Abstract: The present invention relates to the use of the compound biperiden as a MALT1 inhibitor in the treatment of a cancerous disease. The invention in particular relates to a combination of biperiden and a phenothiazine for use in the treatment of a cancerous disease. In a further aspect, the present invention is directed to a pharmaceutical composition for the treatment of a cancerous disease which comprises biperiden as a MALT1 inhibitor. Furthermore, a pharmaceutical composition is disclosed which comprises biperiden and at least a phenothiazine. In a further aspect, the invention relates to the use of biperiden in the treatment of a cancerous disease. The invention further provides a kit which comprises a container that includes biperiden and at least one container that includes a phenothiazine compound.