Bavarian Nordic (Germany)

Chikungunya virus (CHIKV) causes periodic outbreaks and is endemic in more than 110 countries. VIMKUNYA, a CHIKV virus-like particle (CHIKV VLP) vaccine, was recently approved by regulators in the United States, European Union, and United Kingdom. Efficacy of VIMKUNYA in endemic settings is difficult to evaluate due to outbreak unpredictability. We used cynomolgus macaques, which model human CHIKV viremia and disease, to assess CHIKV VLP vaccine efficacy. Doses as low as 1.25 mg of CHIKV VLP with aluminum hydroxide adjuvant and passively transferred IgG from vaccinated humans significantly reduced viremia, disease, and joint pathology. Despite having IgG doses yielding neutralizing titers below the established predicted protective threshold of ≥100, animals fared better than the CHIKV-infected control animals, suggesting clinical benefits may occur at lower antibody levels. These findings demonstrate immunogenicity and protective efficacy of CHIKV VLP and relevance of neutralizing antibodies in protection, reinforcing its use in humans to protect against chikungunya disease.

Abstract In the last decade, immunotherapy has revolutionized cancer treatment. However, the lack of potent therapy-induced immune responses against solid tumors due to the immune-suppressive tumor microenvironment (TME) is still a major drawback. One approach to reprogram TME is virotherapy, which can target tumors via destruction of infected tumor cells as well as activating immune cell populations in the TME. A versatile and safe tool for virotherapy is modified vaccinia virus Ankara (MVA), which has already been approved by the FDA as a non-replicating vaccine against smallpox and monkeypox and is also in clinical trials against other infectious diseases and cancer. In the current study, we deciphered the anti-tumorigenic effect of a novel MVA vector encoding a tumor associated antigen (TAA) and the costimulatory molecules IL-12 and 4-1BBL, called MVA-TAA-4-1BBL-IL12. We could show that repetitive intratumoral (IT) injection of MVA-TAA-4-1BBL-IL12 resulted in strong tumor growth control, shrinkage and/or complete elimination of tumors and induction of tumor-specific CD8 T cell response. Furthermore, MVA-TAA-4-1BBL-IL12 treatment promoted a systemic anti-tumor immune response not only against the treated tumor but also untreated, distant tumors. Importantly, local virotherapy also resulted in the generation of tumor-specific memory response, which protected mice against local recurrence after rechallenge. As a conclusion, our findings show that MVA-TAA-4-1BBL-IL12 IT treatment induces an effective anti-tumorigenic immune response in different solid tumor models, which gives rise to long-term protection against cancer recurrence. Citation Format: Cigdem Atay Langbein, Raphael Giessel, Mahmad Ismail Housni, Kerstin Lämmermann, Barbara Bathke, André Riedl, Jürgen Hausmann, Markus Kalla, Paul Chaplin, Hubertus Hochrein, José Medina-Echeverz, Maria Hinterberger. Intratumoral administration of modified vaccinia Ankara expressing a tumor associated antigen and the costimulatory molecules IL-12 and 4-1BBL induces potent systemic long-term immune responses against murine tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB223.

The induction of antiviral innate immunity by systemic immunization with live virus can be employed to positively impact the response to therapeutic vaccination. We previously demonstrated that systemic immunization with a non-replicating MVA encoding CD40 ligand (CD40L) enhances innate immune cell activation and function, and triggers potent antitumor CD8+ T cell responses in different murine tumor models. Antitumor efficacy was increased when combined with tumor targeting antibodies. Here we report the development of TAEK-VAC-HerBy (TVH), a first-in-class human tumor antibody enhanced killing (TAEK) vaccine based on the non-replicating MVA-BN viral vector. It encodes the membrane bound form of human CD40L, HER2 and the transcription factor Brachyury. TVH is designed for therapeutic use in HER2- or Brachyury-expressing cancer patients in combination with tumor targeting antibodies. To preclude possible oncogenic activities in infected cells and to prevent binding of vaccine-encoded HER2 by monoclonal antibodies trastuzumab and pertuzumab, genetic modifications of HER2 were introduced in the vaccine. Brachyury was genetically modified to prevent nuclear localization of the protein thereby inhibiting its transcriptional activity. CD40L encoded in TVH enhanced human leukocyte activation and cytokine secretion in vitro. Lastly, TVH intravenous administration to non-human primates was proven immunogenic and safe in a repeat-dose toxicity study. Nonclinical data presented here highlight TVH as a first-in-class immunotherapeutic vaccine platform currently under clinical investigation.

BackgroundMVA-BN-brachyury-TRICOM is a recombinant vector-based therapeutic cancer vaccine designed to induce an immune response against brachyury. Brachyury, a transcription factor overexpressed in advanced cancers, has been associated with treatment resistance, epithelial-to-mesenchymal transition, and metastatic potential. MVA-BN-brachyury-TRICOM has demonstrated immunogenicity and safety in previous clinical trials of subcutaneously administered vaccine. Preclinical studies have suggested that intravenous administration of therapeutic vaccines can induce superior CD8+ T cell responses, higher levels of systemic cytokine release, and stronger natural killer cell activation and proliferation. This is the first-in-human study of the intravenous administration of MVA-BN-brachyury-TRICOM.MethodsBetween January 2020 and March 2021, 13 patients were treated on a phase 1, open-label, 3+3 design, dose-escalation study at the National Institutes of Health Clinical Center. The study population was adults with advanced solid tumors and was enriched for chordoma, a rare sarcoma of the notochord that overexpresses brachyury. Vaccine was administered intravenously at three DLs on days 1, 22, and 43. Blood samples were taken to assess drug pharmacokinetics and immune activation. Imaging was conducted at baseline, 1 month, and 3 months post-treatment. The primary endpoint was safety and tolerability as determined by the frequency of dose-limiting toxicities; a secondary endpoint was determination of the recommended phase 2 dose.ResultsNo dose-limiting toxicities were observed and no serious adverse events were attributed to the vaccine. Vaccine-related toxicities were consistent with class profile (ie, influenza-like symptoms). Cytokine release syndrome up to grade 2 was observed with no adverse outcomes. Dose-effect trend was observed for fever, chills/rigor, and hypotension. Efficacy analysis of objective response rate per RECIST 1.1 at the end of study showed one patient with a partial response, four with stable disease, and eight with progressive disease. Three patients with stable disease experienced clinical benefit in the form of improvement in pain. Immune correlatives showed T cell activation against brachyury and other tumor-associated cascade antigens.ConclusionsIntravenous administration of MVA-BN-brachyury-TRICOM vaccine was safe and tolerable. Maximum tolerated dose was not reached. The maximum administered dose was 109 infectious units every 3 weeks for three doses. This dose was selected as the recommended phase 2 dose.Trial registration numberNCT04134312.

BackgroundVirus-based vaccines and appropriate costimulation potently enhance antigen-specific T cell immunity against cancer. In the present study, we exploit both innate and adaptive immune responses triggered by a novel recombinant modified vaccinia virus Ankara (rMVA) encoding a Tumor-Associated Antigen (TAA) and the costimulatory CD40L against solid tumors in combination regimes to overcome tumor-induced resistance to immunotherapy.Material and MethodsSubcutaneous murine tumors were induced in C57BL/6 or Balb/c mice using syngeneic tumor cell lines. When tumors were established (60–80 mm3) mice were intravenously injected with rMVA-CD40L. Tumor growth monitoring and immune cell analysis was performed.ResultsTherapeutic treatment with rMVA-CD40L resulted in the control of established tumors in several independent tumor models. This antitumor effect was based on the generation of non-exhausted, systemic tumor-specific cytotoxic CD8+ T cells that was essential for therapeutic efficacy. Strikingly, rMVA-CD40L also induced strong NK cell activation and enhanced cytotoxicity. Moreover, the combination of rMVA-CD40L and tumor targeting antibodies resulted in increased therapeutic antitumor efficacy. This therapeutic combination relied on Fcγ receptor-expressing immune cells as well as on NK cells.ConclusionWe describe a novel and translationally relevant therapeutic synergy between viral vaccination and CD40L costimulation. We show strengthened antitumor immune responses when both rMVA-CD40L-induced innate and adaptive immune mechanisms are exploited by combining immunotherapeutic regimes, such as TAA targeting antibodies. This finding could have a direct positive impact in therapeutic regimens where TAA targeting antibodies could be employed.Disclosure InformationM. Hinterberger: A. Employment (full or part-time); Significant; Bavarian Nordic. J. Medina-Echeverz: A. Employment (full or part-time); Significant; Bavarian Nordic. M. Testori: A. Employment (full or part-time); Significant; Bavarian Nordic. M. Geiger: A. Employment (full or part-time); Significant; Bavarian Nordic. R. Giessel: A. Employment (full or part-time); Significant; Bavarian Nordic. B. Bathke: A. Employment (full or part-time); Significant; Bavarian Nordic. R. Kassub: A. Employment (full or part-time); Significant; Bavarian Nordic. F. Gräbnitz: A. Employment (full or part-time); Significant; Bavarian Nordic. G. Fiore: A. Employment (full or part-time); Significant; Bavarian Nordic. S. Wennier: A. Employment (full or part-time); Significant; Bavarian Nordic. P. Chaplin: A. Employment (full or part-time); Significant; Bavarian Nordic. M. Suter: A. Employment (full or part-time); Significant; Bavarian Nordic. H. Hochrein: A. Employment (full or part-time); Significant; Bavarian Nordic. H. Lauterbach: A. Employment (full or part-time); Significant; Bavarian Nordic.

To the Editor: The trial of modified vaccinia Ankara (MVA) reported by Pittman et al. (Nov. 14 issue)1 was underpowered to detect one of the most serious but underrecognized complications of the established vaccines ACAM2000 and Dryvax — myopericarditis (myocarditis and pericarditis). Studies have shown an incidence of approximately 1 case of clinical myopericarditis in 250 persons who have received one of these two vaccines.2 The trial conducted by Pittman et al., which enrolled 220 participants in the MVA group, probably would have failed to detect a similar incidence of cardiac events. Furthermore, the symptoms of myopericarditis can be subtle .

Toll-like receptor (TLR) 13 and TLR2 are the major sensors of Gram-positive bacteria in mice. TLR13 recognizes Sa19, a specific 23S ribosomal (r) RNA-derived fragment and bacterial modification of Sa19 ablates binding to TLR13, and to antibiotics such as erythromycin. Similarly, RNase A-treated Staphylococcus aureus activate human peripheral blood mononuclear cells (PBMCs) only via TLR2, implying single-stranded (ss) RNA as major stimulant. Here, we identify human TLR8 as functional TLR13 equivalent that promiscuously senses ssRNA. Accordingly, Sa19 and mitochondrial (mt) 16S rRNA sequence-derived oligoribonucleotides (ORNs) stimulate PBMCs in a MyD88-dependent manner. These ORNs, as well as S. aureus-, Escherichia coli-, and mt-RNA, also activate differentiated human monocytoid THP-1 cells, provided they express TLR8. Moreover, Unc93b1(-/-)- and Tlr8(-/-)-THP-1 cells are refractory, while endogenous and ectopically expressed TLR8 confers responsiveness in a UR/URR RNA ligand consensus motif-dependent manner. If TLR8 function is inhibited by suppression of lysosomal function, antibiotic treatment efficiently blocks bacteria-driven inflammatory responses in infected human whole blood cultures. Sepsis therapy might thus benefit from interfering with TLR8 function.

Modified vaccinia virus Ankara (MVA) has been shown to be suitable for the generation of experimental vaccines against cancer and infectious diseases, eliciting strong humoral and cellular immune responses. In viral vectored vaccines, strong recombinant antigen expression and timing of expression influence the quantity and quality of the immune response. Screening of synthetic and native poxvirus promoters for strong protein expression in vitro and potent immune responses in vivo led to the identification of the MVA13.5L promoter, a unique and novel naturally occurring tandem promoter in MVA composed of two 44 nucleotide long repeated motifs, each containing an early promoter element. The MVA13.5L gene is highly conserved across orthopoxviruses, yet its function is unknown. The unique structure of its promoter is not found for any other gene in the MVA genome and is also conserved in other orthopoxviruses. Comparison of the MVA13.5L promoter activity with synthetic poxviral promoters revealed that the MVA13.5L promoter produced higher levels of protein early during infection in HeLa cells and particularly in MDBK cells, a cell line in which MVA replication stops at an early stage before the expression of late genes. Finally, a recombinant antigen expressed under the control of this novel promoter induced high antibody titers and increased CD8 T cell responses in homologous prime-boost immunization compared to commonly used promoters. In particular, the recombinant antigen specific CD8 T cell responses dominated over the immunodominant B8R vector-specific responses after three vaccinations and even more during the memory phase. These results have identified the native MVA13.5L promoter as a new potent promoter for use in MVA vectored preventive and therapeutic vaccines.