Towards a common framework for defining ancillary material quality across the development spectrum.

Ancillary materials (AMs) play a critical role in the manufacture of cell and gene therapies, and best practices for their quality management are the subject of ongoing discussion. Given that the final product cannot be sterilized, AM quality becomes increasingly critical to the clinical advancement of cell and gene therapies. Despite a lack of direct legislative direction regarding AM quality, internationally harmonized guidance is available from several industry-standard bodies that describe the principles and application of a risk-based approach to AM qualification and related supply-chain risk management. According to a best-practice risk-based approach, AMs must be adequately qualified to a degree that reflects the level of risk the material presents to patient safety and the drug product's specification. This general approach can be implemented in different ways, and balancing quality with cost of goods is critical to the cost-effective manufacture of advanced therapy medicinal products. In some cases, it may be preferable or necessary to use AMs that are produced in compliance with current Good Manufacturing Practice. However, developers may be able to suppress manufacturing costs without undermining safety or regulatory compliance in the case that a material presents a lower risk profile. Despite a great deal of attention and interest in the quality of AMs in the cell and gene therapy space, there is still a need for greater harmonization to create a shared understanding of what constitutes a risk-based approach to AM production and sourcing. In this article, we propose a staged approach to AM quality that achieves a balance between the competing demands of risk mitigation and cost of goods containment at the various stages of AM quality development. Our novel, heuristic framework for communication among AM suppliers, users and regulators aims to bring down development and manufacturing costs and lessen the workload around regulatory compliance.