Stem cell gene therapy: faster and cheaper

A compact "gene modifier" for the treatment of cancer has been created

Oleg Lischuk, N+1

American scientists have developed and tested a compact semi-automatic system for obtaining individual genetically modified hematopoietic cells of patients in medical institutions. The results of the work are published in the journal Nature Communications (Adair et al., Semi-automated closed system manufacturing of lentivirus gene-modified haematopoietic stem cells for gene therapy).

Gene therapy using bone marrow stem cells (CD34+) has great potential for the treatment of various diseases, such as hemoglobinopathies, chronic viral infections (including HIV) and some forms of cancer. Genetic modification of these cells is carried out outside the body to eliminate the risk of changing other cells. The process of obtaining modified hematopoietic cells takes place in several stages. First, a bone marrow sample is taken or leukopheresis is performed with the mobilization of a growth factor. Then the resulting cells are cultured on a specially selected nutrient medium. After that, a transgen is introduced into them with the help of a neutralized lentivirus. The modified cells are cleaned of reagent residues and other impurities and, finally, a drug based on them is prepared and tested for administration to the patient. Currently, this process, in accordance with the GMP standard of good manufacturing practice, is carried out in a clean room in a laboratory worth millions of dollars, which dramatically reduces the availability of such therapy.

To eliminate the need for expensive production, employees of the Fred Hutchinson Center for Cancer Research and the University of Washington in Spokane joined forces with the California company Miltenyi Biotec. A compact isolated system for obtaining modified hematopoietic cells (GM-CD34+) was based on the CliniMACS Prodigy device manufactured by the company, designed for automatic pre-processing of a biological sample, immunomagnetic isolation and purification of the necessary cells.

A programmable unit was added to this device for cell culture, the introduction of a transgene into them, the analysis of the obtained GM-CD34+ and the preparation of the final drug for administration to the patient. Since the program required in each case is set by the operator, the system was called semi-automatic. It occupies an area of about 0.46 square meters and can be installed on a laboratory table, it requires one or two operators to maintain it (for comparison, modern production occupies a hundred times more area and requires the efforts of five to ten people). Since the entire production cycle is isolated from the external environment, the operation of the system does not require sterile conditions – it can be installed in any medical center. The process of obtaining modified cells takes from 25 to 30 hours (in modern production it takes more than 80 hours).

Genomodification of cells using a new system and in a traditional way.
Figure from an article in Nature Communications

During the tests, the human cells obtained in the system successfully took root and began to function in the bone marrow of immunodeficient mice. In addition, the pig-tailed macaques' own bone marrow cells (Macaca nemestrina) prepared in the system restored their hematopoiesis after myeloablation (complete destruction of hematopoietic cells by chemotherapy), and the production of all blood cells was stable for more than a year of observations.

According to the head of development Jennifer Adair, the cost of the system for buyers will be about 150 thousand dollars. An individual kit for the treatment of a specific disease, containing reagents, a nutrient medium, a viral vector with a transgen and a sterile container with an infusion system for the final drug, will cost approximately 26 thousand dollars. At the same time, obtaining GM-CD34+ in a research laboratory now costs 38-55 thousand dollars.

Currently, none of the types of gene therapy based on hematopoietic cells is approved for clinical use. However, thousands of patients with dozens of congenital, infectious and oncological diseases have already taken part in clinical experiments, many of which have been recognized as successful. This allows us to expect the introduction of such therapy into clinical practice in the coming years.

Portal "Eternal youth" http://vechnayamolodost.ru  24.10.2016