Overview of the LUX-Lung clinical trial program of afatinib for non-small cell lung cancer

Tyrosine kinase inhibitors (TKIs) have emerged as first-line treatment for the management of epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC). Erlotinib and gefitinib were the initial TKIs to be approved for lung cancer and showed improved response rates compared with chemotherapy. Afatinib is an irreversible ErbB family blocker that has also been shown to be active in EGFR-mutated NSCLC. Afatinib has been tested as first-line treatment of advanced NSCLC in the LUX-Lung trial program, as well as in the second- and third-line settings. In this article, we will review the data from the 8 reported LUX-Lung trials.

Next-Generation Covalent Irreversible Kinase Inhibitors in NSCLC: Focus on Afatinib

First-generation, reversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), erlotinib and gefitinib, represented an important addition to the treatment armamentarium for non-small-cell lung cancer (NSCLC) patients with activating EGFR mutations. However, all patients inevitably develop acquired resistance to these agents, primarily due to secondary EGFR mutations, molecular aberrations affecting other signaling pathways, or transformation to small-cell histology. It was hypothesized that development of second-generation TKIs with broader inhibitory profiles could confer longer-lasting clinical activity and overcome acquired resistance to first-generation inhibitors. Here, we review the development of afatinib, an irreversible ErbB family blocker that potently inhibits signaling of all homodimers and heterodimers formed by the EGFR, human epidermal growth factor receptor (HER)-2, HER3, and HER4 receptors. In two phase III trials in patients with EGFR mutation-positive NSCLC, first-line afatinib significantly improved progression-free survival (PFS) and health-related quality of life versus standard-of-care chemotherapy. Moreover, in preplanned sub-analyses, afatinib significantly improved overall survival in patients harboring EGFR Del19 mutations. Afatinib has also demonstrated clinical activity in NSCLC patients who had progressed on erlotinib/gefitinib, particularly when combined with cetuximab, and offers ‘treatment beyond progression’ benefit when combined with paclitaxel versus chemotherapy alone. Furthermore, a recent phase III study demonstrated that PFS was significantly improved with afatinib versus erlotinib for the second-line treatment of patients with squamous cell carcinoma of the lung. The activity of afatinib in both first-line and relapsed/refractory settings may reflect its ability to irreversibly inhibit all ErbB family members. Afatinib has a well-defined safety profile with characteristic gastrointestinal (diarrhea, stomatitis) and cutaneous (rash/acne) adverse events.