Background: There is a lack of effective treatment for metastatic adenoid cystic carcinoma (ACC), a usually indolent tumor. We studied the efficacy of imatinib mesylate, a potent inhibitor of KIT tyrosine kinase, in patients with KIT-positive metastatic ACC.
Method: Five patients with lung metastasis were treated in a pilot study with imatinib 400 mg by mouth twice a day. Mutations of c-kit and platelet-derived growth factor receptor (PDGFR)-alpha in tumors from these patients were analyzed.
Results: Disease progression was noted in three of five patients during the short treatment periods, ranging from 2 to 3 weeks. Three patients died of disease within 6 months. No detectable mutations were found in c-kit and PDGFR-alpha.
Conclusion: We observed an unexpected high progression rate of metastatic ACC within short periods during imatinib treatment. Use of imatinib to treat cancers without c-kit or PDGFR-alpha mutation should be approached with caution.
(c) 2005 Wiley Periodicals, Inc.