MHRA Safety alert: Dimethyl fumarate (Tecfidera): risk of progressive multifocal leukoencephalopathy (PML)

Dimethyl fumarate (Tecfidera) is authorised to treat adults with relapsing-remitting multiple sclerosis, to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease.

A recent European review of safety data identified 11 cases of PML with lymphopenia associated with Tecfidera treatment, including 3 cases in patients with mild lymphopenia (lymphocyte counts defined as lymphocyte counts between 0.8×10⁹ per litre and the lower limit of normal [per local laboratory]). These reports were received within an estimated exposure to Tecfidera of more than 475,000 patients.

The risk of PML in patients with mild lymphopenia has been added to the product information (summary of product characteristics), alongside a new contraindication for suspected or confirmed PML. The marketing authorisation holder of Tecfidera has sent a letter to HCPs to inform of this new advice.

Reference link: https://www.gov.uk/drug-safety-update/dimethyl-fumarate-tecfidera-updated-advice-on-the-risk-of-progressive-multifocal-leukoencephalopathy-pml-associated-with-mild-lymphopenia