Assessment of survival in a 2-year comparative study of lanthanum carbonate versus standard therapy.

OBJECTIVE: Epidemiological data link elevated levels of serum phosphorus with increased mortality among patients with chronic kidney disease. Recent data also suggest improved survival with the use of dietary phosphate binders in patients on dialysis. However, few studies have comprehensively evaluated the survival benefit associated with different phosphate binders. A post-hoc survival analysis was undertaken of lanthanum carbonate (Fosrenol *) versus standard therapy.

RESEARCH DESIGN AND METHODS: Patients on dialysis enrolled in a phase 3, 2-year, comparative safety study were randomized 1:1 to lanthanum carbonate or standard therapy to treat serum phosphorus to a target of < or =5.9 mg/dL (1.90 mmol/L). Patients (N = 1354) were followed up for survival status during, or after completion of or discontinuation from the study.

MAIN OUTCOME MEASURES: Survival was measured by time from first dose of study medication to all-cause mortality or last contact.

RESULTS: The distribution of follow-up time was similar in the lanthanum carbonate and standard therapy groups (mean 23.7 versus 23.9 months [median 27.0 versus 26.0 months], respectively). Serum phosphorus levels were similar across treatment groups, as patients were treated to target. At follow-up, 19.9% (135/680) of patients treated with lanthanum carbonate had died versus 23.3% (157/674) on standard therapy (log-rank p = 0.18). In the subgroup of patients aged >65 years (n = 336), 27.0% (44/163) of lanthanum-carbonate-treated patients had died compared with 39.3% (68/173) on standard therapy (log-rank p = 0.04).

CONCLUSION: In these survival analyses, overall mortality was similar in the lanthanum carbonate and standard therapy groups, but results suggest that there was a survival benefit associated with lanthanum carbonate treatment for patients aged >65 years, who are likely to carry the greatest burden of vascular calcification. These results were similar to those observed in the Dialysis Clinical Outcomes Revisited study, a prospective trial of sevelamer hydrochloride designed to assess survival.