C-Stem, a new technology fro scale up of cell therapy production

Abstract

Background & Aim Most stem cells, including Human pluripotent stem cells (hPSCs) are adherent cells. The historical standard of culture is in 2D at the bottom of Petri dishes. This technology allowed for the first trials in cell therapy but is limited by: i) reproducibility issues, ii) scalability, iii) high cost due to labor intensive manipulation of the cells, and iv) genomic instability. For cell therapy applications, cell quality reflects the culture process and large quantities of cells are required for allogenic strategies. 2D automation enables reproducible clinical batch production but commercial batch sizes will require further scale up. Suspension culture in bioreactors is a straightforward choice for scale up with two main techniques: i) microcarriers, where the cells grow attached to their surface or ii) spheroids, where cells grow in 3D aggregates. In both culture conditions the cells’ exposure to shear stress in the bioreactors limits further scale up. Methods, Results & Conclusion The C-Stem™ technology addresses this challenge by encapsulating cells within hollow alginate hydrogel capsules, 250 µm in diameter with 30 µm thick walls. Capsules both protect cells form shear stress and let small molecules (smaller than 150 kDa), gas, nutrients and waste in and out. Inside the capsule, hPSCs are seeded in extracellular matrix to mimic in vivo conditions. The capsules are produced at high throughput (5000 per second) with proprietary microfluidics. The C-Stem™ technology allows for 100x fold expansion per week of hPSCs and their differentiation in traditional bioreactors. At the PSC stage, C-Stem™ significantly improves cell viability as compared to standard 2D PSC culture. C-Stem™ promotes pluripotency, yields biomimetic hPSC “epiblastoids” and maintains state of the art genomic integrity. Addressing current manufacturing issues, the process is fully integrated from seeding to harvest, scalable, single use, closed and aligned with cGMP requirements. Most 2D and 3D protocols can be transposed in C-Stem™. Preclinical results will be presented for Parkinson's disease cell therapy. Fully mature dopaminergic neuronal microtissues are differentiated from hPSCs within capsules. They are then engrafted in Parkinson's disease rat model striata. This results in behavioral correction of rats within 6 weeks of surgery, thereby reducing by a factor 2-3 the recovery time as compared to standard progenitor engraftment.