This paper summarizes the proceedings of a workshop held at Trinity Hall, Cambridge to discuss comparability and includes additional information and references to related information added subsequently to the workshop. Comparability is the need to demonstrate equivalence of product after a process change; a recent publication states that this ‘may be difficult for cell-based medicinal products’. Therefore a well-managed change process is required which needs access to good science and regulatory advice and developers are encouraged to seek help early. The workshop shared current thinking and best practice and allowed the definition of key research questions. The intent of this report is to summarize the key issues and the consensus reached on each of these by the expert delegates.

Consistent and robust manufacturing is essential for the translation of cell therapies, and the utilisation automation throughout the manufacturing process may allow for improvements in quality control, scalability, reproducibility and economics of the process. The aim of this study was to measure and establish the comparability between alternative process steps for the culture of hiPSCs. Consequently, the effects of manual centrifugation and automated non-centrifugation process steps, performed using TAP Biosystems’ CompacT SelecT automated cell culture platform, upon the culture of a human induced pluripotent stem cell (hiPSC) line (VAX001024c07) were compared. This study, has demonstrated that comparable morphologies and cell diameters were observed in hiPSCs cultured using either manual or automated process steps. However, non-centrifugation hiPSC populations exhibited greater cell yields, greater aggregate rates, increased pluripotency marker expression, and decreased differentiation marker expression compared to centrifugation hiPSCs. A trend for decreased variability in cell yield was also observed after the utilisation of the automated process step. This study also highlights the detrimental effect of the cryopreservation and thawing processes upon the growth and characteristics of hiPSC cultures, and demonstrates that automated hiPSC manufacturing protocols can be successfully transferred between independent laboratories.

Step-pool structures (vortex weirs) are being used to provide (1) vertical stabilization during high flow, and (2) low-flow instream habitat in restoration of disturbed low-gradient streams. A study of eight steep, coarse-grained mountain streams in Colorado identified the geomorphic and hydraulic characteristics of natural step-pool structures and was used to develop a design procedure for sizing and spacing step-pool structures. Regression equations were developed for determining the pool length, scour depth, maximum pool width, and the amount of contraction required to provide downstream tailwater control. Independent variables included step height, channel slope, 25-year unit discharge, and active channel width. Other requirements identified included confinement of flow over the weir, a low-flow notch, sizing and interlocking of the boulders comprising the step, adequate tailwater control and bank protection in the downstream pool. The sizing and arrangement of the particles comprising the step centers around a few key particles termed anchor boulders that are the largest size class found within the channel, and are on the order of 1 m in diameter. They provide stability to the weir and confinement of flow over the weir. Boulder size is not controlled by the channel hydraulics, but rather by availability and lithology.

a b s t r a c tAutomation will likely to play a key role in the development of scalable manufacturing processes for cell-based therapies. In this study, we have compared the effects of manual centrifugation and automated non-centrifugation cell culture process steps, performed using TAP biosystems' CompacT SelecT automated cell culture platform, upon hMSC morphology, number, viability, surface marker expression, Short tandem repeat (STR) profile, and paracrine function. Furthermore, the comparability between flow cytometry analyses of hMSCs, performed at multiple sites, was investigated. No significant difference in hMSC growth and characteristics was observed between cells cultured using either the manual centrifugation process step or the automated non-centrifugation process step, in which residual dissociation agent is carried over. However, some variability in paracrine activity was observed between hMSCs cultured using alternative process steps. It is also apparent that differences in analytical methods can influence the inter-laboratory reproducibility of hMSC flow cytometry analysis, although differences in culture may also contribute to the variability observed in the expression of 2 of the 8 surface markers examined. This novel investigation into the effects of these two key process steps will help to improve the understanding of the influence of automated cell culture upon various cell culture parameters, as well as upon process comparability.