Gene Therapy, Results

Bluebird’s gene therapy for beta-thalassemia falls short of a cure, but still wows in 22 patients

After going back to the drawing board to come up with a better gene therapy for beta-thalassemia, a disease that interferes with the body’s ability to produce hemoglobin, investigators working for bluebird bio $BLUE have produced some compelling data to demonstrate that their therapy can eliminate or reduce the need for blood transfusions.

But they don’t have a cure — yet.

Publishing in the New England Journal of Medicine, the researchers report that they tested the treatment in 22 patients. In the 9 patients with the most severe form of the disease, they report they were able to dramatically reduce the need for blood transfusions by 73% and eliminate it for now in 3. Six of those patients, though, have needed to continue transfusions. And 12 of 13 patients with a less severe form of the disease currently no longer require blood transfusions after a single treatment — with a median of 26 months transfusion-free.

The interim data greatly expands on the patient experiences they can now bank on to demonstrate the efficacy of the attempt at a once-and-done therapy which affects hundreds of thousands of patients. And the investigators have not abandoned an attempt to find a complete cure for all.

“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,” Harvard Medical’s Philippe Leboulch told their in-house pub. “But there is also hope with protocol modifications we have introduced in our Phase III trials.”

Bluebird — run by CEO Nick Leschly — was forced to go back and change the manufacturing process on LentiGlobin after some uneven responses early on. Last summer, the company came up with some encouraging data on the first three patients.

The gene therapy is made by extracting blood stem cells from patients and inserting a functional beta-globin gene into them, transplanting them after a round of chemo to clear their bone marrow.

Jerome Groopman in The New Yorker writes:

The challenge now is finding ways to implement a complex, potentially life-saving treatment in parts of the world where medical care is limited. Established facilities for autologous marrow transplantation already exist in many developed nations, as do laboratories that can introduce a healthy globin gene into stem cells. But, in some parts of the world where beta thalassemia is most common, these facilities do not yet exist.

Contrary to what the enthusiasts may be presenting today, there’s clearly room for improvement. And bluebird is clearly not alone in the field trying to produce a cure. CRISPR Therapeutics, for example, has been using its gene editing tech to see if it can find a lasting cure for the disease. And those other programs, including efforts at Bellicum, will likely continue to see if they can leapfrog bluebird with something better.

bluebird bio CEO Nick Leschly Getty

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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