Abstract
KEY POINTS: Oxylanthanum carbonate (OLC) was well tolerated with fewer than 10% of patients stopping treatment due to side effects. More than 90% of patients with hyperphosphatemia taking OLC achieved effective phosphate control. Two thirds of patients required three or fewer OLC tablets per day to control serum phosphate. BACKGROUND: In patients with kidney failure receiving maintenance dialysis, hyperphosphatemia is managed by dietary phosphate restriction and the provision of phosphate binders. Oxylanthanum carbonate (OLC) is a phosphate binder in development with high potency and formulated in a small pill swallowed whole. METHODS: We conducted a phase 2, open-label, single-arm, multicenter trial in adult patients receiving maintenance hemodialysis with hyperphosphatemia. The primary objective was to evaluate the tolerability of OLC at clinically effective doses with a goal serum phosphate (sP) concentration ≤5.5 mg/dl. The trial included washout, titration, and maintenance periods. Eligible patients had sP ≥4.0 and ≤7.0 mg/dl for at least 8 weeks before screening while receiving thrice weekly hemodialysis and a stable phosphate binder regimen. Patients started titration when sP was >5.5 mg/dl and entered maintenance once sP was ≤5.5 mg/dl. The starting dose of OLC during titration was 1500 mg/d (500 mg thrice daily). We assessed tolerability on the basis of the incidence of discontinuations due to treatment-related adverse events (TRAEs). RESULTS: Eighty-six patients were treated with OLC during the study. At screening, sP was ≤5.5 mg/dl in 51 (59%) patients. Seventy-eight (91%) patients entered maintenance, and 71 (91%) patients achieved sP ≤5.5 mg/dl on a median OLC dose of 500 mg three times a day. The most common TRAEs were gastrointestinal and included diarrhea (9%) and vomiting (6%); all other TRAEs were reported in <5% of patients. Three (4%) patients discontinued drug due to TRAEs. Minimal to no systemic absorption of lanthanum was observed after administration of OLC 1000 mg thrice daily. CONCLUSIONS: In this open-label phase 2 trial, OLC was well tolerated and enabled sP control in >90% of patients with a low pill burden (two thirds of patients receiving three or fewer tablets/day). CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: NCT06218290.