Therapeutic Experience of Progressive Multifocal Leukoencephalopathy Development during Ofatumumab Therapy for Chronic Lymphocytic Leukemia.

A 79-year-old man experienced cognitive impairment and visual field defects during ofatumumab therapy for chronic lymphocytic leukemia refractory to combination chemotherapy. Magnetic resonance imaging revealed T1-weighted low-intensity and T2-weighted high-intensity lesions with patchy gadolinium enhancement in the subcortical white matter. A diagnosis of progressive multifocal leukoencephalopathy was made after the detection of John Cunningham virus (JCV) DNA in his cerebrospinal fluid (CSF). Following plasma exchange and the administration of mirtazapine and mefloquine, the JCV DNA levels in the CSF decreased. However, the patient died 55 days after treatment was initiated. Ofatumumab treatment appears to be associated with the development of progressive multifocal leukoencephalopathy.