Quantifying the risks and benefits of natalizumab in relapsing multiple sclerosis.

Using published data, we quantified the risk and benefits of natalizumab in relapsing multiple sclerosis using quality-adjusted life years (QALYs) as a metric. Over the first 2 years of therapy, the negative health effects from progressive multifocal leukoencephalopathy were small (loss of 0.001 QALYs) relative to the positive effects on relapses and disability resulting in 0.033 QALYs (12 quality-adjusted days) gained. For context, we performed an analogous calculation for interferon beta-1a, which also had a net health benefit of 0.033 QALYs (12 quality-adjusted days).