Fosrenol data show evidence of trends towards improved bone formation in CKD stage 5 patients

Treatment with the phosphate binder FOSRENOL(R) (lanthanum carbonate) was associated with slight improvements in bone formation in chronic kidney disease (CKD) Stage 5 patients with hyperphosphatemia (high phosphorus levels in the blood), according to long-term (two-year) data presented at the American Society of Nephrology (ASN) meeting. Additional studies presented at ASN document the efficacy and safety of the reformulated and higher-dose FOSRENOL tablets.

Of the approximately 20 million Americans who have some form of kidney disease, more than 530,000 have developed CKD Stage 5. Even with dialysis and a low-phosphorus diet, most CKD Stage 5 patients in the United States will develop hyperphosphatemia. Without effective treatment, hyperphosphatemia may lead to renal osteodystrophy, a collection of bone diseases characterized by bone pain, brittle bones, skeletal deformities and fractures.

“Renal osteodystrophy develops early during chronic kidney disease, so by the time many patients reach dialysis, they may have painful and debilitating bone conditions. Treating hyperphosphatemia through diet and an effective phosphate binder can help patients maintain bone health while on dialysis,” explained Hartmut H. Malluche, M.D., study author and chief of Nephrology, Bone and Mineral Metabolism in the Department of Internal Medicine at the University of Kentucky College of Medicine. “Our study showed that FOSRENOL treatment was associated with increased bone formation in participants and that there were no signs of bone abnormalities, such as progressive evolution of mineralization defects or decreases in bone turnover.”

This planned sub-study of a large Phase III clinical trial evaluated potential differences between standard therapy and lanthanum carbonate on the evolution of abnormalities of bone turnover, bone balance and mineralization in patients with CKD Stage 5. Investigators used bone biopsies to assess participants’ bone health at baseline and at one and two years of treatment with FOSRENOL (n=32 and 32, respectively) or standard phosphate binder therapy (n=34 and 24, respectively). The study results showed that FOSRENOL effectively reduced serum phosphorus levels. In addition, FOSRENOL treatment was associated with lower serum calcium, higher serum parathyroid hormone (PTH) and increased biochemical parameters indicative of bone formation. Individual patients showed improvements in their bone turnover and formation after two years of FOSRENOL treatment, compared to standard treatment (n=12 and 3, respectively).

During year two, a greater proportion of patients in the standard therapy group showed movement of bone volume away from the normal range compared with the FOSRENOL group (50 percent versus 31 percent). Similarly, improvements toward normal bone formation rates were seen in 38 percent of patients receiving FOSRENOL at both one and two years. Patients in the standard therapy group showed improvements of only 24 and 12 percent at one and two years, and bone formation worsened in 63 percent of the patients in the two-year group. The results were not measured for statistical significance.

“The lower calcium and higher PTH levels in patients treated with FOSRENOL may allow health care professionals a greater window for use of vitamin D analogs to improve bone health in patients on dialysis,” added Dr. Malluche.

Additional Data Demonstrate FOSRENOL as Monotherapy Is Effective in Patients With CKD Stage 5

In a separate 12-week, open-label Phase IIIb study in CKD Stage 5 patients most participants treated with only FOSRENOL experienced reduced serum phosphorus and enhanced achievement of Kidney Disease Outcomes Quality Initiative (K/DOQI) targets, including those previously receiving combination phosphate binder therapy.

“FOSRENOL is an effective, well-tolerated phosphate binder that may simplify treatment for CKD Stage 5 patients,” said Alastair J. Hutchison, M.D., Renal Unit, Manchester Royal Infirmary. “Changing patients to FOSRENOL monotherapy, not only reduces serum phosphorus levels, but also reduces phosphate binder pill burden.”

The majority of participants who reached the K/DOQI target required approximately 3 grams (g) of FOSRENOL daily, demonstrating that most patients can be controlled with a single 1 g tablet per meal. (Dosing based on three meals per day. Number of meals per day may vary. To achieve certain doses, additional tablets may be required.)

Of the 367 patients enrolled, 274 (75 percent) completed the study. Mean serum phosphorus levels at enrollment for the patients taking only one alternative phosphate binder was 6.14 mg/dL, with just 36 percent achieving the K/DOQI target, but after converting to FOSRENOL and completing 12 weeks of monotherapy, 52 percent reached the target (P < 0.05). Similarly, mean levels of patients receiving two binders were 6.11 mg/dL at screening, with only 35 percent reaching the K/DOQI target, but the proportion increased to 44 percent after completing 12 weeks of FOSRENOL monotherapy.

Majority of CKD Stage 5 Patients Achieved Phosphorus Control on Reformulated and Higher Dose FOSRENOL Tablets

According to another study evaluating the efficacy and safety of reformulated FOSRENOL, higher daily doses, 3,750 or 4,500 milligrams (mg), of FOSRENOL may provide serum phosphorus control for those CKD Stage 5 patients who do not respond to doses of 3 g per day, without a dose-related increase in adverse events.

“This study demonstrates that higher doses of FOSRENOL may help patients with difficult to control serum phosphorus levels reach K/DOQI targets,” said Rajnish Mehrotra, M.D., Division of Nephrology and Hypertension, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center. “The reduction in phosphate binder tablet burden that higher doses of FOSRENOL? provides may help improve patient adherence to their medication regimen and, thus, their phosphorus control.”

Of note, participants previously receiving monotherapy with sevelamer HCl, with a highest total daily dose of 14,400 mg (18 tablets), required a markedly smaller daily dose of FOSRENOL in the study. The total average FOSRENOL daily doses at weeks four, eight and 24 did not exceed 3,500 mg, 4,200 mg and 3,400 mg, respectively, resulting in patients needing a maximum of five FOSRENOL tablets to maintain phosphorus control.

Managing Hyperphosphatemia

Phosphorus, an element found in nearly all foods, is absorbed from the gastrointestinal tract into the bloodstream. When the kidneys fail, they no longer effectively remove phosphorus. While the normal adult range for phosphorus is 2.5 to 4.5 mg/dL, the blood phosphorus levels of many patients on dialysis often exceed 6.5 mg/dL. Such levels have been linked to a significantly higher morbidity and mortality risk for patients who have undergone at least one year of dialysis. Research has shown that for each mg/dL increase in mean serum phosphorus, the relative risk of death increases by six percent. There are no controlled clinical trials with FOSRENOL demonstrating a reduction in morbidity or mortality.

Hyperphosphatemia is managed with a combination of dialysis, diet restriction and phosphorus-binding agents, since diet and dialysis alone generally cannot adequately control phosphorus levels. Such binders “soak up” phosphorus in the gastrointestinal tract, before it can be absorbed into the blood, and aid patients in maintaining acceptable levels of mean serum phosphorus.

Despite the availability of phosphorus-binding agents, it remains a challenge for some CKD Stage 5 patients to maintain target ranges. According to the K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease, Guideline 3, Evaluation of Serum Phosphorus Levels, fewer than 30 percent of dialysis patients are able to maintain serum phosphorus levels in the target range.

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