Prophylactic treatment with CN-105 improves functional outcomes in a murine model of closed head injury.

The treatment of traumatic brain injury (TBI) in military populations is hindered by underreporting and underdiagnosis. Clinical symptoms and outcomes may be mitigated with an effective pre-injury prophylaxis. This study evaluates whether CN-105, a 5-amino acid apolipoprotein E (ApoE) mimetic peptide previously shown to modify the post-traumatic neuroinflammatory response, would maintain its neuroprotective effects if administered prior to closed-head injury in a clinically relevant murine model. CN-105 was synthesized by Polypeptide Inc. (San Diego, CA) and administered to C57-BL/6 mice intravenously (IV) and/or by intraperitoneal (IP) injection at various time points prior to injury while vehicle treated animals received IV and/or IP normal saline. Animals were randomized following injury and behavioral observations were conducted by investigators blinded to treatment. Vestibulomotor function was assessed using an automated Rotarod (Ugo Basile, Comerio, Italy), and hippocampal microglial activation was assessed using F4/80 immunohistochemical staining in treated and untreated mice 7 days post-TBI. Separate, in vivo assessments of the pharmacokinetics was performed in healthy CD-1. IV CN-105 administered prior to head injury improved vestibulomotor function compared to vehicle control-treated animals. CN-105 co-administered by IP and IV dosing 6 h prior to injury also improved vestibulomotor function up to 28 days following injury. Microglia counted in CN-105 treated specimens were significantly fewer (P = 0.03) than in vehicle specimens. CN-105 improves functional outcomes and reduces hippocampal microglial activation when administered prior to injury and could be adapted as a pre-injury prophylaxis for soldiers at high risk for TBI.

An Exploratory Analysis of Biomarkers of Perihematomal Edema in the CN-105 in Participants with Acute Supratentorial Intracerebral Hemorrhage (CATCH) Trial.

OBJECTIVE: To identify biomarkers with potential to indicate severity of perihematomal edema and secondary tissue injury after intracerebral hemorrhage (ICH), and which could be used as surrogate markers in future clinical trials for novel ICH therapeutics. MATERIALS AND METHODS: This exploratory cohort study compared trends in neuroinflammatory biomarker levels in 18 consecutively enrolled patients with acute supratentorial ICH and 16 patients treated with the investigational neuroprotective therapy CN-105 to identify a panel of 10 biomarkers. Biomarker levels over five days post-hemorrhage were then compared with edema volumes in a larger sample of patients treated with CN-105. RESULTS: Mean normalized edema volumes increased over time; higher CRP levels were associated with increased edema volumes (p = 0.006, r = 0.56). Higher IL8, IL10, MCP, and MMP-9 levels were associated with decreased edema volumes (p = 0.005, r =-0.57; p = 0.02, r =-0.51; p = 0.02, r =-0.52; p = .002, r =-0.63, respectively). IL1-RA, IL1-B, IL23, vWF, and IL17 levels were not significantly associated with edema volumes (p > 0.05). CONCLUSIONS: This exploratory study provides some of the first insights into the longitudinal associations between markers of neuroinflammation and development of perihematomal edema and secondary tissue injury in human ICH. We hypothesize that these biomarkers could be used as surrogates for treatment effect in novel therapies intended to limit neuroinflammation after ICH.

Development of mRNA manufacturing for vaccines and therapeutics: mRNA platform requirements and development of a scalable production process to support early phase clinical trials.

The remarkable success of SARS CoV-2 mRNA-based vaccines and the ensuing interest in mRNA vaccines and therapeutics have highlighted the need for a scalable clinical-enabling manufacturing process to produce such products, and robust analytical methods to demonstrate safety, potency, and purity. To date, production processes have either not been disclosed or are bench-scale in nature and cannot be readily adapted to clinical and commercial scale production. To address these needs, we have advanced an aqueous-based scalable process that is readily adaptable to GMP-compliant manufacturing, and developed the required analytical methods for product characterization, quality control release, and stability testing. We also have demonstrated the products produced at manufacturing scale under such approaches display good potency and protection in relevant animal models with mRNA products encoding both vaccine immunogens and antibodies. Finally, we discuss continued challenges in raw material identification, sourcing and supply, and the cold chain requirements for mRNA therapeutic and vaccine products. While ultimate solutions have yet to be elucidated, we discuss approaches that can be taken that are aligned with regulatory guidance.

CN-105 in Participants with Acute Supratentorial Intracerebral Hemorrhage (CATCH) Trial.

BACKGROUND: Endogenous apolipoprotein (apo) E mediates neuroinflammatory responses and recovery after brain injury. Exogenously administered apoE-mimetic peptides effectively penetrate the central nervous system compartment and downregulate acute inflammation. CN-105 is a novel apoE-mimetic pentapeptide with excellent evidence of functional and histological improvement in preclinical models of intracerebral hemorrhage (ICH). The CN-105 in participants with Acute supraTentorial intraCerebral Hemorrhage (CATCH) trial is a first-in-disease-state multicenter open-label trial evaluating safety and feasability of CN-105 administration in patients with acute primary supratentorial ICH. METHODS: Eligible patients were aged 30-80 years, had confirmed primary supratentorial ICH, and were able to intiate CN-105 administration (1.0 mg/kg every 6 h for 72 h) within 12 h of symptom onset. A priori defined safety end points, including hematoma volume, pharmacokinetics, and 30-day neurological outcomes, were analyzed. For clinical outcomes, CATCH participants were compared 1:1 with a closely matched contemporary ICH cohort through random selection. Hematoma volumes determined from computed tomography images on days 0, 1, 2, and 5 and ordinal modified Rankin Scale score at 30 days after ICH were compared. RESULTS: In 38 participants enrolled across six study sites in the United States, adverse events occurred at an expected rate without increase in hematoma expansion or neurological deterioration. CN-105 treatment had an odds ratio (95% confidence interval) of 2.69 (1.31-5.51) for lower 30-day modified Rankin Scale score, after adjustment for ICH score, sex, and race/ethnicity, as compared with a matched contemporary cohort. CONCLUSIONS: CN-105 administration represents an excellent translational candidate for treatment of acute ICH because of its safety, dosing feasibility, favorable pharmacokinetics, and possible improvement in neurological recovery.

Combination of alphavirus replicon particle-based vaccination with immunomodulatory antibodies: therapeutic activity in the B16 melanoma mouse model and immune correlates.

Induction of potent immune responses to self-antigens remains a major challenge in tumor immunology. We have shown that a vaccine based on alphavirus replicon particles (VRP) activates strong cellular and humoral immunity to tyrosinase-related protein-2 (TRP2) melanoma antigen, providing prophylactic and therapeutic effects in stringent mouse models. Here, we report that the immunogenicity and efficacy of this vaccine is increased in combination with either antagonist anti-CTL antigen-4 (CTLA-4) or agonist anti-glucocorticoid-induced TNF family-related gene (GITR) immunomodulatory monoclonal antibodies (mAb). In the challenging therapeutic setting, VRP-TRP2 plus anti-GITR or anti-CTLA-4 mAb induced complete tumor regression in 90% and 50% of mice, respectively. These mAbs had similar adjuvant effects in priming an adaptive immune response against the vaccine-encoded antigen, augmenting, respectively, approximately 4- and 2-fold the TRP2-specific CD8(+) T-cell response and circulating Abs, compared with the vaccine alone. Furthermore, while both mAbs increased the frequency of tumor-infiltrating CD8(+) T cells, anti-CTLA-4 mAb also increased the quantity of intratumor CD4(+)Foxp3(-) T cells expressing the negative costimulatory molecule programmed death-1 (PD-1). Concurrent GITR expression on these cells suggests that they might be controlled by anti-GITR mAbs, thus potentially explaining their differential accumulation under the two treatment conditions. These findings indicate that combining immunomodulatory mAbs with alphavirus-based anticancer vaccines can provide therapeutic antitumor immune responses in a stringent mouse model, suggesting potential utility in clinical trials. They also indicate that tumor-infiltrating CD4(+)Foxp3(-)PD-1(+) T cells may affect the outcome of immunomodulatory treatments.

Alphavirus replicon particles expressing TRP-2 provide potent therapeutic effect on melanoma through activation of humoral and cellular immunity.

BACKGROUND: Malignant melanoma is the deadliest form of skin cancer and is refractory to conventional chemotherapy and radiotherapy. Therefore alternative approaches to treat this disease, such as immunotherapy, are needed. Melanoma vaccine design has mainly focused on targeting CD8+ T cells. Activation of effector CD8+ T cells has been achieved in patients, but provided limited clinical benefit, due to immune-escape mechanisms established by advanced tumors. We have previously shown that alphavirus-based virus-like replicon particles (VRP) simultaneously activate strong cellular and humoral immunity against the weakly immunogenic melanoma differentiation antigen (MDA) tyrosinase. Here we further investigate the antitumor effect and the immune mechanisms of VRP encoding different MDAs. METHODOLOGY/PRINCIPAL FINDINGS: VRP encoding different MDAs were screened for their ability to prevent the growth of the B16 mouse transplantable melanoma. The immunologic mechanisms of efficacy were investigated for the most effective vaccine identified, focusing on CD8+ T cells and humoral responses. To this end, ex vivo immune assays and transgenic mice lacking specific immune effector functions were used. The studies identified a potent therapeutic VRP vaccine, encoding tyrosinase related protein 2 (TRP-2), which provided a durable anti-tumor effect. The efficacy of VRP-TRP2 relies on a novel immune mechanism of action requiring the activation of both IgG and CD8+ T cell effector responses, and depends on signaling through activating Fcγ receptors. CONCLUSIONS/SIGNIFICANCE: This study identifies a VRP-based vaccine able to elicit humoral immunity against TRP-2, which plays a role in melanoma immunotherapy and synergizes with tumor-specific CD8+ T cell responses. These findings will aid in the rational design of future immunotherapy clinical trials.

Randomized, double-blind, Phase 1 trial of an alphavirus replicon vaccine for cytomegalovirus in CMV seronegative adult volunteers.

Development of a cytomegalovirus (CMV) vaccine is a priority. We evaluated a two component alphavirus replicon particle vaccine expressing CMV gB or a pp65/IE1 fusion protein, previously shown to induce robust antibody and cellular immune responses in mice, in a randomized, double-blind Phase 1 clinical trial in CMV seronegative subjects. Forty subjects received a lower dose (LD) or higher dose (HD) of vaccine or placebo by intramuscular or subcutaneous injection at Weeks 0, 8 and 24. The vaccine was well tolerated, with mild to moderate local reactogenicity, minimal systemic reactogenicity, and no clinically important changes in laboratory parameters. All vaccine recipients developed ex vivo, direct IFN-gamma ELISPOT responses to CMV antigens (maximal mean spot-forming cells per 10(6) PBMC in LD and HD groups of 348 and 504 for pp65, 83 and 113 for IE1, and 138 and 114 for gB), and neutralizing antibodies (maximal geometric mean titer 110 with LD and 218 with HD). Polyfunctional CD4(+) and CD8(+) T cell responses were detected by polychromatic flow cytometry. This alphavirus replicon particle vaccine was safe and induced neutralizing antibody and multifunctional T cell responses against three CMV antigens that are important targets for protective immunity.

Development and preclinical evaluation of an alphavirus replicon vaccine for influenza.

We used a propagation-defective, single-cycle, alphavirus replicon vector system to produce virus-like replicon particles (VRP) expressing the hemagglutinin (HA) and neuraminidase (NA) proteins from influenza A/Wyoming/03/2003 (H3N2). Efficient production methods were scaled to produce pilot lots of HA VRP and NA VRP and clinical lots of HA VRP. HA VRP-induced high-titered antibody responses in mice, rabbits and rhesus macaques, as measured by ELISA or hemagglutination inhibition (HI) assays, and robust cellular immune responses in mice and rhesus macaques, as measured by IFN-gamma ELISPOT. NA VRP also induced cellular immune responses in mice. A toxicology study with HA VRP and NA VRP in rabbits showed no adverse effects in any parameter. These studies support clinical testing of alphavirus replicon vaccines for influenza.

Development and preclinical evaluation of an alphavirus replicon particle vaccine for cytomegalovirus.

We used a replication-incompetent, single-cycle, alphavirus replicon vector system to produce virus-like replicon particles (VRP) expressing the extracellular domain of human cytomegalovirus (CMV) glycoprotein B or a pp65/IE1 fusion protein. Efficient production methods were scaled to produce pilot lots and clinical lots of each alphavirus replicon vaccine component. The vaccine induced high-titered antibody responses in mice and rabbits, as measured by ELISA and CMV neutralization assays, and robust T-cell responses in mice, as measured by IFN-gamma ELISPOT assay. A toxicity study in rabbits showed no adverse effects in any toxicology parameter. These studies support clinical testing of this novel CMV alphavirus replicon vaccine in humans.

A novel alphavirus vaccine encoding prostate-specific membrane antigen elicits potent cellular and humoral immune responses.

PURPOSE: Prostate-specific membrane antigen (PSMA) is an attractive target for active immunotherapy. Alphavirus vaccines have shown promise in eliciting immunity to tumor antigens. This study investigated the immunogenicity of alphavirus vaccine replicon particles (VRP) that encode PSMA (PSMA-VRP). EXPERIMENTAL DESIGN: Cells were infected with PSMA-VRP and evaluated for PSMA expression and folate hydrolase activity. Mice were immunized s.c. with PSMA-VRP or purified PSMA protein. Sera, splenocytes, and purified T cells were evaluated for the magnitude, durability, and epitope specificity of the anti-PSMA response. Antibodies were measured by flow cytometry, and cellular responses were measured by IFN-gamma enzyme-linked immunospot and chromium release assays. Cellular responses in BALB/c and C57BL/6 mice were mapped using overlapping 15-mer PSMA peptides. A Good Laboratory Practice-compliant toxicology study was conducted in rabbits. RESULTS: PSMA-VRP directed high-level expression of active PSMA. Robust T-cell and B-cell responses were elicited by a single injection of 2 x 10(5) infectious units, and responses were boosted following repeat immunizations. Anti-PSMA responses were detected following three immunizations with 10(2) infectious units and increased with increasing dose. PSMA-VRP was more immunogenic than adjuvanted PSMA protein. Responses to PSMA-VRP were characterized by Th-1 cytokines, potent CTL activity, and IgG2a/IgG2b antibodies. T-cell responses in BALB/c and C57BL/6 mice were directed toward different PSMA peptides. Immunogenic doses of PSMA-VRP were well tolerated in mice and rabbits. CONCLUSIONS: PSMA-VRP elicited potent cellular and humoral immunity in mice, and specific anti-PSMA responses were boosted on repeat dosing. PSMA-VRP represents a promising approach for immunotherapy of prostate cancer.

Comparison of two cancer vaccines targeting tyrosinase: plasmid DNA and recombinant alphavirus replicon particles.

PURPOSE: Immunization of mice with xenogeneic DNA encoding human tyrosinase-related proteins 1 and 2 breaks tolerance to these self-antigens and leads to tumor rejection. Viral vectors used alone or in heterologous DNA prime/viral boost combinations have shown improved responses to certain infectious diseases. The purpose of this study was to compare viral and plasmid DNA in combination vaccination strategies in the context of a tumor antigen. EXPERIMENTAL DESIGN: Using tyrosinase as a prototypical differentiation antigen, we determined the optimal regimen for immunization with plasmid DNA. Then, using propagation-incompetent alphavirus vectors (virus-like replicon particles, VRP) encoding tyrosinase, we tested different combinations of priming with DNA or VRP followed by boosting with VRP. We subsequently followed antibody production, T-cell response, and tumor rejection. RESULTS: T-cell responses to newly identified mouse tyrosinase epitopes were generated in mice immunized with plasmid DNA encoding human (xenogeneic) tyrosinase. In contrast, when VRP encoding either mouse or human tyrosinase were used as single agents, antibody and T-cell responses and a significant delay in tumor growth in vivo were observed. Similarly, a heterologous vaccine regimen using DNA prime and VRP boost showed a markedly stronger response than DNA vaccination alone. CONCLUSIONS: Alphavirus replicon particle vectors encoding the melanoma antigen tyrosinase (self or xenogeneic) induce immune responses and tumor protection when administered either alone or in the heterologous DNA prime/VRP boost approaches that are superior to the use of plasmid DNA alone.

Alphavirus replicon particles containing the gene for HER2/neu inhibit breast cancer growth and tumorigenesis.

INTRODUCTION: Overexpression of the HER2/neu gene in breast cancer is associated with an increased incidence of metastatic disease and with a poor prognosis. Although passive immunotherapy with the humanized monoclonal antibody trastuzumab (Herceptin) has shown some effect, a vaccine capable of inducing T-cell and humoral immunity could be more effective. METHODS: Virus-like replicon particles (VRP) of Venezuelan equine encephalitis virus containing the gene for HER2/neu (VRP-neu) were tested by an active immunotherapeutic approach in tumor prevention models and in a metastasis prevention model. RESULTS: VRP-neu prevented or significantly inhibited the growth of HER2/neu-expressing murine breast cancer cells injected either into mammary tissue or intravenously. Vaccination with VRP-neu completely prevented tumor formation in and death of MMTV-c-neu transgenic mice, and resulted in high levels of neu-specific CD8+ T lymphocytes and serum IgG. CONCLUSION: On the basis of these findings, clinical testing of this vaccine in patients with HER2/neu+ breast cancer is warranted.

Doxorubicin and paclitaxel enhance the antitumor efficacy of vaccines directed against HER 2/neu in a murine mammary carcinoma model.

INTRODUCTION: The purpose of the present study was to determine whether cytotoxic chemotherapeutic agents administered prior to immunotherapy with gene vaccines could augment the efficacy of the vaccines. METHODS: Mice were injected in the mammary fat pad with an aggressive breast tumor cell line that expresses HER2/neu. The mice were treated 3 days later with a noncurative dose of either doxorubicin or paclitaxel, and the following day with a gene vaccine to HER2/neu. Two more doses of vaccine were given 14 days apart. Two types of gene vaccines were tested: a plasmid vaccine encoding a self-replicating RNA (replicon) of Sindbis virus (SINCP), in which the viral structural proteins were replaced by the gene for neu; and a viral replicon particle derived from an attenuated strain of Venezuelan equine encephalitis virus, containing a replicon RNA in which the Venezuelan equine encephalitis virus structural proteins were replaced by the gene for neu. RESULTS: Neither vaccination alone nor chemotherapy alone significantly reduced the growth of the mammary carcinoma. In contrast, chemotherapy followed by vaccination reduced tumor growth by a small, but significant amount. Antigen-specific CD8+ T lymphocytes were induced by the combined treatment, indicating that the control of tumor growth was most probably due to an immunological mechanism. The results demonstrated that doxorubicin and paclitaxel, commonly used chemotherapeutic agents for the treatment of breast cancer, when used at immunomodulating doses augmented the antitumor efficacy of gene vaccines directed against HER2/neu. CONCLUSIONS: The combination of chemotherapeutic agents plus vaccine immunotherapy may induce a tumor-specific immune response that could be beneficial for the adjuvant treatment of patients with minimal residual disease. The regimen warrants further evaluation in a clinical setting.

Characterization and selection of HIV-1 subtype C isolates for use in vaccine development.

HIV-1 genetic diversity among circulating strains presents a major challenge for HIV-1 vaccine development, particularly for developing countries where less sequence information is available. To identify representative viruses for inclusion in candidate vaccines targeted for South Africa, we applied an efficient sequence survey strategy to samples from recently and chronically infected persons residing in potential vaccine trial sites. All 111 sequences were subtype C, including 30 partial gag, 26 partial pol, 27 V2-V3 env, and 28 V5-partial gp41 sequences. Of the 10 viruses cultured from recently infected individuals, 9 were R5 and 1 was R5X4. Two isolates, Du151 and Du422, collected within 2 months of infection, were selected as vaccine strains on the basis of their amino acid similarity to a derived South African consensus sequence The selection of recently transmitted R5 isolates for vaccine design may provide an advantage in a subtype C R5-dominant epidemic. The full-length Du422 gag and Du151 pol and env genes were cloned into the Venezuelan equine encephalitis (VEE) replicon particle (VRP) expression system. Du422 Gag protein expressed from the VRP accumulated to a high level and was immunogenic as demonstrated by cytotoxic T lymphocyte responses in mice vaccinated with gag-VRPs. Optimization of codon use for VRP expression in human cells did not enhance expression of the gag gene. The cloned Du151 env gene encoded a functional protein as demonstrated by fusion of VRP-infected cells with cells expressing CD4 and CCR5. Genes identified in this study have been incorporated into the VEE VRP candidate vaccines targeted for clinical trial in South Africa.

Alphavirus replicon particles as candidate HIV vaccines.

Replicon particles based on Venezuelan equine encephalitis virus (VEE) contain a self-replicating RNA encoding the VEE replicase proteins and expressing a gene of interest in place of the viral structural protein genes. Structural proteins for packaging of replicon RNA into VEE replicon particles (VRPs) are expressed from separate helper RNAs. Aspects of the biology of VEE that are exploited in VRP vaccines include 1) expression of very high levels of immunogen, 2) expression of immunizing proteins in cells in the draining lymph node, and 3) the ability to induce mucosal immunity from a parental inoculation. Results of experiments with VRPs expressing green fluorescent protein or influenza virus hemagglutinin (HA) demonstrated that specific mutations in the VRP envelope glycoproteins affect both targeting in the draining lymph node and efficiency of the immune response in mice. VRPs expressing either the matrix-capsid portion of Gag, the full-length envelope gp160, or the secreted gp140 of cloned SIVsm H-4i were mixed in a cocktail and used to immunize macaques at 0, 1, and 4 months. Neutralizing antibodies against SIVsm H-4 were induced in 6 of 6 vaccinates and CTL in 4 of 6. An intrarectal challenge with the highly pathogenic SIVsm E660 was given at 5 months. A vaccine effect was seen in reduced peak virus loads, reduced virus loads both at set point and at 41 weeks postchallenge, and preserved or increased CD4 counts compared to controls. A candidate VRP HIV vaccine expressing Clade C Gag contains a sequence that is very close to the South African Clade C consensus and was selected from a recent seroconverter in the Durban cohort to represent currently circulating genotypes in South Africa. A GMP lot of this vaccine has been manufactured and tested for a phase I trial in the first months of 2002.