SBIR-STTR Award

B-cell lymphomas include Hodgkin's, and non-Hodgkin's lymphoma (NHL) (eg. mantle cell lymphoma (MCL), follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and Burkitt lymphoma). More than 70,000 people will be diagnosed with these B-cell malignancies in the U.S. this year and more than 19,000 will die from NHL alone. B-cell lymphomas can affect numerous organs including the lymph nodes, spleen, liver, and bone marrow. Many patients who receive treatment for B-cell lymphomas become refractory to all available therapies and often die from disease. Thus, there is a significant need to identify newer therapeutics with greater activity and fewer side effects. The novel biologic agent Leukothera(R) (leukotoxin; LtxA) specifically targets active leukocyte function antigen-1 (LFA-1) expressed on white blood cells (WBCs). Malignant WBCs constantly express high levels active LFA-1, allowing LtxA to target specifically diseased cells while minimally affecting healthy cells and tissue. LtxA employs several mechanisms of cell death to intoxicate susceptible WBCs. We have found that cell lines and primary cells from patients with newly diagnosed, relapsed, and refractory leukemia and lymphoma are highly sensitive to LtxA. In preclinical studies, LtxA shows significant efficacy using humanized mouse models for leukemia. In addition, single- dose LtxA administered intravenously into rhesus monkeys was active, highly specific for WBCs, and well-tolerated. No effect was seen on red blood cells, platelets, hemoglobin, or markers of organ toxicity. However, no studies have yet examined LtxA for the treatment of B- cell lymphoma. Thus, based on our encouraging preclinical studies for leukemia, we propose to test LtxA using in vitro and in vivo B-cell lymphoma model systems. The data that we generate from the work described in this application is necessary to provide proof-of-principle and mechanistic knowledge for subsequent clinical testing in lymphoma patients.

Public Health Relevance:
B-cell lymphomas kill thousands of people each year. We are developing a biotherapeutic agent (leukotoxin) that has targeted specificity for malignant white blood cells. Our studies will test the hypothesis that leukotoxin can be used for the treatment of B-cell lymphomas employing in vitro and in vivo models.

Public Health Relevance Statement:
B-cell lymphomas kill thousands of people each year. We are developing a biotherapeutic agent (leukotoxin) that has targeted specificity for malignant white blood cells. Our studies will test the hypothesis that leukotoxin can be used for the treatment of B-cell lymphomas employing in vitro and in vivo models.

NIH Spending Category:
Cancer; Clinical Research; Hematology; Hodgkin's Disease; Lymphoma; Orphan Drug; Rare Diseases

Project Terms:
Adverse effects; Affect; Antigens; B lymphoid malignancy; B-Cell Lymphomas; base; Biological Models; Biological Products; Blood Platelets; Bone Marrow; Burkitt Lymphoma; cancer cell; Cell Death; Cell Line; Cell surface; Cells; Collaborations; Data; Diagnosis; Disease; Dose; efficacy testing; Erythrocytes; Follicular Lymphoma; Hemoglobin; Hodgkin Disease; humanized SCID mouse; In Vitro; in vivo; in vivo Model; Institutes; Killings; Knowledge; large cell Diffuse non-Hodgkin's lymphoma; leukemia; leukemia/lymphoma; Leukocytes; leukotoxin; Liver; lymph nodes; Lymphoma; Macaca mulatta; Malignant - descriptor; Malignant lymphoma, lymphocytic, intermediate differentiation, diffuse; Malignant Neoplasms; Methods; mouse model; Newly Diagnosed; NOD/SCID mouse; Non-Hodgkin's Lymphoma; novel; novel therapeutics; Organ; outcome forecast; Patients; preclinical study; Refractory; Relapse; research clinical testing; research study; Sampling; Screening procedure; Specificity; Spleen; Testing; Tissues; Toxic effect; Work

B-cell lymphoma is cancer of B-lymphocytes and accounts for more than 20,000 deaths in the U.S. each year. While many patients respond to currently available therapy, there is a high rate of cancer relapse and inability for the patients o tolerate chemotherapy. Thus, there is a significant need to make available to these patients newer therapies that are more effective and better tolerated than the drugs that are currently used. Actinobac Biomed, Inc. is developing a natural biologic therapy that seeks out and kills a subset of white blood cells (WBCs). This therapy, Leukothera(R) (LtxA; leukotoxin), is a native protein derived from an oral bacterium. LtxA binds specifically to the active form of lymphocyte function associated antigen- 1 (LFA-1) and causes cell death. LFA-1 is found exclusively on WBCs, and malignant WBCs overexpress the molecule, making them ideal targets for the drug. During the phase I stage of this STTR application, we showed that 1) LtxA kills malignant B-cells using a unique mechanism of action, which involves Fas death receptor and caspase 8; 2) lymph node tissue samples from B-cell lymphoma patients express high levels of LFA-1; 3) LtxA causes complete regression of tumors in a humanized mouse model for B-cell lymphoma and results in long-term survival; 4) the drug is well-tolerated, highly active, and does not cause a neutralizing immune response in healthy dogs or a dog with naturally-occurring lymphoma, and 5) we have initiated expression and production of recombinant LtxA in a cGMP drug manufacturing facility in preparation for Investigational New Drug (IND)-enabling studies and clinical trials. Important pharmaceutical properties of LtxA include: 1) the drug works rapidly in vivo, within minutes or less; 2) doses as low as 0.5 g/kg have been shown to be highly active in animals; 3) neutralizing antibody to LtxA is not generated in healthy or diseased animals, even after repeat dosing; and 4) the high specificity of the drug allows targeting of a subset of WBCs and complete depletion of WBCs has never been observed with LtxA treatment. During this STTR phase II proposal, Actinobac will carry out IND-enabling studies that will be included in the IND application to the FDA.

Public Health Relevance Statement:


Public Health Relevance:
B-cell lymphomas kill thousands of people each year. We are developing a biotherapeutic agent (Leukothera(R)) that has targeted specificity for malignant white blood cells. This phase II application will accomplish studies that are required for FDA approval to start testing in human patients with B-cell lymphoma.

Project Terms:
Accounting; Addendum; Animals; Antibodies; Authorization documentation; B-Cell Lymphomas; B-lymphocyte Cancer; B-Lymphocytes; Binding (Molecular Function); Biological Products; Biological Response Modifier Therapy; Biotechnology; Cancer Relapse; Canis familiaris; caspase-8; Cell Death; Cessation of life; chemotherapy; Clinical Trials; Cyclic GMP; Detection; Dose; Drug Kinetics; Drug Targeting; Escherichia coli; Evaluation; Genes; Human; Immune response; immunogenic; in vivo; International; Investigational Drugs; Investigational New Drug Application; Killings; Leukocytes; leukotoxin; Lymph Node Tissue; Lymphocyte Function-Associated Antigen-1; Lymphoma; Malignant - descriptor; manufacturing facility; Marketing; Methods; mouse model; neutralizing antibody; NOD/SCID mouse; oral bacteria; overexpression; Patients; Pharmaceutical Preparations; Pharmacodynamics; Pharmacologic Substance; Phase; phase 1 study; Plasma; Plasmids; preclinical safety; preclinical study; Preparation; Production; Property; Proteins; public health relevance; Rattus; receptor; Recombinants; Regimen; Safety; Sampling; scale up; Small Business Technology Transfer Research; Specificity; Staging; symposium; Testing; Tissue Sample; Toxicology; tumor; Work