A Study of the Efficacy and Safety of Imatinib Mesylate in Patients With Unresectable or Metastatic Gastrointestinal Stromal Tumors Expressing C-kit Gene

Open, Randomized, Phase II Study of Glivec in Patients With Unresectable or Metastatic Gastrointestinal Stromal Tumors Expressing C-kit Plus 10 Year Extension Study

In the core study, participants with unresectable or metastatic gastrointestinal stromal tumors expressing c-kit were treated with either 400 mg or 600 mg imatinib mesylate for 3 years. The 10 year extension study allowed participants, who successfully completed the core study, to continue study treatment with imatinib mesylate provided they still benefited from treatment and did not demonstrate safety concerns as per the investigator's opinion.

Inclusion Criteria:

• Men and non-pregnant women ≥18 years of age with the histopathologically documented diagnosis of malignant GIST that was unresectable and/or metastatic. Confirmation of KIT (CD117) expression via immunohistochemical analysis of tumor sample was also required
• At least one measurable lesion, as defined by Southwestern Oncology Group (SWOG) Solid Tumor Response Criteria, which had not been previously embolized or irradiated
• Performance status ≤3 as defined by the Eastern Cooperative Oncology Group (ECOG) criteria, as well as a life expectancy ≥6 months and adequate end organ function defined as follows: Total bilirubin <1.5 times upper limit of normal (ULN), aspartate aminotransferase (SGOT) and alanine aminotransferase (SGPT) <2.5 x ULN (or <5 x ULN if hepatic metastases were present), creatinine <1.5 x ULN, absolute neutrophil count (ANC) >1.5 x 10^9/L, platelet count >100 x 10^9/L

Exclusion Criteria:

• Patients with fewer than five years of disease-free survival from any other (non-GIST) malignancy except if the other malignancy was not currently clinically significant and did not require active intervention or if the other malignancy was a basal cell skin cancer or a cervical carcinoma in situ
• Patients with known brain metastases
• Evidence of any of the following disorders: Grade III/IV cardiac failure as defined by the New York Heart Association Criteria, severe concomitant disease, acute or known chronic liver disease (i.e. chronic active hepatitis, cirrhosis) or HIV infection
• Chemotherapy or other investigational therapy within four weeks prior to study entry (six weeks for nitrosourea or mitomycin-C) and/or radiotherapy to ≥25% of the bone marrow
• Inability to cooperate
• Major surgery within two weeks or exposure to other investigational agents within 28 days of entry into the study

Other protocol-defined inclusion / exclusion criteria may have applied.