Relaxivity and In Vivo Human Performance of Brand Name Versus Generic Ferumoxytol

Area of Science:

• Radiology
• Medical Imaging
• Pharmacology

Background:

• Ferumoxytol, an iron-oxide agent, is used off-label for contrast-enhanced MRI and MRA.
• Generic ferumoxytol is now available, prompting evaluation of its imaging performance relative to the brand-name product.
• Cost-effectiveness is a key consideration with the introduction of generic alternatives.

Purpose of the Study:

• To compare the relaxation-concentration dependence and MRI performance of brand-name and generic ferumoxytol.
• To determine optimal flip angles and weight-based dosing for ferumoxytol in MRA.
• To assess the interchangeability of generic ferumoxytol for MRA procedures.

Main Methods:

• Phantom studies evaluated relaxation rates (R1, R2, R2*) across varying iron concentrations (0.3–2.1 mM) at 1.5 T and 3.0 T.
• In vivo crossover study in healthy volunteers assessed MRA image quality with incremental ferumoxytol doses (1–7 mg/kg) and optimized flip angles (10°–40°).
• Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated to compare imaging performance.

Main Results:

• No statistically significant or clinically relevant differences were found in relaxation-concentration curves between brand-name and generic ferumoxytol in phantom experiments.
• In vivo studies revealed no clinically relevant differences in image quality between the two ferumoxytol products.
• The optimal flip angle range was determined to be 20°–30°, with an optimal dose of 5 mg/kg for both products.

Conclusions:

• Brand-name and generic ferumoxytol exhibit equivalent MRI performance.
• Ferumoxytol products can be used interchangeably for MRA.
• The findings support the use of generic ferumoxytol, potentially reducing healthcare costs.