males. Females were administered the drug from pre-mating through early embryonic development. The dose of 70 mg/kg/day of bosutinib resulted in reduced fertility in males as demonstrated by 16% reduction in the number of pregnancies. There were no lesions in the male reproductive organs at this dose. This dose of 70 mg/kg/day resulted in exposure (AUC) in male rats approximately equal to that in humans at the 500 mg/day dose of bosutinib. Fertility (number of pregnancies) was not affected when female rats were treated with bosutinib. However, there were increased embryonic resorptions at greater than or equal to 10 mg/kg/day of bosutinib (40% of the human exposure), and decreased implantations and reduced number of viable embryos at 30 mg/kg/day of bosutinib (1.4 times the human exposure).
Clinical Studies
Imatinib-Resistant or -Intolerant Ph+ Chronic Phase (CP), Accelerated Phase (AP) and Blast Phase (BP) CML
A single-arm, Phase 1/2 open-label, multicenter trial was conducted to eva luate the efficacy and safety of Bosulif 500 mg once daily in patients with imatinib-resistant or -intolerant CML with separate cohorts for chronic, accelerated, and blast phase disease previously treated with one prior TKI (imatinib) or more than one TKI (imatinib followed by dasatinib and/or nilotinib). The definition of imatinib resistance included (1) failure to achieve or maintain any hematologic improvement within four weeks; (2) failure to achieve a complete hematologic response (CHR) by 3 months, cytogenetic response by 6 months or major cytogenetic response (MCyR) by 12 months; (3) progression of disease after a previous cytogenetic or hematologic response; or (4) presence of a genetic mutation in the BCR-Abl gene associated with imatinib resistance. Imatinib intolerance was defined as inability to tolerate imatinib due to toxicity, or progression on imatinib and inability to receive a higher dose due to toxicity. The definitions of resistance and intolerance to both dasatinib and nilotinib were similar to those for imatinib. The protocol was amended to exclude patients with a known history of the T315I mutation after 396 patients were enrolled in the trial.
The efficacy endpoints for patients with CP CML previously treated with one prior TKI (imatinib) were the rate of attaining MCyR at week 24 and the duration of MCyR. The efficacy endpoints for patients with CP CML previously treated with both imatinib and at least 1 additional TKI were the cumulative rate of attaining MCyR by week 24 and the duration of MCyR. The efficacy endpoints for patients with previously treated AP and BP CML were confirmed complete hematologic response (CHR) and overall hematologic response (OHR).
The trial enrolled 546 patients with CP, AP or BP CML. Of the total patient population 73% were imatinib resistant and 27% were imatinib intolerant. In this trial, 53% of patients were males, 65% were Caucasian, and 20% were 65 years old or older. Of the 546 treated patients, 503 were considered eva luable for efficacy. Patients were eva luable for efficacy if they had received at least one dose of Bosulif and had a valid baseline efficacy assessment. Among eva luable patients, there were 266 patients with CP CML previously treated with one prior TKI (imatinib), 108 patients with CP CML previously treated with both imatinib and at least 1 additional TKI, and 129 patients with advanced phase CML previously treated with at least one TKI.
Median duration of Bosulif treatment was 22 months in patients with CP CML previously treat |
