This pilot clinical trial studies dabrafenib and trametinib in treating patients with ameloblastoma and a specific mutation (change) in the BRAF gene. Dabrafenib and trametinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth.
PRIMARY OBJECTIVES: I. To observe the response rate of ameloblastoma to dabrafenib and trametinib at 6 weeks. SECONDARY OBJECTIVES: I. Feasibility and safety in this patient population. II. Response will be assessed pathologically. III. Two main histologic assays for treatment response will be used: tumor necrosis and phosphorylated-mitogen-activated protein kinase kinase 1 (MEK), phosphorylated-extracellular signal-regulated kinase (ERK), and Ki-67 levels as measured by immunohistochemistry. OUTLINE: Patients receive dabrafenib orally (PO) twice daily (BID) every 12 hours and trametinib 2 mg daily PO for 6 weeks in the absence of disease progression or unacceptable toxicity. Patients whose disease is judged to be not amenable to resection will continue dabrafenib and trametinib indefinitely as long as there has not been tumor progression. After completion of study treatment, patients are followed up for at least 4 weeks.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
1
Given PO
Given PO
Stanford University, School of Medicine
Stanford, California, United States
Tumor Response
Tumor response was assessed per the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Overall tumor response was assessed as the number of participants achieving either a complete response (CR) or a partial response (PR). The criteria are: * CR = Disappearance of all target lesions * PR = ≥ 30% decrease in the sum of the longest diameter of target lesions * Overall Response (OR) = CR + PR * Progressive disease (PD) = 20% increase in the sum of the longest diameter of target lesions, and/or the appearance of one or more new lesion(s) * Stable disease (SD) = Small changes that do not meet any of the above criteria The outcome is reported as the number of participants achieving the different levels of tumor response per RECIST, a number without dispersion.
Time frame: 6 weeks
Percent Tumor Necrosis
Percent of tumor necrosis at the time of endpoint biopsy or surgical resection will be assessed. The tumor specimen from resection will be examined and the volume of the necrosis compared to the volume of the total tumor determined by central pathology. Percent tumor necrosis, in increments of 10%, will be determined. The outcome will be reported as the mean percent tumor necrosis, with standard deviation.
Time frame: 6 weeks
Change in Proliferation
An immunohistochemical laboratory analysis to assess proliferation will be performed on the initial pre-treatment biopsy (baseline) vs either the endpoint tumor biopsy or the tumor specimen from the resection. Ki-67 immunohistochemistry will be scored by at least 2 pathologists using percentage positive cells as the primary metric. Proliferation will be assessed as the difference from baseline in Ki-67 labeling to the end of treatment (tumor biopsy or the tumor specimen). The outcome will be expressed as the mean, with standard deviation.
Time frame: 6 weeks
Phosphorylation of Tumor Markers MEK and ERK
An immunohistochemical laboratory analysis to assess phosphorylation of the tumor markers MEK and ERK on the initial pre-treatment biopsy (baseline) vs either the endpoint tumor biopsy or the tumor specimen from the resection. Immunohistochemistry will be scored by at least 2 pathologists using percentage positive cells and intensity of staining as the primary metrics. Phosphorylation of MEK and ERK will be assessed as the observed difference in phosphorylated MEK and ERK labeling from baseline to the end of treatment (tumor biopsy or the tumor specimen). The outcome will be expressed as the mean, with standard deviation.
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Time frame: 6 weeks