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Nov 15, 2007 (Vol. 27, No. 20)

Letter to the Editor: What About Tysabri as an MS Treatment?

A reader takes umbrage with a GEN article on therapies for this disease.

  • Dear Editor,

    I find it incomprehensible that Melissa Elder, in her review of existing and pending treatments for MS (“Four Therapies Dominate MS Treatment,” October 1, 2007 GEN, pg. 16), simply ignores the existence of Tysabri (natalizumab), a treatment approved for relapsing forms of MS in the U.S. and relapsing-remitting MS in the European Union.

    According to data that has been published in the New England Journal of Medicine, after two years, Tysabri treatment led to a 68% relative reduction (p<0.001) in the annualized relapse rate compared to placebo and reduced the relative risk of disability progression by 42–54% (p<0.001). This efficacy far outstrips that of the four approved treatments highlighted in this review (or the data that has been published from the Phase II/III candidates also reviewed).

    At the recent “ECTRIMS” conference, a Post Hoc Analysis of Phase III AFFIRM Study (one of the Tysabri Phase III studies) was analyzed to determine the proportion of disease-free patients in the AFFIRM study based upon clinical and MRI criteria. The proportion of disease-free patients over two years was significantly higher in the Tysabri-treated group compared with the placebo group regardless of how disease-free was defined.

    Mary L. Severson, Ph.D., J.D.

    Melissa Elder’s Response

    Kalorama Information is first and foremost engaged in market analysis, not clinical research or patient education, and revenue is key in assessing commercial success in any class of therapies. While efficacy is an important factor that can have revenue impact, other factors—marketing strategy, distribution, regulatory requirements, and brand perception—also have significant impact.

    In our analysis, Tysabri was considered, along with several other therapies in the MS treatment market. However, from a revenue standpoint, Tysabri does not currently measure up to other available MS treatments. Although recent efficacy data may display a therapy worthy of higher revenues, Tysabri has a shaky history and, due to potentially harmful side effects, requires a diligent patient-monitoring process.

    Tysabri was originally introduced to the U.S. market in November 2004. In 2005, the product was voluntarily withdrawn from the market by the manufacturer. New warnings and prescribing education has brought this treatment back to the market.

    The FDA approved the return of Tysabri to the market to delay the accumulation of physical disability and reduce the frequency of relapses in those with relapsing MS and as a treatment meant for patients who have not responded or tolerated other marketed MS treatments.

    In June 2006 and July 2006, Tysabri was reintroduced to the U.S. and European markets, respectively; Tysabri was approved in Canada in October 2006. As part of the FDA approval, patients must mandatorily register for the TOUCH program along with their physicians to minimize the risk of progressive multifocal leukoencephalopathy (PML), which caused the withdrawal of the product from the market in the first place due to the reported complications and death. Since Tysabri’s return to the market, there have been no new incidents of PML.

    The relaunch of the product generated revenues of $38.1 million for Tysabri during the 2006 year. This figure is significantly overshadowed by Biogen Idec’s lead MS therapy, Avonex, which generated sales of $1.7 billion in 2006, up from $1.5 billion in 2005 and $1.4 billion in 2004. Furthermore, half-year 2007 sales of Tysabri, reported by Biogen Idec, were $77 million, again a high contrast to the half-year sales generated by Avonex of $910 million.

    Additionally, in comparing Tysabri to the other three products on the market—Compaxone, Rebif, and Betaseron—all of which exceed $1 billion annually, Tysabri will be fortunate to reach $300 million in the 2007 year.

    While we certainly understand the enthusiasm of clinicians and patient advocacy groups concerning this treatment option, Kalorama Information’s intent in our contribution to GEN and in our full-length market analysis was only to report the commercial status of MS therapeutics and the facts of the marketplace.

    Melissa Elder

    Analyst

    Kalorama Information



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