Bluebird bio builds its case for gene therapy as first sickle cell patient responds

Nick Leschly, CEO of Bluebird Bio

Bluebird bio ($BLUE) is building its new-wave gene therapy pipeline one patient and one disease at a time. And today the biotech took another step forward in its carefully planned march toward a possible accelerated approval for its lead program, noting that their first sickle cell disease (SCD) patient has been responding remarkably well to their therapy while adding evidence of improved durability in responses for beta-thalassemia.

As of May, investigators say, the first of 8 patients being treated with LentiGlobin BB305 in a Phase I/II safety and efficacy study for SCD--a 13-year-old boy--had been weaned off blood transfusions for three months. A mutation in the gene needed to make hemoglobin, a protein that carries oxygen in the blood, is responsible for SCD, making it a prime target for a gene therapy. 

At 6 months postinfusion "the proportion of anti-sickling hemoglobin (HbAT87Q + HbF) accounted for 45% of all hemoglobin production (40% HbAT87Q + 5% HbF)," notes the company. Thirty percent should be enough for a disease-modifying effect, say Bluebird execs.

"Sickle cell disease does not spontaneously resolve itself," says Bluebird CEO Nick Leschly, in Vienna for a meeting of the European Hematology Association. "The first patient ever treated is off to an amazing start."

Single-patient responses have to be handled carefully in biotech. Some companies like to cherry-pick responses to clinical-stage assets or lean on anecdotal one-offs to curry favorable press attention. But gene therapy--using a virus to insert a corrective gene and potentially provide a lasting fix to some terrible diseases--can credibly claim a clinical success with a handful of patients, making a single initial response noteworthy, though far from conclusive.

The focus now will be on adding additional clinical outcomes on SCD while tracking the responses of patients in beta-thalassemia. Bluebird used this occasion to note that two of its subjects in their beta-thalassemia trial have now been transfusion-independent for up to 16 months.

Bluebird's clinical trial strategy has generated some significant investor enthusiasm for the company, which was among the first to jump through the newly reopened IPO window in the summer of 2013. Benefiting from the spotlight on gene therapy, where a new wave of biotechs are now active, Bluebird's market cap has swelled to close to $6 billion.  

The gene therapy field has made a big comeback in the past two years, raising the prospect that safely inserting corrective genes can cure quite a few maladies, or at least provide an enduring response. Bluebird, though, expects to start looking for an approval while it's still tracking patients. And that has helped generate an ongoing discussion about how these therapies might be paid for.

Payers understandably may not want to pay upfront for a decades-long benefit, says Leschly, but there could be a mix of upfront payments followed by a pay-as-you-go policy. But that's a discussion that will include a lot of different players as they evaluate the payoff--one patient at a time. 

- here's the release

Special Report: The 25 most influential people in biopharma in 2015 - Nick Leschly - bluebird bio