Abstract | PURPOSE: EXPERIMENTAL DESIGN: Twenty-nine AML patients each received a single dose of SU11248, escalated from 50 to 350 mg, in increments of 50 mg and cohorts of three to six patients. FLT3 phosphorylation and plasma pharmacokinetics were evaluated at seven time points over 48 h after SU11248 administration, and FLT3 genotype was determined. Study drug-related adverse events occurred in 31% of patients, mainly grade 1 or 2 diarrhea and nausea, at higher dose levels. RESULTS: Inhibition of FLT3 phosphorylation was apparent in 50% of FLT3-wild-type (WT) patients and in 100% of FLT3-mutant patients. FLT3 internal tandem duplication (ITD) mutants showed increased sensitivity relative to FLT3-WT, consistent with preclinical predictions. The primary end point, strong inhibition of FLT3 phosphorylation in >50% patients, was reached in 200 mg and higher dose cohorts. Downstream signaling pathways were also inhibited; signal transducer and activator of transcription 5 (STAT5) was reduced primarily in internal tandem duplication patients and at late time points in FLT3-WT patients, whereas extracellular signal-regulated kinase (ERK) activity was reduced in the majority of patients, independent of FLT3 inhibition. CONCLUSIONS: This novel translational study bridges preclinical models to the patient setting and provides the first evidence of anti-FLT3 activity in patients. Proof of target inhibition accomplishes a crucial milestone in the development of novel oncology therapeutics.
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Authors | Anne-Marie O'Farrell, James M Foran, Walter Fiedler, Hubert Serve, Ron L Paquette, Maureen A Cooper, Helene A Yuen, Sharianne G Louie, Heidi Kim, Susan Nicholas, Michael C Heinrich, Wolfgang E Berdel, Carlo Bello, Mark Jacobs, Paul Scigalla, William C Manning, Stephen Kelsey, Julie M Cherrington |
Journal | Clinical cancer research : an official journal of the American Association for Cancer Research
(Clin Cancer Res)
Vol. 9
Issue 15
Pg. 5465-76
(Nov 15 2003)
ISSN: 1078-0432 [Print] United States |
PMID | 14654525
(Publication Type: Clinical Trial, Clinical Trial, Phase I, Journal Article, Multicenter Study, Research Support, U.S. Gov't, Non-P.H.S.)
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Chemical References |
- Enzyme Inhibitors
- Indoles
- Proto-Oncogene Proteins
- Pyrroles
- FLT3 protein, human
- Receptor Protein-Tyrosine Kinases
- fms-Like Tyrosine Kinase 3
- Mitogen-Activated Protein Kinases
- Sunitinib
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Topics |
- Administration, Oral
- Adult
- Aged
- Blast Crisis
(pathology)
- Enzyme Inhibitors
(administration & dosage, blood, toxicity)
- Female
- Genotype
- Humans
- Indoles
(administration & dosage, blood, toxicity)
- Leukemia, Myeloid, Acute
(drug therapy, pathology)
- Male
- Metabolic Clearance Rate
- Middle Aged
- Mitogen-Activated Protein Kinases
(metabolism)
- Phosphorylation
- Proto-Oncogene Proteins
(antagonists & inhibitors)
- Pyrroles
(administration & dosage, blood, toxicity)
- Receptor Protein-Tyrosine Kinases
(antagonists & inhibitors)
- Sunitinib
- fms-Like Tyrosine Kinase 3
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