UPDATED: Pfizer wins FDA approval for orphan chronic myelogenous leukemia drug

Pfizer has won FDA approval for bosutinib, an orphan drug for chronic myelogenous leukemia. The treatment--to be marketed as Bosulif--tackles tyrosine kinase, which spurs development of abnormal white cells in patients.

A spokesperson for Pfizer ($PFE) tells FierceBiotech this evening that the drug will cost less than $8,200 a month. The oral therapy will be dosed at 500 mg daily.

"With the approval of tyrosine kinase inhibitors, we are seeing improvements in the treatment of CML based on a better understanding of the molecular basis of the disease," said Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research. "These improvements have been observed in chronic and accelerated phases of CML."

Pfizer had been counting on an approval for a trio of drugs at the end of the summer, including tofacitinib and Eliquis, but the pharma giant has been temporarily stymied on both those fronts as regulators take additional time to ponder applications. Bosutinib may not be the big approval that Pfizer needs now, but it may help take some of the sting out of its big setback with the late-stage failure of the Alzheimer's drug bapineuzumab, partnered with Johnson & Johnson ($JNJ) and Elan ($ELN).

"Bosulif is the third new medicine from Pfizer Oncology's pipeline to be approved by the FDA in just 13 months, a remarkable achievement that reflects our commitment to advancing the science in cancer drug development and delivering on Pfizer's innovative core," said Garry Nicholson, president and general manager, Pfizer Oncology Business Unit. 

Bosulif has been approved for patients with chronic, accelerated or blast phase Philadelphia chromosome positive CML who either don't respond to currently approved therapies or can't tolerate them. That includes imatinib. In its release, the FDA notes that among the patients taking the drug, "33 percent had their blood counts that returned to normal range (complete hematologic response) and 55 percent achieved normal blood counts with no evidence of leukemia (overall hematologic response) within the first 48 weeks of treatment."

The agency estimates that 5,430 Americans will be diagnosed with CML this year.

- here's the release from the FDA
- read the release from Pfizer

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