Bluebird offers a promising peek at a potential cure for sickle cell

bluebird's David Davidson

Bluebird bio ($BLUE), at work on a gene therapy for a rare blood disorder, unveiled some early but promising data on the one-time treatment's secondary indication of curing sickle cell disease, sending the biotech's value further skyward.

Bluebird's treatment, LentiGlobin, uses a modified virus to correct defects in the beta-globin gene and get the body back to producing the hemoglobin it needs to survive. The company has thus far demonstrated a curative signal in beta-thalessmia, a rare disorder with no approved treatments, and bluebird believes the gene therapy's hemoglobin-boosting profile could make a functional cure for the more common sickle cell disease.

Now, for the first time, the biotech is shedding some light on how LentiGlobin is faring against its second target, releasing a peek at data to be presented at next month's European Hematology Association meeting.

In its ongoing trial on beta-thalessmia and sickle cell, bluebird has treated one patient, codenamed 1204, who has the latter disease. Coming into the study, 1204 needed chronic blood transfusions to stem the symptoms of sickle cell. Three months after LentiGlobin treatment, however, 1204's anti-sickling hemoglobin levels rose to 9.4%, bluebird said. And a month-and-a-half later, that number jumped to 24%, all with no hospitalizations or sickle cell-related complications, according to the company.

As of February, 1204 had a total hemoglobin level of 31.6%, bluebird said, and, looking at historic sickle cell data, the company believes patients who hit the 30% threshold have the potential to be free of the disease's life-threatening effects.

The results, while early and from a single patient, are "very encouraging," bluebird Chief Medical Officer David Davidson said in a statement. And investors, long enamored with bluebird's approach to gene therapy, would seem to agree. The biotech's shares jumped as much as 13% in premarket trading on Thursday, following a roughly 6% spike earlier this week.

The sickle cell news comes as bluebird hammers out a path to the FDA in beta-thalessmia, on Monday revealing plans to start two 15-patient trials that will follow subjects for two years with a primary endpoint of relief from blood transfusions, adding results from those studies to data from a pair of ongoing trials to make up its application. The FDA has already granted its breakthrough-therapy designation to bluebird's beta-thalessmia program, promising access to top agency officials and a speedy review process.

Bluebird's lead treatment differs from many of the other gene therapies in development around the world, which involve inserting corrective genes directly into a patient. Instead, bluebird's method works by removing a patient's hematopoietic stem cells, equipping them with a functional beta-globin gene and then reinserting them through infusion.

- read the statement

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