Clinical trials find most adverse events for a new drug, but postmarketing surveillance is essential to find rare events, even though they may underestimate the frequency of these events because of underreporting.
Other reports suggest the emergence of uncommon infectious complications associated with alemtuzumab, especially Listeria meningitis. Listeria infection can occur within days of alemtuzumab treatment, and the use of preventive sulfamethoxazole-trimethoprim treatment is now advocated in the United Kingdom.
Overall, these adverse events remind clinicians that they must balance the benefits of alemtuzumab, which is highly effective, against its potential risks.
Paolo A. Muraro, MD, PhD is a professor of neurology, neuroimmunology, and immunotherapy at Imperial College London. Neil J. Scolding MD, PhD, is director of the Bristol Institute of Clinical Neurosciences at the University of Bristol (England). Robert J. Fox, MD, is a neurologist at the Mellen Center for Multiple Sclerosis at the Cleveland Clinic in Ohio. All of the authors reported financial relationships with companies marketing MS drugs. Their comments are derived from an editorial accompanying the adverse event reports (Neurology. 2018 Mar 30. doi: 10.1212/WNL.0000000000005409).
