Acute acalculous cholecystitis: A new safety risk for patients with MS treated with alemtuzumab.

Objective: To evaluate acute acalculous cholecystitis (AAC) as a potential safety risk for patients treated with alemtuzumab.

Methods: The Food and Drug Administration Adverse Event Reporting System and the medical literature were searched for cases of AAC in conjunction with alemtuzumab for all clinical indications.

Results: Eight spontaneously reported cases meeting the case definition of AAC in close temporal association with alemtuzumab use were identified. Based on established criteria within the Food and Drug Administration Division of Pharmacovigilance for causality assessment, 4 cases were assessed as probable while 4 were possible. All cases occurred in patients with relapsing-remitting multiple sclerosis. Seven of the 8 cases presented with AAC during or shortly after alemtuzumab treatment, thereby suggesting an acute cytokine release syndrome as a putative pathogenic mechanism. The cases identified in this review differ from the typical AAC cases described in the medical literature based on female preponderance, lack of concurrent critical illnesses, inconsistent presence of other risk factors, and resolution with conservative treatment in the majority of cases.

Conclusions: AAC represents a new and potentially life-threatening adverse event associated with alemtuzumab use in relapsing-remitting multiple sclerosis. In cases seen to date, early and conservative treatment resulted in good clinical outcome, although the natural history of AAC in this population without critical illness is not well defined. Awareness of this safety risk by general and specialty neurologists is important for prompt recognition and optimal management.