Chronic myelogenous leukemia patients exhibit altered bone and mineral metabolism while receiving imatinib

07-13-2006

Patients with chronic myelogenous leukemia or gastrointestinal stromal tumors receiving imatinib mesylate exhibited altered bone and mineral metabolism.

According to recent research published in the New England Journal of Medicine, "Imatinib mesylate inhibits several tyrosine kinases, including BCR-ABL, the C-KIT receptor, and the platelet-derived growth factor receptors (alpha) and (beta), all of which are associated with disease. We observed that hypophosphatemia developed in some patients with either chronic myelogenous leukemia or gastrointestinal stromal tumors who were receiving imatinib."

"We identified 16 patients who had low serum phosphate levels and 8 patients who had normal serum phosphate levels, all of whom were receiving imatinib," explained E. Berman and colleagues, Memorial Sloan-Kettering Cancer Center. "We performed the following biochemical measurements: whole-blood levels of ionized calcium, plasma levels of intact parathyroid hormone, and serum levels of total calcium, phosphate, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, magnesium, and markers of bone formation (bone alkaline phosphatase and osteocalcin) and bone resorption (N-telopeptide of collagen cross-links); urinalysis; and phosphate, calcium, and creatinine levels in 'spot' urine specimens.

"Patients in the low-phosphate group (median serum phosphate level, 2.0 mg/dL [0.6 mmol/L]; normal level, >2.5 mg/dL [0.8 mmol/L]) had elevated parathyroid hormone levels and low-to-normal serum calcium levels, were younger, and were receiving a higher dose of imatinib than patients in the normal-phosphate group (median level, 3.2 mg/dL [1.0 mmol/L]). Both groups had high levels of phosphate excreted in the urine and markedly decreased serum levels of osteocalcin and N-telopeptide of collagen cross-links."

The researchers concluded, "Hypophosphatemia, with associated changes in bone and mineral metabolism, develops in a proportion of patients taking imatinib for either chronic myelogenous leukemia or gastrointestinal stromal tumors. The drug may inhibit bone remodeling (formation and resorption), even in patients with normal serum phosphate levels."

Berman and colleagues published their study in New England Journal of Medicine (Altered bone and mineral metabolism in patients receiving imatinib mesylate. N Engl J Med, 2006;354(19):2006-2013).

For additional information, contact E. Berman, Memorial Sloan-Kettering Cancer Center, Dept. Med, Leukemia Service, 1275 York Avenue, New York City, NY 10021, USA.

The publisher's contact information for the New England Journal of Medicine is: Massachusetts Medical Society, Waltham Woods Center, 860 Winter St., Waltham, MA 02451-1413, USA.

Keywords: New York, New York, United States, Chronic Myelogenous Leukemia, Chronic Myeloid Leukemia, Diet and Nutrition, Cancer Drugs, Gastroenterology, Growth Factor Receptors, Hormones, Imatinib Mesylate, Metabolism, Pharmaceuticals, Proteins, Proteomics, Cancer Therapy, Tyrosine Kinase.

This article was prepared by Clinical Oncology Week editors from staff and other reports. Copyright 2006, Clinical Oncology Week via NewsRx.com.