(Reuters) - Biotech firm Bluebird Bio Inc said its experimental gene therapy continued to exhibit a positive effect in an ongoing early-stage study of patients with rare types of blood disorders.
The product, LentiGlobin, is being tested in patients with beta-thalassemia major and those with severe sickle cell disease (SCD), two hereditary conditions.
The drugmaker said on Thursday two patients suffering from beta-thalassemia did not require blood transfusion at 14 months and 11 months, respectively, after receiving LentiGlobin.
Beta-thalassemia results in lower levels of hemoglobin in the blood.
One SCD patient, who had been receiving chronic transfusions prior to the trial, began to be weaned away from transfusions after day 37, the company said. The patient received the last transfusion on day 88.
The data also found that the patient achieved an anti-sickling hemoglobin rate of 31.6 percent, which reduces or eliminates his risk of serious conditions associated with the disease.
The patient has not had a post-treatment hospitalization for a sickle cell disease-related event, the company said.
"The SCD patient is showing everything we would want to see at this point to demonstrate highly promising proof-of-concept" J.P. Morgan analysts wrote in a note.
SCD is caused by an abnormal form of hemoglobin that results in a break-down of red blood cells.
No patient experienced drug-related adverse event during the study so far, Bluebird said.
The therapy involves the insertion of a functional human beta-globin gene into the patient's stem cells, which are then transplanted back into the patient.
It was granted breakthrough therapy status in February by the U.S. Food and Drug Administration to treat beta-thalassemia, speeding up the development process.
Breakthrough therapy designation is based on initial trial data and granted to drugs with the potential to treat serious diseases better than existing therapies.
The Cambridge, Massachusetts-based company's shares were up 4.9 percent at $173.93 on the Nasdaq.
(Reporting By Samantha Kareen Nair in Bengaluru; Editing by Sriraj Kalluvila)