The Food and Drug Administration has approved a drug from Spectrum Pharmaceuticals to treat patients with a rare, aggressive form of cancer that affects the lymph nodes.

The agency cleared the drug, Beleodaq, to treat peripheral T-cell lymphoma that has returned after earlier treatments or has not responded to any treatments. An estimated 70,800 Americans will be diagnosed with the cancer this year and 18,990 will die from it, according to the National Cancer Institute.

The drug works by stopping an enzyme that makes T-cells cancerous. T-cells are a type of white blood cell that helps the immune system fight off infections and foreign cells.

The FDA approved Beleodaq under its accelerated approval program, which grants early approval to drugs based on promising test results. In this case FDA said a small study of Beleodaq showed that more than 25 percent of patients given the drug had their cancer tumors disappear or shrink. Under FDA policy, Spectrum Pharmaceuticals will have to confirm the drug's benefits in larger, follow-up studies.

Spectrum Pharmaceuticals Inc. has been positioning itself to deal with falling sales of its biggest drug, the colon cancer treatment Fusilev, which has been pressured by lower-cost generics. Last July the company bought Talon Therapeutics to gain the company's leukemia drug Marqibo, which it began selling in September.

The company has three approved drugs: Fusilev, Folotyn for peripheral T-cell lymphoma and Marqibo, which is approved to treat recurrences of a rare type of leukemia.

Spectrum Pharmaceuticals Inc. rose 46 cents, or 5.3 percent, to $9.17 in midday trading.