Common ATMP PPQ/CPV Gaps—and Fixes



Common ATMP PPQ/CPV Gaps—and Fixes

Published on 01/12/2025

Identifying and Addressing Common ATMP PPQ/CPV Gaps

Introduction to PPQ and CPV in Advanced Therapy Medicinal Products (ATMP)

Advanced Therapy Medicinal Products (ATMP) represent a complex and rapidly evolving class of pharmaceuticals that include gene therapies, somatic cell therapies, and tissue-engineered products. Given their unique characteristics, validation of these products through Process Performance Qualification (PPQ) and Continued Process Verification (CPV) presents unique challenges. Compliance with well-established regulatory frameworks is essential, including guidelines set forth by the FDA, EMA, and MHRA.

This guide will navigate through common gaps identified in PPQ and CPV specific to ATMPs, elucidate the regulatory expectations, and provide actionable fixes to mitigate identified deficiencies. Special emphasis will be placed on critical quality attributes (CQAs), potency identity, and the complexities associated with closed systems and single-use systems.

Understanding Process Performance Qualification (PPQ)

Process Performance Qualification (PPQ) is a critical phase in the lifecycle of ATMPs. It entails a comprehensive assessment of the production process to ensure that it consistently produces a product that meets predetermined specifications and quality attributes. Key expectations include evidence of efficacy against anticipated manufacturing variations, assessment of aseptic processing, and more recently, a robust viral clearance validation strategy.

Among the most significant challenges in PPQ are the planning and execution of relevant spiking studies that demonstrate viral clearance efficiency in the presence of various potential contaminating agents. Moreover, regulatory bodies such as the FDA have underscored the importance of these validations in guidelines such as ICH Q5A(R2), which provides frameworks for assessing viral risks associated with biological products.

Common Gaps in PPQ for ATMPs

Identifying gaps in PPQ can be daunting due to the complexity of ATMPs. Common areas where these gaps arise include:

  • Inadequate viral clearance validation: Many PPQ submissions lack robust data demonstrating the efficacy of viral clearance measures.
  • Insufficient design of spiking studies: Spiking studies must be well-structured and conducted to provide reliable data on viral clearance and should reflect the real manufacturing scenario.
  • Inconsistency in aseptic controls: The convergence of closed systems and single-use systems raises distinct challenges in maintaining sterility and preventing contamination during manufacturing.
  • Poorly defined critical quality attributes (CQAs): The potency and identity of products need rigorous assessment to justify their claimed therapeutic effects.
  • Chain of identity custody (COI) lapses: Proper tracking and documentation are fundamental, particularly when utilizing complex supply chains in ATMP development.

Solutions to Address PPQ Gaps

Each identified gap in the PPQ process requires specific corrective actions. The following sections outline practical solutions:

1. Strengthening Viral Clearance Validation

To strengthen viral clearance validation:

  • Conduct extensive literature reviews to finalize the method of spiking studies aimed at assessing viral clearance performance under worst-case conditions.
  • Standardize protocols for spiking studies to include a variety of viruses that may be relevant to the manufacturing process, ensuring a realistic assessment of risk.
  • Perform simulations that mirror actual production scenarios, considering factors such as material quality and operational variations.

2. Designing Robust Spiking Studies

Robust design of spiking studies includes:

  • Defining appropriate spiking concentrations based on literature-recommended levels and those observed in real-world tissue bank or gene therapy formulations.
  • Incorporating various modalities for spiking to assess scenarios involving low and high viral loads effectively.
  • Collecting data from held lots to prove efficacy across varying conditions.

3. Enhancing Aseptic Controls

To enhance aseptic controls in closed and single-use systems:

  • Develop a well-defined risk assessment process to identify potential points of contamination throughout the manufacturing process.
  • Ensure regular audits of aseptic techniques, including the verification of system integrity and sterilization effectiveness.
  • Utilize appropriate technologies—such as real-time monitoring systems—to detect breaches in sterility during the manufacturing process.

4. Defining Critical Quality Attributes (CQAs)

Defining clearly the CQAs for ATMPs involves:

  • Establishing a cross-functional team to identify and evaluate the importance of each CQA, to prioritize the attributes that directly impact product efficacy and safety.
  • Utilizing analytics and statistical process control to monitor CQAs during manufacturing to ensure that deviations are detected and corrected timely.
  • Incorporating feedback mechanisms through both preclinical studies and post-marketing surveillance to inform and refine CQA definitions.

5. Ensuring Chain of Identity Custody (COI)

To guarantee robust chain of identity custody, organizations should:

  • Implement digital tracking solutions to monitor products throughout their lifecycle within the facility and during transport to strengthen accountability.
  • Conduct regular training with staff to emphasize the importance of COI and best practices for documentation.
  • Perform audits and validation checks regularly to identify any lapses in custody that might compromise product integrity.

Continued Process Verification (CPV) in AGMPs

Continued Process Verification (CPV) represents an extension of the validation lifecycle, ensuring that processes continue to operate within the specified limits throughout the product lifecycle. This includes continuous monitoring of processes and systems, with a systematic approach to identifying trends and deviations from established performance metrics.

Common CPV gaps in ATMPs often manifest during early commercial stages due to insufficient data collection or poorly defined metrics. Stakeholders must uphold compliance with global regulatory standards and continuously adapt to evolving scientific and technological advancements.

Effective CPV protocols may include:

  • Establishment of key performance indicators (KPIs) aligning with product CQAs and operational efficiency.
  • Routine reviewing of process data to identify performance trends, with guided actions established for any deviations noted.
  • Engaging with regulatory authorities throughout the CPV approach for a harmonized understanding of expectations and performance outcomes.

Conclusion

In the validation of Advanced Therapy Medicinal Products (ATMPs), gaps in Process Performance Qualification (PPQ) and Continued Process Verification (CPV) often hinder the timely advancement of promising therapies. By systematically addressing these challenges through robust validation strategies, including comprehensive viral clearance validation, compelling spiking study design, fortified aseptic controls, well-defined CQAs, and stringent chain of custody practices, pharmaceutical professionals can enhance the reliability and safety of ATMPs produced.

This tutorial underlines prevalent regulatory expectations such as those defined in EMA’s guidelines and provides actionable insights to ensure compliance with international standards. A proactive approach to PPQ and CPV will not only satisfy regulatory obligations but also bolster public confidence in these innovative treatment modalities, ultimately enhancing patient outcomes.