Gene therapy shows promise in curing sickle cell

LentiGlobin is a one-time procedure that involves repairing stem cells

Sickle cell disease, which is a group of inherited red blood cell disorders, affects about 100,000 people in the United States, according to the Atlanta-based Centers for Disease Control and Prevention. A new gene therapy could give them hope for a cure.

Sickle cell is caused by a mutation in the gene that tells your body to make hemoglobin, the iron-rich compound that makes blood red and enables red blood cells to carry oxygen from your lungs throughout your body.

In sickle cell anemia, the abnormal hemoglobin causes red blood cells to become rigid, sticky and misshapen. Both mother and father must pass the defective form of the gene for a child to be affected.

According to the clinical trial, 35 patients who had the one-time procedure, called LentiGlobin, are now producing healthy red blood cells with healthy hemoglobin.

Not only that, those patients have suffered none of the severe pain episodes that come with the disease, said lead researcher Dr. Julie Kanter, director of the University of Alabama at Birmingham’s Adult Sickle Cell Clinic. “It’s the beginning of a new life” for them, she added.

The clinical trial involved doctors across the country, including Dr. Lakshmanan Krishnamurti, who ,during that time, was director of the bone marrow transplantation program at Aflac Cancer and Blood Disorders Center at Children’s Healthcare of Atlanta, and a professor of pediatrics at Emory University School of Medicine.

LentiGlobin involves removing stem cells from a person’s bone marrow. Lab technicians then expose those cells to a virus that inserts into them a healthy copy of the hemoglobin gene.

The patient’s remaining bone marrow is killed off with chemotherapy, and the repaired stem cells are implanted and start producing healthy hemoglobin.

“This is kind of like doing a bone marrow transplant into yourself,” said Dr. Lewis Hsu, chief medical officer of the Sickle Cell Disease Association of America.

Almost all of the defective genes displayed promising signs three years past their treatment. Those signs, indicative of a permanent cure, were:

  • Almost all their red blood cells contained healthy hemoglobin rather than the faulty hemoglobin caused by defective genes.
  • Their red blood cells are breaking down at a normal rate; sickle cell disease usually causes the cells to break down much faster.
  • None had experienced severe pain episodes that landed them in the emergency department; prior to treatment, they typically suffered more than three a year.

Kanter told HealthDay News she expects LentiGlobin will move to U.S. Food and Drug Administration approval within the next couple of years.

“Unfortunately, I think for a long time it will be very expensive. The next steps of this are how do you make it easier and less expensive and more available,” she said.

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