Drugs Not Equal in Phosphorus Lowering

[okarol]

Drugs Not Equal in Phosphorus Lowering
Jody A. Charnow
October 30 2009

This article is part of our ongoing coverage of Renal Week 2009. Click here for a complete list of our Renal Week Live articles.

Lanthanum carbonate treatment achieved greater reductions in serum phosphorus than did sevelamer hydrochloride in a study of hemodialysis (HD) patients with elevated serum phosphorus, according to new research.

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) for sevelamer hydrochloride.

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 finished four weeks of treatment with each binder 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.

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 for sevelamer hydrochloride at week 1 (39.3% vs. 25.8%) and week 4 (51.8% vs. 38.5%).

“These results suggest that lanthanum carbonate is an effective phosphate binder for sustained control of serum phosphorus in dialysis patients,” the authors concluded.

“This is an important study as it is the only randomized comparative study of two noncalcium containing phosphate binders,” said Dr. Sprague. “This study demonstrated that three lanthanum carbonate pills daily appeared to be more effective than eight sevelamer hydrochloride pills daily in controlling serum phosphorus in stable HD patients. The use of three tablets of lanthanum carbonate compared to eight of sevelamer daily has the potential to increase patient compliance and thus achieve successful phosphate control.”

Posted Oct. 30, 2009 - 11:58 pm PT as an unedited blog
Updated and edited Oct. 30, 2009 - 8:40 pm PT

[Zach]

Also to consider is the fact that some lanthanum which remains unbound is absorbed into the body.

As the "Important Safety Information" on lanthanum carbonate advertisements states: "While lanthanum has been shown to accumulate in the GI tract, liver, and bone in animals, the clinical significance in humans is unknown."

Perhaps now is a good time to study that unknown clinical significance in humans.