ability to drive the clinical trials forward as well as to build [our staff] and capabilities a little more aggressively inside the company,” says Leschly, a former partner at Boston-based Third Rock Ventures, who left the venture firm to dedicate himself to Bluebird after Third Rock led Bluebird’s Series B round last March. “We feel that the progress we’ve made so far really warrants this long-term strategy.”
To Leschly, the company’s biggest accomplishment to date is that all the patients treated with its gene therapies appear to be doing very well. In the case of its first two treatments, a patient’s own blood stem cells are drawn from his bone marrow. Once the patient’s stem cells have been taken out of his body, a deactivated virus is used to deliver a normal version of a disease-causing gene into the stem cells. Later, the patient’s own stem cells that have been modified via gene therapy are implanted back into his body. The goal is that the stem cells with the normal version of the gene will prosper in the patient’s body and lead to the formation of healthy cells with the corrected gene. And the therapies can be given to the patients just once, as opposed to standard treatments, which patients need to take on a regular basis.
With its treatment for beta-thalassemia, which affects about 60,000 people globally, the patient who got the gene therapy was able to live without needing regular blood transfusions to replenish his supply of oxygen-carrying red blood cells. Another potential advantage of Bluebird’s treatment is that patients with the disease may be able to avoid getting bone marrow transplants, which put them at risk of developing a potentially lethal condition in which certain transplanted cells attack the transplant recipient’s healthy tissues. The risk of those attacks, called graft-versus-host disease, increases substantially when transplants come from donors who are not close relatives of the recipient. (Ideally, the transplanted cells come from a brother or sister.)
Yet make no mistake. Bluebird and the gene therapy field have a long way to go to prove that the treatments are safe and effective for patients. There are still no FDA-approved gene therapies, and there have been some high-profile failures in the field over the past two decades. About two years ago, biotech giant Genzyme (which is an investor in Bluebird) disappointed investors when a 289-patient clinical trial to test its gene therapy for peripheral artery disease failed. Still, the wins that Bluebird and others have wracked up in recent years have started give investors more confidence that gene therapies could deliver on some of their promise for patients.
“Gene therapy has come a long way towards realizing its potential as a clinically relevant treatment modality,” ARCH’s Gillis, the new board member at Bluebird, said in a statement. “We believe bluebird bio is at the forefront of several important advances in the field and is uniquely positioned to meet the significant treatment void for patients with severe genetic diseases.”
Leschly says that his firm also sees Big Pharma and large biotechs warming up to the field. “It’s an exciting time for Bluebird and I think the field more broadly,” he says, “because we’ve seen a lot of interest from the outside world, meaning Big Pharma companies and big biotech companies, who really are interested in the orphan drug space and the therapeutic modality of gene therapy.”
