Data from the first study to compare ibandronate with pamidronate(Drug information on pamidronate) (Aredia) in the treatment of malignant hypercalcemia were presented at the 37th annual meeting of the American Society of Clinical Oncology. The results demonstrated that rates of response, time to response, and time to onset of lower calcium levels were similar between the two compounds. However, in the subset of patients with severe hypercalcemia (initial serum calcium > 3.5 mmol/L), ibandronate appeared statistically superior to pamidronate in restoring calcium levels to normal.
"This preliminary comparative data is an important addition to the body of evidence on ibandronate in the clinical setting. Patients with severe malignant hypercalcemia are at high risk of significant clinical complications; therefore, these new data are of interest to practicing oncologists," said Martin Pecherstorfer, MD, from the Wilheminspital in Vienna, Austria, who presented the results.
Calcium Levels Decrease Significantly
The trial was conducted in 19 centers and enrolled 72 patients with hypercalcemia of malignancy (corrected serum calcium > 2.7 mmol/L). Each patient received a single infusion of either ibandronate or pamidronate, and serum calcium levels were measured daily. Four days postinfusion, patients treated with ibandronate showed a mean reduction in corrected serum calcium of 0.73 mmol/L vs 0.57mmol/L for pamidronate. Moreover, patients with severe hypercalcemia (baseline corrected serum calcium above 3.5 mmol/L, n = 11) treated with ibandronate experienced a statistically significant greater mean improvement than those treated with pamidronate.
Among the drug-related adverse effects was an increase in body temperature, combined with flu-like symptoms, ie, pain in muscles, bone pain, headache, pain in the extremities, hot flushes, and increased sweating. The number of adverse events and their profile did not differ between the ibandronate and pamidronate groups.