The US Food and Drug Administration (FDA) has granted orphan drug designation for Actimab-A, an alpha radiolabeled antibody, to treat patients over the age of 60 who are newly diagnosed with acute myeloid leukemia (AML).
Actimab-A consists of the CD33 antibody lintuzumab linked to the actinium-225 payload. The product is currently under investigation in a multicenter, phase 1/2 trial of elderly AML patients.
The company developing Actimab-A, Actinium Pharmaceuticals, Inc., recently announced positive interim data from this trial.
Nine patients were evaluable. They had a median age of 76 (range, 73-81) and intermediate- or poor-risk cytogenetics.
The median overall survival was 5.4 months (range, 2.2-24 months), but survival was better for the 7 patients who had secondary AML. These patients had a median overall survival of 9.1 months from study entry (range, 2.3-24 months).
Two secondary AML patients lived longer than 12 months, and the longest surviving patient lived more than 24 months.
Two dosing levels of Actimab-A have been evaluated to date (0.5 or 1.0 μCi/kg/fraction), and the study is ongoing at higher doses until the maximum tolerated dose is reached.
Actinium expects additional data from this trial to be available in 2015.
“The FDA’s decision to grant orphan drug status for Actimab-A is a significant milestone for the company and recognizes the need for innovative new approaches to treat AML,” said Kaushik J. Dave, PhD, President and CEO of Actinium.
“The designation will provide Actinium access to various development benefits and financial incentives from the agency, including an exemption from prescription drug user fees for Actimab-A for this indication and, if the drug receives marketing approval, it will enjoy 7 years of market exclusivity in the United States.”
