title: Sunitinib treatment in pediatric patients with advanced GIST following failure of imatinib.
abstract: BACKGROUND
  Sunitinib inhibits KIT and other members of the split-kinase-domain family of receptor tyrosine kinases. Sunitinib prolongs survival in adult patients with imatinib-resistant gastrointestinal stromal tumor (GIST). We report the experience with sunitinib in pediatric patients with advanced GIST following failure of imatinib.
  
  
  METHODS
  Sunitinib therapy was provided through a treatment-use protocol. Patients were 10-17 years old at enrollment. All patients had GIST resistant to imatinib therapy. Sunitinib was administered daily for 4 weeks in 6-week treatment cycles. KIT and platelet-derived growth factor receptor alpha (PDGFRA) genotyping of tumor tissue were performed.
  
  
  RESULTS
  One patient achieved a partial response, five patients had stable disease and one patient had progressive disease on sunitinib. The duration of disease stabilization was between 7 and 21+ months, with a mean of 15 months. Time to tumor progression was longer on sunitinib than on prior imatinib treatment for five of six patients. Two patients experienced grade 3 adverse events. All other adverse events were grade 1-2. None of the five patients tested had mutations in KIT or PDGFRA.
  
  
  CONCLUSIONS
  Sunitinib treatment was associated with substantial initial antitumor activity and acceptable tolerability in this group of pediatric patients with imatinib-resistant GIST.
authors.affiliation: Pediatric Oncology, Dana-Farber Cancer Institute and Department of Medicine, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Janeway
authors.forename: Karen H
authors.initials: KH
authors.lastname: Albritton
authors.forename: Annick D
authors.initials: AD
authors.lastname: Van Den Abbeele
authors.forename: Gina Z
authors.initials: GZ
authors.lastname: D'Amato
authors.forename: Paolo
authors.initials: P
authors.lastname: Pedrazzoli
authors.forename: Salvatore
authors.initials: S
authors.lastname: Siena
authors.forename: Joel
authors.initials: J
authors.lastname: Picus
authors.forename: James E
authors.initials: JE
authors.lastname: Butrynski
authors.forename: Marcus
authors.initials: M
authors.lastname: Schlemmer
authors.forename: Michael C
authors.initials: MC
authors.lastname: Heinrich
authors.forename: George D
authors.initials: GD
authors.lastname: Demetri