In a powerful example of bench-to-bedside science showing how observations made in the lab can spark life-altering therapies in clinic, an international team of clinician-investigators has announced that gene therapy for patients with a severe form of the blood disorder beta-thalassemia can be safe and effective.
The research team reports that a one-time treatment with the gene therapy known as LentiGlobin BB305 vector reduced or eliminated the need for blood transfusions in 22 patients with severe beta-thalassemia. The team's results are published in The New England Journal of Medicine.
"It was always our hope to bring our research findings to patients," said co-corresponding author. "We have taken our work from the lab, through preclinical models, and past the proof-of-principle stage, and are now able to gauge its effectiveness in patients with this disease. It is immensely gratifying."
Beta-thalassemia is a genetic disorder that impairs the body's ability to produce a key component of hemoglobin, a critical protein in red blood cells that carries oxygen to organs and tissue. Beta-thalassemia and sickle-cell disease are related disorders - both hamper hemoglobin production and can have lifelong repercussions. From toddlerhood on, people with the most severe forms of beta-thalassemia require monthly blood transfusions to replenish their red blood cell supplies along with iron chelation to remove extra iron from the body.
In the study researchers teamed up with a second group of U.S. and international clinical investigators in Australia and Thailand to share data and results from their respective phase II clinical trials. In total, the two teams treated 22 patients at six different sites around the world. Among nine patients with the most severe form of beta-thalassemia, the one-time treatment reduced the need for red-blood cell transfusions by 73 percent. Three of the nine subsequently discontinued transfusions altogether. Twelve of the 13 patients with a slightly less severe form of the disease no longer needed any blood transfusions after treatment. The team reports no safety concerns - treatment-related adverse effects were typical of those seen in patients who receive cell transplants of their own stem cells.
"When you have an anecdote of a single patient, you never know if it will be confirmed. Here, with a multi-center trial in a larger number of patients, we see a convergence of results, and we can measure the magnitude of the therapeutic effect," said the author. "There is room for improvement, as we'd like to see the elimination of dependency on transfusion even for patients with the most severe form of the disease; but there is also hope with protocol modifications we have introduced in our phase III trials."
Based on these results, two pre-drug marketing phase III clinical trials have begun.
Gene therapy for beta-thalassemia safe, effective in people
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