Cutaneous T-Cell Lymphoma (CTCL) has risen dramatically and consistently since 1973 with approximately 1,600 new cases of CTCL diagnosed each year in the US. Currently, there is no cure for CTCL and it is characterized by a chronic, relapsing course that requires repeat treatment regimens. The survival and response rate to CTCL therapeutics are only 20-30%. Overexpression of the CD25 and CCR4 receptors is a prominent molecular characteristic of CTCL. Research led by Dr. Zhirui Wang at the University of Colorado has led to the development of a diphtheria toxin-based CCR4-IL2 bispecific immunotoxin comprised of human IL2 and anti-human CCR4 scFv, which targets CD25+ and/or CCR4+ tumors such as those present in CTCL. Preliminary in vivo studies have demonstrated promising preclinical efficacy of the therapeutic in a mouse tumor model showing 106% improvement in survival (69 vs. 33.5 days) compared to a previously FDA-approved CTCL treatment, which is a human IL2 fusion toxin. Dr. Wang’s work could help create a new class of CTCL treatments. Importantly, the surface receptors CCR4 and CD25 are also expressed on effector tumor-infiltrating regulatory T-cells (Tregs). Therefore, a potential follow-on indication for the bispecific immunotoxin is depletion of tumor infiltrating CCR4+ or/and CD25+ Tregs to treat broad spectrum of cancers. The IND-enabling (including toxicology) and GMP production studies are ongoing and supported by NIH STTR FastTrack grant and Colorado Advanced Industries Accelerator grant.