WEDNESDAY, March 1, 2017 (HealthDay News) -- Researchers are reporting early success using gene therapy to treat, or even potentially cure, sickle cell anemia. <\/p>\n
The findings come from just one patient, a teenage boy in France. But more than 15 months after receiving the treatment, he remained free of symptoms and his usual medications. <\/p>\n
That's a big change from his situation before the gene therapy, according to his doctors at Necker Children's Hospital in Paris. <\/p>\n
For years, the boy had been suffering bouts of severe pain, as well as other sickle cell complications that affected his lungs, bones and spleen. <\/p>\n
Medical experts stressed, however, that much more research lies ahead before gene therapy can become an option for sickle cell anemia. <\/p>\n
It's not clear how long the benefits will last, they said. And the approach obviously has to be tested in more patients. <\/p>\n
\"This is not right around the corner,\" said Dr. George Buchanan, a professor emeritus of pediatrics at the University of Texas Southwestern Medical Center in Dallas. <\/p>\n
That said, Buchanan called the results a \"breakthrough\" against a disease that can be debilitating and difficult to treat. <\/p>\n
Buchanan, who wasn't involved in the research, helped craft the current treatment guidelines for sickle cell. <\/p>\n
\"This is what people have been wanting and waiting for,\" he said. \"So it's exciting.\" <\/p>\n
Sickle cell anemia is an inherited disease that mainly affects people of African, South American or Mediterranean descent. In the United States, about 1 in 365 black children is born with the condition, according to the U.S. National Heart, Lung, and Blood Institute. <\/p>\n
It arises when a person inherits two copies of an abnormal hemoglobin gene -- one from each parent. Hemoglobin is an oxygen-carrying protein in the body's red blood cells. <\/p>\n
When red blood cells contain \"sickle\" hemoglobin, they become crescent-shaped, rather than disc-shaped. Those abnormal cells tend to be sticky and can block blood flow -- causing symptoms such pain, fatigue and shortness of breath. Over time, the disease can damage organs throughout the body. <\/p>\n
There are treatments for sickle cell, such as some cancer drugs, Buchanan pointed out, but they can be difficult to manage and have side effects. <\/p>\n
There is one potential cure for sickle cell, Buchanan said: a bone marrow transplant. <\/p>\n
In that procedure, doctors use chemotherapy drugs to wipe out the patient's existing bone marrow stem cells -- which are producing the faulty red blood cells. They are then replaced with bone marrow cells from a healthy donor. <\/p>\n
A major problem, Buchanan said, is that the donor typically has to be a sibling who is genetically compatible -- and free of sickle cell disease. <\/p>\n
\"We've known for a long time that bone marrow transplants can work,\" Buchanan said. \"But most patients don't have a donor.\" <\/p>\n
That's where gene therapy could fit in. Essentially, the aim is to genetically alter patients' own blood stem cells so they don't produce abnormal hemoglobin. <\/p>\n
In this case, the French team, led by Dr. Marina Cavazzana, of Necker Children's Hospital's biotherapy department, focused on a gene called beta globin. In sickle cell anemia, beta globin is mutated. <\/p>\n
First, the researchers extracted a stem cell supply from their teen patient's bone marrow, before using chemotherapy to wipe out the remaining stem cells. <\/p>\n
Then they used a modified virus to deliver an \"anti-sickling\" version of the beta globin gene into the stem cells they'd removed pre-chemo. The modified stem cells were infused back into the patient. <\/p>\n
Over the next few months, the boy showed a growing number of new blood cells bearing the mark of the anti-sickling gene. The result was that roughly half of his hemoglobin was no longer abnormal. <\/p>\n
In essence, Buchanan explained, the therapy \"converted\" the patient to sickle-cell trait -- that is, a person who carries only one copy of the abnormal hemoglobin gene. Those individuals don't develop sickle cell disease. <\/p>\n
\"This is encouraging,\" said Dr. David Williams, president of the Dana-Farber\/Boston Children's Cancer and Blood Disorders Center. <\/p>\n
But, he cautioned, \"the caveat is, this is one patient, and 15 months is a short follow-up.\" <\/p>\n
Williams and his colleagues are studying a different approach to sickle cell gene therapy. It aims to restart the body's production of healthy fetal hemoglobin -- to replace the abnormal \"adult\" hemoglobin seen in sickle cell. <\/p>\n
The hope, Williams said, is that gene therapy will ultimately offer a one-time treatment that cures sickle cell. But no one knows yet whether that will happen. <\/p>\n
According to Williams, two key questions are: What's the long-term safety? And will the altered stem cells last for a patient's lifetime? <\/p>\n
If gene therapy is proven to work, there will no doubt be practical obstacles to its widespread use, according to Buchanan. It's a high-tech treatment, and many sickle cell patients are low-income and far from a major medical center, he said. <\/p>\n
But, Buchanan said, the new findings have now \"opened a door.\" <\/p>\n
The study was partly funded by Bluebird Bio, the company developing the therapy. <\/p>\n
The results were published March 1 in the New England Journal of Medicine. <\/p>\n
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View post: WEDNESDAY, March 1, 2017 (HealthDay News) -- Researchers are reporting early success using gene therapy to treat, or even potentially cure, sickle cell anemia. The findings come from just one patient, a teenage boy in France. But more than 15 months after receiving the treatment, he remained free of symptoms and his usual medications Continue reading
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