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.
Since those early trials, the company said its current treatments using LentiGlobin BB305 for the treatment of beta-thalassemia major and severe sickle cell disease, are more potent forms of therapy, capable of producing much larger quantities of hemoglobin for patients suffering the disorders of the blood.
That information was not enough to calm investors though, who dumped the stock on Monday. However, the stock is showing a slight rebound this morning, hitting $82.87 per share. Cory Kasimov, an analyst with J.P. Morgan, said the sell-off is an overreaction to the news about the one patient, but added it was hardly surprising.
“Given recent focus on/concern around competition for LentiGlobin [BB305], on top of the overall skittishness of the biotech market, we aren’t surprised to see this knee-jerk reaction, though we think it’s overdone and would expect shares to rebound as investors have time to actually digest the update,” The Street reported Kasimov as saying.
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.
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.
David Davidson, chief medical officer for bluebird, said 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. 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.
The early clinical experience with HPV569 represented a crucial proof of concept for the potential of gene therapy to bring life-changing treatment to patients in need,” Davidson said in a statement. “The data from the LG001 study were invaluable to our efforts over the last five years to optimize our gene therapy approach with improvements to the potency, robustness and manufacturing for the next-generation lentiviral vector, BB305.”
In a Monday presentation at the Annual Congress of the European Hematology Association, Cavazzana said despite the one patient in question who required the transfusions, the “expression of HbA and the vector copy number in peripheral blood leukocytes, a measure of the persistence of the gene therapy, have remained largely unchanged.” Since those early trials and the leaps in treating hemoglobinopathies with gene therapies such as BB305, are resulting in “substantially improved vector copy number and HbA expression.”
October 20, 2015
By Alex Keown, BioSpace.com Breaking News Staff