INSPECTIONS UNDER THE QBD PARADIGM
Traditionally, inspections have been conducted using the FDA systems-based approach and in accordance with CDER's Compliance
Program 7356.002M "Inspection of Licensed Biological Therapeutic Drug Products" (15). However, questions arise as to the
expected impact of QbD and recent initiatives on prelicense or preapproval inspections for therapeutic proteins. Other questions,
such as how these inspections will differ from those of the past, what types of documents should the firms have available
for inspection, and whether there are any other changes envisioned under the auspices of QbD will be examined in the following
During prelicense or preapproval inspections under a QbD paradigm, the FDA inspection team will evaluate the implementation
and effectiveness of the process design as described in the application and whether knowledge and risk management have been
transferred successfully from development to manufacturing. It will be crucial to have FDA involved early on in product development
to establish consensus of critical elements. The inspection will evaluate the quality system and its effectiveness regarding
consistent product quality, change control procedures, process improvements, deviation management, and knowledge and risk
management during the product lifecycle.
The oversight of the quality system is crucial under a QbD paradigm for the release of consistent product and perhaps even
real-time release. Change management is of the utmost importance to ensure that opportunities for process improvements are
acted upon as process and product knowledge increases during the product lifecycle and as data are gathered and technological
advances made. Under QbD, a firm should be able to make process improvement changes without being constrained by regulatory
requirements as long as these changes are justified through quality risk management. The inspection team would review these
changes that may not require the submission of supplements. Because the members of the inspection team are also the reviewers
of the applications, they understand and know the product history to evaluate the risk of these changes.
Screening and testing of raw materials, such as cell banks, would receive more scrutiny on inspection, as frequently the starting
materials define a process. Vendor qualification, supply chain oversight, and sampling and testing plans would be reviewed
during the inspection. Variability of raw materials and change management would be assessed. Current emphasis is on excluding
complex biologically derived raw materials whenever possible and/or treating materials for inactivation or limitation of adventitious
agents. This trend is expected to continue. Such approaches are in agreement with a QbD paradigm where risks are eliminated
or mitigated through process design.
With respect to microbial control, elements of a QbD-based inspection could be the evaluation of risk assessment and analysis
for identification of in-process controls and the establishment of appropriate limits based on process capability for bioburden
and endotoxin. In addition, investigators would review sampling and testing plans for in-process monitoring at crucial manufacturing
steps in lieu of end-product monitoring, and evaluate process analytical technology and in-line or at-line sensors for early
detection of microbial contamination. There is even the possibility of real-time release through the implementation of alternate
and rapid microbiological methods and through the use of an effective microbial control strategy. A QbD inspection would evaluate
the overall control strategy, including elements of facility and equipment qualification and maintenance as well as raw material
screening and supplier management. Special emphasis would be placed on process design, testing, and monitoring programs that
demonstrate robustness and consistency. Even though these control-strategy elements exist today, they would be optimized for
best performance results and would be scrutinized more by investigators under the QbD paradigm. The inspection team would
review documents that present and justify the control and optimization of such important aspects of product quality assurance.
The emphasis of inspection would be on in-process testing in lieu of end-product testing. Crucial steps of the process would
be identified and appropriate sampling and testing plans implemented through the following:
- Development studies
- Risk assessments
- Process vulnerabilities to microbial contamination
- Microbial growth potential of product and other process solutions
- Impact of microbial contamination on process failure or variability
- Identification of open operations prone to contamination
- Studies to support extensive hold times, if needed, or limited hold steps where appropriate
- Lifetime use studies for purification media (i.e., resins and membranes)
- Validation and verification of cleaning processes, especially resins and filter membranes
- Use of microbial reduction filters at critical steps
- Effectiveness of process design for microbial control
- Validity of risk assessments and periodic evaluation and updates as knowledge increases.
Under a QbD paradigm, new manufacturing facilities will be designed for appropriate containment and segregation of operations,
best practices for cleaning and disinfection, and appropriate level of environmental monitoring. Risk assessments for adventitious
agent ingress, contamination, and cross-contamination would be reviewed on inspection. It is important to note that different
considerations apply to single and multiproduct facilities, product changeover, new product introductions, open versus closed
operations, and sanitization versus sterilization of equipment.
The inspection of the future will focus more on process and product consistency based on manufacturing history and data. The
history of microbial or viral contamination would be reviewed along with any measures implemented to prevent and mitigate
future occurrences. The disposition of possibly contaminated product and quality oversight will be assessed. Investigations
and root cause determinations, corrective and preventive actions, and periodic review of risk assessments would be evaluated.
Furthermore, it is becoming more evident that inspections of manufacturing and testing sites of the future will rely more
heavily on technology. More elements of the quality system continue to be managed through computerized systems. Investigators
will need to know how to navigate through these systems and request appropriate documents for review as well as understand
the integration of these systems for consistent process and product quality.