Bosutinib Joins Crowd of CML-Focused Drugs

Although chronic myeloid leukemia (CML) is a life-threatening disease, it usually can be managed as a chronic disease by therapies, including Gleevec (imatinib) or two newer drugs, Sprycel (dasatinib) or Tasigna (nilotinib). However, when those three drugs fail to slow cancer progression, patients must turn to drugs that are still in clinical study. One of those drugs, bosutinib, has shown efficacy in patients who have progressed on these approved CML treatments.

After two years of data, the ongoing, early-phase Study 200 has shown bosutinib may be an effective therapy for patients who have progressed on at least two lines of therapy. The trial examined bosutinib in 118 CML patients who were intolerant or had progressed on Gleevec, and then either Tasigna or Sprycel. After 24 weeks, 26 percent of patients had a major cytogenetic response, with half having a complete response (complete disappearance of cancer cells from the bone marrow). Common side effects included diarrhea, nausea and rash.

The drug maker, Pfizer, is planning on submitting bosutinib for FDA review in previously treated patients based on Study 200 data. Another bosutinib trial called BELA, also presented at the American Society of Hematology this past December, examined the drug against Gleevec in newly diagnosed patients, but had lukewarm results. However, Pfizer is preparing to submit bosutinib for approval in the first-line setting in these patients, as well.

Correction: As of Dec. 3, Pfizer is preparing to submit bosutinib for approval in the first-line setting only in the European Union.