Christian Grunwitz

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 encoded antigen by DC populations and macrophages in various lymphoid compartments. RNA-LPX triggers interferon-α (IFNα) release by plasmacytoid DCs and macrophages. Consequently, DC maturation in situ and inflammatory immune mechanisms reminiscent of those in the early systemic phase of viral infection are activated. We show that RNA-LPX encoding viral or mutant neo-antigens or endogenous self-antigens induce strong effector and memory T-cell responses, and mediate potent IFNα-dependent rejection of progressive tumours. A phase I dose-escalation trial testing RNA-LPX that encode shared tumour antigens is ongoing. In the first three melanoma patients treated at a low-dose level, IFNα and strong antigen-specific T-cell responses were induced, supporting the identified mode of action and potency. As any polypeptide-based antigen can be encoded as RNA, RNA-LPX represent a universally applicable vaccine class for systemic DC targeting and synchronized induction of both highly potent adaptive as well as type-I-IFN-mediated innate immune mechanisms for cancer immunotherapy.

Selective Glucocorticoid Receptor Agonists for the Treatment of Inflammatory Bowel Disease: Studies in Mice with Acute Trinitrobenzene Sulfonic Acid Colitis

Despite being a mainstay of inflammatory bowel disease (IBD) therapy, glucocorticoids (GCs) still carry significant risks with respect to unwanted side effects. Alternative drugs with a more favorable risk/benefit ratio than common GCs are thus highly desirable for the management of IBD. New and supposedly selective glucocorticoid receptor (GR) agonists (SEGRAs), with dissociated properties, have been described as promising candidates for circumventing therapeutic problems while still displaying full beneficial anti-inflammatory potency. Here, we report on compound A [CpdA; (2-((4-acetophenyl)-2-chloro-N-methyl)ethylammonium-chloride)] and N-(4-methyl-1-oxo-1H-2,3-benzoxazine-6-yl)-4-(2,3-dihydrobenzofuran-7-yl)-2-hydroxy-2-(trifluoromethyl)-4-methylpentanamide (ZK216348), two GR agonists for the treatment of experimental colitis. Their therapeutic and anti-inflammatory effects were tested in the acute trinitrobenzene sulfonic acid-mediated colitis model in mice against dexamethasone (Dex). In addition to their influence on immunological pathways, a set of possible side effects, including impact on glucose homeostasis, steroid resistance, and induction of apoptosis, was surveyed. Our results showed that, comparable with Dex, treatment with CpdA and ZK216348 reduced the severity of wasting disease, macroscopic and microscopic damage, and colonic inflammation. However, both SEGRAs exhibited no GC-associated diabetogenic effects, hypothalamic pituitary adrenal axis suppression, or development of glucocorticoid resistance. In addition, CpdA and ZK216348 showed fewer transactivating properties and successfully dampened T helper 1 immune response. Unlike ZK216348, the therapeutic benefit of CpdA was lost at higher doses because of toxic apoptotic effects. In conclusion, both SEGRAs acted as potent anti-inflammatory agents with a significantly improved profile compared with classic GCs. Although CpdA revealed a narrow therapeutic window, both GR agonists might be seen as a starting point for a future IBD treatment option.

mRNA Cancer Vaccines—Messages that Prevail

During the last decade, mRNA became increasingly recognized as a versatile tool for the development of new innovative therapeutics. Especially for vaccine development, mRNA is of outstanding interest and numerous clinical trials have been initiated. Strikingly, all of these studies have proven that large-scale GMP production of mRNA is feasible and concordantly report a favorable safety profile of mRNA vaccines. Induction of T-cell immunity is a multi-faceted process comprising antigen acquisition, antigen processing and presentation, as well as immune stimulation. The effectiveness of mRNA vaccines is critically dependent on making the antigen(s) of interest available to professional antigen-presenting cells, especially DCs. Efficient delivery of mRNA into DCs in vivo remains a major challenge in the mRNA vaccine field. This review summarizes the principles of mRNA vaccines and highlights the importance of in vivo mRNA delivery and recent advances in harnessing their therapeutic potential.

CIMT 2015: The right patient for the right therapy - Report on the 13th annual meeting of the Association for Cancer Immunotherapy.

The 13th Annual Meeting of the Association for Cancer Immunotherapy (CIMT) brought together more than 800 scientists in Mainz, Germany, from May 11–13, 2015, to present and discuss current research on various fields of cancer immunotherapy. Special focus was set on personalized approaches, and independent of the specific therapeutic strategy, the exploitation of mutated neoantigens predominated all sessions - in line with the motto of this years meeting, “The right patient for the right therapy.”

CIMT 2013: advancing targeted therapies--report on the 11th Annual Meeting of the Association for Cancer Immunotherapy, May 14-16 2013, Mainz, Germany.

The 11th Annual Meeting of Association for Cancer Immunotherapy (CIMT) welcomed more than 700 scientists around the world to Mainz, Germany and continued to be the largest immunotherapy meeting in Europe. Renowned speakers from various fields of cancer immunotherapy gave lectures under CIMT2013’s tag: “Advancing targeted therapies” the highlights of which are summarized in this meeting report.

Monitoring Translation Activity of mRNA-Loaded Nanoparticles in Mice

Targeting mRNA to eukaryotic cells is an emerging technology for basic research and provides broad applications in cancer immunotherapy, vaccine development, protein replacement, and in vivo genome editing. Although a plethora of nanoparticles for efficient mRNA delivery exists, in vivo mRNA targeting to specific organs, tissue compartments, and cells remains a major challenge. For this reason, methods for reporting the in vivo targeting specificity of different mRNA nanoparticle formats will be crucial. Here, we describe a straightforward method for monitoring the in vivo targeting efficiency of mRNA-loaded nanoparticles in mice. To achieve accurate mRNA delivery readouts, we loaded lipoplex nanoparticles with Cre-recombinase-encoding mRNA and injected these into commonly used Cre reporter mouse strains. Our results show that this approach provides readouts that accurately report the targeting efficacy of mRNA into organs, tissue structures, and single cells as a function of the used mRNA delivery system. The method described here establishes a versatile basis for determining in vivo mRNA targeting profiles and can be systematically applied for testing and improving mRNA packaging formats.

CIMT 2017: Anniversary symposium - Report on the 15th CIMT Annual Meeting of the Association for Cancer Immunotherapy

The 15th Annual Meeting of the Association for Cancer Immunotherapy (CIMT) took place May 10–11, 2017, Mainz, Germany during which scientists and CIMT members from all over the world not only celebrated CIMT`s 15th Anniversary but also had the chance to present and discuss the past and current status, and the future of cancer immunotherapy. This annual symposium report highlights and summarizes the sessions held in various fields of this promising cancer therapy.

CIMT 2016: Mechanisms of efficacy in cancer immunotherapy — Report on the 14th Annual Meeting of the Association for Cancer Immunotherapy May 10–12 2016, Mainz, Germany

Lena M. Kranz, Matthias Birtel, Lina Hilscher, Christian Grunwitz, Jutta Petschenka, Fulvia Vascotto, Mathias Vormehr, Ralf-Holger Voss, Sebastian Kreiter, and Mustafa Diken TRON-Translational Oncology at the University Medical Center of the Johannes Gutenberg University Mainz gGmbH, Mainz, Germany; Research Center for Immunotherapy (FZI), University Medical Center of the Johannes Gutenberg University, Mainz, Germany; BioNTech RNA Pharmaceuticals GmbH, Mainz, Germany

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

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 determine the biodistribution of RNA-LPX, irrespective of the types of lipids used, and a slightly negative particle net charge was able to specifically transfect lymphoid-resident antigen presenting cells (APCs). Following uptake by CD11c+ DCs, pDCs and macrophages in the marginal zone of the spleen and in other lymphoid organs, predominantly by macropinocytosis, RNA recognition via TLR7 triggered two transient waves of type I IFN production by pDCs (early response) and macrophages (delayed response), which established an inflammatory, lymphocyte-activating milieu reminiscent of that initiated during the early systemic phase of viral infection. These IFNα receptor (IFNAR)-dependent immune mechanisms were required for DCs to mature, migrate into the T cell zones and express RNA-encoded tumor antigens. Presentation on MHC class I and II in the context of upregulated CD40, CD69 and CD86 elicited strong effector and memory CD8 and CD4 T cell immunity against viral, mutant neo-antigens or self-antigens, which was able to reject progressive tumors in therapeutic mouse models of melanoma, colon carcinoma and human papilloma virus (HPV)-associated cancer. In an ongoing phase I dose escalation study, the first cohort of three patients with advanced melanoma received RNA-LPX encoding four shared tumor antigens at doses lower than those used in the mouse studies. All patients showed a dose-dependent IFNα- and IP-10-dominated cytokine response, developed de novo CD4 and CD8 T cell responses or enhanced pre-existing immunity against the encoded self-antigens NY-ESO-I, Tyrosinase and MAGE-A3, and have stable disease to date. These results support the preclinically identified mode of action and strong potency of this approach in the clinical setting. Our study presents a novel class of systemically administered nanoparticulate RNA vaccines acting by body-wide delivery of encoded antigens to APCs and simultaneous initiation of a strong type I IFN-driven immunostimulatory program. Precise DC targeting in lymphoid compartments is accomplished using well-known lipid carriers and only by manipulating the net charge of the nanoparticles. RNA-LPX vaccines appear to mimic infectious non-self and thus mobilize both adaptive and innate immune mechanisms, connecting effective cancer immunotherapy with host pathogen-defense mechanisms. The simple but highly versatile design allows vaccine preparation with any type of RNA-encoded antigen and may thus be regarded as a universally applicable, first-in-class vaccine platform for cancer immunotherapy. Citation Format: Lena M. Kranz, Mustafa Diken, Heinrich Haas, Sebastian Kreiter, Carmen Loquai, Kerstin C. Reuter, Martin Meng, Daniel Fritz, Fulvia Vascotto, Hossam Hefesha, Christian Grunwitz, Mathias Vormehr, Yves Husemann, Abderraouf Selmi, Andreas N. Kuhn, Janina Buck, Evelyna Derhovanessian, Richard Rae, Sebastian Attig, Jan Diekmann, Robert A. Jabulowsky, Sandra Heesch, Jessica Hassel, Peter Langguth, Stephan Grabbe, Christoph Huber, Ozlem Tureci, Ugur Sahin. Systemic RNA vaccines: Connecting effective cancer immunotherapy with antiviral defense mechanisms [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A004.

CIMT 2014: Next waves in cancer immunotherapy--report on the 12th annual meeting of the Association for Cancer Immunotherapy: May 6–8 2014, Mainz, Germany.

More than 900 scientists around the world visited the 12th Annual Meeting of the Association for Cancer Immunotherapy (CIMT) in Mainz, Germany from 6–8 May, 2014. Recent advancements in various specific fields of cancer immunotherapy were discussed in Europe`s largest meeting of this kind under the motto “Next Waves in Cancer Immunotherapy,” the highlights of which are summarized in this meeting report.