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Reducing PML risk on Tysabri

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  • Reducing PML risk on Tysabri

    A study of extending time between doses of Tysabri is ongoing. Last September data presented at the ACTRIMS/ECTRIMS meeting in Boston showed there were no cases of PML among 684 JCV positive MSers extending time between Tysabri doses to 5, 6, 7, or 8 weeks.

    The percentage of patients in dose extension with no radiological activity (82%), the percentage with no clinical activity (77%) and the percentage of patients with no combined disease activity (62%) was remarkably similar to the standard dosing (4 week) group. The percentages of patients with no new T2 lesions and those having relapses were actually less in those on extended dosing.

    Those on extended dosing comprised 861 JCV positive person years. The study made note that 1248 patient years were needed to reach statistical significance at 0.05 level. That would occur in June or July, 2015 if the extended dosing group remains PML-free.

    Two cases of PML were reported in the standard dosing group of 674 people; no cases of PML in the extended dosing group of 684 people.

    Some JCV positive people having success on Tysabri understandably may want to wait for data from the extended dosing study before halting treatment due to PML concern. If extending time between doses is a method to diminish the risk of PML it will prove extremely helpful to those having good results with Tysabri.

    The JCV titers of those participating in variable durations of dose extension ranged between 0.05 and 4.50.
    Google “JCV Test Stratifies PML risk in Antibody-Positive MS" to find a simple chart on PML risk.

    A JCV antibody index greater than 1.5 shows 1 PML case in 1000 taking Tysabri for 2 years or less. That figure jumps to 8 cases in 1000 over 2 years on Tysabri. A large increase to be sure, however, many people think about their PML risk and neglect to give proper consideration to their MS risk, IMO. MS progression without Tysabri presents a huge risk, also.

    The MS-UK.org site has an article titled, “MS Rebound After Stopping Tysabri”. It states the probability of MS rebound at 39% with severe recurring relapses in 9%.

    The recent PBS special, Cancer: Emperor of All Maladies listed a 1 in 3 chance for women of developing cancer. When risk of heart disease is combined with risk of cancer there is a greater than 50% chance of developing one of those. An 8 in 1000 chance of developing PML is a big risk but nowhere near the risk of 500 in 1000 when the risk of cancer and heart disease are combined.

    Judging risk is an individual assessment. Studies have shown doctors are much more risk-averse than patients. However, when doctors become patients they seem more than willing to try novel treatments for their own maladies, in my observation.

    Bottom line is that it is your life and your choice for critical treatment, IMO. No one has you in mind more than you do. A doctor is going to do the best for you within the confines of running an efficient practice, IMO. A doctor’s opinion is very important but a capable patient has every right to choose the treatment which best fits him.

    Best to all facing difficult decisions!

  • #2
    Increasing Tysabri Dosing Interval May Cut PML Risk

    Medpagetoday posted the above titled article which may be Googled, part of which is quoted below:

    “—No sacrifice of efficacy seen in retrospective analysis.

    WASHINGTON -- Freedom from relapse was maintained in multiple sclerosis patients on natalizumab (Tysabri) who received the infusion drug less frequently than the recommended 4-week interval, with lower risk of progressive multifocal leukoencephalopathy (PML), preliminary results from an ongoing analysis indicated.

    Among 886 patients treated with "extended" dosing at 10 multiple sclerosis centers nationwide, the mean annualized relapse rate was the same at 0.1 per year as in 1,078 patients receiving natalizumab at the standard 4-week interval, according to Lana Zhovtis-Ryerson, MD, of NYU Langone Medical Center in New York City. MRI lesions counts were also similar.

    Although patients testing positive for the JC virus -- the pathogen whose reactivation triggers PML, a sometimes fatal brain inflammation -- comprised 59% of the extended dosing group, none have so far developed PML, she reported here at the American Academy of Neurology's annual meeting.

    With a total of 1,023 patient-years of exposure to natalizumab in this JC-positive subgroup, published risk algorithms show an expected incidence of 2.5 cases, Zhovtis-Ryerson and colleagues calculated.”

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