Re-examining natalizumab and PML

Reactions 1359 - 9 Jul 2011

Re-examining natalizumaband PML

"Earlier diagnosis through enhanced clinical vigilanceand aggressive treatment" may improve survival fornatalizumab recipients who develop progressivemultifocal leukoencephalopathy (PML), according to amultinational research team.

The researchers found that a shorter interval betweenonset of symptoms and PML diagnosis and morelocalised disease on MRI are linked to improved survival.Reviewing the data for the first 35 postmarketing casesof natalizumab-induced PML (following clinical statusupdates performed by the treating physicians), theresearchers also identified younger age and lessdisability at PML diagnosis as factors associated withimproved survival.

Characteristics of survivorsThe 35 reported cases involved 10 men and

25 women aged 27–59 years; natalizumab exposure atdiagnosis ranged from 12–44 (mean 26.6) infusions. Ofthis group, 25 patients (71%) were alive at the time ofanalysis. Compared with fatal cases, survivors wereyounger (median age, 40 vs 54 years), had a shorterinterval to PML diagnosis (median 31 vs 40.5 days) andhad lower Expanded Disability Status Scale scores priorto PML onset (median 3.5 vs 5.5). Based on MRI findingsat diagnosis, the majority of survivors (86%) had uni- ormultilobar disease while widespread disease wasevident in 70% of fatal cases. Among the fatal cases, themean interval from diagnosis to death was 3.1 months(range 1–10.5).

Assessing clinical status among survivors using theKarnofsky Performance Scale showed that four patientshad mild disability, nine had moderate disability andtwelve had severe disability.*

* Details of three of these cases are available in this issue p28; see803056694

Vermersch P, et al. Clinical outcomes of natalizumab-associated progressivemultifocal leukoencephalopathy. Neurology 76: 1697-1704, No. 20, 17 May2011 803056698

» Editorial comment: Clinical data for 28 cases of PMLreported between July 2006 and November 2009 havepreviously been reviewed; see Reactions 1303 p6;803017588.

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Reactions 9 Jul 2011 No. 13590114-9954/10/1359-0001/$14.95 © 2010 Adis Data Information BV. All rights reserved