54 msfocusmagazine.org Biogen and AbbVie withdraw Zinbryta for relapsing MS BiogenandAbbVieannouncedthevoluntary worldwidewithdrawal of Zinbryta forrelapsing multiple sclerosis. The companies believe that characterizing the complex and evolving benefit/risk profile of Zinbryta will not be possible going forward, given the limited number of patients being treated. Dr. Thrower: The voluntary withdrawal of Zinbryta from the worldwide market should serve as a reminder to all of us that any drug that modulates the immune system can have potential health risks. A typical MS therapy undergoes two years of double-blind placebo- controlled testing and another year of open label testing. During the first phase, neither the patients nor the healthcare providers know whether the active drug or a placebo is being used. During the second phase, patients and healthcare providers know that the active drug is being used. Clinical studies typically are very selective in the types of patients that may be enrolled. Once the drug is FDA-approved however, the drug may be used in a muchwidervarietyof patients.While every effort is made to ensure the safety of a drug before it gets approval by a regulatory body such as the FDA, some side effects may not appear until the drug is used in larger numbers of people over longer periods of time. Researchers will now look more closely at Zinbryta to see if the side effects can be prevented in the future. Study: Extending dosing intervals reduces deadly side effect risk from MS drug According to a new study led by MS specialists at NYU Langone Health, a commonly-prescribed multiple sclerosis infusion medication linked to a rare but serious side effect is safer to use when dosing intervals are extended. The findings showed that extending dosing of natalizumab from every four weeks to every five to 12 weeks significantly reduced the risk of developing a rare but potentially fatal brain infection called progressive multifocal leukoencephalopathy. The findings could influence how neurologists prescribe the medication. The authors presented their findings at the Americas Committee for Treatment and Research in Multiple Sclerosis Forum 2018 in San Diego. Dr. Thrower: Tysabri is arguably one of our most effective treatment options in managing relapsing forms of multiple sclerosis. Over Medicine & Research Doctor’s Notes The Doctor’s Notes column includes analysis from Ben Thrower, M.D., MS Focus senior medical advisor. Dr. Thrower draws from the top news stories of the quarter and explains what the news means to you, the person with MS.