How does alemtuzumab cause stroke? It is unlikely to be due to secondary autoimmune disease as it occurs too soon after administration. Could it be due to a mechanism that triggers thrombotic mechanisms, for example via platelet activation? Alemtuzumab causes an early and transient low platelet count (thrombocytopenia), which may be related to thrombosis.
Adapted excerpt from the FDA website:
The U.S. Food and Drug Administration (FDA) is warning that rare but serious cases of stroke and tears in the lining of arteries in the head and neck have occurred in patients with multiple sclerosis (MS) shortly after they received alemtuzumab. These problems can lead to permanent disability and even death. As a result, the FDA has added a new warning about these risks to the prescribing information in the drug label and to the patient Medication Guide. They have also added the risk of stroke to the existing Boxed Warning, FDA’s most prominent warning.
The FDA is recommending that patients or their caregivers should seek emergency treatment as soon as possible if the patient experiences signs or symptoms of a stroke or tears in the lining of the head and neck arteries, called arterial dissection, which can include:
Most patients taking alemtuzumab who developed stroke or tears in the artery linings developed symptoms within 1 day of receiving alemtuzumab. One patient reported symptoms that occurred 3 days after treatment.
- Sudden numbness or weakness in the face, arms, or legs, especially if it occurs on only one side of the body
- Sudden confusion, trouble speaking, or difficulty understanding speech
- Sudden trouble seeing in one or both eyes
- Sudden trouble with walking, dizziness, or loss of balance or coordination
- Sudden severe headache or neck pain
Health care professionals should advise patients at every alemtuzumab infusion to seek immediate emergency medical attention if they experience symptoms of ischemic or hemorrhagic stroke or cervicocephalic arterial dissection. The diagnosis is often complicated because early symptoms such as a headache and neck pain are not specific. Promptly evaluate patients who complain of symptoms consistent with these conditions.
In the nearly 5 years since FDA approved alemtuzumab in 2014 to treat relapsing forms of MS, the FDA have identified 13 worldwide cases of ischemic and hemorrhagic stroke or arterial dissection that occurred shortly after the patient received alemtuzumab (see Data Summary). This number includes only reports submitted to FDA,* so additional cases that they are unaware of may have occurred. Twelve of these cases reported symptoms within 1 day of receiving alemtuzumab. As a result, the FDA has added a new warning about this risk in the Warnings and Precautions section of the prescribing information in the drug label. They have also added the risk of stroke to the existing Boxed Warning, FDA’s most prominent warning.
To help FDA track safety issues with medicines, they are urging health care professionals to report side effects from Alemtuzumab or other medicines to the FDA MedWatch program.
Labels: Alemtuzumab, carotid dissection, FDA, Stroke