IV Iron Formulation Eases CKD Anemia
Bruce Spinowitz, MD
Ferumoxytol, a semi-synthet-ic iron oxide formulated with mannitol, may be a safe and effective IV iron treatment for anemia in CKD patients not on dialysis.
Investigators conducted an open-label, randomized study of 304 nondialysis CKD patients comparing ferumoxytol with an oral iron control group. Patients randomized to ferumoxytol had a significantly greater increase in hemoglobin at day 35 compared with patients on oral iron.
In addition, a significantly higher proportion of patients randomized to ferumoxytol achieved an increase in hemoglobin of 1 g/dL or greater at day 35 and a significantly greater increase in serum ferritin at day 21 compared with patients who re-ceived oral iron.
“This is the largest trial comparing an IV iron to oral iron,” said lead investigator Bruce Spinowitz, MD, associate clinical professor of medicine at Weill Cornell Medical College in New York City, and associate director of nephrology at New York Hospital Medical Center in Queens, N.Y.
“Ferumoxytol's major advantage is the amount and the speed of delivery of the iron, which is important in the dialysis setting and the doctor's office as well.” Ferumoxytol delivers 510 mg of iron in 17 seconds, which is a larger amount of iron per dose than any other available IV iron therapy, Dr. Spinowitz said. It also contains lower levels of free iron than other iron preparations. Each vial of the drug contains 30 mg/mL of iron and 44 ng/mL of mannitol.The study population had a mean age of 64 years. Patients were randomized in a 3-to-1 ratio to receive either two doses of 510 mg of ferumoxytol within one week or 200 mg of oral elemental iron daily for three weeks. A total of 228 patients received the IV preparation and 76 received oral iron at 20 U.S. sites between May 2004 and August 2006.
In 238 patients making up the efficacy-evaluable population (182 on ferumoxytol and 56 on oral iron), ferumoxytol produced a significantly greater mean increase in hemoglobin compared with patients receiving oral iron (ferumoxytol 0.86 g/dL vs. oral iron 0.06 g/dL). Increases in serum ferritin were significantly greater in the ferumoxytol group than the oral iron group at day 21 (ferumoxytol 551 ng/mL vs. oral iron 8.9 ng/mL).
“Oral iron essentially does not raise hemoglobin all that much because in the CKD setting, whether pa-tients are on dialysis or not, patients don't absorb iron as well. The other issue with oral iron is that between 25% and 50% of patients just do not tolerate it in the amounts they need because of GI side effects,” Dr. Spinowitz said. “With this compound, we found that it was safe and void of any anaphylactic reactions.”
Moreover, adverse events occurred in 52% of the oral iron recipients compared with only 35% of the ferumoxytol-treated patients. Drug-related adverse events (none of them serious) occurred in only 10.6% of patients on ferumoxytol compared with 24% of patients on oral iron. Iron deficiency anemia is a common problem in the CKD population.