Introduction: The epidermal growth factor receptor inhibitor erlotinib is an approved treatment for chemotherapy-refractory advanced non-small-cell lung cancer (NSCLC). Because activated epidermal growth factor receptor signals through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway, adding the oral mTOR inhibitor everolimus to erlotinib may improve efficacy by blocking multiple components of the same pathway. We conducted a phase I study to determine feasible dosages of combination therapy with erlotinib and everolimus for previously treated metastatic or unresectable NSCLC.
Methods: Participants had advanced NSCLC progressing after two or less previous chemotherapy regimens. Feasibility of daily/weekly everolimus plus daily erlotinib was determined using a 6 + 6 dose-escalation design based on the rate of dose-limiting toxicities. Antitumor activity was assessed by the Response Evaluation Criteria In Solid Tumors study.
Results: Of the 94 patients enrolled, 90% had stage IV NSCLC, 19% never smoked, and 15% were current smokers. Eighty-nine patients experienced one or more adverse events possibly related to any study medication. The most common dose-limiting toxicities were stomatitis (n = 5), rash (n = 4), and diarrhea (n = 3). Maximum tolerated doses were everolimus 5 mg per day or 50 mg per week plus erlotinib 150 mg per day. In daily everolimus cohorts (n = 74), nine patients achieved a complete/partial response and 28 had stable disease (median duration disease control, 9.3 months). In weekly everolimus cohorts (n = 20), no tumor response was observed; seven patients had stable disease (median duration, 9.6 months).
Conclusions: Combination therapy with everolimus 5 mg per day or 50 mg per week and erlotinib 150 mg per day provided acceptable tolerability and disease control. A randomized phase II study evaluating this combination in comparison with erlotinib alone is complete and is being analyzed.