By Peyton Macrina
Treatments for blood cancers have been sought after by researchers and medical professionals for years. Although various treatment options are available for patients, each of these display a similar pattern of high rates of relapse or other health complications. Outlooks for patients undergoing these treatments are not always hopeful, and outcomes can seem bleak. However, a relatively new type of gene therapy is emerging with promising results. CAR-T therapy helps to treat blood cancer patients through the targeting of certain protein strands in cancer cells and the prevention of graft-vs-host disease.
CAR-T cell therapy is developed through the modification of T-cells. The T-cells are specifically developed to “express a chimeric antigen receptor” (CAR-T). CAR-T therapy is generally used for blood cancers such as “non-Hodgkin’s lymphomas, some leukemias, and myelomas” (CAR-T). These cancers are known as B-Cell malignancies. This modification allows the cell to single out specific antigens in blood cancers known as CD19 and CD22. These protein strands are the sections where blood cancers are generally expressed, making them the key target area for CAR-T cells. Originally, CD19 was the only strand targeted, as it is the “protein that is expressed by most precursor B acute lymphoblastic leukemia cells,” as well as other cancerous cells (Seattle 41). In certain cases, however, it was found that the CAR-T immunotherapy treatment was unsuccessful due to a second protein strand -CD22- expressing the cells. This left the CAR-T cells unable to detect the strand, as they were not programmed to do so. Experimental treatments for new CAR-T cells able to identify both CD19 and CD22 are currently being performed at Seattle Children’s Research Institute.
Furthermore, CAR-T cell therapy reduces the risk of a patient developing graft-versus-host disease, or, GVHD. Graft-versus-host disease is a “potentially fatal post-transplant complication”, that was particularly common in cases of stem cell treatments (CAR-T). GVHD generally occurs after allogeneic transplantations for B-Cell malignancies are rejected by the body (Hymes 515). GVHD primarily affects the skin, and generally causes mild to severe dermatitis, as well as bilirubin elevation and diarrhea. In cases of severe or chronic graft-versus-host disease, patients can develop widespread calcium deposits, deterioration of muscle strength, ichthyosis, cardiomyopathy, and much more (Hymes 515). Comparatively, in a research study done on 20 patients receiving experimental CAR-T therapy, none developed graft-versus-host disease. The only negative side effects reported were “fever, tachycardia and hypotension” (CAR-T). Eight of the 20 research subjects also showed signs of remission of their B-Cell malignancies, with the longest of these lasting more than 30 months. Although these numbers may not seem very significant, they are very promising for a research study.
CAR-T cell therapy is being used to treat deadly blood cancers in ways never imagined. By targeting certain protein strands in cancerous cells, CAR-T cells can effectively put patients into remission while lowering the risk of graft-versus-host disease. These advancements in B-Cell malignancy cancer treatment are revolutionary for the medical world as well as for patients. Experimental research done on CAR-T cell therapy has had promising results, giving hope for the future. A cure for blood cancers could be closer than once presumed.
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“Seattle Children’s Opens CD22 CAR T-Cell Immunotherapy Trial for Children and Young
Adults Whose Leukemia Escapes CD19 CAR T-Cell Therapy.” Biotech Week, 9 Aug. 2017, p. 41. Academic OneFile, db24.linccweb.org/login?url=http://go.galegroup.com.db24.linccweb.org/ps/i.do?p=AONE&sw=w&u=lincclin_spjc&v=2.1&it=r&id=GALE%7CA499954276&asid=b80812a12bff264e6c17d83c6fa43896. Accessed 6 Sept. 2017.
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