This study aims to assess the efficacy and safety of pembrolizumab in immunocompromised patients with progressive multifocal leukoencephalopathy (PML). This phase II, multicenter, single-arm study includes patients with an underlying cause of immunosuppression hardly reversible, i.e. not the patients with HIV nor those receiving biologics for chronic inflammatory diseases. Patients will receive intravenous pembrolizumab (2 mg/kg, maximum 200 mg) at month 0, 1 and 2 (total of three doses). The primary endpoint will be achieving at least one negative result of JCV viral load in cerebrospinal fluid (CSF) within the M0 to M3 period.
Age ≥ 18 years old
Diagnosis of definite PML since less than 2 months according to American Academy of Neurology
Presence of JCV in the CSF in the last CSF sampling.
Signed informed consent (from the patient, or if unable to consent, from a surrogate)
Patients in whom immune reconstitution is achievable (HIV infection - Multiple sclerosis - Auto-immune and inflammatory diseases)
Patients who have received solid organ transplantation
Hypersensitivity to the active substance or to any of the excipients
Life expectancy less than 1 month