ABSTRACT
PURPOSE: Vascular endothelial growth factor (VEGF) expression is prognostic in melanoma, and the activity of VEGF is mediated in part through the receptor tyrosine kinase Flk-1. A Phase II study of SU5416, a preferential inhibitor of Flk-1, was carried out in patients with metastatic melanoma to determine clinical response, tolerability, and changes in tumor vascular perfusion. EXPERIMENTAL DESIGN: Patients with documented progressive disease and =1 prior therapy were eligible. Central nervous system metastases were allowed if stable off medication. SU5416 (145 mg/m(2)) was administered via a central catheter twice weekly for 8 weeks. Premedication with dexamethasone, diphenhydramine, and a H(2) blocker was required because of the Cremophor vehicle. Tumor vascular perfusion was assessed before treatment and during week 8 by dynamic contrast magnetic resonance imaging, and plasma was analyzed for VEGF. RESULTS: Thirty-one patients were enrolled. Two-thirds had received prior therapy, 21 had visceral metastasis, and 14 had an elevated lactate dehydrogenase. Mean absolute lymphocyte counts were decreased (P = 0.002), and glucose levels were increased (P = 0.001) posttherapy, presumably because of steroid premedication. Four vascular adverse events were observed. Of 26 evaluable patients, 1 experienced a partial response, 1 had stable disease, and 5 had a mixed response. Dynamic contrast magnetic resonance imaging in 5 evaluable patients showed decreased tumor perfusion at week 8 (P = 0.024), and plasma VEGF levels were elevated compared with pretherapy (P = 0.008). CONCLUSIONS: SU5146 appears to be relatively well tolerated in this population. Although the modest clinical activity and potential effects on tumor vascularity may support additional exploration of VEGF as a target in melanoma, effects from steroid premedication limit further investigation of this agent.
Subject(s)
Indoles/therapeutic use , Melanoma/drug therapy , Pyrroles/therapeutic use , Vascular Endothelial Growth Factor Receptor-2/antagonists & inhibitors , Adult , Aged , Angiogenesis Inhibitors/therapeutic use , Female , Glucose/metabolism , Humans , Lymphocytes/metabolism , Magnetic Resonance Imaging , Male , Middle Aged , Neoplasm Metastasis , Neovascularization, Pathologic , Protein Kinase Inhibitors/therapeutic use , Time Factors , Treatment Outcome , Vascular Endothelial Growth Factor A/blood , Vascular Endothelial Growth Factor A/metabolismABSTRACT
BACKGROUND: Gastrointestinal stromal tumors (GIST) are rare mesenchymal tumors that are characterized by constitutive overexpression of the tyrosine kinase receptor KIT (CD117). Imatinib mesylate is a selective inhibitor of tyrosine kinase-mediated activity. This study reports a single-institution experience of surgical resection and the use of imatinib in the treatment of GIST. METHODS: A retrospective review from 1995 to 2002 identified 57 patients (M:F, 29:28; median age, 61 years) with GIST who were treated at the University of Chicago. Twenty-eight patients underwent exploratory surgery with curative intent; 29 patients were referred for treatment of metastatic disease after surgery at outside institutions. Twenty-nine patients were treated with oral imatinib for either metastatic disease (n=26 patients) or in the adjuvant setting after complete resection (n=3 patients). RESULTS: Resections were performed in 53 patients, and metastatic disease was identified in 17 patients at the time of exploratory surgery. Immunohistochemical staining for CD117 was positive in 96% of patients. A size larger than 5 cm, a mitotic rate larger than 1/10 high-power field, and tumor necrosis predicted recurrence in patients after resection. The median follow-up period was 18 months (range, 4-81 months). Twenty-three patients (40%) are alive without disease; 22 patients (39%) are alive with disease; 7 patients died, and 5 patients are lost to follow-up. Among the 26 patients with metastatic disease who were treated with imatinib, 5 deaths have occurred, and disease stabilization or tumor regression was observed initially in 22 patients, with a median duration of response of 19 months. CONCLUSIONS: Complete surgical extirpation remains the only curative treatment of GIST. Imatinib-targeted therapy of metastatic disease yields encouraging clinical responses. The true efficacy of imatinib in this setting, as induction therapy or as an adjuvant treatment in patients with GIST, is unknown pending the completion of ongoing prospective trials.