Pharmacologic profile of diaspirin cross-linked hemoglobin in hemodialysis patients

Abstract

Various hemoglobin compounds have been evaluated as potential oxygen-carrying, blood volume expanders, but toxicity has prevented clinical application. Diaspirin cross-linked hemoglobin (DCLHb) represents a modified hemoglobin compound that is derived from human red blood cells and maintained in a tetrameric configuration by cross-linkages between the two alpha chains of the hemoglobin molecule. In a randomized, placebo-controlled, single-blind, cross-over trial, DCLHb's safety and pharmacologic parameters were evaluated in 18 subjects receiving chronic hemodialytic therapy. A 30-minute infusion of 25, 50, or 100 mg/kg DCLHb or placebo was given at the start of routine hemodialysis. One week later, the alternate treatment (placebo or DCLHb) was administered. Maximum plasma hemoglobin concentrations and terminal half-life values were calculated for each dosage group. Dialysate was collected and assayed for hemoglobin. Changes in systolic and diastolic blood pressure from baseline and the volume of hypertonic saline administered for treatment of hypotension during hemodialysis were measured. The maximum plasma hemoglobin concentrations increased with DCLHb dose and occurred at the end of DCLHb infusion. The mean (±SD) terminal half-life ranged from 2.1 ± 1.0 hours in the 25 mg/kg DCLHb group to 4.3 ± 1.4 hours in the 100 mg/kg group, but did not differ significantly between groups. Mean baseline plasma hemoglobin connected areas under the plasma concentration-time curves increased from 89 to 1,136 mg/hr/dL across the fourfold dose range. Diaspirin cross-linked hemoglobin was not dialyzable as none was detected in dialysate. The maximum increase in systolic blood pressure from baseline increased significantly with DCLHb dose compared with placebo ( P < 0.05). During hemodialysis with DCLHb infusions, significantly less hypertonic saline was administered compared with hemodialysis with placebo infusions, implying greater blood pressure stability with DCLHb. No significant adverse events were noted. Further efficacy and safety studies with multiple-dose DCLHb administration are warranted in hemodialysis patients.