AMAG Pharmaceuticals, Inc. (NASDAQ: AMAG) today announced positive preliminary data from the IDA-303 study. IDA-303 is a single arm, open-label extension study that evaluated the safety and efficacy of repeat dosing with ferumoxytol in patients with persistent or recurring iron deficiency anemia (IDA) regardless of the underlying cause and a history of unsatisfactory oral iron therapy or in whom oral iron could not be used. Patients were eligible to enroll in the IDA-303 extension study after they completed IDA-301, which was a double-blind, placebo-controlled trial that randomized patients to receive either a one gram intravenous course of ferumoxytol or placebo, the results of which were previously reported by the company and presented at the American Society of Hematology annual meeting in December 2012.
A total of 634 patients were enrolled and qualified for ongoing observation/treatment in IDA-303. Of the 634 patients enrolled in IDA-303, 471 had previously received one treatment course with ferumoxytol in the IDA-301 study, and the remainder had received placebo. Patients were eligible for ferumoxytol treatment in IDA-303 if their hemoglobin levels fell below 11 g/dL and their transferrin saturation (TSAT) levels were less than 20%. During the course of the IDA-303 study, 337 patients were treated with ferumoxytol; 151 of these patients had received placebo in IDA-301 and therefore received their first course of ferumoxytol in the IDA-303 study. A total of 244 patients received a second course of ferumoxytol, of whom 186 patients had received their first course in IDA-301. The remainder of patients enrolled in IDA-303 did not receive treatment, suggesting the durability of response to the first course of ferumoxytol administered in the IDA-301 study.
The primary efficacy endpoint of the extension study was the mean change in hemoglobin from baseline to week five following the first course of ferumoxytol. The 151 patients who received their first course of therapy in IDA-303 achieved a statistically significant mean increase in hemoglobin from baseline to week five of 2.6 g/dL. This change was consistent with the 2.7 g/dL increase in hemoglobin reported for ferumoxytol-treated patients in both the IDA-301 and IDA-302 studies.