Drug Development

Bluebird bio adds a key process to pioneering gene therapy as it ramps up a pivotal PhIII

David Davidson, bluebird CMO

David Davidson, bluebird CMO

Bluebird bio believes it has developed a new process that will make a marked improvement in their pioneering gene therapy programs, promising to deliver a significant impact on patient outcomes in a newly-launched pivotal study for LentiGlobin.

Late last year, bluebird bio execs were forced to explain why the latest data on LentiGlobin had proved disappointing in a small set of sickle cell patients being tested. Instead of the cure that bluebird $BLUE was looking for, several patients experienced a less than optimal response in producing anti-sickling hemoglobin, which caused more than a few investors in the company to do a double take on the company’s prospects.

The problem, bluebird said at the time, was that the vector copy number measuring the level of cells which had been corrected by gene therapy fell short of expectations. In an interview with TheStreet’s Adam Feuerstein at the time, CMO David Davidson said that that problem might be attributed to the fact that researchers had not removed enough of the diseased bone marrow.

Today, bluebird says it has begun the pivotal Phase III study for beta-thalassemia. And Davidson tells me that they’re making a crucial correction in the manufacturing process, adding two unidentified small molecules — a pair of “transduction enhancers” added to its stem cell manufacturing process — that the bellwether biotech has evidence to believe can have a marked impact on the vector copy number and the potential to cure its top slate of disease targets.

The market bid up bluebird’s shares by 9% Thursday morning.

“We’re very excited about the two small molecules,” Davidson tells me this morning, with in vitro evidence of an improvement in the vector copy numbers as well as in vivo data from a mouse model to back it up.

“We’re planning to apply the same manufacturing process with the improvement across the LentiGlobin program, including sickle cell,” he adds. That involves the pivotal study in patients with transfusion-dependent beta-thalassemia and non-β0/β0 genotypes as well as an upcoming study with β0/β0 genotypes.

Bluebird isn’t revealing exactly what these two molecules are, in part for competitive reasons, says Davidson. They’ll be able to reveal more about it at ASH at the end of the year, and the investigator says that they’ll be able to get firm patient responses 6 to 12 months out, making this more of a 2017 story.

It’s particularly significant for bluebird that the company can proceed right into Phase III without getting a new IND, says Wedbush’s David Nierengarten, who’s bullish on the company’s prospects.

Bluebird helped make gene therapy hot with its first, early snapshots of some dramatic effects on individual patients. Targeting some extremely rare diseases, one or two patients can tell a lot about a company’s prospects. But it’s also becoming clearer that not all gene therapies are created equally, making these kinds of ongoing improvements crucial to the longterm success of the companies.

The jury is still out on bluebird, but the company isn’t sitting still with the technology it has.

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Sr. Manager, Regulatory Affairs, CMC
CytomX Therapeutics San Francisco, CA
Marketing Associate - Demand Generation
Catalytic Data Science Charleston, SC
Associate Principal, Life Sciences Partnerships
Flatiron Health New York City or San Francisco

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