Welcome to the Wang Lab
Zhirui Wang, DVM, PhD
Research Interests
Wang lab's research interest and expertise is using a unique diphtheria toxin resistant yeast Pichia pastoris expression system as a platform to develop diphtheria toxin-based recombinant immunotoxins for cancer treatment and transplantation tolerance induction.
Active Research Projects
CCR4-IL Bispecific Immunotoxin for Targeted Therapy of Cutaneous T-cell Lymphoma
We have developed a CCR4-IL2 bispecific immunotoxin (CCR4-IL2-IT) for targeted therapy of cutaneous T-cell lymphoma (CTCL). CCR4-IL2-IT is genetically engineered to contain both anti-human CCR4 scFv and human IL2 fused to a truncated diphtheria toxin. CCCR4-IL2-IT has demonstrated promising preclinical efficacy in a human CTCL mouse model showing 106% improvement in survival (69 vs. 33.5 days) compared to an IL-2 fusion toxin (Ontak®-like). We have also demonstrated that CCR4-IL2-IT is significantly more effective than FDA-approved Adcetris® (a leading drug in CTCL clinical market) in the same human CTCL mouse model. Recently, we have completed non-GLP toxicology studies of CCR4-IL2-IT in both rats and minipigs with excellent toxicity profile. Currently, Investigational New Drug (IND)-enabling studies of CCR4-IL2-IT are ongoing supported by NCI STTR FastTrack grant, Colorado OEDIT grant and University of Colorado Spark grant. Our goal is to prepare an IND-ready package and move CCR4-IL2-IT into CTCL human clinical trials.
Bivalent Anti-human CD47 Immunotoxin for Targeted Therapy of T-cell Acute Lymphoblastic Leukemia
We have developed a diphtheria toxin-based bivalent anti-human CD47 immunotoxin (bi-CD47-IT) for targeted therapy of CD47+ cancers. Bi-CD47-IT demonstrated compelling in vivo efficacy in multiple T-cell acute lymphoblastic leukemia (T-ALL) cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) mouse models. Bi-CD47-IT significantly prolonged the median survival of the tumor-bearing mice and highly effectively depleted the T-ALL blast cells in the peripheral blood, spleen, liver, bone marrow, brain, and spinal cord in the T-ALL CDX and PDX mouse models. Bi-CD47-IT cured 60% of tumor-bearing mice in a T-ALL Molt-4 CDX mouse model. CD47 is also expressed on normal tissues with low binding avidity, including red blood cells and lymphocytes. Specificity is a concern. We have analyzed the in vitro binding avidity and hemagglutination of bi-CD47-IT in human red blood cells, finding no binding or hemagglutination. We further performed a toxicity study of bi-CD47-IT in humanized mice, which showed that bi-CD47-IT transiently depleted the human lymphocytes. Bi-CD47-IT possesses the “optimal” binding avidity, with effective binding to human CD47+ T-ALL tumor cells, no binding to human red blood cells and weak binding to human lymphocytes. We believe that bi-CD47-IT is a promising and safe therapeutic drug candidate for the targeted therapy of broad-spectrum CD47+ cancers.
CCR4 Immunotoxin for Cancer Immunotherapy via Treg Depletion
Currently no FDA-approved drug specifically and efficiently depletes tumor-infiltrating effector Tregs. CCR4 is highly and specifically expressed on the surface of tumor-infiltrating effector Tregs. CCR4 is one of the recognized targets to deplete tumor-infiltrating effector Tregs. We have developed a diphtheria toxin-based anti-human CCR4 immunotoxin (CCR4-IT) for cancer immunotherapy via Treg depletion. We have demonstrated that CCR4-IT effectively and specifically depleted CCR4+Foxp3+ Tregs in both naïve cynomolgus monkeys and miniature swine. Recent preliminary data demonstrated that combination immunotherapy of CCR4-IT with Pembrolizumab (anti-PD-1 mAb) shows remarkably improved effectiveness compared with Pembrolizumab alone in a cell-line derived xenograft (CDX)-based humanized mouse triple-negative breast cancer (TNBC) model.
Novel CD154 Targeted Therapeutics to Facilitate Vascularized Composite Allotransplantation Tolerance
We have developed a species-specific high-affinity anti-porcine CD154 nanobody using a synthetic nanobody library based-yeast surface display platform. The lack of Fc domain in the anti-porcine CD154 nanobody is expected to reduce off-target effects including thromboembolic side effects. We then genetically engineered the high-affinity anti-porcine CD154 nanobody to truncated diphtheria toxin DT390 to generate a species-specific anti-porcine CD154 immunotoxin. We hypothesize that combination of the depletion of porcine memory alloreactive CD154+ T cells known to interfere with immune tolerance induction using the anti-porcine CD154 immunotoxin with porcine CD40/CD154 co-stimulation blockade using the high-affinity anti-porcine CD154 nanobody will prolong vascularized composite allotransplantation (VCA) graft survival and significantly improve VCA tolerance induction.
Featured Publications
Bivalent CD47 immunotoxin for targeted therapy of T-cell acute lymphoblastic leukemia
11/19/2024
CD47 is overexpressed on the surface of many types of cancer cells, including T-cell acute lymphoblastic leukemia (T-ALL) cells. In this study, we have developed a diphtheria toxin (DT)-based bivalent anti-human CD47 immunotoxin (bi-CD47-IT) for the targeted therapy of CD47+ cancers using a unique DT-resistant yeast Pichia pastoris expression system. Bi-CD47-IT demonstrated compelling in vivo efficacy in multiple...
Toxicology, pharmacokinetics, and immunogenicity studies of CCR4-IL2 bispecific immunotoxin in rats and minipigs
02/15/2024
We have developed a diphtheria toxin-based recombinant human CCR4-IL2 bispecific immunotoxin (CCR4-IL2-IT) for targeted therapy of cutaneous T-cell lymphoma (CTCL). CCR4-IL2-IT demonstrated superior efficacy in an immunodeficient mouse CTCL model. Recently, we have compared the in vivo efficacy of CCR4-IL2-IT versus Brentuximab (FDA approved leading drug in CTCL market) in the same immunodeficient...
05/15/2023
Cutaneous T-cell lymphoma (CTCL) encompasses two main subtypes: mycosis fungoides and Sezary syndrome. Global response rates for the systemic treatment of mycosis fungoides and Sezary syndrome are approximately 30%, and none of these treatments are thought to be curative. C-C chemokine receptor type 4 (CCR4) and CD25 are encouraging targets for the treatment of CTCL and are individually targeted by mogamulizumab...
02/04/2021
Epidermal growth factor receptor (EGFR) is often overexpressed in head and neck squamous cell carcinoma (HNSCC) and represents a top candidate for targeted HNSCC therapy. However, the clinical effectiveness of current Food and Drug Administration (FDA)-approved drugs targeting EGFR is moderate, and the overall survival rate for HNSCC patients remains low. Therefore, more effective treatments are urgently needed. In...
Bispecific human IL2-CCR4 immunotoxin targets human cutaneous T-cell lymphoma
03/13/2020
The majority of clinically diagnosed cutaneous T-cell lymphomas (CTCL) highly express the cell-surface markers CC chemokine receptor 4 (CCR4) and/or CD25. Recently, we have developed diphtheria toxin-based recombinant Ontak®-like human IL2 fusion toxin (IL2 fusion toxin) and anti-human CCR4 immunotoxin (CCR4 IT). In this study, we first compared the efficacy of the CCR4 IT vs IL2 fusion toxin for targeting human CD25+ CCR4+ CTCL...
Diphtheria toxin-based anti-human CD19 immunotoxin for targeting human CD19+ tumors
04/04/2017
CD19 is expressed on normal and neoplastic B cells and is a promising target for immunotherapy. However, there is still an unmet need to further develop novel therapeutic drugs for the treatment of the refractory/relapsing human CD19+ tumors. We have developed a diphtheria toxin-based anti-human CD19 immunotoxin for targeting human CD19+ tumors. We have constructed three isoforms of the CD19 immunotoxin: monovalent...
11/19/2015
Regulatory T cells (Treg) play an important role in modulating the immune response and has attracted increasing attention in diverse fields such as cancer treatment, transplantation and autoimmune diseases. CC chemokine receptor 4 (CCR4) is expressed on the majority of Tregs, especially on effector Tregs. Recently we have developed a diphtheria-toxin based anti-human CCR4 immunotoxin for depleting CCR4(+) cells in vivo. In this...
Porcine Treg depletion with a novel diphtheria toxin-based anti-human CCR4 immunotoxin
10/29/2016
Regulatory T cells (Tregs) are known to play an important role in immunoregulation and have been shown to facilitate induction of transplantation tolerance. Chemokine (C-C motif) receptor 4 (CCR4) is expressed on the surface of effector Tregs involved in controlling alloimmune and autoimmune responses. Recently we have developed a novel diphtheria-toxin based anti-human CCR4 immunotoxin for depleting CCR4+ cells in vivo. In this study...
Diphtheria-toxin based anti-human CCR4 immunotoxin for targeting human CCR4(+) cells in vivo
04/25/2015
CC chemokine receptor 4 (CCR4) has attracted much attention as a promising therapeutic drug target for CCR4(+) tumor cells and Tregs. CCR4 is expressed on some tumor cells such as T-cell acute lymphoblastic leukemia (ALL), adult T-cell leukemia/lymphoma (ATLL), adult peripheral T cell lymphoma (PTCL) and cutaneous T cell lymphoma (CTCL). CCR4 is also expressed on majority of Tregs, mainly effector Tregs. In this study we have successfully...
Development of a diphtheria toxin based antiporcine CD3 recombinant immunotoxin
09/09/2011
Anti-CD3 immunotoxins, which induce profound but transient T-cell depletion in vivo by inhibiting eukaryotic protein synthesis in CD3+ cells, are effective reagents in large animal models of transplantation tolerance and autoimmune disease therapy. A diphtheria toxin based antiporcine CD3 recombinant immunotoxin was constructed by fusing the truncated diphtheria toxin DT390 with two identical tandem single chain variable...