A decade of natalizumab and PML: Has there been a tacit transfer of risk acceptance?

The interplay between each of the stakeholder's responsibilities and desires clearly has resulted in continued widespread use of natalizumab with substantial risks and an ongoing quest for better risk mitigation. In the United States, regulatory actions codified the process of risk acceptance - and risk transfer - by escalating monitoring and information transfer to physicians and patients. Management of medication-related risks is a core function of regulatory agencies such as the Food and Drug Administration (FDA), European Medicines Agency (EMA), and the medical community. The interaction among stakeholders in medicine, pharma, regulatory bodies, physicians, and patients, sometimes has changed without overt review and discussion. Such is the case for natalizumab, an important and widely used disease-modifying therapy for multiple sclerosis. A rather silent but very considerable shift, effectively transferring increased risk for progressive multifocal leukoencephalopathy (PML) to the physicians and patients, has occurred in the past decade. We believe this changed risk should be clearly recognized and considered by all the stakeholders.