TAK-659 is an inhibitor of spleen tyrosine kinase (syk), with potential anti-inflammatory, immunomodulating, and antineoplastic activities. Spleen tyrosine kinase inhibitor TAK-659 may inhibit the activity of syk, which abrogates downstream B-cell receptor (BCR) signaling and leads to an inhibition of B-cell activation, chemotaxis, adhesion and proliferation. Note: TAK-659 free base is less stable. This product is supplied as dihydrochloride form.