The US Food and Drug Administration has approved a new use for the drug Revlimid (lenalidomide). It will now be available to people with multiple myeloma that has not responded to other treatments. The drug is already approved to treat a certain type of myelodysplastic syndrome, a bone marrow disorder that can sometimes lead to leukemia.

Revlimid, made by Celgene Corporation, is given along with the steroid drug dexamethasone. In 2 clinical trials, this combination was better than dexamethasone alone in delaying cancer progression. Patients on Revlimid plus dexamethasone went about 37 weeks before their cancer started growing again, compared to 20 weeks for those on dexamethasone alone.

Multiple myeloma causes plasma cells in the blood to grow out of control. The disease is expected to strike about 16,500 people in the US in 2006 and kill more than 11,000. Standard treatment often includes chemotherapy and stem cell transplant. The drug thalidomide is also used.

Revlimid is similar to thalidomide. Because both drugs can cause severe birth defects, their use is strictly monitored, and patients of childbearing age must agree to use birth control measures to assure they do not become pregnant or cause a pregnancy during treatment.

Revlimid can also have other severe side effects, including low white blood cell count (neutropenia) and low platelet count (thrombocytopenia). The drug also raises the risk of blood clots in the legs and lungs. Less serious side effects may include constipation, fatigue, muscle cramps, and diarrhea.