- Central laboratory confirmation of the presence of the T790M mutation in tumor tissue in Cohort A and the presence or absence of the T790M mutation in tumor tissue in Cohort B. Centrally indeterminate, unknown or invalid specimens are not acceptable. Biopsy material obtained from either primary or metastatic tumor tissue and sent to the central laboratory must be within 60 prior to dosing study drug but following disease progression on the first EGFR TKI