Abstract A004: Systemic RNA vaccines: Connecting effective cancer immunotherapy with antiviral defense mechanisms

Abstract Mechanisms of antiviral host defense are important for survival and evolutionarily optimized for high sensitivity and potency. Intending to harvest the multitude of highly specialized and intertwined pathogen immune defense programs for cancer immunotherapy, we simulated a systemic pathogen intrusion into the blood stream by intravenous injection of lipid-formulated, tumor antigen-encoding mRNA nanoparticles. These RNA-lipoplexes (RNA-LPX) were directed to various lymphoid tissues, including the spleen, lymph nodes and bone marrow, which provide the ideal microenvironment for efficient priming and amplification of T cell responses. Solely the RNA-to-lipid ratio was discovered to de…

Abstract CT034: A first-in-human phase I/II clinical trial assessing novel mRNA-lipoplex nanoparticles for potent melanoma immunotherapy

Abstract Therapeutic vaccination with tumor antigen-encoding RNAs by local administration is currently being successfully employed in various clinical trials. Advancing from local to more efficient systemic targeting of antigen-presenting cells (APCs), we have developed pioneering RNA-lipoplex (RNA(LIP)) immunotherapeutics for intravenous application based on the employment of well-known lipid carriers without the need for functionalization of particles with molecular ligands. The novel RNA(LIP) formulation has been engineered to preserve RNA integrity after intravenous injection and physicochemically optimized for efficient uptake and expression of the encoded antigen by APCs in various ly…

Abstract CT020: MERIT: introducing individualized cancer vaccines for the treatment of TNBC - a phase I trial

Abstract The majority of metastatic cancers remain incurable since the current methods of treatment often fail to target the heterogeneous nature of each individual patient's tumor. Personalized approaches targeting each individual patient's tumor may therefore bring significant improvements. The Mutanome Engineered RNA Immuno-Therapy (MERIT) consortium will clinically validate a pioneering RNA-based immunotherapy concept for the treatment of triple negative breast cancer (TNBC) by targeting shared tumor antigens and individual neo-antigens in TNBC patients. MERIT combines two personalized treatment concepts: (i) treatment with vaccines containing “off-the-shelf” mRNAs selected from a pre-s…

Abstract CT202: IVAC MUTANOME: Individualized vaccines for the treatment of cancer

Abstract Cancer arises from the accumulation of genomic alterations and epigenetic changes that constitute a hallmark of cancer. Owing to the molecular heterogeneity in cancer, only a minor fraction of patients profit from approved therapies. Available targeted therapies can only address alterations common to a particular type of cancer and induce transient effects due to the generation of resistant sub-clones. In contrast, the IVAC MUTANOME project aims to immunologically target multiple cancer mutations uniquely expressed in a given patient's tumor. The IVAC MUTANOME approach should be applicable to the majority of patients irrespective of the tumor entity and offers the potential to expl…

Synthetic mRNAs with Superior Translation and Stability Properties

The translational efficiency and stability of synthetic mRNA in both cultured cells and whole animals can be improved by incorporation of modified cap structures at the 5'-end. mRNAs are synthesized in vitro by a phage RNA polymerase transcribing a plasmid containing the mRNA sequence in the presence of all four NTPs plus a cap dinucleotide. Modifications in the cap dinucleotide at the 2'- or 3'-positions of m(7)Guo, or modifications in the polyphosphate chain, can improve both translational efficiency and stability of the mRNA, thereby increasing the amount and duration of protein expression. In the context of RNA-based immunotherapy, the latter is especially important for antigen producti…

Improving mRNA-Based Therapeutic Gene Delivery by Expression-Augmenting 3' UTRs Identified by Cellular Library Screening.

Synthetic mRNA has emerged as a powerful tool for the transfer of genetic information, and it is being explored for a variety of therapeutic applications. Many of these applications require prolonged intracellular persistence of mRNA to improve bioavailability of the encoded protein. mRNA molecules are intrinsically unstable and their intracellular kinetics depend on the UTRs embracing the coding sequence, in particular the 3′ UTR elements. We describe here a novel and generally applicable cell-based selection process for the identification of 3′ UTRs that augment the expression of proteins encoded by synthetic mRNA. Moreover, we show, for two applications of mRNA therapeutics, namely, (1) …

Abstract CT032: A first-in-human phase I/II clinical trial assessing novel mRNA-lipoplex nanoparticles for potent cancer immunotherapy in patients with malignant melanoma

Abstract Immunotherapeutic approaches have evolved as promising and valid alternatives to available conventional cancer treatments. Amongst others, vaccination with tumor antigen-encoding RNAs by local administration is currently successfully employed in various clinical trials. To allow for a more efficient targeting of antigen-presenting cells (APCs) and to overcome potential technical challenges associated with local administration, we have developed a novel RNA immunotherapeutic for systemic application based on a fixed set of four liposome complexed RNA drug products (RNA(LIP)), each encoding one shared melanoma-associated antigen. The novel RNA(LIP) formulation was engineered (i) to p…

A first-in-human phase I/II clinical trial assessing novel mRNA-lipoplex nanoparticles encoding shared tumor antigens for potent melanoma immunotherapy

Abstract LB-130: Combinatorial treatment with intratumoral cytokine mRNAs results in high frequency of tumor rejection and development of anti-tumor immunity across a range of preclinical cancer models

Abstract Cancer immunotherapy localized to the tumor microenvironment holds great potential to promote innate and adaptive immune responses against tumors, while avoiding toxicities related to systemic administration of immuno-modulatory therapeutics. Current strategies for tumor-targeted, gene-based delivery of immune therapies face limitations in the clinic due to suboptimal target expression, anti-vector immunity, potential for unwanted genomic rearrangements and other off target effects. We developed a highly potent synthetic mRNA-based platform for in vivo transfection and sustained intratumoral expression of immuno-modulatory molecules that is capable of inducing immunity to tumor spe…

Local delivery of mRNA-encoded cytokines promotes antitumor immunity and tumor eradication across multiple preclinical tumor models

Local immunotherapy ideally stimulates immune responses against tumors while avoiding toxicities associated with systemic administration. Current strategies for tumor-targeted, gene-based delivery, however, are limited by adverse effects such as off-targeting or antivector immunity. We investigated the intratumoral administration of saline-formulated messenger (m)RNA encoding four cytokines that were identified as mediators of tumor regression across different tumor models: interleukin-12 (IL-12) single chain, interferon-α (IFN-α), granulocyte-macrophage colony-stimulating factor, and IL-15 sushi. Effective antitumor activity of these cytokines relied on multiple immune cell populations and…

IVAC MUTANOME: A first-in-human phase I clinical trial targeting individual mutant neoantigens for the treatment of melanoma

Generation of TCR-Engineered T Cells and Their Use To Control the Performance of T Cell Assays

Abstract The systematic assessment of the human immune system bears huge potential to guide rational development of novel immunotherapies and clinical decision making. Multiple assays to monitor the quantity, phenotype, and function of Ag-specific T cells are commonly used to unravel patients’ immune signatures in various disease settings and during therapeutic interventions. When compared with tests measuring soluble analytes, cellular immune assays have a higher variation, which is a major technical factor limiting their broad adoption in clinical immunology. The key solution may arise from continuous control of assay performance using TCR-engineered reference samples. We developed a simp…

Abstract CT156: A first-in-human phase I/II clinical trial assessing novel mRNA-lipoplex nanoparticles encoding shared tumor antigens for immunotherapy of malignant melanoma

Abstract Therapeutic vaccination with tumor antigen-encoding RNAs is being investigated in various clinical trials. Typically, the RNA vaccine is administered intradermally, subcutaneously or intranodally with the intention to get expression of the encoded antigens in local antigen-presenting cells (APCs). We have developed a novel class of RNA-lipoplex (RNA(LIP)) immunotherapeutics for intravenous application, which allow systemic targeting of APCs. RNA(LIP) is a novel nanoparticulate formulation of lipid-complexed mRNA which selectively delivers the functional mRNA to APCs in lymphoid compartments body-wide for efficient mRNA uptake and expression of the encoded antigen by APCs. Moreover,…

Abstract CT022: IVAC® MUTANOME - A first-in-human phase I clinical trial targeting individual mutant neoantigens for the treatment of melanoma

Abstract One of the hallmarks of cancer is the inherent instability of the genome leading to multiple genomic alterations and epigenetic changes that ultimately drive carcinogenesis. These processes lead to a unique molecular profile of every given tumor and to substantial intratumoral heterogeneity of cancer tissues. Recently, a series of independent reports revealed that pre-formed neoantigen specific T-cell responses are of crucial relevance for the clinical efficacy of immune checkpoint inhibitors. However, spontaneous immune recognition of neoantigens seems to be a rare event with only less than 1% of mutations inducing a T-cell response in the tumor-bearing patient. Accordingly, only …

Determinants of intracellular RNA pharmacokinetics: Implications for RNA-based immunotherapeutics

RNAs with optimized properties are increasingly investigated as a tool to deliver the genetic information of complete antigens into professional antigen-presenting dendritic cells for HLA haplotype-independent antigen-specific vaccination against cancer. As the dose of the antigen and duration of its presentation are critical factors for generating strong and sustained antigen-specific immune responses, improvement of the immunobioavailability of RNA-based vaccines has been a recurrent subject of research. Substantial increase of the amount of antigen produced from RNA can be achieved by optimizing RNA stability and translational efficiency. Both features are determined by cis-acting elemen…

Personalized RNA mutanome vaccines mobilize poly-specific therapeutic immunity against cancer

T cells directed against mutant neo-epitopes drive cancer immunity. However, spontaneous immune recognition of mutations is inefficient. We recently introduced the concept of individualized mutanome vaccines and implemented an RNA-based poly-neo-epitope approach to mobilize immunity against a spectrum of cancer mutations. Here we report the first-in-human application of this concept in melanoma. We set up a process comprising comprehensive identification of individual mutations, computational prediction of neo-epitopes, and design and manufacturing of a vaccine unique for each patient. All patients developed T cell responses against multiple vaccine neo-epitopes at up to high single-digit p…

Abstract B041: A novel nanoparticular formulated tetravalent RNA cancer vaccine for treatment of patients with malignant melanoma

Abstract Immunotherapeutic approaches have evolved as promising and valid alternatives to available conventional cancer treatments. Amongst others, vaccination with tumor antigen-encoding RNAs by local administration is currently successfully employed in various clinical trials. To allow for a more efficient targeting of antigen-presenting cells (APCs) we have developed a novel RNA immunotherapeutic for systemic application based on a fixed set of four liposome complexed RNA drug products (RNA(LIP)) each encoding one shared melanoma-associated antigen. Similar to other liposomal drugs, the four injectable RNA(LIP) products constituting the investigational medicinal product will be prepared …

mRNA as a versatile tool for exogenous protein expression.

Several viral and non-viral vectors have been developed for exogenous protein expression in specific cells. Conventionally, this purpose is achieved through the use of recombinant DNA. But mainly due to the risks associated with permanent genetic alteration of cells, safety and ethical concerns have been raised for the use of DNA-based vectors in human clinical therapy. In the last years, synthetic messenger RNA has emerged as powerful tool to deliver genetic information. RNA vectors exhibit several advantages compared to DNA and are particularly interesting for applications that require transient gene expression. RNA stability and translation efficiency can be increased by cis-acting struc…

Abstract CT201: The Mutanome Engineered RNA Immuno-Therapy (MERIT) project

Abstract The Mutanome Engineered RNA Immuno-Therapy (MERIT) consortium will clinically and industrially validate a pioneering RNA-based immunotherapy concept that targets individual tumor antigens and tumor-specific mutations in triple negative breast cancer (TNBC) patients. This biomarker-guided, personalized therapy is a collaborative effort of five partners from academia and industry and is funded by the European Commission's FP7 and led by BioNTech AG. TNBC is an aggressive, molecularly heterogeneous cancer that accounts for 20% of all breast cancer patients. The 5-year survival rate is less than 80%. The molecular heterogeneity across TNBCs results in a lack of common targetable molecu…

Systemic RNA delivery to dendritic cells exploits antiviral defence for cancer immunotherapy

Lymphoid organs, in which antigen presenting cells (APCs) are in close proximity to T cells, are the ideal microenvironment for efficient priming and amplification of T-cell responses. However, the systemic delivery of vaccine antigens into dendritic cells (DCs) is hampered by various technical challenges. Here we show that DCs can be targeted precisely and effectively in vivo using intravenously administered RNA-lipoplexes (RNA-LPX) based on well-known lipid carriers by optimally adjusting net charge, without the need for functionalization of particles with molecular ligands. The LPX protects RNA from extracellular ribonucleases and mediates its efficient uptake and expression of the encod…

Phosphorothioate cap analogs increase stability and translational efficiency of RNA vaccines in immature dendritic cells and induce superior immune responses in vivo

Vaccination with in vitro transcribed RNA coding for tumor antigens is considered a promising approach for cancer immunotherapy and has already entered human clinical testing. One of the basic objectives for development of RNA as a drug is the optimization of immunobioavailability of the encoded antigen in vivo. By analyzing the effect of different synthetic 5' mRNA cap analogs on the kinetics of the encoded protein, we found that m(2)(7,2'-O)Gpp(S)pG (beta-S-ARCA) phosphorothioate caps, in particular the D1 diastereoisomer, profoundly enhance RNA stability and translational efficiency in immature but not mature dendritic cells. Moreover, in vivo delivery of the antigen as beta-S-ARCA(D1)-c…