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How long does it take Ocrevus to work?

Medically reviewed by Carmen Pope, BPharm. Last updated on March 8, 2024.

Official answer


Ocrevus has some effect at reducing disability progression within about 12 weeks; however, it may take at least 6 months or possibly longer for the full effects to be seen. Trials of up to 96 weeks (almost 2 years) duration have shown that:

  • The number of patients with disability progression was significantly lower with Ocrevus compared with REBIF (interferon beta-1a) at 12 weeks (9.1% of those prescribed Ocrevus vs. 13.6% of those prescribed REBIF), and 24 weeks (6.9% vs. 10.5%)
  • 82% to 83% of people taking Ocrevus were relapse-free after 24 weeks compared to 71% to 72% of those taking REBIF
  • People taking Ocrevus had 46% to 47% fewer relapses a year than people prescribed REBIF.
  • Ocrevus (ocrelizumab) 05/2020 Genentech, Inc.
  • Ocrevus. National Multiple Sclerosis Society. 2020,primary%20progressive%20MS%20in%20adults.
  • Hauser SL, Bar-Or A, Comi G, et al. Ocrelizumab versus Interferon Beta-1a
    in Relapsing Multiple Sclerosis. N Engl J Med 2017;376:221-34.
    DOI: 10.1056/NEJMoa1601277

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