Everything you need to know about ‘ready to use’ cells … on a poster

31 October 2022
Development Group

Biologics potency is an important component of an overall CMC analytical control strategy, which is widely determined by cell-based bioassays. However, developing robust and reliable bioassays places increased requirements on the analytical cells with low inter-assay variability (e.g., cell passage number, harvest) to deliver high-quality potency data. ‘Ready to use’ cells (RtU) offer many benefits, including reduced assay variability, and provide a frozen bank of uniform cell stock for utilization directly in an assay.

To understand current industry approaches for RtU cells and recommend best practices for a preparation, testing, and control strategy, the BioPhorum Development Group Bioassay workstream has conducted a benchmarking survey and held discussions around approaches for reliably making RtU cells for bioassays.

The team has also produced a poster on Industry approaches for implementation of ready to use (RtU) cells in bioassays. This contains selected results of this collaboration and aims to encourage discussion on common approaches to RtU cell manufacturing, testing, qualification, and implementation across the industry.

It covers subjects such as:

  • Introduction and terminology
  • Propagation of cell types for banking
  • Logistics: How are RtU cells made and frozen?
  • Qualification vs. validation
  • Assay performance
  • Implementation strategy.

The poster has been successfully presented by three workstream members at two conferences – CASSS Bioassays and BEBPA EUR Bioassays – and the team has had many requests for copies to use back at home sites. It highlights that the team plans to write a technical paper on implementing RtU cells in bioassays.

“There was lots of interest from RtU suppliers and end-users at the BEBPA EUR Bioassay conference and requests for copies of this poster,” said Esther Ong, Senior Scientist, Nonclinical Pharmacology at Fresenius Kabi SwissBioSim GmbH. “The majority of companies that were present at the conference are beginning to use RtU cells and they are looking forward to seeing our paper.”

The poster also mentions the take-home messages from the survey, such as:

  1. RtU cells are defined as cells (immortalized or primary cells) that are used directly from frozen stock with little to no culture
  2. >80% of respondents use RtU cells during some stages of development
  3. The first-line strategy for RtU cells is ‘thaw and use directly’
  4. The most common approach is the implementation of RtU as an extension of the two-tier system of master and working cell banks
  5. Qualification of RtU banks is simplified compared to master/working cell banks with a focus on functionality and assay performance
  6. Most respondents introduce RtU before method qualification/validation, as it is easier from a regulatory point of view.

To see the poster and download a copy for your own discussion, please click here.

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