GENE THERAPY HAS POTENTIAL TO CURE ADULT LEUKEMIA
The study results published in The New England Journal of Medicine and in Science Translational Medicine showed that two of three patients dying of chronic lymphocytic leukemia (CLL) appear cured and a third is in partial remission after infusions of genetically engineered T cells. The treatment uses a form of white blood cells called T cells harvested from each patient. A manmade virus-like vector is used to transfer special molecules to the T cells. One of the molecules, CD19, makes the T cells attack B lymphocytes — the cells that become cancerous in CLL. All this has been done before. These genetically engineered cells are called chimeric antigen receptor (CAR) T cells. They kill cancer in the test tube. But in humans, they die away before they do much damage to tumors.
What’s new about the current treatment is the addition of a special signaling molecule called 4-1BB. This signal does several things: it gives CAR T cells more potent anti-tumor activity, and it somehow allows the cells to persist and multiply in patients’ bodies. Moreover, the signal does not call down the deadly all-out immune attack — the feared “cytokine storm” — that can do more harm than good. This may be why relatively small infusions of the CAR T cells had such a profound effect. Each of the cells killed thousands of cancer cells and destroyed more than 2 pounds of tumor in each patient. The treatment was not a walk in the park for patients. One of the three patients became so ill from the treatment that steroids were needed to relieve his symptoms. The steroid rescue may be why this patient had only a partial remission And there’s a big downside. The CAR T cells that fight CLL also kill off normal B lymphocytes. These are the cells that the body needs to make infection-fighting antibodies. As long as the CAR T cells persist — which may be for the rest of patients’ lives — patients will require regular infusions of immune globulin.
REFERENCE
stm.sciencemag.org
SHANOOB K
FIRST YEAR MPHARM
ALSHIFA COLLEGE OF PHARMACY
No comments:
Post a Comment