Spectrum Pharmaceuticals said that the U. S. health regulators refused to approve its supplementary marketing application for its advanced metastatic colorectal cancer drug Fusilev in its present form, bringing down its shares by 22 percent.

It also said that the Food and Drug Administration (FDA) of U. S. observed that the submission did not display that Fusilev is better than the standard treatment leucovorin, and it did not request any changes to the currently approved indications.

Spectrum plans to urge the FDA to have a meeting to discuss options for approval of fusilev.

Morgan Joseph & Co analyst Shiv Kapoor said, "There is going to be a delay (in Fusilev approval) and it wasn't really expected".

He added that he would wait for FDA to have a meeting with Spectrum to decide the next move required for the approval of the drug.

The drug, Fusilev, is presently approved by the FDA as a rescue after high dose of methotrexate therapy in patients with osteosarcoma, which is a kind of bone cancer.

The drug also indicated to remove the toxic effect and counteract the consequences of impaired methotrexate removal and of unavoidable dose of folic acid antagonist which is a type of chemotherapy.