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

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. [Image: see text] DISCLOSURES: All authors: No reported disclosures.