This is a newer direction of medical treatment where healthy genes are introduced into the body of patients with defective genes causing diseases. The idea is to correct for a previous genetic defect (usually born with) to stop or treat the disease. The treatment induced 'healthy copies' of the gene can compensate for defective or mutated form of the gene in the patients.
This is a group of diseases where patients have a defective(mutated) copy of hemoglobin gene. This gene mutation causes red blood cells to become sickle shaped and die early, leaving a shortage of healthy red blood cells. These sickle cells get tangled up easily leading to blockage in blood vessels, pain, infections and sickness.
People with sickle cell disease have shorter lives due to multi-organ damage from blocked vessels. Gene therapy in sickle cell patients seeks to resolve the sickness by introducing healthy copy of Hemoglobin gene. This treatment is being tried on experimental basis in several hospitals (clinical trials).
Recent encouraging results from 6 such gene-therapy treated sickle-cell patients was published where patients' symptoms were reduced or eliminated. Now a larger effort is underway to test this experimental treatment in a larger number of patients. (This the route to get treatment approved by FDA- i.e., test in smaller group of patients first and then test in larger number of patients to prove the benefit of drug or treatment)
Treating cancer is specially difficult as it can reoccur in the future even after an extensive treatment. Long term relief has thus been a desirable goal of cancer treatment. This goal has been realized in 2 blood cancer patients who are cancer free after 10 years of successful treatment with engineered T cell therapy (CAR T cells).
These results can confirm that new CAR T cells can actually cure patients with leukemia. Leukemia is cancer of the body's blood and bone marrow. Diagnosis of blood cancers is based on a large number of abnormal cells in the blood and shortage of normal cells. This leads to bone pain, weight loss, fever and increased risk of infections. Most patient's cancer comes back after treatment.
T cells are the immunity cells in our body that fight infections and clear pathogens. For CAR T therapy, these T cells are genetically engineered such that they can selectively identify the tumors and kill them. These are also called 'Living drug' as the treatment involves- injecting engineered T cells into the patient. The most significant feature of this treatment is that the CAR T cells can develop memory and live in the patient's body even upto 10 years. It is fair to say that CAR T cells are 'active patrolling agents' in the fields to detect and kill cancer.