Sodium ferric gluconate complex in hemodialysis patients. II. Adverse reactions in iron dextran-sensitive and dextran-tolerant patients.

BACKGROUND: Iron dextran administration is associated with a high incidence of adverse reactions including anaphylaxis and death. Although dextran, rather than iron, is believed to be the cause of these reactions, it is not known whether iron dextran-sensitive patients can be safely administered another form of parenteral iron, sodium ferric gluconate in sucrose (SFGC). METHODS: In a 69 center, prospective, double-blind, controlled trial of safety and tolerability of SFGC, the rate of reactions to SFGC and placebo in 144 iron dextran-sensitive patients was compared with 2194 patients who were previously tolerant to iron dextran preparations. Serum tryptase levels, a marker of mast cell degranulation, also were measured. RESULTS: Among 143 iron dextran-sensitive patients exposed to SFGC, three (2.1%) were intolerant. All three had suspected allergic events to SFGC, including one patient with a serious reaction (0.7%). One dextran-sensitive patient (0.7%) had a suspected allergic reaction after placebo. In contrast, among 2194 iron dextran-tolerant patients, reactions to SFGC were significantly less common, with SFGC intolerance seen in seven patients (0.3%; P = 0.020), including five (0.2%) who had suspected allergic events (P = 0.010), but none who had serious events (0.0%; P = 0.061). Two iron dextran-tolerant patients (0.09%) had allergic-like reactions following placebo injections. Two of the three suspected allergic events in the iron dextran-sensitive group were confirmed as mast cell dependent by a 100% increase in serum tryptase, while there were no confirmed allergic events in the iron dextran-tolerant group. Long-term exposure to SFGC in iron dextran-sensitive patients resulted in intolerance in only one additional patient and no serious adverse events. CONCLUSIONS: Patients with a history of iron dextran sensitivity had approximately sevenfold higher rates of reaction to both placebo and SFGC compared to iron dextran tolerant patients. However, logistic regression analysis, performed to account for the higher reaction rate to placebo, suggests that this increased reactivity was not drug-specific nor immunologically mediated, but represented host idiosyncrasy. These results support the conclusions that reactions to SFGC can be attributed to pseudoallergy, and that SFGC is not a true allergen.

Is it time for a paradigm shift? Is erythropoietin deficiency still the main cause of renal anaemia?

An increasing number of reports documenting resistance to human recombinant erythropoietin (rHuEPO) therapy are challenging the concept that erythropoietin deficiency is the main cause of the anaemia of chronic kidney disease (CKD). In an attempt to establish whether other factors play a more predominant role in the anaemia of CKD, 988 patients receiving dialysis were assessed for a wide range of variables. Data were collected on haematocrit (Hct) levels, rHuEPO dose, dry weight, serum ferritin, transferrin saturation, serum albumin, serum aluminium, serum parathyroid hormone intact, eKt/V for urea, gender, dose of i.v. iron administered, time in hospital, and use of i.v. vancomycin. Hyporesponsiveness to rHuEPO was defined as patients requiring >500 IU/kg/week or failing to achieve Hct levels of >30%. Ninety-two (9.2%) of the 988 patients met the above criteria for hyporesponsiveness to rHuEPO. In 21 of these patients, Hct concentrations remained <30% at 6-month follow-up. There were known haematological causes of refractoriness to rHuEPO in nine of these patients. During extended follow-up, probable causes of hyporesponsiveness were discovered in all but two of the remaining 13 patients. Of 62 dialysis patients who received rHuEPO at doses >500 IU/kg/week, 45 (73%) had Hct concentrations of 33-42%. These patients were responding to the higher doses of rHuEPO with no obvious adverse effects. Lower values of serum ferritin, transferrin saturation, and eKt/V, or higher levels of parathyroid hormone or serum aluminium were not associated with higher rHuEPO dose requirements. These results suggest that erythropoietin deficiency is still the main cause of the anaemia of CKD. Erythropoietin replacement therapy can correct the anaemia in almost all iron replete patients providing enough hormone is given, functional iron deficiency is avoided, aluminium levels and parathyroid toxicities are controlled and that no de novo haematological condition that affects erythropoiesis or red blood cell survival develops. Consideration should be given to modifying the definition of rHuEPO hyporesponsiveness. The US Hct target of 33-36% for haemodialysis patients is narrow and the European target of Hct >33% may be significantly more practical and physiologically relevant.

Sodium ferric gluconate complex in hemodialysis patients: adverse reactions compared to placebo and iron dextran.

BACKGROUND: Parenteral iron is often required by hemodialysis patients to maintain adequate iron stores. Until recently, the only available form of intravenous iron was iron dextran, which is associated with significant adverse reactions, including anaphylaxis and death. Sodium ferric gluconate complex (SFGC) was recently approved for use in the U.S. under FDA's priority drug review. This Phase IV study was designed to evaluate the safety of a single dose of intravenous SFGC as compared to placebo and a historical iron dextran control. METHODS: This multicenter, crossover, randomized, double blind, placebo-controlled prospective comparative study was performed in hemodialysis patients requiring at least 125 mg of elemental iron. The historical control was obtained from a meta-analysis of four publications examining outcomes in patients exposed to iron dextran. SFGC naïve patients were administered SFGC without a test dose, undiluted, at a rate of 125 mg over 10 minutes, and compared to placebo comprising bacteriostatic saline. RESULTS: A total of 2534 patients were enrolled. The incidence of drug intolerance (an adverse event precluding re-exposure) was significantly less [0.44%, confidence interval (CI) 0.21 to 0.71%] after SFGC as compared to the iron dextran control (2.47%, CI 1.87 to 3.07%, P < 0.0001), but higher than after placebo (0.1%, P = 0.02). There was no difference found between SFGC and placebo in serious adverse events. A single life-threatening event occurred after SFGC (0.04%, CI 0.00 to 0.22%), which was significantly less than following iron dextran (0.61%, CI 0.36 to 0.86%), P = 0.0001. CONCLUSION: SFGC is well tolerated when given by intravenous push without a test dose. SFGC has a significantly lower incidence of drug intolerance and life-threatening events as compared to previous studies using iron dextran. The routine use of iron dextran in hemodialysis patients should be discontinued.