3:32AM Ambit Biosciences announces 4 presentations including results of phase 2b randomized, open-label study of lower doses of quizartinib in flt3 itd positive relapsed refractory acute myeloid leukemia patients (AMBI) 8.31 : Co announces four oral presentations given at the 55th Annual ASH Conference in New Orleans, with data highlighting the Company's lead drug candidate, quizartinib.
Results of the Phase 2b Randomized, Open-Label, Study of Lower Doses of Quizartinib in Subjects with FLT3-ITD Positive Relapsed Acute Myeloid Leukemia (AML): The purpose of this study is to assess the efficacy and safety of lower doses of quizartinib in the treatment of patients 18-years or older with relapsed/refractory FLT3 ITD positive AML to further improve the benefit:risk assessment of quizartinib.
This preliminary analysis is based on data available through May 28, 2013 with a minimum of eight weeks of follow up since the last subject first visit. A total of 76 patients were enrolled from May 21, 2012 to March 27, 2013. Median age for all patients was 55 (19-77) and 92% were FLT3-ITD. 35 patients remained in follow-up at the time of the analysis, and are currently censored for overall survival. The following key information was presented:
For dose of 30mg:
The CRc rate was 47 percent (5 percent CR+CRp, 42 percent CRi)
The rate of HSCT after quizartinib use was 32 percent
The median overall survival was 20.7 weeks, with 16/38 patients censored as they remained in follow-up at the time of the analysis
Of the 12 patients who were bridged to HSCT, the median overall survival was 31 weeks
Grade 2 or greater QT prolongation was 11%, with a 5% grade 3 rate and no grade 4 events
For dose of 60mg:
The CRc rate was 47 percent (5 percent CR+CRp, 42 percent CRi)
The rate of HSCT after quizartinib use was 42 percent
The median overall survival was 25.4 weeks, with 19/38 patients censored as they remained in follow-up at the time of the analysis
Of the 16 patients who were bridged to HSCT, the median overall survival is 28.1 weeks
Grade 2 or greater QT prolongation was 17%, with a 3% grade 3 rate and no grade 4 events
Overall conclusions: Both the 30mg and the 60mg doses showed substantial activity in terms of overall CRc rate and bridge to HSCT with impact on improved median OS. The safety profile is similar at both doses yet QTcF prolongation appears dose dependent, with decreased QTcF prolongation at both the 30 and 60mg doses compared to the prior Phase 2 study findings which utilized higher doses of quizartinib.
Next steps include a global phase 3 randomized study of quizartinib in FLT3-ITD(+) patients in 1st relapse planned to start in early 2014 pending final FDA feedback on our recommended starting dose.
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