age of these patients ranged from 25 to 72 years. Additionally, improvements in symptomatology and other organ dysfunction abnormalities were reported by the investigators in the case reports. Improvements were reported in cardiac, nervous, skin/subcutaneous tissue, respiratory/thoracic/mediastinal, musculoskeletal/connective tissue/vascular, and gastrointestinal organ systems.
Clinical studies in unresectable and/or metastatic GIST
One phase II, open-label, randomised, uncontrolled multinational study was conducted in patients with unresectable or metastatic malignant gastrointestinal stromal tumours (GIST). In this study 147 patients were enrolled and randomised to receive either 400 mg or 600 mg orally once daily for up to 36 months. These patients ranged in age from 18 to 83 years old and had a pathologic diagnosis of Kit-positive malignant GIST that was unresectable and/or metastatic. Immunohistochemistry was routinely performed with Kit antibody (A-4502, rabbit polyclonal antiserum, 1:100; DAKO Corporation, Carpinteria, CA) according to analysis by an avidin-biotin-peroxidase complex method after antigen retrieva l.
The primary evidence of efficacy was based on objective response rates. Tumours were required to be measurable in at least one site of disease, and response characterisation based on Southwestern Oncology Group (SWOG) criteria. Results are provided in Table 6.
Table 6 Best tumour response in trial STIB2222 (GIST)
Best response
All doses (n=147)
400 mg (n=73)
600 mg (n=74)
n (%)
Complete response
1(0.7)
Partial response
98 (66.7)
Stable disease
23 (15.6)
Progressive disease
18 (12.2)
Not eva luable
5 (3.4)
Unknown
2 (1.4)
There were no differences in response rates between the two dose groups. A significant number of patients who had stable disease at the time of the interim analysis achieved a partial response with longer treatment (median follow-up 31 months). Median time to response was 13 weeks (95% C.I. 12–23). Median time to treatment failure in responders was 122 weeks (95% C.I 106–147), while in the overall study population it was 84 weeks (95% C.I 71–109). The median overall survival has not been reached. The Kaplan-Meier estimate for survival after 36-month follow-up is 68%.
In two clinical studies (study B2222 and an intergroup study S0033) the daily dose of Glivec was escalated to 800 mg in patients progressing at the lower daily doses of 400 mg or 600 mg. The daily dose was escalated to 800 mg in a total of 103 patients; 6 patients achieved a partial response and 21 stabilisation of their disease after dose escalation for an overall clinical benefit of 26%. From the safety data available, escalating the dose to 800 mg daily in patients progressing at lower doses of 400 mg or 600 mg daily does not seem to affect the safety profile of Glivec.
Clinical study in adjuvant GIST
In the adjuvant setting, Glivec was investigated in a multicentre, double-blind, long-term, placebo-controlled phase III study (Z9001) involving 773 patients. The ages of these patients ranged from 18 to 91 years. Patients were included who had a histological diagnosis of primary GIST expressing Kit protein by immunochemistry and a tumour size 3 cm in maximum dimension, with complete gross resection of primary GIST within 14-70 days prior to registration. After resection of primary GIST, patients were randomised to o |
