Viral vector manufacturers are looking for ways to leverage existing and new platforms with fit-for-purpose reagents (cell lines, plasmid DNA [pDNA], media, transfection reagent) to identify and optimize critical process parameters across all unit operations.

Both upstream steps like transient transfection and the various downstream purification, final formulation, and fill/finish steps have deep impacts on process economics.

Double the production, lower the cost

To address current limits in rAAV viral vector yields and industrial scalability for suspension cell culture systems, Polyplus developed a new chemical-based, animal-free, fit-for-purpose transfection reagent called FectoVIR®^®-AAV. Using this new transfection agent, yields can be increased up to 2-fold compared to those obtained with PEIpro and up to 10-fold compared to those obtained with other commercial PEI-based transfection agents. At the same time, the complexation volume can be reduced from 10% to 1%, facilitating transfection complex preparation for large-scale manufacturing.

Increased productivity is essential for achieving reduced global manufacturing costs. More doses can be obtained per batch in the same sized bioreactor, or the same number of doses can be produced in a smaller bioreactor. In both cases, the greater productivity has a direct impact on the number of batches per year that can be produced and the related cost of goods (COGs).

Just a two-fold boost in titer can have a dramatic impact on the number of doses that can be produced in existing equipment. For a product like Zolgensma^® (onasemnogene abeparvovec-xioi), Novartis’s treatment for babies born with the neurodegenerative disease spinal muscular atrophy, a dose of which comprises 8.8 x 10¹⁴ viral genomes (VG), using FectoVIR^®-AAV would enable production of 328 rather than 118 doses in a 2000 L bioreactor assuming a doubling of the titer. Twice as much product being made using less raw material, consumables, and labor, can make the gene therapy more affordable.

Purpose-driven design

Polyplus is working to make viral vector manufacturing more cost-effective and scalable with enabling products and services. The 2021 launch of FectoVIR^®-AAV transfection reagents and kits was designed to accommodate research to GMP-grade production of adeno-associated virus (AAV) vectors in suspension culture. Compared to traditional PEI-based transfection agents, users can see up to 10-fold increase in titers. Even compared to the advanced PEIpro^® reagent for adherent and suspension AAV and lentiviral (LV) processes from Polyplus, FectoVIR^®-AAV affords a two-fold increase in titer.

With more stability, longer transfer times for the pDNA-reagent complex are achievable with less shear stress and reduced risk for degradation. The greater stability also makes it possible to achieve reproducible functional titers with the working volume of the pDNA-reagent complex solution reduced from 10% with PEI-based reagents to as little as 1%.

Still, transfection is only one piece of the puzzle. The cell line, media and plasmids are also crucial. Polyplus recently acquired eZyvec and its unique plasmid engineering technology to provide both tailored plasmid solutions and fit-for-purpose transfection reagents.

Looking ahead

The Polyplus promise is delivering solutions that power science. A commitment to collaborating with industry leaders to develop fit-for-purpose transfection reagents and tailor-made plasmids marries well with this right-first-time approach to the development of robust and scalable viral-vector manufacturing processes. These types of solutions are helping to address the manufacturing hurdles that must be overcome if affordable gene therapies for the treatment of diseases such as are to be commercialized.