Fabio D’Agostino, Biopharmaceutical Bioprocessing Technology Centre, Newcastle University, reported from Cell Therapy Manufacturing and Gene Therapy Congress in February:
Anthony Davies, President at Dark Horse Consulting, kicked off Day 2 with another interesting plenary highlighting three of the potential game changers in biopharma. Sylvain Arnould, Head of Manufacturing at Cellectis, Jim Faulkner, Head of Manufacturing at Autolus, and Lothar Germeroth, Senior Vice President at Juno Therapeutics, shared with us their insights into this fascinating world of the new magic bullets for cancer called T cell based therapies.
Last November was a good month for T cell based therapies as we learned that a one-year-old child with an aggressive form of acute lymphoblastic leukaemia was cured with one of Cellectis’s products, known as UCART19, at Great Ormond Street Hospital in London.
Cellectis is developing CAR-T cells which are gene edited with their proprietary technology TALEN®. This nuclease-based technology enables them to create allogeneic products from healthy universal donors which can therefore be distributed and available also to patients who do not have enough T cells to undergo an autologous CAR-T therapy (based on their own T cells). Leveraging this and other proprietary technology, they are developing a pipeline of allogeneic products for haematological malignancies as well as solid tumours. CELLforCURE (an LFB group company) in France will manufacture cGMP clinical batches for UCART123, Cellectis’s wholly owned lead product candidate. Other products are also being developed in collaboration with Servier and Pfizer. Other than creating an allogeneic product, their gene editing technology can also be used to improve safety and efficacy.
After T-cells are isolated from healthy donors’ peripheral blood mononuclear cells, these are tested and activated via CD3/CD28 stimulation. CAR and suicide gene are inserted via lentiviral transduction. To further reduce immunogenicity, the TCR gene is also knocked-out along with CD52 which contributes to reduce chemotherapy resistance. Cells are then expanded and CAR positive-TCR negative T cells isolated via CliniMACS®. The product is then frozen and can be used “off the shelf”. One healthy donor could be used to create 500-1000 doses of product.
Now we all are expecting more clinical data to prove efficacy of these breakthrough technologies. In December 2015, Cellectis submitted a clinical trial application to the MHRA to initiate a first-in-human clinical investigation for UCART19 in the UK.
Next Generation CAR-T Cells
Jim Faulkner described Autolus as a next generation engineered T cell company. He went on to explain that recent compelling clinical data is mainly focusing on a small number of therapeutic targets. The vast majority are chasing CD19 as a target in B cell malignancies because CD19 is uniquely expressed on B cells and so represents a ‘clean’ target. However, it is rare that you can define a malignancy with a single antigen and even if you can the cancer often responds by down-regulating the target and ‘escaping’. Also, current CAR-T cell therapies still suffer from quite severe side effects due to the inability of the CAR-T cells to distinguish between healthy and malignant cells. The objective of Autolus is to develop the next generation of CAR-T cell therapies which will be able to selectively target and destroy malignant cells only. Their proprietary technology can also recognize multiple antigens (as opposed to just one) which will allow targeting of tumours that cannot currently be addressed using the single antigen approach.
Current CAR-T manufacturing technologies are based on density gradient with or without mAb/magnetic purification of T cells and activation with artificial APC (e.g. CD3/CD28 Dynabeads) which need to be removed and residual carry-over routinely tested. Furthermore, these raw materials are available only from a limited number of suppliers which is less than ideal in a crowded competitive landscape. Lothar Germeroth explained how Juno have circumvented the need for these approaches with their proprietary Streptamer™ reversible reagents.
The process is no longer based on magnetic beads but on affinity –specific tags (Strep-tags) which are added to CAR proteins of engineered T cells and bind to StrepTactin-coated beads. Strep-tags can then be removed by addition of D-biotin which has even higher affinity for StrepTactin. This reduces the risk of compromising the biological function of the cells and potentially adverse effects of the markers in clinical applications. The fully automated process could enable high recovery of T cells, selective expansion and activation while decreasing processing time and costs. Therefore, Juno could potentially manufacture many personalized cell therapy products with a reduced footprint. This would be a great example of technology integration in the cell therapy industry; a trend which was echoed several times during the Congress.
Effective Manufacturing Strategies
Ohad Kerneli, former VP Manufacturing and Technology at Pluristem, now founder and CEO of Kerneli Ltd, used simple calculations to show it is not possible with current available methods to manufacture 12,000 units a year in a cost effective manner. However, he adds, we should not hide behind the hurdles of the autologous model and its intrinsic customized nature, but rather develop new methods to process and culture cells. Kerneli gave the car industry as an example: 73 million new Range Rovers were sold in 2014, each with over 1800 parts, each totally customized to the customers’ needs and yet, every 68 seconds a new car is born in the manufacturing site in Liverpool. Innovative in-process control technologies are also needed, especially for autologous cell therapy products where the starting biopsy is usually limited and precious.
CMO vs In-House Development
The Cell Therapy Manufacturing Surgery focused on the difficult topic of working with CMO vs in-house development. Lior Raviv, Director of Development at Pluristem, explained why sometimes you do not have a choice but to develop the technology in-house. In his experience at Pluristem, they identify gaps in the production process and look for technologies that could fill them. At this stage, they perform a risk analysis on the impact of the available technology on the critical quality attributes (CQAs). If the risk of change to process repeatability, quality or effectiveness of the product is high, the decision is now based on quality rather than cost. This means that, unless you decide to adapt your process to what is available on the market, you have to develop your own technology. A good understanding of the product CQAs and critical process parameters together with use of risk analysis and tools to control process variability, allows informed decisions with a vision for the future process and product development. These are also key elements to successful scale up and technology transfer to a different site. Continuity of supply chain is also a concern to cell therapy products developers.
Bernie Huyghe, Senior Director at Pfizer, described some of the best practices for outsourcing in cell and gene therapy industry. In response to a question about how long it takes to switch vendors, Huyghe replied that it depends on when in the process and in the development you make the change. For a viral vector change, it can take 1-2 years to find, qualify, produce and test the material prior to use in manufacturing.
The cell and gene therapy industry is developing at a fast pace, but we will probably have to go through some sub-optimal stages before we can develop solid manufacturing standards. Getting it right first time is difficult when diving into the unknowns of innovation.
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Fabio D’Agostino is a passionate life sciences professional with experience in both the medical device and biopharmaceutical industry. An active member of the PDA Cell and Gene Task Force, he has contributed to a number of conferences in the cell and gene therapy industries. He was also instrumental in the launch of the new journal: Cell and Gene Therapy Insights.
After graduating with Honours from the Polytechnic University of Turin (Italy) with a BSc and a Master’s in Biomedical Engineering, he started his career at LivaNova (formerly Sorin Group) before moving to Newcastle University to take an Engineering Doctorate in Biopharmaceutical Process Development. He currently holds a research position at the Institute of Genetic Medicine (Newcastle University) where he is responsible for the development of an innovative platform for modular tissue engineering.