Gene Therapy, Results

#ASH17: Bluebird touts early signs that its new-and-improved sickle cell gene therapy is working

Bluebird bio $BLUE says they’ve been able to gather evidence to help prove that their new-and-improved approach to making a gene therapy for sickle cell disease has the potential to be a consistently effective once-and-done therapy.

Following up on some disappointing evidence of inconsistency among the first small group of patients treated with LentiGlobin, bluebird’s team went back to the drawing board to whip up a new approach to manufacturing that they believed would overcome their initial setback.

Two patients — 1312 and 1313 — were treated using the refined process as least once. (The first was treated twice, first using the old and then the new approach.) Their experiences will be spotlighted at the upcoming ASH meeting in early December, with updates coming on their response.

Mohammed Asmal

It takes a step in a direction we feel is quite positive,” says Mohammed Asmal, bluebird’s VP of clinical development.

That message helped stoke a 15% increase in the biotech’s share price.

The real proof will come when researchers have a chance to see if better cell engraftment allows these patients to produce normal red blood cells, potentially curing the ailment.

It was clear early on among the first group of patients that there was an engraftment problem, says bluebird CEO Nick Leschly. So they decided to take a new course. First, they took action to bat back the inflammation and other problems that occurred in patients’ bone marrow, giving them better stem cells to work with. Then they used a new manufacturing process — to be highlighted at ASH — that gave them a much higher vector copy number to work with, improving the odds of success.

That was clearly apparent in the first patient, who was first treated with a therapy made from the first approach, followed by more effective treatment in the second.

Nick Leschly

“The copy number was (initially) in a range of .3, .5 to 1,” says the CEO. “Now you look across, and we’re now in the range of 2 to 3.” And he adds: “The number of cells modified is dramatically different.”

To be sure, it’s a small number of patients to review, but in sickle cell disease small numbers can be compelling. And bluebird has lots of reasons to tout a new, more effective therapeutic approach after stumbling early on, raising doubts about their ability to beat out other therapies now in the clinic.

That’s what they will be discussing at ASH as they prep for more work with a new batch of patients who will be involved in the pivotal work ahead.


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