439. Iclaprim Use for Acute Bacterial Skin and Skin Structure Infection (ABSSSI) is Not Associated with Hyperkalemia: Phase 3 REVIVE Studies

Abstract Background Trimethoprim inhibits sodium channels in the distal portion of the renal tubule, thereby impairing renal potassium excretion. Trimethoprim has been associated with a greater risk of hyperkalemia compared with other antibiotics (amoxicillin, nitrofurantoin, cefalexin, ciprofloxacin). An analysis of Phase 3 studies was conducted to determine whether iclaprim, under development for ABSSSI and also a selective bacterial dihydrofolate reductase inhibitor like trimethoprim, is associated with hyperkalemia, relative to vancomycin, an antibiotic not associated with hyperkalemia. Methods A post-hoc safety analysis was conducted on pooled results of two Phase 3, double-blind, randomized (1:1), active-controlled trials (REVIVE-1/-2) in patients with ABSSSI. These trials compared iclaprim 80 mg fixed doses with vancomycin 15 mg/kg; both administered intravenously every 12 hours for 5–14 days. Hyperkalemia was defined as serum potassium (K) ≥5.5 mmol/L, if normal at baseline, while on study drug. Hyperkalemia was compared between treatment groups and stratified subgroup comparisons were performed. Results Demographics and baseline disease characteristics were similar between the pooled iclaprim and vancomycin groups (table). Hyperkalemia occurred during treatment in 1.5% (9/592) and 2.5% (15/599) of patients treated with iclaprim and vancomycin, respectively. Of the patients with hyperkalemia, one patient in each treatment group had moderate to severe renal impairment (creatinine clearance [CrCl] 15–59 mL/minute). Among patients with moderate to severe renal impairment on any RAS, KSD or K supplements, hyperkalemia occurred in 1/16 and 0/16 patients in the iclaprim and vancomycin groups, respectively, and in 2/83 and 0/46 patients with mild to no renal impairment. No patients with hyperkalemia experienced adverse events of palpitations, chest pain, myalgia, muscular weakness or fatigue. Conclusion No differences in hyperkalemia were seen between the iclaprim and vancomycin groups in the Phase 3 REVIVE studies. In general, few cases of hyperkalemia occurred among patients with renal impairment treated with concomitant angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers treated with iclaprim. Disclosures All authors: No reported disclosures.