Optimal Vaccine Dose Research Articles

Immunostimulatory/Immunodynamic model of mRNA-1273 to guide pediatric vaccine dose selection.

COVID-19 vaccines, including mRNA-1273, have been rapidly developed and deployed. Establishing the optimal dose is crucial for developing a safe and effective vaccine. Modeling and simulation have the potential to play a key role in guiding the selection and development of the vaccine dose. In this context, we have developed an immunostimulatory/immunodynamic (IS/ID) model to quantitatively characterize the neutralizing antibody titers elicited by mRNA-1273 obtained from three clinical studies. The developed model was used to predict the optimal vaccine dose for future pediatric trials. A 25-μg primary vaccine series was predicted to meet non-inferiority criteria in young children (aged 2-5 years) and infants (aged 6-23 months). The geometric mean titers and geometric mean ratios for this dose level predicted using the IS/ID model a priori matched those observed in the pediatric clinical study. These findings demonstrate that IS/ID models represent a novel approach to guide data-driven clinical dose selection of vaccines.

The association of three vaccination doses with reduced gastrointestinal symptoms after severe acute respiratory syndrome coronavirus 2 infections in patients with inflammatory bowel disease.

The protective efficacy of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination against the new-onset gastrointestinal (GI) symptoms following COVID-19 infection is critical among patients with inflammatory bowel disease (IBD); however, the optimal protective vaccine dose remains unknown. Therefore, this study aimed to clarify whether there is a correlation between SARS-CoV-2 vaccinations and GI symptoms following Omicron infection in patients with IBD. We conducted a multicenter cross-sectional study of IBD patients among three tertiary hospitals in eastern China. Professional physicians collected all data using online questionnaires. The patients were stratified into four groups: patients who were unvaccinated and patients who received one, two, or three vaccination doses. The primary outcome was the presence of any new-onset GI symptoms after SARS-CoV-2 infection before a negative SARS-CoV-2 nucleic acid test or a negative self-testing for antigens. In total, 536 patients with IBD (175 unvaccinated, 31 vaccinated, 166 vaccinated with two doses, and 164 vaccinated with three doses) reported having COVID-19 infection. Compared with the unvaccinated, the three vaccination doses group was associated with reduced GI symptoms after infection (adjusted odds ratio = 0.56, 95% confidence interval 0.34-0.90, P < 0.05). Reduced diarrhea (adjusted odds ratio = 0.54, 95% confidence interval 0.31-0.92, P < 0.05) and nausea or vomiting (adjusted odds ratio = 0.45, 95% confidence interval 0.21-0.92, P < 0.05) were observed in the three vaccination doses group compared with the unvaccinated group. In conclusion, in the 536 patients with IBD who reported COVID-19 infection, we found that the three vaccination doses, but not the one or two doses group, were associated with reduced GI symptoms after infection compared with the unvaccinated group.

Dose optimization of an adjuvanted peptide-based personalized neoantigen melanoma vaccine.

The advancements in next-generation sequencing have made it possible to effectively detect somatic mutations, which has led to the development of personalized neoantigen cancer vaccines that are tailored to the unique variants found in a patient's cancer. These vaccines can provide significant clinical benefit by leveraging the patient's immune response to eliminate malignant cells. However, determining the optimal vaccine dose for each patient is a challenge due to the heterogeneity of tumors. To address this challenge, we formulate a mathematical dose optimization problem based on a previous mathematical model that encompasses the immune response cascade produced by the vaccine in a patient. We propose an optimization approach to identify the optimal personalized vaccine doses, considering a fixed vaccination schedule, while simultaneously minimizing the overall number of tumor and activated T cells. To validate our approach, we perform in silico experiments on six real-world clinical trial patients with advanced melanoma. We compare the results of applying an optimal vaccine dose to those of a suboptimal dose (the dose used in the clinical trial and its deviations). Our simulations reveal that an optimal vaccine regimen of higher initial doses and lower final doses may lead to a reduction in tumor size for certain patients. Our mathematical dose optimization offers a promising approach to determining an optimal vaccine dose for each patient and improving clinical outcomes.

Progress and challenges in production of recombinant Newcastle disease virus hemagglutinin-neuraminidase subunit vaccine

Recombinant Newcastle disease (ND) subunit vaccines are safe, efficacious and compatible with DIVA strategies. Hence, are promising alternatives to conventional live and inactivated vaccines for ND control and prevention. While production of hemagglutinin-neuraminidase (HN)-based ND subunit vaccines have been extensively evaluated at lab-scale, significant barriers impeding successful translation from high-cost, small bench scale production to low-cost mass production remain. This review details current state and challenges in efficacious HN subunit design, advantages and disadvantages of available production routes using different expression hosts together with gaps and solutions regarding quantitative analytical methods used for formulation in dose-efficiency studies. Critical factors influencing HN subunit vaccine immunogenicity such as protein structure, glycosylation and amino acid variations are discussed. Construct design and available expression hosts are then analyzed from viewpoint of yield and quality measured in terms of efficacy. The current deficiency in available quantitative methods for effective dose-efficacy studies is given emphasis, underscoring the importance of robust analytical methods for determination of optimal vaccine dose. The review outlines current state and way forward for the development of HN ND subunit vaccines and other recombinant subunit vaccines for veterinary applications.

The Correlated Beta Dose Optimisation Approach: Optimal Vaccine Dosing Using Mathematical Modelling and Adaptive Trial Design.

Mathematical modelling methods and adaptive trial design are likely to be effective for optimising vaccine dose but are not yet commonly used. This may be due to uncertainty with regard to the correct choice of parametric model for dose-efficacy or dose-toxicity. Non-parametric models have previously been suggested to be potentially useful in this situation. We propose a novel approach for locating optimal vaccine dose based on the non-parametric Continuous Correlated Beta Process model and adaptive trial design. We call this the 'Correlated Beta' or 'CoBe' dose optimisation approach. We evaluated the CoBe dose optimisation approach compared to other vaccine dose optimisation approaches using a simulation study. Despite using simpler assumptions than other modelling-based methods, we found that the CoBe dose optimisation approach was able to effectively locate the maximum efficacy dose for both single and prime/boost administration vaccines. The CoBe dose optimisation approach was also effective in finding a dose that maximises vaccine efficacy and minimises vaccine-related toxicity. Further, we found that these modelling methods can benefit from the inclusion of expert knowledge, which has been difficult for previous parametric modelling methods. This work further shows that using mathematical modelling and adaptive trial design is likely to be beneficial to locating optimal vaccine dose, ensuring maximum vaccine benefit and disease burden reduction, ultimately saving lives.

Identifying COVID-19 optimal vaccine dose using mathematical immunostimulation/immunodynamic modelling

IntroductionIdentifying optimal COVID-19 vaccine dose is essential for maximizing their impact. However, COVID-19 vaccine dose-finding has been an empirical process, limited by short development timeframes, and therefore potentially not thoroughly investigated. Mathematical IS/ID modelling is a novel method for predicting optimal vaccine dose which could inform future COVID-19 vaccine dose decision making. MethodsPublished clinical data on COVID-19 vaccine dose–response was identified and extracted. Mathematical models were calibrated to the dose–response data stratified by subpopulation, where possible to predict optimal dose. Predicted optimal doses were summarised across vaccine type and compared to chosen dose for the primary series of COVID-19 vaccines to identify vaccine doses that may benefit from re-evaluation. Results30 clinical dose–response datasets in adults and elderly population were extracted for four vaccine types and optimal doses predicted using the models. Results suggest that, if re-assessed for dose, COVID-19 vaccines Ad26.cov, ChadOx1 n-Cov19, BNT162b2, Coronavac, and NVX-CoV2373 could benefit from increased dose in adults and mRNA-1273 and Coronavac, could benefit from increased and decreased dose for the elderly population, respectively. DiscussionFuture iterations of COVID-19 vaccines could benefit from re-evaluating dose to ensure most effective use of the vaccine and mathematical modelling can support this.

Abstract CT059: A Phase Ib open label multicenter study with a HER2/neu peptide vaccine administered with cisplatin and 5-fluorouracil or capecitabine chemotherapy shows safety, immunogenicity and clinical response in patients with HER2/Neu overexpressing advanced cancer of the stomach

Abstract Background: HER2/neu is overexpressed in 15-25% of gastric cancer patients and associated with poor prognosis. Alternative treatments to monoclonal antibodies are needed due to cost and global availability issues of mAbs. Thus a B-cell peptide vaccine (IMU-131) was developed, consisting of 3 fused B-cell epitopes (p467) from the HER2/neu extracellular domain coupled to CRM197 applied with the adjuvant Montanide. The current study evaluated the optimal and safe vaccine dose leading to immunogenicity and clinical responses. Material &amp; Methods: In an open-label multicenter Phase Ib trial in SE-Asia and Eastern Europe, 14 patients with HER2/neu overexpressing (++/+++) gastric or gastroesophageal junction adenocarcinoma were recruited to receive 3 injections of IMU-131 (days 0, 14, 35) in combination with chemotherapy (CT) every 21 days. Dose escalation with 10 µg, 30 µg and 50 µg was performed in 3 cohorts. Safety, immunogenicity and clinical responses were evaluated. Results: No SAEs related to administration of IMU-131 were reported. Eleven of 14 patients were evaluable for vaccine-specific immune responses and 10 for tumor growth assessment. Higher p467- and Her-2 specific IgG levels were observed in cohort 2 (30 µg/dose) compared to cohort 1 (10 µg/dose). Two of five patients in cohort 2 showed minimal antibody titers. In contrast, all patients in cohort 3 (50µg/dose) responded to the vaccine with equally high antibody levels. Response rate was an exploratory endpoint and of 10 evaluable patients, 5 patients showed partial response and 4 patients showed stable disease. In cohort 3 the high antibody levels correlated with clinical response, while in cohort 2 only moderate correlations between humoral and clinical responses were observed. In cohort 1 partial response did not correlate with Ab levels, but rather with a high percentage of CD8 T-cells and increased inflammatory cytokine levels (high IFN-γ and TNF-α/IL-10 ratio). Conclusions: The vaccine was well tolerated and safe with antibody responses at the highest dose (50 µg) showing a strong correlation with clinical responses. Thus, a dose of 50 µg was recommended for further evaluation in Phase II, featuring two arms of either IMU 131 plus CT or CT alone. We propose that this vaccine might be of significant medical benefit and further trials are warranted. Citation Format: Ursula Wiedermann, Erika Garner-Spitzer, Yee Chao, Iurie Bulat, Arunee Dechaphunkul, Wichit Arpornwirat, Chaiyut Charoentum, Chia-Jui Yen, Thomas Cheung Yau, Marina Maglakelidze, Suebpong Tanasanvimon, Jedzada Maneechavakajorn, Aumkhae Sookprasert, Li-Yuan Bai, Wen-Chi Chou, Teerapat Ungtrakul, Christoph C. Zielinski, Leslie Chong, Nick Ede, Anthony J Good. A Phase Ib open label multicenter study with a HER2/neu peptide vaccine administered with cisplatin and 5-fluorouracil or capecitabine chemotherapy shows safety, immunogenicity and clinical response in patients with HER2/Neu overexpressing advanced cancer of the stomach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT059.

Interim results of a phase I/IIa trial of a therapeutic CMV vaccine against recurrent glioblastoma (GBM).

2048 Background: Cytomegalovirus (CMV) antigens have been reported in over 90% of GBM tumors. CD4+and CD8+T cells are most frequently directed against the gB and pp65 antigens, respectively, and are immunogenic targets in a CMV-based GBM vaccine. Methods: We have initiated a phase I/IIa clinical trial for patients with recurrent GBM using gB/pp65 enveloped virus-like particles (eVLPs) formulated with GM-CSF and administered intradermally. Subjects are vaccinated monthly until tumor progression, with immunomonitoring performed 2 weeks after each vaccination and MRI exams every 6 weeks. In phase I, eligible patients were age 18-70 with Karnofsky Performance Status at least 70, normal end-organ function, on stable or decreasing corticosteroids of at most 4mg dexamethasone (or equivalent), with recurrent GBM following any standard initial therapy and any number of recurrences. The primary endpoint was safety/tolerability and secondarily to assess immunogenicity. Three vaccine doses (0.4µg, 2µg, and 10µg pp65) were evaluated with 6 subjects in each cohort and DSMB safety review of the first 3 subjects in each cohort prior to enrolling additional subjects. Results: The DSMB identified no DLTs or safety concerns with any of the doses. Grade 2, 3 or 4 AEs occurred in 66%, 22% and 11% of participants, respectively, but were not related to vaccine administration. Twelve men and 6 women were enrolled with a median age 54 (range 39-66). Prior therapies included radiotherapy, temozolomide, and nivolumab. Immunological analyses demonstrate robust boosting of CMV-specific antibody titers and T cell responses against both gB and pp65 antigens in some but not all subjects, across all dose cohorts. Boosting of IFN-gsecreting T cells (measured by ELISPOT) exceeded the assay threshold for several subjects. Stable disease by MRI of 3 months or greater has been observed in 2 subjects in the high dose cohort and 1 subject in the low dose cohort and may correlate with vaccine response. Conclusions: The phase IIa extension phase of the trial planned to begin in Q2 2019 is designed to explore efficacy in an additional 10 subjects that will receive the optimal vaccine dose and includes the additional requirements of unifocal, measurable enhancing tumor 1-3 cm across at first recurrence and no prior immunotherapy. Clinical trial information: NCT03382977.

CMV gB/pp65 eVLPs formulated with GM-CSF as a therapeutic vaccine against CMV-positive tumors.

e14032 Background: Numerous laboratories have demonstrated cytomegalovirus (CMV) antigens in over 90% of GBM tumors, medulloblastoma and breast cancer. Memory CD4+ and CD8+ T cells are most frequently directed against the gB and pp65 antigens at frequencies that can exceed 10%. Thus, CMV gB and pp65 represent attractive, highly immunogenic “foreign” antigen components of a vaccine against CMV-positive tumors that can exploit high precursor frequencies of CD4+ and CD8+ T cells. Methods: Enveloped virus-like particles (eVLPs) are produced after transfection of HEK 293 cells with a plasmid encoding murine leukemia virus Gag plasmid fused in-frame with CMV pp65 antigen, which gives rise to particles. Co-transfected CMV gB plasmid enables particles budding from the cell surface to incorporate the gB protein into the lipid bilayer. Results: Ex vivo studies using PBMCs from GBM patients demonstrated that gB/pp65 eVLPs restimulate both CD4+ and CD8+ T cells at frequencies comparable to those observed for healthy CMV+ subjects, and formulation with GM-CSF augmented IFN-g and CCL3 secretion. Biodistribution studies demonstrated that the gB/pp65 eVLPs remain at the intradermal injection site for at least two weeks, with particles appearing in draining lymph nodes within a few hours. Mechanistic studies demonstrated that monocyte uptake of eVLP particles induces proinflammatory cytokines, which are amplified by gB expression on the surface of the gB/pp65 particles. Immunization of CMV+ rhesus macaques with a macaque-specific version of the vaccine demonstrated the safety of the vaccine and ability to boost pre-existing IFN-g-secreting T cell responses. Conclusions: A phase I/IIa multicenter study designed to demonstrate safety and determine the most immunogenic dose of vaccine in recurrent GBM patients was initiated, with the first subject dosed in January 2018. Up to 3 different antigen dose levels will be evaluated, with 6 subjects in each cohort. Comprehensive safety evaluations and immune-monitoring will be performed 2 weeks after each immunization. Ten additional subjects will be enrolled once an optimal vaccine dose regimen is identified. Subjects will be vaccinated monthly and followed until tumor progression.

Evaluation of immune responses in mice and sheep inoculated with a live attenuated Brucella melitensis REV1 vaccine produced in bioreactor

The Brucella melitensis REV1 vaccine is the most widely employed vaccine for prophylaxis against brucellosis in sheep and goats. The objective of vaccination is disease control in herds or preventing infection in farms. In this study, we produced REV1 vaccine with a protocol, based on the use of liquid medium in a bioreactor, that resulted efficient, safe, relatively fast, and cost-effective. The live attenuated vaccine produced was tested in mice and sheep to investigate its immunogenicity and efficacy. Seventy-two female BALB/c mice were obtained and subdivided in 2 groups, one was stimulated with 1 × 106 colony-forming units (CFUs) of B. melitensis while the other with physiological solution alone and acting as control group. Furthermore, 25 sheep were subdivided into 5 groups: four were inoculated with a B. melitensis dose, ranging from 0.6 × 109 and 3.2 × 109 CFUs and the other was the control group. In addition, a serological diagnosis was performed for sheep by rapid serum agglutination and the complement-fixation test. Immunocompetent cells from both experiment were collected at different times post vaccination and immunostained to evaluate innate and adaptive-immune responses. In mice flow cytometry was used to detect macrophages, T lymphocytes, dendritic cells, memory cells, naïve cells, natural killer cells, major histocompatibility complex type II, B lymphocytes, regulatory T lymphocytes, T helper lymphocytes, cytotoxic T lymphocytes and recently activated CD4+ and CD8+ lymphocytes. In sheep, macrophages, T helper cells, cytotoxic T lymphocytes, regulatory T lymphocytes, dendritic cells, memory cells and naïve lymphocytes, by the same method, were analyzed. The results showed, both in mice and sheep, that the live, attenuated REV1 vaccine stimulated all immunocompetent cells tested, with a balanced innate and adaptive response. In the sheep experiment, the administered vaccine dose was very important because, at the lower doses, immunological tolerance tended to disappear, while, at the highest dose, the immunological tolerance remained active for a long period. In our experimental conditions, the optimal vaccine dose for sheep was 3.2 × 109 CFUs, although a good immune response was found using a dose of 1.6 × 109 CFUs. The vaccine produced in this study could be extensively employed in developing countries to control the brucellosis in sheep and goats.

Clinical trial results of the HER‐2/neu (E75) vaccine to prevent breast cancer recurrence in high‐risk patients

The authors conducted exploratory phase 1-2 clinical trials vaccinating breast cancer patients with E75, a human leukocyte antigen (HLA) A2/A3-restricted HER-2/neu (HER2) peptide, and granulocyte-macrophage colony-stimulating factor. The vaccine is given as adjuvant therapy to prevent disease recurrence. They previously reported that the vaccine is safe and effective in stimulating expansion of E75-specific cytotoxic T cells. Here, they report 24-month landmark analyses of disease-free survival (DFS). These dose escalation/schedule optimization trials enrolled lymph node-positive and high-risk lymph node-negative patients with HER2 (immunohistochemistry [IHC] 1-3(+) ) expressing tumors. HLA-A2/A3(+) patients were vaccinated; others were followed prospectively as controls for recurrence. DFS was analyzed by Kaplan-Meier curves; groups were compared using log-rank tests. Of 195 enrolled patients, 182 were evaluable: 106 (58.2%) in the vaccinated group and 76 (41.8%) in the control group. The 24-month landmark analysis DFS was 94.3% in the vaccinated group and 86.8% in the control group (P = .08). Importantly, because of trial design, 65% of patients received a lower than optimal vaccine dose. In subset analyses, patients who benefited most from vaccination (vaccinated group vs control group) had lymph node-positive (DFS, 90.2% vs 79.1%; P = .13), HER2 IHC 1+-2+ (DFS, 94.0% vs 79.4%; P = .04), or grade 1 or 2 (DFS, 98.4% vs 86.0%; P = .01) tumors and were optimally dosed (DFS, 97.3% vs 86.8%; P = .08). A booster program has been initiated; no patients receiving booster inoculations have recurred. The E75 vaccine has clinical efficacy that is more prominent in certain patients. A phase 3 trial enrolling lymph node-positive patients with HER2 low-expressing tumors is warranted.

Development of AFFITOPE vaccines for Alzheimer's disease (AD) — From concept to clinical testing

Based on the notion that cerebral accumulation of certain Abeta species is central to AD pathogenesis and endowed with the knowledge that emerged during clinical testing of the first human Alzheimer vaccine, AN1792, we designed a new generation of Alzheimer vaccines. Rather than relying on full-length Abeta itself or fragments thereof, AFFITOPE vaccines use short peptides, mimicking parts of the native Abeta sequence, as their antigenic component. The technology created to identify these peptides, termed AFFITOPE-technology, at the same time provides the basis for the multi-component safety concept realized in AFFITOPE vaccines. First, as they are nonself, AFFITOPES don't need to break tolerance typically established against self proteins. This allows us to use aluminium hydroxide, the agent first approved as immunological adjuvant for human use and, thus, exhibiting an excellent safety profile. Second, AFFITOPES employed in Alzheimer vaccines are only 6 amino acids in length, which precludes the activation of Abeta-specific autoreactive T cells. Third, and above all, the AFFITOPE technology allows for controlling the specificity of the vaccine-induced antibody response focusing it exclusively on Abeta and preventing crossreactivity with APP. In a program based on two AFFITOPES allowing neoepitope targeting of Abeta (free N-terminus), this approach was taken all the way from concept to clinical application. Early clinical data support the safety concept inherent to AFFITOPE Alzheimer vaccines. Further clinical testing will focus on the identification of the optimal vaccine dose and immunization schedule. Together, result of these trials will provide a solid basis for clinical POC studies.

Development of a CTL vaccine for Her-2/neu using peptide-microspheres and adjuvants

With the ultimate goal of developing a therapeutic cancer vaccine, we encapsulated the Her-2/neu peptide p369–377 in poly(lactide-co-glycolide) microspheres. This formulation was found to effectively elicit CD8+ cytotoxic T cell (CTL) responses in an HLA-A*0201 transgenic mouse model. In contrast, immunization with either peptide alone or peptide formulated in incomplete Freund's adjuvant (IFA) failed to elicit such CTL responses. Responses induced by the peptide-microsphere formulation were found to peak at approximately 6 weeks post-immunization, and were enhanced by delivering increased doses of peptide and with repeated administrations over time. Co-administration of the peptide-microspheres with adjuvants, including granulocyte–macrophage colony stimulating factor, MPL ® adjuvant and select synthetic Toll-Like Receptor 4 ligands, the aminoalkyl glucosaminide-4 phosphates, significantly augmented CTL responses. These studies provide important guidance for the design of human clinical trials of microsphere vaccines in terms of optimal peptide-microsphere formulation, vaccination regimen, vaccine dose, and adjuvant selection.

The effect of CpG sequences on the B cell response to a viral glycoprotein encoded by a plasmid vector

The effect of palindromic CpG sequences on the B cell response to plasmid vectors expressing a highly immunogenic viral glycoprotein was investigated. Methylation of the CpG sequences of bacterial expression vectors abolished their ability to induce an antibody response to the transgene product in mice. The antibody response could be rescued by concomitant injection of oligonucleotides carrying immunostimulatory sequences. The B cell response to two plasmid vectors, both expressing the same viral glycoprotein but containing a different content of the highly stimulatory AACGTT motif, was compared. Comparable B cell responses were induced to the two constructs given at an optimal vaccine dose while the vector containing additional palindromic sequences resulted in higher antibody titers at a suboptimal dose. These data indicate that deletion of CpG motifs or methylation of such sequences in plasmid DNA can abrogate the immune response to the vector encoded antigen and might thus enhance their usefulness as gene therapy vehicles.