Erlotinib Therapy and Subsequent Development of Mechanisms of Secondary Resistance in Patients With NSCLC

PRIMARY OBJECTIVE -To prospectively assess the frequency of different genetic mechanisms of secondary resistance in patients' tumors during treatment with erlotinib (e.g., T790M mutations, MET amplification). * Correlate these genetic changes with patient demographic data and clinical outcomes (time to progression, survival, sites of recurrence/progression). * Search for novel mechanisms of acquired resistance to erlotinib. * Identify whether these genetic changes are present at low levels in initial pretreatment tumor specimens. SECONDARY OBJECTIVE(S) 1. To measure the steady-state plasma concentrations of erlotinib during the course of patients' treatment. * Determine if the development and/or resolution of skin toxicity is related to plasma erlotinib concentrations. * Determine if the development of disease progression while on erlotinib is correlated with declines in plasma erlotinib concentrations. * Assess the plasma levels in patients whose smoking status has been biochemically verified to determine if smoking is associated with lower erlotinib plasma concentration. 2. To analyze from both free plasma DNA and DNA from circulating tumor cells of erlotinib-treated patients for the original sensitizing EGFR mutations and genetic changes associated with secondary resistance. 3. To measure clinical outcomes in patients with known sensitizing mutations in their tumor EGFR when treated with first-line erlotinib. * Response rate * Time to progression * Median overall survival