Lentiviruses are an essential tool for many cell and gene therapies (C&GT) but in a relatively new therapeutic area, guidance on lentiviral vector (LV) manufacturing is limited. In this blog, we explore the new comprehensive guidance published by the Alliance for Regenerative Medicine (ARM) and The National Institute for Innovation in Manufacturing Biopharmaceuticals (NIIMBL). By drawing from the experience of lentivirus manufacturing experts, including Pratima Cherukuri, CSO at Genezen, the guidance aims to harmonize manufacturing techniques and methods between companies.

In the past five years, the potential of C&GTs has been realized, with increasing numbers of drugs gaining approval for use. The rapid expansion of this therapeutic area has driven a rise in the global C&GT manufacturing services market, which is expected to be valued at USD $30.04 billion by 2027.

With approximately 2,024 gene therapies in the development pipeline (1), ARM has identified a lack of well-defined best practices for their development and manufacturing. To remedy this, the Alliance has drawn on the experience of C&GT manufacturing experts globally to develop comprehensive guidance with a focus on applying quality by design (QbD). Adding to their existing “A-mAb” and “A-Gene” guidance, “A-Cell” is a case study-based guide to integrating QbD principles in cell therapy chemistry, manufacturing, and controls (CMC) programs.

Lentivirus in cell & gene therapies

Of the C&GT therapies currently in the pipeline of genetically modified cell therapies, 48% are CAR-T therapies (1). These involve modifying the patient’s T cells to express chimeric antigen receptors (CARs), allowing them to specifically target cancerous cells and elicit an immune response. Modification of T cells is currently predominantly achieved using lentiviruses.

Lentiviruses are enveloped viruses in the Retroviridae family and are excellent tools for facilitating treatments where the patient’s cells are transduced ex vivo like CAR therapies. This is due to their ability to carry a large cassette insert (up to 8.5 kb), transduce both diving and non-dividing cells, and integrate their genetic material into the target cell genome.

Production of lentiviral vectors is far from simple, and the complexity of the processes involved means that there is currently a great deal of heterogeneity in methods adopted by manufacturers globally.

A shared approach to lentivirus manufacture is needed

Lentivirus manufacturing can be thought of as being split into plasmid design, upstream processing, downstream processing, and fill-finish. Throughout each step, there are important considerations and choices to make while being aware of regulatory requirements. Some of these areas currently lack essential guidance, leading to manufacturers adopting differing approaches.

Current FDA guidance does not specifically address plasmid DNA products for noninfectious therapeutic indications, like CAR therapies. As a result, determining the testing needs for viral contamination and clearance at the plasmid design stage can be a significant challenge.

Traditionally, gamma-radiated fetal bovine serum (FBS) has been used in the upstream processing step of LV production for producer cell growth. Issues surrounding consistency in FBS constitution, and the risk of animal-related disease have driven manufacturers towards using serum-free methods. Again, there is little guidance surrounding this subject, so there is some degree of variety in the alternative methods chosen.

Another area where further guidance is required is SARS-CoV-2 testing. Although the FDA has outlined expectations for C&GT risk assessments for SARS-CoV-2 transmission via products, there are no specific testing recommendations for source material, intermediates in-process, or final drug products.

Without uniform advice, projects that move between facilities could encounter challenges and delays when different methods and technologies have been used, ultimately slowing the time taken for potentially vital C&GTs to reach patients.

Comprehensive guidance on lentivirus CMC programs

The ARM’s A-Cell “Lentiviral Vector and Manufacturing Process” chapter provides guidance on the design, development, and scalable manufacture of lentiviruses while applying QbD principles. Drawing on the experience of expert lentivirus manufacturers this chapter offers a central source of knowledge on:

• Starting materials
• Upstream manufacturing processes
• Downstream manufacturing processes
• Process characterization and qualification
• Internal and external manufacturing testing
• Product testing and characterization
• Stability

By following this guidance, the biopharma value chain can ensure a smooth transition of projects between facilities. A shared understanding of the technologies and manufacturing methods used can help to mitigate delays and improve communications throughout facilities, companies, and projects. As the C&GT area grows, this harmonization will become increasingly important, and companies can look to this guidance for strategic insight into scaling.

To learn more about how the experience and expertise at Genezen helped to develop the guidance on lentivirus manufacturing found in A-Cell and how it could support your next project, get in touch today.

References
American Society of Gene + Cell Therapy. Gene, Cell & RNA Therapy Landscape Q2 2022 Quarterly Data Report