SBIR-STTR Award

Cancer immunotherapy is predicated on overcoming immune tolerance to tumors and facilitating immune- mediated tumor cell killing. Current approaches include the use of therapeutic cancer vaccines, adoptive transfer of immune effectors, and the use of immunostimulatory monoclonal antibodies that block immune checkpoints. Although these therapies have shown promise in treating many types of cancer, they are not effective in all patients. A frequent basis for treatment failure appears to be a tumor microenvironment that does not support the recruitment or infiltration of tumor-reactive T cells. At Kineta, we are developing small- molecule compounds that target RIG-I-like receptor pathways, and other IRF3-inducing pathways, to stimulate innate immunity. Because of the unique immune-stimulating properties of these IRF3 agonists, we have begun to evaluate their potential as cancer immunotherapeutics. Our proof-of-concept compound, KIN1312, induces immunogenic cell death, a cell death pathway that elicits an innate immune activation cascade within the tumor microenvironment that primes a T cell response against tumor neoantigens and that recruits activated T cells into the tumor. KIN1312 inhibits tumor growth in mice, and mice exhibiting tumor regression in response to KIN1312 are immune to re-challenge with live tumor cells of the same type. In this Phase I application, we will evaluate a panel of structure-activity relationship (SAR)-derived KIN1312 analogs, and a small number of compounds representing alternative chemical scaffolds, with the goal of improving overall potency and drug- like properties. In Aim 1, we will screen compounds for their ability to induce cytokine production in mouse and human cancer cells and to induce apoptotic cell death. In addition, we will measure the ability of compounds to induce translocation of calreticulin to the outer cell membrane, the release of damage-associated molecular patterns, and dendritic cell activation. In parallel, we will rank compounds for desirable drug-like properties including aqueous solubility, metabolic stability, and formulation compatibility. At least four unique chemical series will be chosen for advancement to Aim 2. In Aim 2, we will determine the effects of these compounds on tumor growth in mice. We evaluate the therapeutic effects of the compounds by injection of compound into tumors induced by implantation of CT26 cancer cells. In parallel, we will assess the antitumor effects of systemic (intravenous) administration of KIN1312 that has been formulated in liposomes. We will also use liposome formulated KIN1312 to perform an initial evaluation of in vivo safety. From these studies, we will select a lead and backup chemical series for advancement to Phase II, which will include second-stage medicinal chemistry optimization and preclinical development as a novel immunotherapy aimed at modifying the tumor microenvironment to facilitate immune-mediated tumor cell killing.

Public Health Relevance Statement:
PROJECT NARRATIVE The goal of cancer immunotherapy is to stimulate the immune system to specifically target and eliminate tumor cells. We are developing a new type of immunotherapy drug that induces cancer cell death in such a way that the dying cancer cells stimulate a tumor-specific immune response to eliminate tumor growth and prevent tumor reoccurrence. Because of this mechanism of action, our drug may be used to improve the efficacy of other immunotherapies, such as immune checkpoint blockers.

Project Terms:
Adjuvant; Adoptive Transfer; Agonist; analog; Anthracyclines; Antigen Presentation; Antigens; antitumor effect; Apoptosis; Apoptotic; aqueous; base; Binding Proteins; Biological Assay; Blocking Antibodies; calreticulin; cancer cell; cancer immunotherapy; Cancer Model; cancer type; Cancer Vaccines; CD8-Positive T-Lymphocytes; Cell Death; cell killing; Cell membrane; Cell surface; Cells; Chemical Structure; Chemicals; chemokine; CT26; cytokine; Cytotoxic agent; Data; Dendritic cell activation; Dendritic Cells; design; DNA; drug development; Endoplasmic Reticulum; Evaluation; Exhibits; Formulation; Genetic; Goals; high throughput screening; Human; Immune; immune activation; Immune Checkpoint; immune checkpoint blockers; Immune checkpoint inhibitor; Immune response; Immune system; Immune Tolerance; immunogenic cell death; Immunotherapeutic agent; Immunotherapy; implantation; improved; In Vitro; in vitro Assay; in vivo; in vivo evaluation; Infiltration; Injections; Injury; Innate Immune Response; intravenous administration; IRF3 gene; Kinetics; Lead; lead candidate; lead optimization; Ligands; Liposomes; Malignant Neoplasms; Measures; Mediating; melanoma; Metabolic; Methods; Modeling; Molecular; Monoclonal Antibodies; Mus; Natural Immunity; neoantigens; neoplastic cell; novel; Nucleic Acids; Oral; Ovarian; oxaliplatin; Pancreas; pathogen; Pathway interactions; Patients; Pattern; Pattern recognition receptor; Permeability; Pharmaceutical Chemistry; Pharmaceutical Preparations; Phase; Plasma Proteins; Population; Pre-Clinical Model; preclinical development; prevent; Production; Property; Radiation therapy; receptor; Receptor Signaling; recruit; research clinical testing; response; RNA; Safety; scaffold; Series; Signal Transduction; small molecule; Solubility; Stress; Structure-Activity Relationship; T cell response; T-Lymphocyte; Therapeutic; Therapeutic Effect; Therapeutic Uses; Tissues; Treatment Failure; tripolyphosphate; tumor; tumor growth; tumor microenvironment; uptake; Viral; Virus

This SBIR Phase II research program is focused on developing a small-molecule cancer immunotherapy drug that targets and activates the RIG-I like receptor (RLR) pathways, pattern-recognition receptors that function as intracellular sensor of RNA virus infection. Our small molecule agonists directly activate dendritic cells to prime an anti-tumor T cell response, and they induce immunogenic cell death (ICD) in cancer cells, a programmed cell death pathway that elicits an innate immune activation cascade within the tumor microenvironment. ICD primes a T cell response against tumor neoantigens and recruits activated T cells into the tumor. When administered by intratumoral injection, our lead series compounds, represented by the proof of concept example KIN1312, inhibit tumor growth in mice, and mice exhibiting complete tumor regression are immune to re-challenge with live tumor cells of the same type. In our Phase I studies, we used a structure-activity relationship (SAR) approach to identify KIN1312 analogs with improved drug-like properties, target binding, cellular potency, and efficacy. We obtained orthogonal confirmation of in vivo efficacy by demonstrating tumor regression in mouse CT26 and B16F10 tumor models, and we established that our agonists induce apoptosis in human cancer cell lines, but not in non-malignant primary cells. In addition, we demonstrated that combining KIN1312 with an anti-CTLA4 immune checkpoint inhibitor in the CT26 tumor model improved tumor regression and survival beyond that provided by either treatment alone. In Phase II, our goal is to select a lead preclinical candidate for advancement to investigational new drug (IND)-enabling studies as a new cancer immunotherapy. In Aim 1, we will use advanced SAR, structural biology, and formulation approaches to further optimize our innate immune agonists and to enable systemic administration. In Aim 2, we will determine the in vivo efficacy of these compounds in diverse tumor models and compare intratumoral and systemic routes of delivery. Compounds will be examined both as a monotherapy and in combination with immune checkpoint inhibitors and other immunotherapies. In Aim 3, we will define mechanisms of action and immune correlates of efficacy. High-priority compounds that exhibit synergistic activity with immune checkpoint inhibitors or other immunotherapies will be evaluated in toxicokinetic assays. Together, these studies will allow us to select intratumoral or systemic delivery for clinical proof of concept, and to select a lead preclinical candidate for advancement to IND-enabling studies. When used in combination with immune checkpoint inhibitors or engineered T cell therapies that target solid tumors, our RLR agonists have the potential to substantially expand the number of patients that could benefit from cancer immunotherapy.

Public Health Relevance Statement:
PROJECT NARRATIVE We are developing a new type of cancer immunotherapy drug that induces the death of cancer cells in a way that stimulates the immune system to recognize and eliminate tumors and prevent their reoccurrence. Because of this mechanism of action, our drug may substantially improve the efficacy of other cancer immunotherapies, such as immune checkpoint blockers, which are currently effective in only a minority of patients.

Project Terms:
adaptive immunity; Agonist; analog; anti-CTLA4; Antibodies; Apoptosis; Binding; Biological Assay; Biophysics; cancer cell; Cancer cell line; cancer immunotherapy; cancer type; Cells; Cessation of life; Chemicals; Clinical; Combined Modality Therapy; CT26; cytokine; Dendritic Cells; Drug Targeting; engineered T cells; Exhibits; Family; fighting; Formulation; Goals; Human; Immune; immune activation; immune checkpoint blockade; immune checkpoint blockers; Immune checkpoint inhibitor; Immune system; immunogenic cell death; immunogenicity; Immunotherapeutic agent; Immunotherapy; improved; in vivo; Injections; Investigational Drugs; IRF3 gene; Knock-out; Lead; lead optimization; lead series; Malignant Neoplasms; meetings; Minority; Modeling; Modification; Morbidity - disease rate; Mus; neoantigens; neoplastic cell; Non-Malignant; Pathway interactions; Patients; Pattern recognition receptor; Pharmaceutical Chemistry; Pharmaceutical Preparations; pharmacokinetics and pharmacodynamics; Phase; phase 1 study; pre-clinical; preclinical development; prevent; programs; Property; receptor; receptor function; recruit; Research; Resistance; RNA Virus Infections; RNA Viruses; Route; Safety; sensor; Series; Small Business Innovation Research Grant; small molecule; Solid Neoplasm; Specificity; structural biology; Structure; Structure-Activity Relationship; T cell response; T cell therapy; T-Lymphocyte; targeted treatment; Therapeutic Index; Toxic effect; Toxicokinetics; tumor; tumor growth; tumor microenvironment