Phase I/II Study of HSP90 Inhibitor AUY922 and Erlotinib for EGFR-Mutant Lung Cancer With Acquired Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors

Purpose AUY922 is an HSP90 inhibitor that causes degradation of HSP chaperones and their client proteins, including epidermal growth factor receptor. We conducted a phase I/II trial to evaluate AUY922 and erlotinib for patients with EGFR-mutant lung cancer and disease progression during erlotinib treatment. Patients and Methods All patients had developed acquired resistance after treatment with erlotinib and underwent repeat tumor biopsies before study entry to assess for EGFR T790M. In phase I, 18 patients were treated with AUY922 intravenously once per week and erlotinib once per day in 28-day cycles using a 3 + 3 dose-escalation design. In phase II, 19 additional patients were treated at the maximum-tolerated dose. The primary end point of the phase II trial was complete plus partial response rate. Results In phase I (n = 18), three patients were treated in each cohort, except the highest-dose cohort (AUY922 70 mg and erlotinib 150 mg), which expanded to six patients because of a dose-limiting toxicity...