Lentiviral vectors are one of the foundational technologies of cell and gene therapy. Along with adenoviral vectors, they are one of the most widely used means of introducing genetic information into cells.
They are used in the lab, the manufacturing facility, and the clinic, particularly for the production of therapies for rare disease. For example, the approved gene therapies Skysona and Zynteglo are made using lentiviral vectors as is Rocket Pharmaceutical’s leukocyte adhesion deficiency-1 candidate, Kresladi.
Yet, despite their importance to the industry, current vector production processes are far from optimal, says Adriano Leuzzi, head of process development at Italy-based manufacturing and development services firm, ReiThera.
“The manufacturing challenges are mainly related to scalability, productivity—use of the right cell line, media, and transfection reagents that can effectively deliver the plasmids inside the cell at the right efficiency—and process yield,” he tells GEN.
Lentiviral vectors are also highly sensitive to temperature and pH changes—as well as to damage caused by shear forces in culture. And this can be a major problem during process development, Leuzzi says.
“All of these aspects need to be considered from the early stage of the development process up to the late stage of cGMP clinical production. The goal is to build a robust and easily scalable manufacturing platform to target the highest performance process and meet the regulatory quality requirements needed to ensure safety, purity, and efficacy.”
Technology
The good news is that bioprocessing technologies and methods are emerging that can help industry achieve this goal, Leuzzi points out.
“The shift to cost-effective, high-titer suspension cells instead of the adherent cell systems that dominate vector production at present may ensure an easier scale-up process in stirred-tank bioreactors and facilitate more effective mid-downstream procedures for product purification.
“Similarly, the use of single-use bioreactors and the design of modular downstream purification platforms associated with an early identification of the potential Critical Process Parameters (pCPPs), may ensure easy scale-up and scale-out processes and a successful tech-transfer from plant to plant, maximizing the overall LV platform success rate.”
Technology—more specifically process control software—can also help manufacturers address vector quality issues.
“To mitigate potential fluctuations in productivity and process/product-related impurities that can impact critical quality attributes, dedicated software for process optimization and related technologies should be introduced to characterize the process within defined operative ranges for example, using a temperature-controlled system for buffer preparation and media or product storage during the main critical manufacturing operations,” Leuzzi says.
And looking forward, artificial intelligence could soon play a role in making vector production more efficient, according to Leuzzi.
“Adopting software based on machine-learning technologies associated with a smart interpretation and data-driven use of AI coupled with human experience and technology know-how, may help scientists, engineers, and manufacturers improve the benefit of the LV platform, reducing the process timing while allowing manufacturing to remain focused on the most important point: at the end of the production lines, there is a patient.”
