Safety of Off‐Label Use of Ferumoxtyol as a Contrast Agent for MRI: A Systematic Review and Meta‐Analysis of Adverse Events

Ferumoxytol has been studied as an alternative to gadolinium-based MRI contrast agents, but regulatory body warnings currently limit its use.Estimate the adverse event rate in patients undergoing MRI with ferumoxytol as a contrast agent.Systematic review.Thirty-nine studies including 5411 ferumoxytol administrations in 4336 patients.Multiple databases were searched for studies using ferumoxytol as an off-label MRI contrast agent in any patient population as of April 2020. Studies were eligible for inclusion if they reported the number and severity of adverse events (classified by American College of Radiology [ACR] severity of acute reactions). Risk of bias was assessed using the ROBINS-I tool.The proportion of administrations with adverse events was calculated using random effects meta-analysis of proportions.No deaths related to ferumoxytol administration were reported. Sixteen studies reported immediate adverse events in 3849 patients undergoing 4901 ferumoxytol administrations. Ninety-seven immediate adverse events were reported and the pooled adverse event proportion for immediate adverse events was 0.02 (95% confidence interval [CI] 0.02-0.02). Twenty-three studies reported time-unspecified adverse events in 487 patients undergoing 510 ferumoxytol administrations. Five time-unspecified adverse events were reported; the pooled adverse event proportion for time-unspecified adverse events was 0.01 (95% CI 0.00-0.04). 88% of adverse events were mild (90/102), 11% (11/102) were moderate, and 1% (1/102) was severe. Sixteen studies were at low risk of bias, 23 studies were at serious risk of bias. Subgroup analysis by patient population revealed no significant variability (adult vs. pediatric). No studies evaluated the use of ferumoxytol as an alternative to patients who had a prior hypersensitivity reaction to gadolinium-based contrast agents (GBCAs).The overall adverse event rate for off-label ferumoxytol use as an MRI contrast agent is 2%, with rare severe reactions and no deaths. To date, there are no studies evaluating the safety of ferumoxytol as an alternative to GBCAs in patients with a prior hypersensitivity reaction.2 TECHNICAL EFFICACY STAGE: 5.