CureVac (Germany)

HIV/SIV-specific CD8+ T cell responses are typically unable to control viral rebound following antiretroviral therapy (ART) interruption (ATI). To investigate whether enhancing the magnitude and activation of SIV-specific CD8+ T cells at the time of ATI can improve the immune interception of reactivating SIV infections, we vaccinated SIVmac239-infected rhesus macaques (RMs) on ART, boosting immediately prior to ATI, with a nucleoside-unmodified mRNA vaccine expressing SIVmac239 Gag (mRNA/SIVgag) alone or in combination with Nef (mRNA/SIVnef) and Pol (mRNA/SIVpol). The mRNA/SIVgag vaccine was effective in boosting Gag-specific CD8+ T cells in blood and lymphoid tissues. Following ATI, the mRNA/SIVgag vaccine group showed a significant delay in time to measurable viral rebound compared with controls and manifested lower plasma viral loads (PVLs) for up to 6 weeks after rebound. Similarly, RMs that received mRNA/SIVgag, mRNA/SIVnef, and mRNA/SIVpol also manifested a delay in SIV rebound compared with controls, suggesting that boosting SIV-specific CD8+ T cells during ATI can enhance early immune targeting of reactivating SIV infections. However, viral control was not sustained long term as PVLs were similar across vaccinees and controls by 24 weeks after rebound, highlighting the need for adjunctive therapies to improve the durability of virologic control elicited by CD8+ T cell-targeting vaccines.

BackgroundUropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs), which are increasingly antibiotic resistant and frequently recur. Novel therapeutics are sought to treat and prevent recurrent UTIs (rUTIs), including vaccines. Key virulence factor FimH, which mediates bacterial adhesion to host cells and biofilm formation, is a promising target for a vaccine against UPEC. We assessed the immunogenicity of mRNA-based nanoparticle vaccines against UPEC containing FimH as the encoded antigen.MethodsLipid nanoparticle (LNP)-formulated mRNA vaccines encoding FimH as a monomeric, pre-binding conformation protein (FimHDG), or a multimeric protein nanoparticle (PNP) through fusion to Helicobacter pylori ferritin (FimHDG-Ferritin) were developed. Immunogenicity was assessed in vivo in female BALB/cAnNRj mice and female Wistar rats following three intramuscular (IM) injections of FimHDG or FimHDG–Ferritin mRNA vaccines, or comparator protein subunit vaccines. Antibody levels and functional response were measured in serum and urine by ELISA and bacterial adhesion inhibition (BAI) assays. T cell response was characterized by flow cytometry.ResultsIn both animal models, unmodified FimHDG and FimHDG-Ferritin mRNA vaccines induced higher functional serum antibody levels compared with the protein subunit vaccine control, at the tested dosages. FimHDG-Ferritin resulted in greater binding antibody levels and higher splenic FimH-specific CD4+ and CD8+ T cell responses compared with monomeric FimHDG in both models, resulting in its nomination as lead candidate vaccine design. Validation in rats demonstrated that N1mΨ nucleoside modification further enhanced FimHDG-Ferritin immunogenicity compared with unmodified mRNA.ConclusionsThe mRNA vaccine FimHDG-Ferritin with N1mΨ-modified nucleosides is a promising candidate for further development as a vaccine against UPEC.

BackgroundThe investigational therapeutic mRNA-based vaccine, CVGBM, encodes five class 1 and three class 2 segments derived from tumor-associated antigens (TAAs) with potential relevance in glioblastoma (GBM). Here, we present results from an ongoing, first-in-human study evaluating the safety and immunogenicity of CVGBM in patients with newly-diagnosed and surgically resected MGMT-unmethylated GBM.Materials and MethodsEligible patients were HLA-A*02:01-positive and had newly-diagnosed MGMT-unmethylated GBM (CNS WHO Grade 4) with a gross total or partial resection and completed radiotherapy with or without concomitant temozolomide. The study consists of a dose escalation and a dose expansion part. Patients received intramuscular injections of CVGBM on Days 1, 8, 15, 29, 43, 57 and 71 (main treatment period) plus six optional doses at 6-week intervals (maintenance period). Primary endpoints are safety, tolerability and dose-limiting toxicities (DLTs), whereas immunogenicity is an exploratory endpoint. Blood samples for assessment of cell-mediated immunity by interferon-y ELISPOT were collected on days 1, 43, 71, 78, 99, and 181 (Day 181 only if the patient did not receive maintenance treatment) and for assessment of serum cytokines and chemokines on days 1, 2, 8, 43, 44, 71, 72, and 78.Results16 patients have been enrolled in the dose escalation part (three patients each received 12 µg, 25 µg, 50 µg, and seven received 100 µg of mRNA, respectively). All patients completed the 2-week DLT evaluation period without DLTs, and 100 µg was selected as the recommended dose for trial expansion based on safety data from all cohorts. The most common treatment emergent AEs were short-lived chills, pyrexia, headache and fatigue mostly of mild to moderate severity. Seven patients experienced Grade 3 AEs after the DLT period, assessed as potentially treatment related to CVGBM by investigators and evenly distributed across dose cohorts. CVGBM vaccine induced immunogenicity was mainly de novo and observed in 77% of evaluable patients, in which 67% showed an antigen-specific T cell immune response to multiple TAAs. Innate immune cytokines were also transiently induced upon vaccination.ConclusionsCVGBM was generally well tolerated up to a dose level of 100 µg and was able to induce antigen-specific T-cell responses in the vast majority of patients.L.L. de Freitas Chama: A. Employment (full or part-time); Significant; CureVac SE. P. Romer Roche: A. Employment (full or part-time); Significant; CureVac SE. G. Tabatabai: None. P. Freres: None. P. Hau: None. M. Glas: None. C. Seidel: None. L. von Baumgarten: None. M.C. Burger: C. Other Research Support (supplies, equipment, receipt of drugs or other in-kind support); Modest; Boehringer Ingelheim. M. van den Bent: None. M. Falk: A. Employment (full or part-time); Significant; CureVac SE. P. Kelemen: A. Employment (full or part-time); Significant; CureVac SE. F. Schwenke: A. Employment (full or part-time); Significant; CureVac SE. J. Hess: A. Employment (full or part-time); Significant; CureVac SE. B. Srivastava: A. Employment (full or part-time); Significant; CureVac SE. T. Seibel: A. Employment (full or part-time); Significant; CureVac SE. S.D. Koch: A. Employment (full or part-time); Significant; CureVac SE. U. Gnad-Vogt: A. Employment (full or part-time); Significant; CureVac SE.

Messenger RNA (mRNA)-based therapies are a promising approach to medical treatment. Except for infectious diseases, no other disease has mRNA-based therapies available. The eye is an ideal model for mRNA therapeutic development because it requires limited dosing. Proliferative vitreoretinopathy (PVR) is a blinding condition caused by retinal detachment that now lacks available medical treatment, with surgery as the only treatment option. We previously implicated runt-related transcription factor-1 (RUNX1) as a driver of epithelial-to-mesenchymal transition (EMT) in PVR and as a critical mediator of aberrant ocular angiogenesis when up-regulated. On the basis of these findings, an mRNA was designed to express a dominant-negative inhibitor of RUNX1 (RUNX1-Trap). We show that RUNX1-Trap delivered in polymer-lipidoid complexes or lipid nanoparticles sequestered RUNX1 in the cytosol and strongly reduced proliferation in primary cell cultures established from fibrotic membranes derived from patients with PVR. We assessed the preclinical efficacy of intraocular delivery of mRNA-encoded RUNX1-Trap in a rabbit model of PVR and in a laser-induced mouse model of aberrant angiogenesis often used to study wet age-related macular degeneration. mRNA-encoded RUNX1-Trap suppressed ocular pathology, measured as pathological scores in the rabbit PVR model and leakage and lesion size in the laser-induced choroidal neovascularization mouse model. mRNA-encoded RUNX1-Trap also strongly reduced proliferation in a human ex vivo explant model of PVR. These data demonstrate the therapeutic potential of mRNA-encoded therapeutic molecules with dominant-negative properties, highlighting the potential of mRNA-based therapies beyond standard gene supplementation approaches.

BackgroundNeoantigens expressed and presented by tumor cells can be recognized by the immune system and facilitate destruction of tumors by cytotoxic CD8+ T cells. The main source of neoantigens has been single nucleotide variations with only one amino acid difference from a wildtype protein. We have instead focused on a class of neoantigens that arise from insertions and deletions (indels) or other gene re-arrangements, leading to formation of neo-open reading frame peptides (NOPs). NOPs are stretches of novel amino acid sequences containing numerous potentially highly immunogenic epitopes and therefore provide a valuable source of neoantigens with the capability to improve efficacy of cancer vaccines.MethodsThe analysis of The Cancer Genome Atlas (TCGA) database and in-house sequenced human tumor samples was used to predict expression of shared neoantigens resulting from indels and other gene re-arrangements. Several selected candidates underwent thorough in vitro experimental validation to confirm tumor cell presentation and immunogenicity of NOPs. Additionally, we tested immunogenicity of mouse surrogate NOPs identified via the same pipeline in the melanoma cell line B16F10 by encoding ten different NOP sequences in an mRNA vaccine.ResultsWe identified several different NOP sequences with predicted expression in human tumor samples that were selected for further validation. From each tested NOP, one or multiple epitopes were binding in vitro to either HLA-A*02:01, HLA-A*01:01, or HLA-A*24:02 allele. Presentation of epitopes on the tumor cell surface was confirmed by eluting the epitopes from HLA alleles followed by mass spectrometry analysis. We also detected presence of antigen specific CD8+ T cells in blood of healthy donors by tetramer staining. In vitro expanded NOP specific CD8+ T cell clones were able to recognize target positive tumor cell lines as measured by increased activation and degranulation markers. In vivo immunogenicity assessment after vaccination of mice with a mRNA vaccine encoding B16F10-derived NOPs showed large number (up to 60%) of polyfunctional CD8+ T cells, and to lower extent also CD4+ T cells after in vitro re-stimulation of splenocytes with NOP peptide pools. Deconvolution confirmed that 3/10 of NOPs induced CD8+ T cell responses and 2/10 NOPs mounted CD4+ T cells responses.ConclusionsThe neo-open reading frame peptides represent a class of experimentally validated, highly immunogenic neoantigens, suitable to induce robust in vivo immune responses when encoded in an mRNA vaccine format.

Licensed rabies virus vaccines based on whole inactivated virus are effective in humans. However, there is a lack of detailed investigations of the elicited immune response, and whether responses can be improved using novel vaccine platforms. Here we show that two doses of a lipid nanoparticle-formulated unmodified mRNA vaccine encoding the rabies virus glycoprotein (RABV-G) induces higher levels of RABV-G specific plasmablasts and T cells in blood, and plasma cells in the bone marrow compared to two doses of Rabipur in non-human primates. The mRNA vaccine also generates higher RABV-G binding and neutralizing antibody titers than Rabipur, while the degree of somatic hypermutation and clonal diversity of the response are similar for the two vaccines. The higher overall antibody titers induced by the mRNA vaccine translates into improved cross-neutralization of related lyssavirus strains, suggesting that this platform has potential for the development of a broadly protective vaccine against these viruses.

Abstract Purpose: Immunotherapy for hepatocellular carcinoma (HCC) shows considerable promise in improving clinical outcomes. HepaVac-101 represents a single-arm, first-in-human phase I/II multicenter cancer vaccine trial for HCC (NCT03203005). It combines multipeptide antigens (IMA970A) with the TLR7/8/RIG I agonist CV8102. IMA970A includes 5 HLA-A*24 and 7 HLA-A*02 as well as 4 HLA-DR restricted peptides selected after mass spectrometric identification in human HCC tissues or cell lines. CV8102 is an RNA-based immunostimulator inducing a balanced Th1/Th2 immune response. Patients and Methods: A total of 82 patients with very early- to intermediate-stage HCCs were enrolled and screened for suitable HLA haplotypes and 22 put on study treatment. This consisted in a single infusion of low-dose cyclophosphamide followed by nine intradermal coadministrations of IMA970A and CV8102. Only patients with no disease relapse after standard-of-care treatments were vaccinated. The primary endpoints of the HepaVac-101 clinical trial were safety, tolerability, and antigen-specific T-cell responses. Secondary or exploratory endpoints included additional immunologic parameters and survival endpoints. Results: The vaccination showed a good safety profile. Transient mild-to-moderate injection-site reactions were the most frequent IMA970A/CV8102-related side effects. Immune responses against ≥1 vaccinated HLA class I tumor-associated peptide (TAA) and ≥1 vaccinated HLA class II TAA were respectively induced in 37% and 53% of the vaccinees. Conclusions: Immunotherapy may provide a great improvement in treatment options for HCC. HepaVac-101 is a first-in-human clinical vaccine trial with multiple novel HLA class I– and class II–restricted TAAs against HCC. The results are initial evidence for the safety and immunogenicity of the vaccine. Further clinical evaluations are warranted.

Abstract A third dose of CVnCoV, a former candidate mRNA vaccine against SARS-CoV-2, was previously shown to boost neutralizing antibody responses against SARS-CoV-2 wild-type in adults aged 18-60 and >60 years in a phase 2a clinical study. Here we report neutralizing antibody responses to wild-type and a variant of concern, Delta, after a third dose on day (D) 57 and D180. Neutralization activity was assessed using a microneutralization assay. Comparable levels of neutralizing antibodies against wild-type and Delta were induced. These were higher than those observed after the first two doses, irrespective of age or pre-SARS-CoV-2-exposure status, indicating that the first two doses induced immune memory. Four weeks after the third dose on D180, neutralizing titers for wild-type and Delta were two-fold higher in younger participants than in older participants; seroconversion rates were 100% for wild-type and Delta in the younger group and for Delta in the older group. A third CVnCoV dose induced similar levels of neutralizing responses against wild-type virus and the Delta variant in both naïve and pre-exposed participants, aligning with current knowledge from licensed COVID-19 vaccines that a third dose is beneficial against SARS-CoV-2 variants.