ABSTRACT
BACKGROUND: Vatalanib (PTK787/ZK 222584) inhibits a few tyrosine kinases including KIT, platelet-derived growth factor receptors (PDGFRs) and vascular endothelial growth factor receptors (VEGFRs). We report efficacy and safety results of vatalanib in advanced gastrointestinal stromal tumour (GIST) resistant to imatinib or both imatinib and sunitinib. PATIENTS AND METHODS: Forty-five patients whose metastatic GIST had progressed on imatinib were enrolled. Nineteen (42.2%) patients had received also prior sunitinib. Vatalanib 1250 mg was administered orally daily. RESULTS: Eighteen patients (40.0%; 95% confidence interval (CI), 25.7-54.3%) had clinical benefit including 2 (4.4%) confirmed partial remissions (PR; duration, 9.6 and 39.4 months) and 16 (35.6%) stabilised diseases (SDs; median duration, 12.5 months; range, 6.0-35.6+ months). Twelve (46.2%) out of the 26 patients who had received prior imatinib only achieved either PR or SD compared with 6 (31.6%, all SDs) out of the 19 patients who had received prior imatinib and sunitinib (P=0.324). The median time to progression was 5.8 months (95% CI, 2.9-9.5 months) in the subset without prior sunitinib and 3.2 (95% CI, 2.1-6.0) months among those with prior imatinib and sunitinib (P=0.992). Vatalanib was generally well tolerated. CONCLUSION: Vatalanib is active despite its narrow kinome interaction spectrum in patients diagnosed with imatinib-resistant GIST or with imatinib and sunitinib-resistant GIST.
Subject(s)
Antineoplastic Agents/therapeutic use , Phthalazines/therapeutic use , Pyridines/therapeutic use , Adult , Aged , Aged, 80 and over , Benzamides , Disease-Free Survival , Drug Resistance, Neoplasm , Female , Gastrointestinal Stromal Tumors/drug therapy , Humans , Imatinib Mesylate , Indoles/therapeutic use , Male , Middle Aged , Phthalazines/adverse effects , Piperazines/therapeutic use , Protein Kinase Inhibitors/therapeutic use , Pyridines/adverse effects , Pyrimidines/therapeutic use , Pyrroles/therapeutic use , SunitinibABSTRACT
BACKGROUND: We evaluated safety and efficacy of PTK787/ZK222584 (PTK/ZK), a novel tyrosine kinase inhibitor of KIT, platelet-derived growth factor receptors and vascular endothelial cell growth factor receptors (VEGFRs), in patients with imatinib-resistant gastrointestinal stromal tumor (GIST). This is the first study of PTK/ZK in this population. PATIENTS AND METHODS: Patients with metastatic GIST that had progressed after >/= 4-week treatment with imatinib mesylate were eligible. Prior VEGFR-2 inhibitor therapy was not permitted. PTK/ZK 1250 mg orally once-daily was administered to 15 patients (accrued as a two-stage procedure), most of whom (n = 11) had been unsuccessfully treated with imatinib 800 mg daily, until treatment failure. Patients were monitored at 4- to 8-week intervals. RESULTS: All 15 patients enrolled were eligible; two (13%) achieved partial response (PR), eight (53%) had stable disease (SD) >/=3 months, and five (33%) progressed. The clinical benefit rate (PR + SD) was 67% (95% CI 38% to 86%). Median time to progression was 8.5 months (range 0.9-24.8+ months). Three patients had not progressed at the time of analysis, including one PR at 24.8 months and two SDs at 16.6 and 18.6 months on treatment. PTK/ZK was generally well tolerated. CONCLUSION: PTK/ZK 1250 mg p.o. once daily is active and well tolerated in patients with imatinib-resistant GIST.
Subject(s)
Antineoplastic Agents/therapeutic use , Drug Resistance, Neoplasm , Gastrointestinal Neoplasms/drug therapy , Gastrointestinal Stromal Tumors/secondary , Phthalazines/therapeutic use , Piperazines/pharmacology , Protein Kinase Inhibitors/therapeutic use , Pyridines/therapeutic use , Pyrimidines/pharmacology , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Salvage Therapy , Adult , Aged , Benzamides , Disease Progression , Female , Gastrointestinal Neoplasms/pathology , Gastrointestinal Stromal Tumors/drug therapy , Humans , Imatinib Mesylate , Male , Middle Aged , Neoplasm Proteins/antagonists & inhibitors , Piperazines/therapeutic use , Proto-Oncogene Proteins c-kit/drug effects , Pyrimidines/therapeutic use , Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitorsABSTRACT
Imatinib mesylate is a molecular-targeted agent, shown to be effective in chronic myeloid leukemia and gastrointestinal stromal tumors (GIST). The latter may currently serve as a model on which speculating how the future of molecular-targeted therapy in solid tumors will be. So far, some lessons have been learnt. 1) Molecular-targeted therapy can be effective in the advanced disease setting, resulting in major tumor responses. 2) Patterns of tumor responses may be peculiar, radiologically and pathologically. 3) Anti-tumor activity may be highly predictable by assessing tumor molecular biology. 4) The methodology of clinical development of molecular-targeted agents may differ from standard chemotherapy in some respects, because, say, the preclinical rationale may be stronger, thus increasing the Bayesian prior probability of efficacy, or the optimal dose cannot be determined separately from the assessment of activity and efficacy. 5) Molecular-targeted agents will hardly remain "orphan drugs", if effective. 6) While an obvious impact on survival in the advanced disease setting has been clearly demonstrated, the biologic and clinical impact of molecular-targeted therapy still needs to be elucidated. Its eradicating capabilities, as well as the implications of secondary resistance, are to be understood. 7) Integrated, multimodality approaches, including surgery, may still be of value in the molecular-targeted therapy era.