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Bluebird Reports Early Results From Upgraded Gene Therapy

Xconomy Boston — 

One of the year’s most closely watched clinical studies could lead to a landmark approval of a gene therapy and throw wide open the debate over how to pay for expensive drugs. The first drips of data have emerged.

Bluebird Bio (NASDAQ: BLUE) says the first three patients—of 15 total expected—have had good results from a revised version of its LentiGlobin gene therapy to treat certain genetic variants of the rare blood disease beta-thalassemia, which causes severe anemia and requires frequent transfusions.

Bluebird has changed the way it manufactures the product, which requires extracting a patient’s bone marrow cells, altering their DNA outside the body, then reintroducing the cells to the patient. This study, called NORTHSTAR-2, is the first test of the improved process, which regulators said last year would not require rewinding its clinical program back to the beginning—a sigh of relief at the time for the company and its shareholders.

Caveats abound. The results are not only a small sample size, they are also early. Typically data from three patients in a study would not be worth singling out. But Bluebird, of Cambridge, MA, is trying to produce a type of medicine never approved before in the U.S. (Two have been approved in Europe, but one never took hold.)

And the FDA has already shown willingness to consider approval of medicines for rare diseases based on tiny sample sizes—with considerable controversy, in the case of a drug approved last year to treat Duchenne muscular dystrophy.

In one NORTHSTAR-2 patient, the healthy version of the blood protein hemoglobin has reached normal levels six months after a single dose of treatment. The second patient’s healthy hemoglobin levels are rising but lower than the first patient after three months. The third patient is only two months out from treatment.

For patients with good results, the treatment’s staying power will be crucial. Bluebird wants it to be a one-time cure, as of course will patients. Insurers will undoubtedly want the same—but what to do if something that costs hundreds of thousands or more than a million dollars, stops working after a few years?

Bluebird officials say they have already begun talking to payers about “pay for performance” arrangements. “Our hope is to tie outcomes of the patient to the value generated,” says chief financial and strategic officer Jeff Walsh. “It can come in many different forms.” (Xconomy reported on several creative drug-pricing ideas in this article.)

Bluebird hopes to make a case for approval for beta-thalassemia before U.S. and European regulators, perhaps in 2019, using data from the NORTHSTAR-2 trial and from previous trials that used the older LentiGlobin version. The main goal of NORTHSTAR-2 is for patients to produce enough of their own healthy hemoglobin to eliminate the need for regular blood transfusions. The first patient has reached that goal, says chief medical officer David Davidson.

The new version of LentiGlobin product, among other things, squeezes more copies of the correct gene into each targeted cell—more shots on goal to change each malfunctioning cell for the better, in other words.

The NORTHSTAR-2 patient with six months of results to report has fared better than similar beta-thalassemia patients six months after they received the previous version of LentiGlobin in a study called HGB-204. The NORTHSTAR-2 patient is producing 13.3 g/DL of hemoglobin, within the normal range for a woman; the median production among 10 HGB-204 patients after six months was 9.7 g/DL.

A doctor working on the study is presenting the data, along with updates from its LentiGlobin treatment for sickle cell disease, at the European Hematology Association meeting this weekend.