement of natalizumab infusions for an additional 24 weeks. Investigators at each of the study’s 31 clinical sites selected the choice of alternative treatment.