In advanced epidermal growth factor receptor (EGFR)-mutant non-small-cell lung cancer (NSCLC), treatment with afatinib, a second-generation EGFR-tyrosine kinase inhibitor (TKI), confers a significant survival benefit over platinum-based chemotherapy. The first-generation EGFR-TKIs gefitinib and erlotinib in combination with bevacizumab have improved progression-free survival. We hypothesized that the combination of afatinib with bevacizumab would further improve efficacy, and conducted a phase I trial to test this hypothesis.
Untreated patients with advanced EGFR-mutant NSCLC were enrolled. The primary endpoint was safety. Two doses of afatinib, 40mg/day (level 0) and 30mg/day (level -1), were evaluated in combination with 15mg/kg bevacizumab every 3 weeks. Optimal dosing was determined by dose-limiting toxicity (DLT), with the concentration at which ≤4 of 12 patients experienced toxicity considered the recommended dose.
Nineteen patients were enrolled (level 0:5, level -1:14). Three of the five patients at level 0 experienced a DLT, which indicated that this dose was unfeasible. Three patients at level -1 developed a DLT of grade 3 non-hematological toxicity, which was soon resolved. Grade 3 or worse adverse events were experienced by all five patients at dose level 0 (diarrhea in 2, skin rash in 1, hypoxia in 1, and paronychia in 1), and by three patients at level -1 (diarrhea in 2 and anorexia in 1). Among 16 evaluable patients, 1 had a complete response, 12 had partial responses, and 0 had progressive disease.
Afatinib plus bevacizumab (level -1) was well tolerated and showed evidence of favorable disease control. This combination therapy may represent a potent therapeutic option for patients with EGFR-mutant NSCLC.