Technologies used for cell and gene therapy development have come a long way but there are still important challenges associated with lentivirus manufacture. GMP plasmids account for a substantial proportion of raw material costs. And customers that procure plasmids from third-party manufacturers run the risk of supply chain disruptions that can impact both timelines.
Transfecting GMP plasmids into cells is also a complex, multi-step process, one that becomes less efficient at virus per cell production and highly variable at larger scales, said Alec Nielsen, PhD, Asimov’s co-founder and CEO. “In a traditional transient transfection where you’re mixing in these plasmids and transfection reagents with the cells, some cells receive zero plasmids [while] some of the cells receive thousands of plasmids.” The result is inconsistent batches of cells that perform very differently in experiments.
To address these issues, Asimov recently introduced two new product offerings to the cell and gene therapy market that are part of its LV Edge system portfolio.
This week, the company launched a new service for lentivirus production that eliminates GMP plasmid transfection. The so-called LV Edge Producer cell line development service generates clones that achieve E9 TU/mL unconcentrated lentiviral titers for chimeric antigen receptor (CAR) transgenes with no transient transfection required, according to Asimov.
This release follows the January launch of the LV Edge Packaging system, which enables a single plasmid transfection and is designed for customers who want more control over the transfection process. The system consists of a clonal, suspension-adapted packaging cell line with stably-integrated lentiviral genes under inducible control, model-guided DNA design to optimize transgene expression powered Asimov’s computer-aided design software, and robust, ready-to-transfer processes and protocols.
Asimov’s early technology was originally developed by Nielsen and three other co-founders at the Massachusetts Institute of Technology and Boston University. They launched Asimov in 2017 to commercialize their platform for designing bacterial genetic circuits using techniques from synthetic biology and computational biology. Today, the company is “overwhelmingly focused on engineering mammalian systems” for “the design and manufacture of therapeutics,” Nielsen told GEN in an interview this week. And it aims to make a dent in costs and complexity associated with lentiviral manufacturing through its portfolio of products.
By providing both a service and a laboratory option, Asimov gives customers multiple ways to access it’s technology based on their needs while reaping the benefits of lower manufacturing costs and complexity. In both iterations, Asimov transfects three out of the four GMP plasmids. The outstanding plasmid harbors the gene of interest which might be a chimeric antigen receptor in the case of an engineered cell therapy, for example. “The general idea behind both [products] is to move away from the traditional way that lentivirus is produced by scientists, which relies upon transecting typically four GMP grade plasmids into a host cell to produce virus,” Nielsen explained. The final plasmid to be transfected in both cases contains the customer’s gene of interest. Furthermore, “One of the pieces of technology that we’ve developed with these systems is a computational platform for DNA design that allows us to optimize the sequence of the gene of interest. Through these algorithmically guided optimizations, we can get even greater expression.”
This is the primary area where the products diverge. Customers of the LV Edge Packaging product transfect in the final plasmid themselves. Designed as an off-the-shelf solution that can be deployed in the lab, this option is best suited for use with early-stage clinical products where customers have to move quickly to run experiments and generate data needed to de-risk therapeutic assets, Nielsen said. According to numbers provided by Asimov, the packaging system achieves high harvest titers of over E8 TU/mL across multiple CAR transgenes and enables tuneable transgene expression in the transduced cell.
For LV Edge Producer cell line customers, Asimov handles the final step of integrating the final plasmid with the gene of interest as a service. Transfections are performed in Asimov’s cell line development facility based in Boston. It takes longer for customers to get their clones with the service option—less than 6 months from sequence transfer to stable, clonal cell line—but Asimov believes that the benefits, including reduced transfection complexity, should make it an attractive option compared to current options, especially for customers who need lentivirus for clinical or commercial scale production in large pharmaceutical companies, small to mid-sized biotechnology companies, as well as contract development and manufacturing organizations.
“Probably the most common use case is for engineered cell therapies to target cancer,” Nielsen said. But there’s increasing demand from scientists looking to do ex vivo cell engineering also in the context of oncology.
Feedback from early users of both solutions has been positive in terms of the performance and the transferability of the cell lines. Customers also report good correlation between the transduction of different cell types such as T-cells. “As the engineered cell therapy field continues to progress and an increasing number of diseases [are treated] with engineered cell therapy, that [will] dramatically increase the requirement for lentivirus,” Nielsen noted. “There are certain solid tumors which have gigantic patient populations” and technologies like the LV Edge system are “a key piece in unlocking an economical process to treat some of these larger patient indication diseases.”
