SAN DIEGO—Lanthanum carbonate treatment achieved greater reductions in serum phosphorus than did sevelamer hydrochloride in a study of hemodialysis (HD) patients with elevated serum phosphorus.

The study enrolled 182 HD patients with serum phosphorus levels of 6 mg/dL or higher and calcium levels of 8.4 mg/dL or higher. Investigators led by Stuart M. Sprague, DO, of NorthShore University HealthSystem, Northwestern University, Evanston, Ill., randomized patients to receive either lanthanum carbonate or sevelamer hydrochloride for four weeks.

Following a two-week washout period, patients switched to the other phosphate binder. Clinicians initiated treatment at a dose of 2,250 mg/day for lanthanum carbonate (one 750-mg tablet three times daily with meals) and 4,800 mg/day for sevelamer hydrochloride (two 800-mg tablets three times a day with meals), which was increased to 3,000 mg/day for lanthanum (three 1000-mg tablets daily) and 6400 mg/day (eight 800 mg tablets daily).

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Of the 182 patients, 174 constituted the intent-to-treat (ITT) population. These were patients who received at least one dose of study medication and had at least one post-dose serum phosphorus measurement. Within the ITT population, the researchers identified a “completer” population consisting of 119 subjects who completed four weeks of treatment with both binders and had a valid serum phosphorus measurement at week 4 of each treatment period.

In the completer group, lanthanum carbonate was associated with a significant 0.50 mg/dL greater reduction in serum phosphorus at week 4 compared with sevelamer hydrochloride, Dr. Sprague’s group reported here at the American Society of Nephrology’s Renal Week conference.

In addition, the proportion of patients defined as responders—those having a 25% or greater reduction in serum phosphorus from baseline—was significantly larger for lanthanum carbonate than sevelamer hydrochloride at week 1 (39.3% vs. 25.8%) and week 4 (51.8% vs. 38.5%).