A prospective, multicenter, phase 2 study of imatinib mesylate in korean patients with metastatic or unresectable gastrointestinal stromal tumor

Oncology. 2009;76(5):326-32. doi: 10.1159/000209384. Epub 2009 Mar 23.

Abstract

Objectives: This prospective, multicenter, phase 2 study evaluated the efficacy and safety of imatinib mesylate and assessed KIT and PDGFRA gene mutation status in Korean patients with gastrointestinal stromal tumors (GISTs).

Methods: Forty-seven patients with pathologically proven KIT-positive metastatic or unresectable GISTs were accrued from eight institutions in Korea. Imatinib was administered orally at 400 mg once daily. In case of disease progression, the dose was escalated to 600 mg once daily, then 400 mg twice daily. KIT and PDGFRA mutations were analyzed in 29 of the 47 patients.

Results: Imatinib produced partial responses in 30 patients (63.8%; 95% confidence interval, 50.1-77.6%) and stable disease in 13 patients (27.7%). The median time to response was 2.6 months (range, 1.0-6.2 months). With a median follow-up of 62 months (range, 32-67 months), 4-year progression-free survival and overall survival rates were 50 and 65%, respectively. The most common adverse events were anemia, neutropenia, edema, and skin rash (predominantly of grade 1-2). There were no treatment-related deaths. In the subset evaluated for mutational status, 24 patients (82.8%) had KIT exon 11 mutations and 1 (3.4%) had a KIT exon 9 mutation.

Conclusions: Imatinib is effective and safe in Korean patients with metastatic or unresectable GIST.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Agents / therapeutic use*
  • Benzamides
  • Female
  • Gastrointestinal Stromal Tumors / drug therapy*
  • Gastrointestinal Stromal Tumors / genetics
  • Gastrointestinal Stromal Tumors / pathology
  • Genotype
  • Humans
  • Imatinib Mesylate
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Piperazines / therapeutic use*
  • Polymorphism, Genetic
  • Prognosis
  • Prospective Studies
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Proto-Oncogene Proteins c-kit / genetics
  • Proto-Oncogene Proteins c-kit / metabolism
  • Pyrimidines / therapeutic use*
  • Receptor, Platelet-Derived Growth Factor alpha / genetics
  • Receptor, Platelet-Derived Growth Factor alpha / metabolism
  • Remission Induction
  • Risk Factors
  • Survival Rate
  • Treatment Outcome

Substances

  • Antineoplastic Agents
  • Benzamides
  • Piperazines
  • Pyrimidines
  • Imatinib Mesylate
  • Protein-Tyrosine Kinases
  • Proto-Oncogene Proteins c-kit
  • Receptor, Platelet-Derived Growth Factor alpha