The present disclosure provides a
cytokine-based bioactivatable
drug construct (“VitoKine”) platform that aims to reduce systemic mechanism-based toxicities and lead to broader therapeutic utility for proteins and cytokines such as IL-15 and IL-2 for the treatment of
cancer, autoimmune diseases, inflammatory diseases,
viral infection,
transplantation and various other disorders. The novel VitoKine constructs of the present invention comprise: 1) a tissue or
disease site targeting
moiety D1 domain (“D1”), 2) a bioactivatable
moiety D2 domain (“D2”), and a concealing
moiety D3 domain (“D3”). Importantly, because the “active moiety” of the VitoKine construct will remain
inert until activated locally by
proteases that are upregulated in diseased tissues, this will limit binding of the active moiety to the receptors or to the targets in the
peripheral or on the
cell-surface of non-diseased cells and tissue to prevent over-activation of the pathway and reduce undesirable “on-target”“off tissue” toxicities. Additionally, the inertness of the VitoKine active moiety prior to
protease activation will significantly decrease the potential
antigen or target sink, and thus, prolong the
in vivo half-life and result in improved
biodistribution,
bioavailability and therapeutic
efficacy.