An Investigational Medicinal Product Dossier – Quality section (IMPD) is a foundational component of every Clinical Trial Application (CTA). It describes the Chemistry, Manufacturing and Controls (CMC) strategy for the investigational drug substance and drug product, including the proposed control strategy supporting clinical use.
In early-phase development, sponsors frequently rely on their Contract Development and Manufacturing Organization (CDMO) to prepare substantial portions of the IMPD. While this approach is operationally efficient and ensures alignment with current manufacturing execution, it may inadvertently introduce constraints that affect long-term CMC flexibility.
An IMPD should not be viewed merely as a description of the current manufacturing process. It should be developed as a strategic regulatory document that supports clinical progression, technology transfer, lifecycle management, and future process evolution.
The Risk of Over-Specification
CDMO-authored IMPD sections are often highly tailored to the existing manufacturing environment. Common challenges include:
- Process descriptions closely linked to specific equipment, facilities, or operational practices
- Excessive procedural detail rather than emphasis on critical process understanding
- Control strategies designed around current manufacturing capabilities instead of phase-appropriate regulatory expectations
- Limited modularity, making future process changes or site transfers more complex
While these approaches may satisfy immediate filing needs, they can reduce regulatory flexibility later in development.
Overspecification during early clinical phases may:
- Complicate comparability assessments following process optimization, scale-up, analytical method evolution, or site transfer
- Increase the regulatory burden associated with process changes
- Constrain scale-up activities or CDMO transitions
- Create unnecessary alignment challenges with evolving ICH expectations, including Q8, Q9, and Q10 principles
A Strategic Approach to IMPD Development
An effective Quality IMPD should balance scientific rigor with lifecycle flexibility. Rather than documenting every operational detail, the dossier should focus on the elements most relevant to product quality, patient safety, and process control.
Key principles include:
- Clearly defined Critical Quality Attributes (CQAs) linked to clinical performance
- Risk-based identification and justification of Critical Process Parameters (CPPs)
- Platform-agnostic process descriptions where appropriate
- Phase-appropriate control strategies that evolve alongside product and process understanding
- Sufficient detail to satisfy regulatory expectations without unnecessarily constraining future development
This approach enables sponsors to maintain strategic optionality while supporting regulatory compliance throughout clinical development.
The Role of the CDMO — and the Need for Independent Regulatory Oversight
CDMOs provide essential expertise in process development, manufacturing, analytical methods, and operational execution. Their contribution to IMPD preparation is therefore critical.
However, authorship of the IMPD also requires a broader regulatory perspective — one that considers:
- future process development,
- lifecycle management,
- comparability strategy,
- global regulatory expectations,
- and long-term commercialization objectives.
For this reason, sponsors benefit from ensuring that IMPD development is guided not only by manufacturing expertise, but also by independent regulatory-CMC strategy expertise.
Conclusion
As development programs advance, the IMPD becomes more than a clinical trial requirement. It becomes a regulatory framework that can either facilitate or restrict future development activities.
The key question for sponsors is therefore not simply:
Does the IMPD describe the current process adequately?
But rather:
Does the IMPD support the future CMC strategy of the product?
