2002 CTOS Annual Meeting Oral Presentations — Medical Oncology

PHASE 2 TRIAL WITH IMATINIB (GLIVEC, STI571) IN PATIENTS WITH GASTO-INTESTINAL STROMAL TUMORS (GIST): ACTIVITY RESULTS AFTER 1 YEAR. A STUDY OF THE EORTC SOFT TISSUE AND BONE SARCOMA GROUP (STBSG)
[Abstract ID: 29]

Category: Medical Oncology

Presentation: Oral

Authors: Jaap Verweij¹, Allan van Oosterom², Jean-Yves Blay³, Ian Judson⁴, Sjoerd Rodenhuis⁵, Axel Le Cesne⁷, Pancras Hogendoorn⁶, Martine Van Glabbeke¹⁰, Sasa Dimitrijevic⁸, Ole S. Nielsen⁹

Author Institutions: ¹Rotterdam Cancer Institute and University Hospital, Netherlands; ²University Hospital Gasthuisberg Leuven, Belgium; ³Centre Leon Berard Lyon, France; ⁴Royal Marsden Hospital London, United Kingdom; ⁵Netherlands Cancer Institute Amsterdam, Netherlands; ⁶Leiden University Medical Center, Netherlands; ⁷Institut Gustave Roussy Villejuif, France; ⁸Novartis Oncology Basle, Switzerland; ⁹Aarhus Kommune Hospital, Denmark; ¹⁰EORTC Data Center Brussels, Belgium

Presenter: Jaap Verweij
verweij@onch.azl.nl

Correspondent: Jaap Verweij
verweij@onch.azl.nl
Rotterdam Netherlands 3075 EA
Ph: +31 10 4391338
Fax: +31 10 4391003

Objectives: From January to March 2002, the STBSG has included 27 patients with GIST in a phase II trial of imatinib.

Methods: Patients were treated at a dose of 400 mg b.i.d. (the maximum tolerated dose according to the results of the previous STBSG phase I trial in soft tissue sarcoma).

Results: Median age was 56 years (range: 30-75), 19 patients were male (70%), performance status (WHO scale) was 0 in 12 cases (44%) and 1 in 15 cases. The reported disease origin was gastro-intestinal in 17 patients (63%) and retro/intra-abdominal in 10 cases; 14 patients (52%) had received prior chemotherapy.
Side effects have been reported elsewhere (ASCO 2002, abstract 1609).
One year after the end of accrual, 22 patients were still under protocol therapy. A total of 19 patients (70%) have responded to therapy (1CR, 18PR); 2 of these patients progressed after 261 and 323 days of treatment respectively, but were kept on treatment. Five patients had a stabilization of their disease, ongoing for 280, 371 and 391 days in 3 cases. The 3 other patients had progressive disease at the first disease evaluation (8 weeks). The 1-year estimate (Kaplan-Meier) of progression free survival is 73% (s.e.: 9%). So far, 2 patients have died (both from progression). The 1-year survival estimate is 96% (s.e.: 4%).

Conclusions: These results indicate that the activity of imatinib in GIST is long lasting. STBSG has subsequently randomized 946 patients in a phase III trial to compare the activity of the drug administered at 400mg/day and 400mg b.i.d.