Published on 29/11/2025

Reference Change Triggers: ECs for Bioassays

Protocols for bioassays in the biopharmaceutical industry must adhere to rigorous standards to ensure product safety and efficacy. This article highlights critical aspects, including viral clearance validation, and addresses the complexities introduced within the scope of single-use and closed systems. In addition, our focus is on establishing a robust framework for understanding how changes in the manufacturing process can trigger reference changes, critical for regulatory compliance under the guidelines of FDA, EMA, and PIC/S.

Understanding the Need for Reference Change Triggers

For professionals engaged in biologics, advanced therapy medicinal products (ATMP), and validation practices, defining and understanding reference change triggers is paramount. Reference change triggers are essential elements in ensuring the integrity of bioassays utilized to assess the potency and identity of biologics. Such systems fall under both the FDA and EMA expectations regarding the validation of bioassays and must account for variability arising from changes in materials, processes, or even equipment.

The importance of understanding these triggers particularly amplifies when dealing with complex critical quality attributes (CQAs) related to potency and identity, as they can significantly impact the overall therapeutic efficacy of biologic products. Hurdles in the change management process can be compounded when working with single-use systems, necessitating a thorough understanding of how these systems interface within existing processes.

Plan for Conducting Viral Clearance Validation

Viral clearance validation is a critical component of the safety assessments required for biologic and ATMP therapies. A comprehensive plan must be laid out, following the guidelines provided in ICH Q5A(R2), to navigate the challenges associated with viral contaminants in biologics.

• Assessment of Viral Risks: Conduct a thorough risk assessment to identify potential viral agents that may be introduced during manufacturing. This includes analyzing raw materials, culture media, and other inputs.
• Spiking Studies: Design and execute necessary spiking studies that simulate the potential contamination scenario. This is a crucial component for assessing the efficacy of the viral clearance steps incorporated into your process.
• Choose Appropriate Clearance Methods: Select viral clearance methods relevant to your product’s manufacturing process. Options include filtration, heat inactivation, and chemical treatment, all of which must be validated before implementation.
• Documentation and Reporting: Document every step of the validation process, from study design to outcomes. This is imperative for regulatory compliance and for ongoing monitoring of the viral clearance procedures.

Implementing Spiking Studies in Validation Protocols

Spiking studies serve as a critical tool when adhering to viral clearance validation protocols. These studies help confirm that manufacturing processes can eliminate any viral contaminants effectively, thus ensuring the safety of the final product. When developing spiking studies, consider the following steps:

• Selection of Viral Agents: Choose relevant viral agents based on the a priori risk assessment. Ensure that these agents are representative of potential viral contaminants relevant to the raw materials and manufacturing processes used.
• Design of Spiking Experiments: Plan how to spike the material with selected viral agents at various stages of the manufacturing process to provide data on clearance efficacy. Ensure the experiments account for worst-case scenario conditions.
• Analysis of Results: Use validated analytical methods to assess the viral load pre- and post-manufacturing steps. Ensure clear data analysis to determine the effectiveness of the viral clearance measures.
• Regulatory Considerations: Align the design and methodology of spiking studies with regulatory expectations and guidelines from ICH Q5A(R2) to ensure acceptance by regulatory bodies.

Closed Systems and Their Role in Validation

Closed systems are integral to modern biopharmaceutical manufacturing, particularly for ATMPs and biologics where contamination risk must be mitigated. In the context of bioassay validation, several factors must be considered when utilizing closed systems:

• Design Considerations: Closed systems should be designed to minimize exposure to external contaminants. This may involve laminar flow hoods, isolation technologies, and other aseptic controls as referenced in Annex 1.
• Validation of Systems: It is essential to validate the closed systems periodically through rigorous testing to confirm their operational integrity and capability to function within defined parameters without incurring contamination.
• Training and Operator Protocols: Staff should be properly trained in the use of closed systems, with established protocols to follow that minimize contamination risks and maintain aseptic conditions.
• Monitoring and Controls: Implement continuous monitoring systems to assess variables such as temperature, pressure, and environmental contamination within closed systems.

Single-Use Systems: Considerations and Implementation

Single-use systems (SUS) have become vital in reducing cross-contamination risks and improving throughput in manufacturing processes. When developing protocols around SUS, several key elements should be scrutinized:

• Design and Compatibility: Assess the materials used within single-use components to ensure compatibility with the drug substance and that they do not introduce leachables or extractables compromising product quality.
• Cross-Functional Collaboration: Foster collaboration between manufacturing, quality assurance, and validation teams to ensure that single-use systems align with existing process validation efforts and do not alter reference attributes of the medication.
• Lifecycle Management: Implement robust lifecycle management practices to manage changes in single-use systems over time, including adjustments in manufacturing protocols or introduction of new system features.
• Post-Use Analysis: Evaluate the components of single-use systems post-implementation to assess any impact on product quality, yield, and safety attributes.

Complex Critical Quality Attributes and Chain of Identity Custody

The potency and identity of biologics hinge on well-established CQAs. Understanding these attributes and their implications on manufacturing processes is crucial for regulatory compliance. The following steps illustrate how to manage CQAs within biologics manufacturing:

• Define CQAs: Establish clear definitions and criteria for CQAs pertinent to potency and identity, focusing on measurable parameters essential for product efficacy.
• Implement Chain of Identity Custody: Develop a robust process for maintaining a chain of identity custody (COI) throughout the manufacturing process. This includes tracking and documenting the journey of product materials from sourcing to the final product.
• Regular Review and Assessment: Conduct regular reviews of CQAs against defined benchmarks to ensure compliance and detect any deviations that could negatively impact product quality.
• Collaboration with Regulators: Maintain open channels of communication with regulatory bodies such as the EMA to ensure that your approach to managing CQAs meets current expectations and guidance.

Tailoring PPQ and CPV for Advanced Therapy Medicinal Products (ATMP)

Tailoring the Process Performance Qualification (PPQ) and Continuous Process Verification (CPV) is essential in the context of ATMPs due to their unique manufacturing challenges. Here are key considerations:

• Risk-Based Approach: Adopt a risk-based approach tailored to the specific attributes and mechanisms of action of ATMPs. This is essential to adapt your PPQ protocol accordingly.
• Dynamic Adjustments: Implement dynamic adjustments within the CPV framework to adapt to changing manufacturing conditions, ensuring that quality parameters remain within acceptable limits.
• Documentation and Compliance: Ensure robust documentation practices throughout the PPQ and CPV processes to demonstrate compliance with regulatory expectations, including maintaining a comprehensive record of changes to processes and their effects on ATMP quality.
• Long-Term Monitoring: Establish a framework for long-term monitoring of product performance once in use to continually assess product quality and safety over time.

Outcome and Conclusion

The streamlined management of reference change triggers, alongside comprehensive plans for viral clearance validation and the smart implementation of single-use and closed systems, lays a solid foundation for robust bioassay practices in the biopharmaceutical field. Additionally, careful consideration of complex CQAs and the tailoring of PPQ and CPV measures enables pharmaceutical professionals to adhere to stringent regulatory requirements while ensuring product safety and efficacy. By following these guidelines, professionals can achieve compliance with global regulatory bodies such as the WHO, FDA, EMA, and others.

In conclusion, staying proactive in understanding and addressing potential reference change triggers will facilitate better quality management systems within bioassays and enhance overall product integrity, ultimately leading to safer patient outcomes.