Report of Severe Adverse Effects of MS Drug Alemtuzumab

Symptoms worsened significantly in two patients after treatment

The multiple sclerosis (MS) therapy alemtuzumab––marketed in the United States as Lemtrada (Genzyme Corporation)––may trigger severe, unpredictable adverse effects, according to German researchers. Writing in Lancet Neurology, the scientists report on two patients in whom the infusion of alemtuzumab significantly worsened symptoms. The team also describes a treatment that successfully curbed the adverse effects.

Alemtuzumab is an antibody that binds to the protein CD52 on the surface of certain immunocytes, mainly T and B lymphocytes, leading to the depletion of almost all lymphocytes.

The two patients received alemtuzumab because they had highly active MS despite numerous prior treatments and because they experienced severe relapses, with inflammation in the central nervous system (CNS). Six months after the treatment with alemtuzumab, these symptoms worsened significantly. Using magnetic resonance imaging, the researchers discovered a new mode of inflammation: they found areas in the brain with numerous ring-enhancing lesions. The patients had not displayed this pattern in their previous medical histories. It is unclear, however, whether the observed adverse events represented increased MS activity or an independent secondary autoimmune process.

In both cases, the neurologists were able to curb the adverse effects, and the observed ring-shaped deposits in the brain receded. At one year after the treatment, the patients remained stable. In addition to a blood-plasma exchange, both patients were treated with the antibody rituximab, which is directed against B lymphocytes. The researchers suspect that these immunocytes were responsible for the observed adverse effects seen with alemtuzumab. They propose that the measures they applied could also benefit other patients who develop similar adverse events during treatment with alemtuzumab.

MS is the most common neurological condition in young adults. It is characterized by chronic inflammation in the CNS. The body’s immune system attacks the insulating layer around nerve fibers (myelin) and permanently damages the cellular protuberances. Ten different classes of medications have been approved for the treatment of patients with MS.

Source: Ruhr University Bochum; January 18, 2017.