Direct Activation of STING in the Tumor Microenvironment Leads to Potent and Systemic Tumor Regression and Immunity

The present invention relates to engineered multivalent and multispecific binding proteins, methods of making, and specifically to their uses in the prevention, diagnosis, and/or treatment of disease.

Dual variable domain immunoglobulins and uses thereof

The rapid detection of microbial agents is essential for the effective initiation of host defence mechanisms against infection. Understanding how cells detect cytosolic DNA to trigger innate immune gene transcription has important implications - not only for comprehending the immune response to pathogens but also for elucidating the causes of autoinflammatory disease involving the sensing of self-DNA and the generation of effective antitumour adaptive immunity. The discovery of the STING (stimulator of interferon genes)-controlled innate immune pathway, which mediates cytosolic DNA-induced signalling events, has recently provided important insights into these processes, opening the way for the development of novel immunization regimes, as well as therapies to treat autoinflammatory disease and cancer.

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STING: Infection, inflammation and cancer

The clinical benefit of therapeutic cancer vaccines has been established. Whereas regression of lesions was shown for premalignant lesions caused by HPV, clinical benefit in cancer patients was mostly noted as prolonged survival. Suboptimal vaccine design and an immunosuppressive cancer microenvironment are the root causes of the lack of cancer eradication. Effective cancer vaccines deliver concentrated antigen to both HLA class I and II molecules of DCs, promoting both CD4 and CD8 T cell responses. Optimal vaccine platforms include DNA and RNA vaccines and synthetic long peptides. Antigens of choice include mutant sequences, selected cancer testis antigens, and viral antigens. Drugs or physical treatments can mitigate the immunosuppressive cancer microenvironment and include chemotherapeutics, radiation, indoleamine 2,3-dioxygenase (IDO) inhibitors, inhibitors of T cell checkpoints, agonists of selected TNF receptor family members, and inhibitors of undesirable cytokines. The specificity of therapeutic vaccination combined with such immunomodulation offers an attractive avenue for the development of future cancer therapies.

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Therapeutic cancer vaccines

Stimulator of interferon genes (STING) is a cytosolic receptor that senses both exogenous and endogenous cytosolic cyclic dinucleotides (CDNs), activating TBK1/IRF3 (interferon regulatory factor 3), NF-κB (nuclear factor κB), and STAT6 (signal transducer and activator of transcription 6) signaling pathways to induce robust type I interferon and proinflammatory cytokine responses. CDN ligands were formulated with granulocyte-macrophage colony-stimulating factor (GM-CSF)-producing cellular cancer vaccines--termed STINGVAX--that demonstrated potent in vivo antitumor efficacy in multiple therapeutic models of established cancer. We found that rationally designed synthetic CDN derivative molecules, including one with an Rp,Rp dithio diastereomer and noncanonical c[A(2',5')pA(3',5')p] phosphate bridge structure, enhanced antitumor efficacy of STINGVAX in multiple aggressive therapeutic models of established cancer in mice. Antitumor activity was STING-dependent and correlated with increased activation of dendritic cells and tumor antigen-specific CD8(+) T cells. Tumors from STINGVAX-treated mice demonstrated marked PD-L1 (programmed death ligand 1) up-regulation, which was associated with tumor-infiltrating CD8(+)IFNγ(+) T cells. When combined with PD-1 (programmed death 1) blockade, STINGVAX induced regression of palpable, poorly immunogenic tumors that did not respond to PD-1 blockade alone.

STING agonist formulated cancer vaccines can cure established tumors resistant to PD-1 blockade

A principal barrier to the development of effective vaccines is the availability of adjuvants and formulations that can elicit both effector and long-lived memory CD4 and CD8 T cells. Cellular immunity is the presumptive immune correlate of protection against intracellular pathogens: a group composed of bacteria, viruses and protozoans that is responsible for a staggering level of morbidity and mortality on a global scale. T-cell immunity is also correlated with clinical benefit in cancer, and the development of therapeutic strategies to harness the immune system to treat diverse malignancies is currently undergoing a renaissance. Cyclic dinucleotides (CDNs) are ubiquitous small molecule second messengers synthesized by bacteria that regulate diverse processes and are a relatively new class of adjuvants that have been shown to increase vaccine potency. CDNs activate innate immunity by directly binding the endoplasmic reticulum-resident receptor STING (stimulator of interferon genes), activating a signaling pathway that induces the expression of interferon-β (IFN-β) and also nuclear factor-κB (NF-κB) dependent inflammatory cytokines. The STING signaling pathway has emerged as a central Toll-like receptor (TLR) independent mediator of host innate defense in response to sensing cytosolic nucleic acids, either through direct binding of CDNs secreted by bacteria, or, as shown recently, through binding of a structurally distinct CDN produced by a host cell receptor in response to binding cytosolic double-stranded (ds)DNA. Although this relatively new class of adjuvants has to date only been evaluated in mice, newly available CDN-STING cocrystal structures will likely intensify efforts in this field towards further development and evaluation in human trials both in preventive vaccine and immunotherapy settings.

https://journals.sagepub.com/doi/pdf/10.1177/2051013613501988

Rationale, progress and development of vaccines utilizing STING-activating cyclic dinucleotide adjuvants:

It is an object of the present invention to provide novel and highly active cyclic-di-nucleotide (CDN) immune stimulators that activates DCs via a recently discovered cytoplasmic receptor known as STING (Stimulator of Interferon Genes). In particular, the CDNs of the present invention are provided in the form of a composition comprising one or more cyclic purine dinucleotides that induce STING-dependent TBK1 activation, wherein the cyclic purine dinuclotides present in the composition are substantially pure Rp,Rp or Rp,Sp stereoisomers, and particularly substantially pure Rp,Rp, or RpSp CDN thiophosphate diastereomers.

Compositions comprising cyclic purine dinucleotides having defined stereochemistries and methods for their preparation and use

The present invention provides cyclic-di-nucleotide (CDN) compounds that inhibit signaling at a recently discovered cytoplasmic receptor known as STING (Stimulator of Interferon Genes). In particular, the CDNs of the present invention are provided in the form of a composition comprising one or more cyclic purine dinucleotides which inhibit STING-dependent TBK1 activation and the resulting production of type I interferon.

Compositions and methods for inhibiting "stimulator of interferon gene" -dependent signalling

Free-living microbes are provided in which the nucleic acid has been modified so that the microbe is attenuated for proliferation and/or which comprise genetic mutations that attenuate the ability of the microbe to repair its nucleic acid Methods of using the modified microbes for the loading, activation, and/or maturation of antigen-presenting cells are also provided Vaccine compositions comprising the modified microbes and/or the antigen-presenting cells and methods of using the vaccines are also provided The microbes may be further modified to include heterologous antigens, such as tumor antigens or infectious disease antigens, for use as a vaccine against cancer or infectious diseases

Modified free-living microbes, vaccine compositions and methods of use thereof

The invention provides a bacterium containing a polynucleotide comprising a nucleic acid encoding a heterologous antigen, as well as fusion protein partners. Also provided are vectors for mediating site-specific recombination and vectors comprising removable antibiotic resistance genes.

Thomas W. Dubensky

Papers

Rationale, progress and development of vaccines utilizing STING-activating cyclic dinucleotide adjuvants:

Compositions comprising cyclic purine dinucleotides having defined stereochemistries and methods for their preparation and use

Compositions and methods for inhibiting "stimulator of interferon gene" -dependent signalling

Modified free-living microbes, vaccine compositions and methods of use thereof

Engineered listeria and methods of use thereof