Vumerity, also known by its generic name diroximel fumarate, is a medication used to treat relapsing forms of multiple sclerosis (MS) [1]. While Vumerity is not a treatment for progressive multifocal leukoencephalopathy (PML), it is important for patients with MS to be aware of PML as a potential risk associated with certain MS therapies [2].
What is Progressive Multifocal Leukoencephalopathy (PML)?
PML is a rare but serious demyelinating disease of the central nervous system that can be caused by the JC virus [3]. It attacks oligodendrocytes, the cells that produce myelin, the protective sheath around nerve fibers [3]. This damage can lead to severe neurological disability and is often fatal [3].
Which MS Drugs Have Been Linked to PML?
Several disease-modifying therapies (DMTs) for multiple sclerosis have been associated with an increased risk of PML. Historically, natalizumab (Tysabri) and fingolimod (Gilenya) were among the first to show a significant link to PML [4]. More recently, dimethyl fumarate (Tecfidera), the precursor drug to Vumerity, and its metabolite monomethyl fumarate have also been associated with PML, though at a lower reported frequency compared to some other MS medications [5][6]. Alemtuzumab (Lemtrada) and rituximab (Rituxan) have also had cases of PML reported in patients treated with them [4].
What is the Risk of PML with Vumerity?
Vumerity is designed to deliver dimethyl fumarate to the body more effectively, aiming to reduce gastrointestinal side effects compared to Tecfidera [1]. However, both Vumerity and Tecfidera metabolize into monomethyl fumarate (MMF) in the body, which is believed to be the active compound [1][5]. Because of this shared active metabolite, there is a theoretical risk of PML with Vumerity, similar to that seen with dimethyl fumarate [5][6].
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How is PML Monitored in MS Patients?
To mitigate the risk of PML, healthcare providers closely monitor patients on MS therapies that carry this potential risk [2]. This monitoring typically includes regular neurological examinations and, in some cases, MRI scans [2]. Specific risk factors for PML include the duration of treatment, the dose of medication, and the patient's degree of immunosuppression [2][3]. For medications like natalizumab, which have a higher documented risk, routine JC virus antibody testing is often employed to assess a patient's risk of developing PML [4].
What Symptoms Should Patients Watch For?
Patients being treated with MS therapies, including those that carry a risk of PML, should be aware of potential symptoms. These can include new or worsening neurological symptoms such as weakness, sensory changes, vision problems, cognitive difficulties, or speech and coordination issues [3]. Any new or unusual neurological symptoms should be reported to a healthcare provider immediately [3].
What Happens If PML is Suspected?
If PML is suspected, treatment with the causative MS therapy is typically discontinued immediately [3]. Diagnosis is often confirmed through MRI and analysis of cerebrospinal fluid (CSF) for the presence of the JC virus [3]. Management of PML is supportive, as there is no specific cure for the infection itself [3].
Sources:
[1] https://www.drugpatentwatch.com/drugs/vumerity
[2] https://www.drugpatentwatch.com/blog/pml-risk-with-multiple-sclerosis-treatments
[3] https://www.drugpatentwatch.com/blog/understanding-progressive-multifocal-leukencephalopathy-pml
[4] https://www.drugpatentwatch.com/blog/multiple-sclerosis-drug-risk-profile-pml
[5] https://www.drugpatentwatch.com/blog/dimethyl-fumarate-pml-risk
[6] https://www.drugpatentwatch.com/blog/vumerity-vs-tecfidera-understanding-the-difference