KIT as a therapeutic target in metastatic melanoma
Richard D Carvajal, Cristina R Antonescu, Jedd D Wolchok, Paul B Chapman, Ruth-Ann Roman, Jerrold Teitcher, Katherine S Panageas, Klaus J Busam, Bartosz Chmielowski, Jose Lutzky, Anna C Pavlick, Anne Fusco, Lauren Cane, Naoko Takebe, Swapna Vemula, Nancy Bouvier, Boris C Bastian, Gary K Schwartz, Richard D Carvajal, Cristina R Antonescu, Jedd D Wolchok, Paul B Chapman, Ruth-Ann Roman, Jerrold Teitcher, Katherine S Panageas, Klaus J Busam, Bartosz Chmielowski, Jose Lutzky, Anna C Pavlick, Anne Fusco, Lauren Cane, Naoko Takebe, Swapna Vemula, Nancy Bouvier, Boris C Bastian, Gary K Schwartz
Abstract
Context: Some melanomas arising from acral, mucosal, and chronically sun-damaged sites harbor activating mutations and amplification of the type III transmembrane receptor tyrosine kinase KIT. We explored the effects of KIT inhibition using imatinib mesylate in this molecular subset of disease.
Objective: To assess clinical effects of imatinib mesylate in patients with melanoma harboring KIT alterations.
Design, setting, and patients: A single-group, open-label, phase 2 trial at 1 community and 5 academic oncology centers in the United States of 295 patients with melanoma screened for the presence of KIT mutations and amplification between April 23, 2007, and April 16, 2010. A total of 51 cases with such alterations were identified and 28 of these patients were treated who had advanced unresectable melanoma arising from acral, mucosal, and chronically sun-damaged sites.
Intervention: Imatinib mesylate, 400 mg orally twice daily.
Main outcome measures: Radiographic response, with secondary end points including time to progression, overall survival, and correlation of molecular alterations and clinical response.
Results: Two complete responses lasting 94 (ongoing) and 95 weeks, 2 durable partial responses lasting 53 and 89 (ongoing) weeks, and 2 transient partial responses lasting 12 and 18 weeks among the 25 evaluable patients were observed. The overall durable response rate was 16% (95% confidence interval [CI], 2%-30%), with a median time to progression of 12 weeks (interquartile range [IQR], 6-18 weeks; 95% CI, 11-18 weeks), and a median overall survival of 46.3 weeks (IQR, 28 weeks-not achieved; 95% CI, 28 weeks-not achieved). Response rate was better in cases with mutations affecting recurrent hotspots or with a mutant to wild-type allelic ratio of more than 1 (40% vs 0%, P = .05), indicating positive selection for the mutated allele.
Conclusions: Among patients with advanced melanoma harboring KIT alterations, treatment with imatinib mesylate results in significant clinical responses in a subset of patients. Responses may be limited to tumors harboring KIT alterations of proven functional relevance. Trial Registration clinicaltrials.gov Identifier: NCT00470470.
Conflict of interest statement
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Carvajal reported being a consultant for Novartis and receiving research support from the American Society of Clinical Oncology, National Institutes of Health, and the US Food and Drug Administration. Dr Wolchok reported being a consultant for Novartis. Dr Chapman reported being a consultant for and receiving research support for travel, accommodations, and meeting expenses from Roche-Genentech. Dr Chmielowski reported being a consultant for Celgene and Prometheus and receiving payment for lectures from Novartis and Prometheus. Dr Lutzy reported being a consultant for Bristol-Myers Squibb, receiving payment for lectures from Millennium and Bristol-Myers Squibb, and receiving research support from Memorial Sloan-Kettering Cancer Center. Dr Bastian reported being a consultant for Novartis, Abbott, sanofi-aventis, DermTech, and Genomel, having patents filed by the University of California, and receiving research support from the US Food and Drug Administration, National Institutes of Health, Melanoma Research Alliance, Canadian Institutes of Health Research, Canadian Cancer Society, European Commission, Jubilaeumsfonds of the Oesterreichische National Bank, and Deutsche Forchungsgemeinschaft. Dr Schwartz reported being a consultant for Pfizer, Tragara, and Pharmagap, and has received research support from the US Food and Drug Administration. No other authors reported any disclosures.
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Source: PubMed