Discrepancies in reported US pricing information for digoxin-Fab

To the Editor:

Chan and Buckley discuss the increasing costs of digoxin-specific antibody Fab fragments (digoxin-Fab) in their recent review published in Clinical Toxicology.¹ They report a price increase of US $370 (US $380 to US $750) occurring in 2013 for digoxin-Fab. These price increases are not reflective of United States average wholesale pricing (AWP) for digoxin-Fab and may represent only Australian costs converted to US currency.

AWP for both Digibind^® and DigiFab^® were considerably higher than those costs published by Chan and Buckley. Prior to 2011, AWP was similar for Digibind^® (US $797 per 38 mg vial) and DigiFab^® (US $786 per 40 mg vial).² After GlaxoSmithKline discontinued Digibind^® sales in the United States in 2011,³ the AWP of DigiFab^® increased by 15% to US $903 per 40 mg vial.² As the only commercially available digoxin-Fab in the United States, the AWP of DigiFab^® has continued to increase as much as 54% occurring in March 2014 to US $2,370 per 40 mg vial, three times higher than the cost of digoxin-Fab reported by Chan and Buckley.² This most recent increase in AWP of DigiFab^® may call into question whether digoxin-Fab continues to be cost-effective with current dosing recommendations. AWP serves as a benchmark for reimbursement in the United States; however, the cost may vary depending on wholesaler contracts or manufacturer rebates. Ultimate cost to the patient is often higher. We agree that further studies are needed to determine a threshold for obtaining cost-effective strategy for digoxin-Fab fragments.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.