ASH meeting: Pfizer's bosutinib disappoints in myeloid leukemia trial; Novartis' Tasigna beats Glivec in CML study

US drugs behemoth Pfizer (NYSE: PFE) had another research setback when it presented new date on its investigational new drug candidate bosutinib at the annual meeting of the American Society of Hematology (ASH), being held in Orlando, Florida, while Swiss major Novartis (NOVN: VX) reported positive results for its Tasigna (nilotinib).

Pfizer noted that, while a significantly higher proportion of patients with newly diagnosed chronic myeloid leukemia who were treated with bosutinib (39%) experienced a major molecular response (MMR), a secondary endpoint, compared with patients treated with imatinib (26%) in the intent-to-treat (ITT) population (p=0.002), the study did not meet its primary endpoint of superior complete cytogenetic response (CCyR) rate at one year versus imatinib (70% vs 68%, respectively, [p=0.601]), in the ITT population.

These results are from a Phase III study of the investigational compound bosutinib as a first-line treatment in patients with Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML), called the Bosutinib Efficacy and safety in chronic myeloid LeukemiA [BELA] study.