Novartis AG's Tasigna received the U.S. Food and Drug Administration's approval to expand its usage to treat children with a rare type of blood cancer.

The drug is now approved to treat adults and children one year of age or older with newly diagnosed Philadelphia chromosome-positive chronic myeloid leukemia in the chronic phase, or Ph+ CML-CP, a type of chronic myeloid leukemia which accounts for about 3% of newly diagnosed childhood leukemia worldwide.

Tasigna is also approved in the U.S. to treat adults and children with Ph+ CML-CP resistant or intolerant to prior tyrosine kinase inhibitor therapy and prior therapy that included Novartis' Gleevec, or imatinib.

Ph+ CML-CP involves body producing malignant white blood cells in patients with a genetic abnormality known as the Philadelphia chromosome. Philadelphia chromosome produces a protein called BCR-ABL that causes the chronic myeloid leukemia cells to grow and reproduce out of control.

The latest approval is based on two studies which demonstrated a cumulative major molecular response rate of 64% among newly diagnosed children and 47.7% where the patients were resistant or intolerant to prior therapy.

A major molecular response means that the amount of BCR-ABL gene in the blood is 1/1000th, or less, of what is expected in someone with untreated chronic myeloid leukemia.