The US Food and Drug Administration (FDA) has approved a drug called Zometa for the treatment of bone metastases caused by cancer, said news reports.

Zometa, made by Novartis Pharmaceuticals, is the first drug approved in the US for for both multiple myeloma (a type of bone cancer) and all other solid tumors. Bone metastases can be caused by a wide range of cancers, and eventually appear in most incurable cancers.

Before the approval of Zometa, the only other option for cancer patients was Aredia. Also made by Novartis, Aredia was approved only for patients with breast cancer or multiple myeloma.

Aredia is an earlier version of a class of drugs called bisphosphonates, the group that includes Zometa. Bisphosphonates work by slowing down the actions of bone cells.

But Zometa is a more potent version of Aredia. It was first approved for the treatment of elevated calcium levels in the bloodstream — a condition called hypercalcemia, which can be related to tumors in bones. Hypercalcemia is one of cancer's common side effects. It can cause extreme fatigue, altered mental status, and even death.

In January, an FDA expert advisory committee voted unanimously in favor of backing Zometa's approval for metastases, which was filed in July 2001.

The advisory committee's recommendation was based on studies that showed an approximate 14% decrease in the number of patients with bone problems, compared to those who did not take Zometa. The studies involved more than 3,000 patients.

But, the committee also pointed out Zometa's potential side effects included kidney damage, which can also occur with other bisphosphonates.

Zometa is the first bisphosphonate approved to treat bone metastases from prostate cancer, a cancer that commonly spreads to the bones. Because of the patient population studied in the clinical trials, the FDA said patients with prostate cancer should have failed at least one hormonal therapy before getting Zometa.