A new strategy for preparing a tailored meningococcal ACWY conjugate vaccine for clinical testing

Advancing regulatory dialogue: In silico models for improved vaccine biomanufacturing - an expert meeting report

On March 30, 2022, Inno4Vac, a public-private partnership funded by the IMI2/EU/EFPIA Joint Undertaking (IMI2 JU), organised a hybrid workshop, titled "Regulatory Dialogue for Road Maps of Implementation of New Tools in Chemistry, Manufacturing, and Controls Dossiers." This event brought together modellers, regulatory experts, and academic and industry professionals specialising in vaccine process and product development. The sessions discussed key parameters and requirements for model development and verification relevant to vaccine biomanufacturing and shelf life. The stability model was highlighted as having the most significant impact on the common technical document (CTD) due to its potential to streamline data requirements. Regulators are open to considering reliable reduced stability data packages (3-12 months) instead of the standard 36 months, potentially expediting product availability. Appropriate study design reduces uncertainty and therefore the risk of making poor decisions. Upstream models are further from the final product, and their role in the control strategy of the product will define their level of risk and, therefore, requirements for validation and inclusion of information in the file. Regulators may consider downstream models high risk as these can be associated with the monitoring and/or control of critical quality attributes and/or be involved in the release of a product. However, requirements for validation and/or dossier content should always be linked to the intended use of the model and its overall role in the control strategy as per the new EMA Quality Innovation Group Considerations regarding Pharmaceutical Process Models. The success of these models hinges on manufacturers providing enough quality data to prove their accuracy in representing real-world processes. Proactive engagement with regulators, supported by detailed evidence, can foster regulator understanding of new models and potentially lead to new guidelines and pathways for model acceptance.

Stability modeling methodologies to enable earlier patient access

Over recent years, confidence has been gained that predictive stability modeling approaches using statistical tools, prior knowledge and industry experience enable, in many instances, a robust and reliable shelf-life/expiry or retest period prediction for medicinal products. These science and risk-based approaches can compensate for not having a complete real-time stability data set to be included in regulatory applications at the time of initial submission and, thereby, accelerate the availability of new medicines. Examples of predictive stability modeling include accelerated stability assessment procedure (ASAP), advanced kinetic modeling (AKM), and novel modeling approaches that involve the use of Bayesian statistics and Artificial Intelligence (AI) applications such as Machine Learning (ML), with applicability to both synthetic and biological molecules. For biologics, product-specific and platform prior knowledge could be used to overcome model limitations known for non-quantitative stability indicating attributes. A successful ongoing verification approach by comparing the predicted data with real-time stability data would be an appropriate risk management approach which is intended to address regulatory concerns, and further build confidence in the robustness of these predictive modelling approaches with regulatory agencies. Global regulatory acceptance of stability modeling could allow patients to receive potential life-saving medications faster without compromising quality, safety or efficacy.

A universal tool for stability predictions of biotherapeutics, vaccines and in vitro diagnostic products

It is of particular interest for biopharmaceutical companies developing and distributing fragile biomolecules to warrant the stability and activity of their products during long-term storage and shipment. In accordance with quality by design principles, advanced kinetic modeling (AKM) has been successfully used to predict long-term product shelf-life and relies on data from short-term accelerated stability studies that are used to generate Arrhenius-based kinetic models that can, in turn, be exploited for stability forecasts. The AKM methodology was evaluated through a cross-company perspective on stability modeling for key stability indicating attributes of different types of biotherapeutics, vaccines and biomolecules combined in in vitro diagnostic kits. It is demonstrated that stability predictions up to 3 years for products maintained under recommended storage conditions (2-8 °C) or for products that have experienced temperature excursions outside the cold-chain show excellent agreement with experimental real-time data, thus confirming AKM as a universal and reliable tool for stability predictions for a wide range of product types.

Development of a New Solid-Phase Extraction Base Method for Free Saccharide Content Estimation of Meningococcal Conjugate Vaccines

GlaxoSmithKline (GSK) is currently developing a fully liquid presentation to ease the administration of the licensed quadrivalent conjugate vaccine (Menveo) against meningococcal serogroup A, C, W, and Y (MenACWY) infections. Herein, we report a new method for determining the free saccharide (FS) content of CRM₁₉₇-MenACWY conjugated antigens, with the aim of improving accuracy and reproducibility. Mathematical models have been used to support technical knowledge in reducing the need for experimental development. This results in an improved, faster, and platform-based technique for FS separation with one single pretreatment applicable to all antigens of the multivalent meningococcal vaccine.

A new fully liquid presentation of MenACWY-CRM conjugate vaccine: Results from a multicentre, randomised, controlled, observer-blind study

BACKGROUND

The currently licensed quadrivalent MenACWY-CRM conjugate vaccine presentation consists of two vials (lyophilised MenA and liquid MenCWY) to be reconstituted before injection. A new fully liquid formulation in a single vial has been developed to further improve the vaccine presentation. Since the MenA structure is subject to hydrolytic degradation, this study was conducted to compare the immunogenicity and safety of the investigational MenACWY-CRM liquid vaccine with the licensed vaccine.

METHODS

In this multicentre, randomised, controlled, observer-blind, phase 2b study, 979 healthy adults were administered a single dose of MenACWY-CRM liquid presentation or the currently licensed MenACWY-CRM vaccine. MenA free saccharide generation was accelerated to approximately 30% in the liquid presentation and MenA polysaccharide O-acetylation was reduced to approximately 40%, according to a controlled procedure. Immunological non-inferiority of the MenACWY-CRM liquid to the licensed vaccine, as measured by human serum bactericidal assay (hSBA) geometric mean titres (GMTs) against MenA 1 month post-vaccination, was the primary study objective. Safety assessment was among the secondary objectives.

RESULTS

Immune responses against each serogroup were similar between the two vaccine groups and was non-inferior for MenA. Adjusted hSBA GMTs for MenA were 185.16 and 211.33 for the MenACWY-CRM liquid presentation and currently licensed vaccine presentation, respectively. The between-group ratio of hSBA GMTs for MenA was 0.88, with a two-sided 95% confidence interval lower limit of 0.64, greater than the prespecified non-inferiority margin of 0.5, thus meeting the primary study objective. Both vaccines were well tolerated. No serious adverse events were considered related to vaccination.

CONCLUSIONS

The levels of MenA free saccharide and polysaccharide O-acetylation did not affect the immunogenicity of the fully liquid presentation, which was demonstrated to be non-inferior to the immunogenicity of the currently licensed MenACWY-CRM vaccine against MenA. The immunogenicity, reactogenicity and safety profiles of the two vaccine presentations were similar.

Immunological non-inferiority of a new fully liquid presentation of the MenACWY-CRM vaccine to the licensed vaccine: results from a randomized, controlled, observer-blind study in adolescents and young adults

A fully liquid MenACWY-CRM vaccine presentation has been developed, modifying the meningococcal serogroup A (MenA) component from lyophilized to liquid. The safety and immunogenicity of the liquid presentation at the end of the intended shelf-life (aged for 24 or 30 months) were compared to the licensed lyophilized/liquid presentation. This multicenter, randomized (1:1), observer-blind, phase 2b study (NCT03433482) enrolled adolescents and young adults (age 10-40 years). In part 1, 844 participants received one dose of liquid presentation stored for approximately 24 months or licensed presentation. In part 2, 846 participants received one dose of liquid presentation stored for approximately 30 months or licensed presentation. After storage, the MenA free saccharide (FS) level was approximately 25% and O-acetylation was approximately 45%. The primary objective was to demonstrate non-inferiority of the liquid presentation to licensed presentation, as measured by human serum bactericidal assay (hSBA) geometric mean titers (GMTs) against MenA, 1-month post-vaccination. Immune responses against each vaccine serogroup were similar between groups. Between-group ratios of hSBA GMTs for MenA were 1.21 (part 1) and 1.11 (part 2), with two-sided 95% confidence interval lower limits (0.94 and 0.87, respectively) greater than the prespecified non-inferiority margin (0.5), thus meeting the primary study objective. No safety concerns were identified. Despite reduced O-acetylation of MenA and increased FS content, serogroup-specific immune responses induced by the fully liquid presentation were similar to those induced by the licensed MenACWY-CRM vaccine, with non-inferior anti-MenA responses. The safety profiles of the vaccine presentations were similar.

Use of Stability Modeling to Support Accelerated Vaccine Development and Supply

Stability assessment of pharmaceuticals in specific storage and shipment conditions is a key requirement to ensure that safe and efficacious products are administered to patients. This is particularly relevant for vaccines, with numerous vaccines strictly requiring cold storage to remain stable. When stability evaluation is exclusively based on real-time data, it may represent a bottleneck for rapid and effective vaccine access. Stability modeling for vaccines represents a key resource to predict stability based on accelerated stability studies; nevertheless, this approach is not fully exploited for these kinds of products. This is likely because of the complexity and diversity of vaccines, as well as the limited availability of dedicated guidelines or illustrative case studies. This article reports a cross-company perspective on stability modeling for vaccines. Several examples, based on the direct experience of the contributors, demonstrate that modeling approaches can be highly valuable to predict vaccines’ shelf life and behavior during shipment or manipulation. It is demonstrated that modeling methodologies need to be tailored to the nature of the vaccine, the available prior knowledge, and the monitored attributes. Considering that the well-established strategies reported in ICH or WHO guidelines are not always broadly applicable to vaccines, this article represents an important source of information for vaccine researchers and manufacturers, setting the grounds for further discussion within the vaccine industry and with regulators.