Progressive multifocal leukoencephalopathy and granule cell neuronopathy with novel mutation flanking VP1 C-terminus in natalizumab-extended interval dosing

Newly diagnosed AIDS patient with cerebellar JC virus

We present a case of a 57-year-old man with newly diagnosed acquired immunodeficiency syndrome (AIDS) infection who initially sought care for progressive dysarthria and gait instability. Neuroimaging and CSF studies revealed a diagnosis of progressive multifocal leukoencephalopathy (PML). Although the patient's human immunodeficiency virus (HIV) decreased considerably in response to anti-retroviral therapy, he continued to deteriorate clinically. Ultimately, the central nervous system (CNS) lesions, which were once centered in the cerebellum, became expansile throughout his posterior fossa. There are few reported cases of cerebellar PML in patients with AIDS.

Progressive multifocal leukoencephalopathy with natalizumab extended or standard interval dosing in the United States and the rest of the world

BACKGROUND

Progressive multifocal leukoencephalopathy (PML), an important identified risk for natalizumab, has been described for standard interval dosing (SID; dosing interval every-4-weeks). Information on PML with natalizumab extended interval dosing (EID; dosing interval >every-4-weeks) in the US and the rest of the world (ROW) is limited.

RESEARCH DESIGN AND METHODS

A retrospective analysis of patient demographics, risk factors, clinical characteristics, and clinical outcomes was conducted on confirmed natalizumab EID and SID PML cases evaluated from Biogen pharmacovigilance systems.

RESULTS

Of 857 confirmed natalizumab PML cases, EID and SID accounted for 7.5% and 92.5%, respectively (US: 12.9% and 87.1%; ROW: 5.4% and 94.6%). PML risk factors included anti-JCV index > 1.5 (US: EID, 56.7% and SID, 12.8%; ROW: EID, 44.1% and SID, 21.0%), mean duration of natalizumab treatment (US: 90.0 and 70.2 months; ROW: 54.1 and 49.8 months), and prior immunosuppressive therapy (US: 20.0% and 21.7%; ROW:11.8% and 18.0%). In the EID and SID groups, 68.8% and 76.0% of patients, respectively, were alive at up to 2 years after diagnosis.

CONCLUSIONS

This analysis provides insights on PML in patients receiving natalizumab that extend current knowledge, particularly regarding PML in patients receiving natalizumab EID, which can be built upon in the future.

Characteristics of Progressive Multifocal Leukoencephalopathy Associated With Sarcoidosis Without Therapeutic Immune Suppression

Importance

Progressive multifocal leukoencephalopathy can occur in the context of systemic sarcoidosis (S-PML) in the absence of therapeutic immune suppression and can initially be mistaken for neurosarcoidosis or other complications of sarcoidosis. Earlier recognition of S-PML could lead to more effective treatment of the disease.

Objective

To describe characteristics of patients with S-PML.

Design, Setting, and Participants

For this case series, records from 8 academic medical centers in the United States were reviewed from 2004 to 2022. A systematic review of literature from 1955 to 2022 yielded data for additional patients. Included were patients with S-PML who were not receiving therapeutic immune suppression. The median follow-up time for patients who survived the acute range of illness was 19 months (range, 2-99). Data were analyzed in February 2023.

Exposures

Sarcoidosis without active therapeutic immune suppression.

Main Outcomes and Measures

Clinical, laboratory, and radiographic features of patients with S-PML.

Results

Twenty-one patients with S-PML not receiving therapeutic immune suppression were included in this study, and data for 37 patients were collected from literature review. The median age of the 21 study patients was 56 years (range, 33-72), 4 patients (19%) were female, and 17 (81%) were male. The median age of the literature review patients was 49 years (range, 21-74); 12 of 34 patients (33%) with reported sex were female, and 22 (67%) were male. Nine of 21 study patients (43%) and 18 of 31 literature review patients (58%) had simultaneous presentation of systemic sarcoidosis and PML. Six of 14 study patients (43%) and 11 of 19 literature review patients (58%) had a CD4+ T-cell count greater than 200/μL. In 2 study patients, a systemic flare of sarcoidosis closely preceded S-PML development. Ten of 17 study patients (59%) and 21 of 35 literature review patients (60%) died during the acute phase of illness. No meaningful predictive differences were found between patients who survived S-PML and those who did not.

Conclusions and Relevance

In this case series, patients with sarcoidosis developed PML in the absence of therapeutic immune suppression, and peripheral blood proxies of immune function were often only mildly abnormal. Systemic sarcoidosis flares may rarely herald the onset of S-PML. Clinicians should consider PML in any patient with sarcoidosis and new white matter lesions on brain magnetic resonance imaging.

Progressive multifocal leukoencephalopathy in dimethyl fumarate-treated multiple sclerosis patients

Dimethyl fumarate (DMF), a fumaric acid with antioxidant and immunomodulatory properties, is among the most commonly used oral therapies for relapsing multiple sclerosis (MS). Progressive multifocal leukoencephalopathy (PML) has been associated with several disease-modifying therapies (DMTs), including DMF in treating MS. We present detailed clinical characteristics of nine PML cases and show that the PML incidence in DMF-treated patients is 0.02 per 1000 patients. In addition to persistent severe lymphopenia, older age appears to be a potential risk for PML. However, younger patients without lymphopenia were also observed to develop PML. DMF-associated PML has occurred in patients with absolute lymphocyte counts (ALCs) above the guideline threshold, suggesting that changes in specific subsets might be more important than total ALC. Furthermore, since DMF has been found to decrease immune cell migration by decreasing the expression of adhesive molecules, the cerebrospinal fluid (CSF) immune profile may also be useful for assessing PML risk in DMF-treated patients. This review provides an up-to-date assessment of PML cases occurring in DMF-treated patients and discusses other potential considerations in light of our current understanding of DMF's mechanism of action on the immune system in the periphery and in the central nervous system (CNS).