By Manuel J. T. Carrondo, Prof. Chem & Biochem Eng., FCT/UNL & Vice-president, iBET
Since the early nineties iBET has been involved in production and purification of viruses for gene therapy. Early on, enveloped retroviruses and non-enveloped adenoviruses where the targets; from late nineties onward lentivirus and baculovirus were added to the portfolio of enveloped viruses and AAV to the non enveloped viruses.
Although originally meant for monogenetic diseases, now some are also produced for cancer treatment (ex. oncolytic adenoviruses made in A547 cells, so replicative) or as reagents for cell therapies (also known as ex-vivo gene therapies).
Having developed scaled down tests and analyticals (including surface plasmom resonance, dynamic light scattering) coupled with its chemical engineering model competencies, iBET has designed membrane or media materials for which our key partners MERCK Millipore, SARTORIUS, GE HealthCare have developed the prototypes tested on our biologies and equipments. In this way, improved DSP processes have been created increasing viral yields and infective to total particle ratios or yields and viability for cell therapies.
Having built our own rigs (see Figure 1) we have been developing two-column simulated moving bed (SMB) continuous processes for viral purification, achieving up to six-fold increase in productivity and 50% increase in recovery. These continuous processes can easily be designed for robustness and work at small, medium or large scales (see Figure 2) opening up improved operation processes improving quality and reducing costs.
More recently, iBET has been establishing scalable and integrated DSP strategies for the clarification, volume reduction (concentration) and washing unit operations for human derived adult and pluripotent stem cells.
Tangential flow filtration (TFF) based processes integrated with perfusion cultures in bioreaction allowed for over 10% extra cell recoveries; such TFF steps were shown to be linearly scalable maintaining constant load (cell/cm2), shear rates and permeate flux parameters – flat sheet cassettes yielding up to 18% extra recovery after a volume reduction factor of 50. To further increase purity, expanded bed adsorption chromatography operated in negative mode, with a new multimodal prototype matrix based on core – shell bead technology was optimised for expanded bed ratios of 1.4.
Specifics of the processes will be shown and discussed.
Interested in learning more? Manuel will be speaking at the upcoming BioProcess International European Summit in Amsterdam the 25-26 April. He will be presenting a session titled “Novel DSP strategies for Gene and Cell Therapies“. Register with the VIP code CQ3562BLOG and save £100 off the current rate. Learn more here.