What happened

Shares of bluebird bio (NASDAQ:BLUE) closed up 13.5% today following the release of abstracts for the American Society of Hematology (ASH) meeting in early December. Bluebird is scheduled to present data for its LentiGlobin gene therapy and its next-generation CAR T therapy, bb21217, as well as data from an early stage trial of BCL11a shRNAmiR in patients with sickle cell disease.

So what

The data on LentiGlobin for transfusion-dependent beta-thalassemia is the most important event for Bluebird's near-term success since the gene therapy is the furthest along of the biotech's pipeline candidates. Today's move, however, is more likely due to the promising data for the earlier-stage candidates.

In a phase 1 trial testing bb21217 on patients with relapsed/refractory multiple myeloma, 6 of 7 patients demonstrated clinical response, which isn't too bad considering the patients had previously received a median of nine prior lines of therapy. One patient had previously been treated with a whopping 17 lines of therapy.

In another phase I study, treatment of sickle cell disease patients with BCL11a shRNAmiR reduced the expression of BCL11A protein by 90% compared to pre-treatment levels. BCL11A is responsible for switching from fetal hemoglobin, which isn't a problem for sickle cell patients, to the defective beta hemoglobin. By turning off the switch, patients no longer had irreversibly sickled cells

Normal and sickled red blood cells

Image source: Getty Images.

Now what

The cutoff for data to be included in the abstract was months ago, so the presentations at the ASH meeting will be important to see if the promising results for bb21217 and BCL11a shRNAmiR hold up when tested on larger patient populations.

Brian Orelli has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends bluebird bio. The Motley Fool has a disclosure policy.