UPDATE 1-Spectrum bone cancer drug approved by US FDA

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LOS ANGELES, March 7 (Reuters) - The U.S. Food and Drug Administration has approved Spectrum Pharmaceuticals Inc's (SPPI.O) Levoleucovorin as a treatment for osteosarcoma, a type of bone cancer, the company said on Friday.

Shares of Irvine, California-based Spectrum rose 50 percent in after-hours trading after news of its first commercial product.

The company said Levoleucovorin is now approved for use after high-dose methotrexate therapy in patients with osteosarcoma, and to diminish the toxicity and counteract the effects of impaired methotrexate elimination or inadvertent overdose of folic acid antagonists.

Spectrum said it plans to seek FDA approval of the drug in colon cancer patients and as an oral tablet by mid-year.

Spectrum said it plans to launch sales of the injectable drug by June.

Shares, which fell 2.8 percent to close at $2.44 on Nasdaq, were higher at $3.65 after hours. (Reporting by Deena Beasley; editing by Carol Bishopric)