Isolator Technology and Automation Enhanced Contamination Control in the Manufacture of Cell and Tissue Culture Derived Regenerative Medicine Products.

Cell and Tissue Derived Therapies – a Growing International Market.
There are several emerging segments of advanced biological products that could reach a market of tens of millions of patients and have a market value well in excess of $200 billion by 2025(1).

If the market value of mesenchymal stem cells from various sources and induced pluripotent stem cells for research purposes alone is considered the market globally is approaching $2 billion at the present time. One of the most significant risks in the production of cells and tissues for therapeutic and research purposes is microbial contamination. These products are susceptible to bacterial, and mold contamination as well as infection by viruses. If these cell and tissue derived products are to be central to, as is widely predicted, a new biotechnology revolution a production system that mitigates risk from these contaminants is essential. The industry will require a means to deliver safe, contamination free products to patients quickly, reliably, safely and efficiently. This will require engineers, scientists and regulators to think very carefully about which technologies should be applied to the problem of culturing, packaging and distributing living cells and tissues for therapeutic uses(2).

The technical circumstances of this problem is further complicated by the requirements of some regenerative medicine products currently under development. The cultivation of cytotherapy products is difficult in and of itself, but the difficulties are complicated even further in the case of engineered tissues. In this case cells, often autologous mesenchymal stem cells, will be grown in sufficient number and then planted or printed onto scaffolds. The scaffolds may either be de-cellularized organs or structures such as heart valves, or they may be porous artificial biomatrices with properties that favor cell adhesion. There are 3D bioprinters capable of building such structures to a specific geometric shape after which they can be populated with cells. In some cases other bioactive materials may also be used(3).

 

 

In the traditional pharmaceutical and biopharmaceutical markets industry has long focused on a product attribute or characteristic known as sterility assurance. Sterility assurance can be attained through the application of two very different contamination control technologies. The first of these is terminal sterilization, a process in which a product is sterilized in its primary package. The sterilization of a product in its primary package requires that both the product substance and the package are sufficiently resistant to the technology used to sterilize the product. The two most common means of terminal sterilization are heat and ionizing radiation which eliminates biologics as candidates for the application of terminal sterilization. Practically only some drugs and medical devices can be terminally sterilized in their primary package.
Whether the product is an engineered tissue or cells modified for therapeutic applications, it is required that all materials coming into contact with the cells be sterilized and be handled in as perfect a “germ-free” environment as humans are able to create.

The prototype of the ideal environment required for the manufacture of finished, ready to administer advanced cell and/or tissue based biologics, is well known to most individuals working on the manufacture or testing of modern day drugs and biologics and is known in that field as the “isolator”. Isolators have been used for drug and traditional biologics manufacturing since late 1980s and although there have been issues that slowed their adaptation they are now widely used in not only aseptic production but also product testing, research/development and production of clinical scale production of investigational new drugs.

Isolators are already widely used in cell processing at the research and cell cultivation for clinical trial products. An example of a highly automated cell processing isolator is shown below (CellPROi system photo courtesy of Shibuya Corporation):
This isolator system bears some resemblance in size and configuration to those used in small-scale aseptic production or sterility testing in the pharmaceutical/biopharmaceutical industry. Like those systems the critical zone of isolator environment is designed to operate at ISO 5 conditions from a particulate air quality perspective. The environment is decontaminated using built in systems with the result being an environment free of microbial contamination. Passboxes are used for the transfer of materials into and out of the system.

While the features listed above may seem typical to those familiar with pharmaceutical/biopharmaceutical isolators there are some very important differences.
First, it is necessary to bring cells taken from a single patient into the system and grow them through three to five passages to cell numbers of 107 cells or more. This requires sterile materials such as media, culture plates, buffer solutions and enzymatic solutions to be brought into the isolator. Passboxes which allow for disinfection of materials brought into and out of the system are required and they must be designed to allow for rapid decontamination and aeration.
This of course, must be done while ensuring that cells derived from a single patient are kept separate for those for a second patient through all phases of cell cultivation. This is accomplished through the use of electronic menus (SOPs) and electronic coding of materials and cell culture systems for unambiguous identification.

A special rapid docking station allows devices such as incubators to be attached and removed from the isolator without any possibility of contaminating the germ free environment. At the clinical scale of production, it is typical for one incubator to be dedicated to the cells or tissue of a single patient. Again electronic control and management of materials flow and production status is necessary to ensure patient safety. It is necessary for technicians to have the ability to examine growing cells to ensure that they have the expected morphology and for this purpose microscopic systems using high definition cameras are necessary. The images from these systems can be displayed on external monitors. Additionally, it is possible to take sterile samples for in-process and final product control without introducing contamination risk. Other equipment as required for a given product can be accommodated including centrifuges for cell pelleting which can be built into the unit and decontaminated in situ.

The system pictured used a dual-arm robot which can be sterilized-in-place along with the isolator decontamination cycle. This six-axis robot is capable of handling all of the cell-culture “manipulations” characteristically done by human technicians. However, the robot has the advantage of operating with absolute reproducibility and since it is fully enclosed in the germ free environment reducing contamination risk. Not only does the robot eliminate risk from personnel contamination as all isolator systems do, it also does not require a human to work through gloves during critical operations thus eliminating risk from glove tears or separations.

While we believe that by using modular isolators with modern automatic process control features, robotics, and electronic procedure/documentation management will result in optimal patient safety, we realize that we are at the earliest stage in the development of advanced biological products. If these products are going to reach their full potential in the improvement of human life they will need to be accessible to the largest possible number of patients. To accomplish this we must develop systems that can operate at much higher throughput levels than are required for the clinical trial scale of production.
We will have to be able to grow more cells and tissue taking up the least possible space while at the same time retaining complete control over product purity and identity throughout the manufacturing process. We will need to be able to grow more cells while reducing the use of incubator shelf space and doing so in warehouse-like incubators without the need for 100s of small individual incubators.
A combination of machine automation and robotics will be necessary to ensure that these systems can operate continuously 24 hours/per day with minimal maintenance downtime. Scaling up our ability to make cell base therapies widely available is the next major challenge we will face as we move into the next decade.

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DR. James AKERS

After earning a Ph.D in medical microbiology with a concentration on virology at the University of Kansas School of Medicine. After serving on the faculty and East Carolina School of Medicine he began working in the pharmaceutical industry in 1981 and has continued to do so for the last 35 years in various capacities. He served as President of PDA from 1991-1993 and served for many years on that organization Board of Directors. He has been a member of the United States Pharmacopeia Expert Committee on Microbiology since 1995 and served as that Committee’s Chairman from 2005 to 2010. Dr. Akers has authored over 100 publications and written 28 text book chapters as well as editing two books. His principal areas of interest are aseptic processing, sterilization, contamination control, and analytical microbiology.

j.e.akers@icloud.com

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Mamoru KOKUBO – SHIBUYA CORPORATION

Dr. Kokubo earned a degree in Agriculture from the University of Shinshu and a doctorate in pharmacology from the University of Kanazawa School of Medicine. Dr. Kokubo is currently director of the Regenerative Medicine System Division at Shibuya Corporation in Kanazawa Japan. Prior to assuming his current position, He was an assistant professor at the University of Kanazawa School of Medicine. He has lectured throughout Japan on isolator technology and hydrogen peroxide decontamination and was the chair of WG for Isolator/ Barrier System Standardization in Japan PDA. He is also a member of international committee on ISO/ TC198 WG9.
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Kazuhiro TANIMOTO – SHIBUYA CORPORATION

DKazuhito Tanimoto graduated from the department of mechanical engineering at Kanazawa University in 1984. He has thirty years of experience in pharmaceutical systems engineering. He is currently chief manager for isolator & decontamination technology for the Shibuya Corporation based in Kanazawa, Japan. He has a wide range of expertise design and engineering of various types of isolator systems and pharmaceutical manufacturing applications. Mr. Tanimoto is a member of ISPE & PDA, and also a member of international committee on ISO/TC198 WG9.

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Références

 1. Stem Cell/Regenerative Medicine Market Estimates. www.grandviewresearch.com 2016.
 2. J. E. Akers and M. Kokubo, Aseptic Manufacturing of Regenerative Medicine Products Using Isolator Technology in Gene Therapy and Cell Therapy Through the Liver; S. Terai and T. Suda editors. Springer Verlag in the Press 2016.
 3. S.V. Murphy and A.Atala. 3D Bioprinting of Tissue and Organs. Nature Biotechnol 32(8) pp773-785. 2014.
 4. J.P. Agalloco and J.E. Akers, Risk Management cGMP and the Evolution of Aseptic Processing Technology; PDA J. Pharm. Sci. Tech. 63(1) pp 8-10, 2009.