Background: Enhanced phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is one of the key adaptive changes accounting for epidermal growth factor receptor (EGFR) inhibitor-resistant growth in head and neck squamous cell carcinoma (HNSCC). We designed a phase II clinical trial of EGFR tyrosine kinase inhibitor (TKI), erlotinib, in association with the mTOR inhibitor, everolimus, based on the hypothesis that the downstream effects of Akt through inhibition of mTOR may enhance the effectiveness of the EGFR-TKI in patients with recurrent/metastatic HNSCC.
Patients and methods: Patients with histologically or cytologically confirmed platinum-resistant HNSCC received everolimus 5 mg and erlotinib 150 mg daily orally until disease progression, intolerable toxicity, investigator or patient decision. Cytokines and angiogenic factors profile, limited mutation analysis and p16 immunohistochemistry status were included in the biomarker analysis.
Results: Of the 35 assessable patients, 3 (8%) achieved partial response at 4 weeks, 1 confirmed at 12 weeks; overall response rate at 12 weeks was 2.8%. Twenty-seven (77%) patients achieved disease stabilization at 4 weeks, 11 (31%) confirmed at 12 weeks. Twelve-week progression-free survival (PFS) was 49%, median PFS 11.9 weeks and median overall survival (OS) 10.25 months. High neutrophil gelatinase lipocalin (P = 0.01) and vascular endothelial growth factor (VEGF) (P = 0.04) plasma levels were significantly associated with worse OS.
Conclusions: The combination of erlotinib and everolimus did not show significant benefit in unselected patients with platinum-resistant metastatic HNSCC despite a manageable toxicity profile. Markers of tumor invasion and hypoxia identify a group of patients with particularly poor prognosis.
Clinical trial number: NCT00942734.
Keywords: EGFR inhibitors; HNSCC; erlotinib; everolimus; mTOR inhibitors.
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