Letter sent to Healthcare Professionals: Tecfidera® (dimethyl fumarate)

Cases of progressive multifocal leukoencephalopathy (PML) now reported in mild lymphopenia therefore letter advises dimethyl fumarate is contraindicated in suspected/confirmed PML and discontinued in severe lymphopoenia (lymphocyte counts < 0.5 ×109/L) persisting for >6 months.

Biogen