Investors Nervous Over bluebird bio's Latest Gene Therapy Updates Released Ahead of American Society of Hematology Conference

Published: Nov 09, 2015

Investors Nervous Over bluebird bio's Latest Gene Therapy Updates Released Ahead of ASH Conference
November 6, 2015
By Alex Keown, BioSpace.com Breaking News Staff

CAMBRDIGE, Mass. – Shares of bluebird bio stock plummeted more than 20 points Thursday after preliminary data released in anticipation of next months’ meeting of the American Society of Hematology (ASH), revealed some of the company’s proprietary gene-therapy treatments for beta-thalassemia may not provide a long-term fix.

fell Thursday from $90.15 per share to $70.95 per share following bluebird’s early data release. This morning the stock is showing signs of a small rebound, trading at $71.42 per share.

The data released by the gene therapy company includes updates on seven beta-thalassemia patients and one sickle cell disease patient on its gene therapy. The data on their treatment with the company’s LentiGlobin is largely positive, but somewhat mixed as well, XCconomy reported. Four of the seven beta-thalassemia patients have not needed a transfusion for at least three months – a procedure the patients were used to undertaking at least once a month. The sickle-cell patient is also responding well to treatment and has not required and is producing about 51.5 percent anti-sickling hemoglobin nine months after treatment, bluebird said.

But, at least two of the three remaining beta-thalassemia patients have needed at least one transfusion and the third is still transfusion dependent, bluebird said in its data. The report indicates the gene therapy treatment is not something that is an effective treatment for every patient. The patients that have not shown as positive a response to the gene therapy treatment have two copies of a genetic mutation—each called b0—that prevents them from producing any beta globin, a subunit of hemoglobin. The patients show some response to the LentiGlobin treatment, and with some tweaks, perhaps patients with the b0/b0 mutation could show greater response.

With ASH still a month away, bluebird will likely provide more up-to-date information on the treatments of these patients. David Davidson, chief medical officer for bluebird, said in October the data obtained from those early trials have been invaluable research in leading to the more effective gene-therapy treatments developed by bluebird today. Davidson said the company’s LentiGlobin BB305 drug product is being evaluated in three ongoing clinical trials for the treatment of patients with beta-thalassemia major and severe sickle cell disease, which is a much larger market for gene therapy than beta-thalassemia, the Motley Fool reported. He said three abstracts related to these ongoing clinical trials will be presented in December at this year’s American Society of Hematology’s Annual Meeting.

LentiGlobin was granted Breakthrough Therapy Status by the U.S. Food and Drug Administration (FDA) in February. The designation is given to drugs expected to treat life-threatening illnesses in order to expedite the development and review of the drug.

Thalassemia is a genetic disorder affecting the production of normal hemoglobin. Beta thalassemia major, also known as Cooley’s anemia, demonstrate abnormal genes that “do not direct the body to make normal beta chains or normal amounts of beta chains,” according to Johns Hopkins. Patients with Cooley’s anemia often require blood transfusions and may not live a full life.

In October bluebird’s stock slid 6.5 percent after the company revealed a patient who underwent an early gene study treatment for beta-thalassemia seven years ago required new treatments following a relapse. Marina Cavazzana, a professor of hematology and lead investigator for bluebird’s HGB-205 clinical study, said the patient she treated in 2007 has required two blood transfusions after experiencing clinical symptoms of anemia. The patient, referred to as subject 1003, was treated for beta-thalassemia major using bluebird’s first-generation HPV569 lentiviral vector. Speaking with the Street, bluebird Senior Vice President of Clinical Development Robert Ross said subject 1003 was "always on the border of needing blood transfusion," even after undergoing the HPV569 lentiviral vector treatment. Ross told The Street that it was not surprising, given the patient’s state, that transfusions were needed seven years later.

In June bluebird struck a deal with Kite Pharma, Inc. to develop T-cell therapies to treat cancer linked to Human papilloma virus (HPV). T-cell receptors are showing promise in boosting the body’s own immune system to combat cancer.

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