Gallium Nitrate to Reenter Hypercalcemia Market
Genta Inc. announced last week that the Food and Drug Administration (FDA) had approved the company's plan to make gallium nitrate injection, or Ganite, widely available in the United States for the first time since the hypercalcemia treatment left the market several years ago.
By inhibiting the resorption of calcium by osteoclasts in growing bone, gallium nitrate reduces the amount of calcium in the blood.
According to the product's FDA-approved labeling (PDF), gallium nitrate is used to treat cancer-related hypercalcemia that is symptomatic and unresponsive to adequate hydration. Symptoms of hypercalcemia include anorexia, fatigue, and impaired mental status and would not be expected in patients with a serum calcium concentration of less than 12 mg/dL.
The product's labeling recommends a five-day regimen of gallium nitrate 200 mg per square meter of body surface area administered each day by intravenous infusion over 24 hours. Each dose should be diluted in 1,000 mL of fluid. The daily dose should be decreased by half in patients with mild hypercalcemia and few symptoms. Regardless of the initial degree of hypercalcemia, treatment with gallium nitrate may stop once a patient's calcium concentration reaches the normal range, even if this occurs before the regimen has been completely administered.
Gallium nitrate must not be given to patients with severe renal impairment, which the labeling defines as a serum creatinine concentration of more than 2.5 mg/dL.
In addition to the contraindication on use of the agent in patients with severe renal impairment, gallium nitrate's labeling has a boxed warning advising against use when a patient must receive an aminoglycoside, amphotericin B, or another drug that may damage the kidneys. The labeling for gallium nitrate strongly recommends that clinicians monitor all patients' serum creatinine concentrations during therapy.
A company spokeswoman said the product, which will be supplied in cartons of five single-dose vials each containing 500 mg of gallium nitrate 25 mg/mL, would be available to pharmacies within the next few weeks.
Gallium nitrate injection is distinct from gallium citrate Ga 67 injection, a radiopharmaceutical used in the diagnosis of Hodgkin's disease, other lymphomas, and certain lung cancers.