Efficacy, safety, and pharmacokinetics of imatinib dose escalation to 800 mg/day in patients with advanced gastrointestinal stromal tumors
- 1 October 2013
- journal article
- Published by Springer Science and Business Media LLC in Investigational New Drugs
- Vol. 31 (5), 1367-1374
- https://doi.org/10.1007/s10637-013-9961-8
Abstract
Imatinib dose escalation has been suggested as an effective therapy for advanced gastrointestinal stromal tumors (GIST) after progression on the standard dose. We evaluated the efficacy, tolerability, and pharmacokinetics of imatinib dose escalation. Eighty-four patients with GIST who received imatinib 800 mg/day as second-line therapy were reviewed. In 66 patients, imatinib plasma trough level (Cmin) at 800 mg/day was measured. The relationships between imatinib exposure and therapeutic efficacy or toxicity were examined by grouping patients into quartiles according to Cmin and its percent change after dose escalation. Disease control was achieved in 56 % of patients. The median progression-free survival (PFS) was 5.1 months. There was a strong tendency for better PFS in patients with KIT exon 9 mutations compared to patients with other genotypes (median PFS 11 vs 4 months, p = 0.051). The common grade 3–4 toxicities were anemia (26 %), neutropenia (11 %), and hemorrhage (5 %). Mean ± standard deviation imatinib Cmin at 800 mg/day and percent Cmin change was 3,552 ± 1,540 ng/mL and 160 ± 101 %, respectively. Body surface area, hemoglobin, and absolute neutrophil count were independent covariates of Cmin at 800 mg/day. Neither Cmin nor its percent change associated with efficacy. The upper three quartiles of percent Cmin change associated with more frequent severe toxicities (56 %) than the lowest quartile (10 %; p = 0.01). Dose escalation to 800 mg/day was active and feasible in GIST after progression on the standard dose. Imatinib Cmin monitoring may help to manage the patients with standard dose-resistant GIST that may require dose escalation.Keywords
This publication has 27 references indexed in Scilit:
- Comparison of Two Doses of Imatinib for the Treatment of Unresectable or Metastatic Gastrointestinal Stromal Tumors: A Meta-Analysis of 1,640 PatientsJournal of Clinical Oncology, 2010
- Primary and Secondary Kinase Genotypes Correlate With the Biological and Clinical Activity of Sunitinib in Imatinib-Resistant Gastrointestinal Stromal TumorJournal of Clinical Oncology, 2008
- Phase III Randomized, Intergroup Trial Assessing Imatinib Mesylate At Two Dose Levels in Patients With Unresectable or Metastatic Gastrointestinal Stromal Tumors Expressing the Kit Receptor Tyrosine Kinase: S0033Journal of Clinical Oncology, 2008
- Population pharmacokinetics of imatinib and the role of α1‐acid glycoproteinBritish Journal of Clinical Pharmacology, 2006
- KIT mutations and dose selection for imatinib in patients with advanced gastrointestinal stromal tumoursEuropean Journal Of Cancer, 2006
- Outcome of patients with advanced gastro-intestinal stromal tumours crossing over to a daily imatinib dose of 800mg after progression on 400mgEuropean Journal Of Cancer, 2005
- Clinical Pharmacokinetics of ImatinibClinical Pharmacokinetics, 2005
- Progression-free survival in gastrointestinal stromal tumours with high-dose imatinib: randomised trialThe Lancet, 2004
- Efficacy and Safety of Imatinib Mesylate in Advanced Gastrointestinal Stromal TumorsNew England Journal of Medicine, 2002
- New Guidelines to Evaluate the Response to Treatment in Solid TumorsJNCI Journal of the National Cancer Institute, 2000