LYPHOMED's CALSTAT IS SAFE AND EFFECTIVE FOR HYPERCALCEMIA

Executive Summary

LYPHOMED's CALSTAT IS SAFE AND EFFECTIVE FOR HYPERCALCEMIA due to malignancy in cancer patients, FDA's Endocrinologic and Metabolic Drugs Advisory Committee unanimously agreed at an Oct. 13 meeting. Commenting on the data presented at the meeting, Committee Reviewer Alwyn Parfitt, MD, Henry Ford Hospital, said: "This agent is more efficacious in terms of both the magnitude [of calcium reduction], the duration for which the . . . calcium is controlled, and the proportion of patients in whom a satisfactory response is obtained" than other hypercalcemic agents. The panel review of Calstat (gallium nitrate) comes only seven months after the company submitted its NDA for the orphan drug. The NDA is based on an open label Phase I/II study in 32 patients, a comparative study to calcitonin in 50 patients, and an interim study analysis of an ongoing comparative trial to etidronate in 52 patients. The recommended dosage is 200 mg/m of continuous I.V. infusion for up to five days. Although the committee endorsed the drug's approval, panel members suggested a number of changes in the labeling proposed by Lyphomed, including restricting the indication to only symptomatic patients with cancer-related hypercalcemia because of concerns of nephrotoxicity. In an FDA review of Calstat, Medical Officer Sam Dutta, MD, said: "Gallium nitrate continuous intravenous infusion appears to be a potent therapeutic regimen for the acute management of cancer-related hypercalcemia. However, its therapeutic benefits need to be critically evaluated against potential toxicities." To address the toxicity concerns, the committee recommended precautions in the labeling. They included advice that patients be started on a saline solution for 48 hours as a first course of action before resorting to the drug, excluding hematologic malignancies from the indication for lack of data. The committee also recommended cautions about the possibility of a "significant" decrease in blood pressure and to discourage long-term, repeated administrations. Lyphomed presented an overview of the three safety and efficacy trials. The summary showed that the incidence of renal insufficiency in cancer-related hypercalcemia patients occurred in 10% of 67 patients on gallium nitrate, while 8% of the 53 control patients and 9% of 430 patients screened for the studies showed renal insufficiency. In the completed comparative trial, the company reported that 75% of patients treated with gallium nitrate reached normal calcium levels versus 31% in the calcitonin group. Furthermore, the average duration for normocalcemia was six days for the gallium nitrate group compared to one day for the calcitonin group.