Safety and efficacy of total dose infusion of 1,020 mg of ferumoxytol administered over 15 min.
Ferumoxytol was approved in June 2009 by the US Food and Drug Administration (FDA) for the treatment of iron deficiency anemia (IDA) in adults with chronic kidney disease. The chief advantages of ferumoxytol over other IV iron preparations are its speed of administration and ability to administer a larger dose at each administration. Several trials using the current approved dosing regimen (510 mg or 17 mL), administered as an undiluted injection at a rate not to exceed one milliliter (30 mg) per second (no faster than 17 seconds) are underway in conditions associated with iron deficiency (heavy uterine bleeding, inflammatory bowel disease, anemia of cancer). Two new Phase 3 trials evaluating ferumoxytol for the treatment of IDA in adults who have a history of unsatisfactory oral iron therapy or in whom oral iron could not be used have been completed, and a supplemental new drug application has been submitted to the FDA. The objective of most of these studies has been to evaluate the efficacy and safety of a 1.02-g course of IV ferumoxytol administered as two doses for the treatment of IDA. This initial regimen requires two visits to complete the infusion. In the US, the standard or most common treatment course of IV iron for patients with IDA is 1 gram, which is an adequate replacement dose for most patients.
Auerbach and colleagues present an elegant study of the safety and tolerability of 1.02 g of IV ferumoxytol administered as a single dose, over 15 minutes, in 1 visit. All patients were observed in the clinic and vital signs were measured and recorded till 60 minutes after IV iron infusion. Following discharge from the clinic, queries were made by telephone at 24 and 48 hours and 7 days. Of 60 recruited patients, 58 received the planned dose. Twenty eight (43%) reported adverse events (AEs), 13 were mild and transient during iron infusion, all resolved within minutes, and 14 presented self limited arthralgias, myalgias and headache 24-48 hours after treatment. This rate of AEs is similar of the reported AE rates in the two Phase 3 studies using two doses of 510 mg approximately 1 week apart. In the secondary endpoints, the authors found a hemoglobin increase of 2.1 g/dL at the first month of IV ferumoxytol infusion and a Hb increase of 2.6 g/dL after 8 weeks.
Although the authors maintain that oral iron remains the standard of care as front line therapy for IDA, IV iron is as least as effective as (in fact better than) oral iron, is better tolerated, and total iron replacement is obtained more rapidly. This study demonstrates the ease, effectiveness and good tolerance of administration of 1 gram of iron in only 15 minutes, reducing visits, samples, time and costs.
– José A. García-Erce