Anti-PD1 Treatment of Progressive Multifocal Leucencephalopathy in a Patient with Multiple Myeloma Treated with Anti-Bcma Bispecific Antibodies: A Case Report

Navarro-Sánchez M, Casanova-Espinosa M, López-Muñoz N, Alonso-Fernández RA, Martínez-López J.

Abstract

Relapsed/refractory multiple myeloma (RRMM) is still an incurable disease with poor prognosis. Bispecific antibodies, such as Teclistamab, are a new promising option for these patients. However, evidence from clinical trials and real-world experience suggest that they increase the risk of infections, including opportunistic infections like Progressive Multifocal Leukoencephalopathy (PML). To date, only two cases of PML in patients receiving Teclistamab have been reported, both with a fatal outcome.

We present the case of a 51-year-old male with MM refractory to three previous lines of treatment. Eight months after initiating treatment, he was diagnosed of PML after developing neurological symptoms such as diplopia and behavioral changes. Teclistamab was interrupted and treatment with intravenous immunoglobulin (IVIg) and anti-PD1 (pembrolizumab) was initiated. Although there was no improvement in neurological symptoms nor image findings, the patient is still alive 32 months further the diagnosis of PML with slightly clinical improvement of PML and in complete remission with no detectable MRD.

Despite the limited treatment options available, this case shows the importance of early treatment of PML stopping Anti-BCMA therapy and using anti- PD-1 and shows an exceptionally time of survival after diagnosis given the ominous prognosis these patients usually have.