Pembrolizumab Experience in a Patient with Progressive Multifocal Leukoencephalopathy Following Multiple Myeloma Treatment: A Case Report and Literature Review.

INTRODUCTION: Progressive multifocal leukoencephalopathy (PML) is a progressive demyelinating infection of the central nervous system. PML arises in immunosuppressive conditions or circumstances necessitating immunosuppressive treatment, such as malignancies. Recently, data have been published regarding the use of different immune checkpoint inhibitors (ICIs) for the treatment of PML. However, the extent to which ICIs impact and improve PML in individual patients remains uncertain.

CASE: A 68-year-old female patient, diagnosed with multiple myeloma in 2012 and with a history of using various chemotherapeutic agents, presented with dizziness, gait disturbances, and speech difficulties. The patient was diagnosed with PML and started on pembrolizumab treatment. This treatment led to improvements in both clinical symptoms and imaging findings.

CONCLUSION: Regardless of the underlying cause in PML, the use of ICIs can improve the clinical course of the disease and prolong the patient's lifespan.