Estimating the Economic Burden of Progressive Multifocal Leukoencephalopathy in the United States: A Literature Review and Assessment

OBJECTIVES: Progressive multifocal leukoencephalopathy (PML) is a brain disease that can occur in immunosuppressed patients due to activation of the polyomavirus. PML is often fatal and thus can impose a significant disease burden on individuals. Through a focused literature review, we aimed to assess what is known about the economic burden of PML to support a full assessment at a population level.

METHODS: Economic burden depends on demographic, epidemiological, clinical, and economic factors. A literature review was conducted using PubMed and Scopus to identify information to support an aggregate economic burden assessment of PML. Duplicates were removed, and the remaining studies were screened for inclusion.

RESULTS: Thirty-one studies were identified with the most common being observational studies (N = 15) and US-based (N = 22) with a focus on treatment (N = 12), prognosis (N=6), and epidemiology (N = 5). The incidence of PML in multiple sclerosis (MS) patients using natalizumab received the most attention in the literature. Natalizumab-associated PML can be treated with plasma exchange or immunoadsorption. PML also occurs in patients with AIDS, hematological malignancies, and organ transplants. The medicines used to treat PML—cytarabine, cidofovir, and mefloquine—have been studied, but none has shown clear clinical benefit. Mortality, with associated high end-of-life costs, occurs in 60% of HIV patients with PML 2-years post-diagnosis. For surviving patients, the lack of remyelination leaves 80% of survivors with permanent neurologic deficits.

CONCLUSIONS: PML, as a lethal disease without highly effective treatments, imposes significant economic burden on a subset of immunocompromised patients. As yet, there is no published analysis that characterizes well the aggregate economic burden. Nonetheless, clinical strategies are under development to alleviate the obvious burden, including genetic testing to identify those at risk as well as new drug regimens.