Pfizer's bosutinib fails to meet primary endpoint in clinical trial

Pfizer on Monday announced Phase III study results at the American Society of Hematology meeting that showed that its experimental chronic myeloid leukaemia treatment, bosutinib, failed to meet its primary goal of "superior complete cytogenic response" at one year compared with Novartis' Gleevec (imatinib). However, the drugmaker noted that a significantly higher proportion of newly diagnosed patients treated with bosutinib experienced a major molecular response, compared with patients treated with Gleevec.
The BELA study randomised 502 patients to receive bosutinib or Gleevec. After one year, 70 percent of patients treated with Pfizer's drug experienced a cytogenic response, compared to 68 percent of patients given Novartis' drug. For the secondary endpoint, 39 percent of patients treated with bosutinib experienced a major molecular response, compared to 26 percent of patients in the Gleevec arm. In addition, data indicated that fewer patients progressed to an advanced phase of disease, there were fewer deaths, and patients responded faster to Pfizer's treatment.
However, 25.4 percent of patients treated with Pfizer's therapy experienced "serious" adverse events, compared to 13.5 percent of those treated with Novartis' drug. As a result, 19.4 percent of patients discontinued use of bosutinib, compared to 5.6 percent of subjects taking Gleevec. Although enrolment in the study is now closed, researchers will continue to follow participants for safety and efficacy outcomes.
Mace Rothenberg, senior vice president of clinical development and medical affairs for Pfizer's oncology business unit, noted that "based on the totality of evidence from the bosutinib clinical development programme, we are actively engaged in discussions with regulatory authorities." Pfizer noted that bosutinib is also currently being studied in a separate trial in patients with previously treated chronic myeloid leukaemia.
Reference Articles
Pfizer drug fails to beat Novartis’s Gleevec in trial - (Bloomberg)
Pfizer myeloid leukemia treatment fails to meet primary endpoint - (NASDAQ)
Pfizer announces Phase 3 results of investigational compound bosutinib in patients with newly diagnosed chronic myeloid leukemia - (Pfizer)
Pfizer's investigational compound bosutinib fails to meet primary endpoint - (Stock Markets Review)
**Published in "First Word"