Clinical utility of a blood-based EGFR mutation test in patients receiving first-line erlotinib therapy in the ENSURE, FASTACT-2, and ASPIRATION studies.

OBJECTIVE: Patients with advanced non-small-cell lung cancer (NSCLC) with an adenocarcinoma component are recommended to undergo epidermal growth factor receptor (EGFR) mutation testing when being considered for EGFR targeted therapy. We conducted an exploratory analysis to inform the clinical utility of EGFR mutation testing in blood cell-free DNA using the cobas®EGFR Mutation Test v2. MATERIALS AND METHODS: Two EGFR mutation tests, a tissue-based assay (cobas® v1) and a tissue- and blood-based assay (cobas® v2) were used to analyze matched biopsy and blood samples (897 paired samples) from three Asian studies of first-line erlotinib with similar intent-to-treat populations. ENSURE was a phase III comparison of erlotinib and gemcitabine/platinum, FASTACT-2 was a phase III study of gemcitabine/platinum plus erlotinib or placebo, and ASPIRATION was a single-arm phase II study of erlotinib. Agreement statistics were evaluated, based on sensitivity and specificity between the two assays in subgroups of patients with increasing tumor burden. RESULTS: Patients with discordant EGFR (tissue+/plasma-) mutation status achieved longer progression-free and overall survival than those with concordant (tissue+/plasma+) mutation status. Tumor burden was significantly greater in patients with concordant versus discordant mutations. Pooled analyses of data from the three studies showed a sensitivity of 72.1% (95% confidence interval [CI] 67.8-76.1) and a specificity of 97.9% (95% CI 96.0-99.0) for blood-based testing; sensitivity was greatest in patients with larger baseline tumors. CONCLUSIONS: Blood-based EGFR mutation testing demonstrated high specificity and good sensitivity, and offers a convenient and easily accessible diagnostic method to complement tissue-based tests. Patients with a discordant mutation status in plasma and tissue, had improved survival outcomes compared with those with a concordant mutation status, which may be due to their lower tumor burden. These data help to inform the clinical utility of this blood-based assay for the detection of EGFR mutations.

Examining Treatment Outcomes with Erlotinib in Patients with Advanced Non-Small Cell Lung Cancer Whose Tumors Harbor Uncommon EGFR Mutations.

INTRODUCTION: Exon 19 deletions and the exon 21 L858R mutation of the epidermal growth factor receptor gene (EGFR) predict activity of EGFR tyrosine kinase inhibitors, including erlotinib; however, the ability of less common EGFR mutations to predict efficacy of erlotinib is unclear. METHODS: The efficacy of erlotinib in individual patients with rare EGFR mutations from the MERIT, SATURN, TITAN, TRUST, ATLAS, BeTa, and FASTACT-2 trials was analyzed and compared with data from the literature. RESULTS: In the patients tested for biomarkers, the frequency of rare mutations identified here ranged from 1.7% (eight of 467) in the SATURN study to 7.4% (27 of 364) in ATLAS. Some rare mutations were associated with greater clinical benefit from EGFR tyrosine kinase inhibitor therapy or improved prognosis independent of treatment, whereas others appeared to have a poorer prognosis. In particular, exon 18 G719 mutations, exon 19 K757R and E746G mutations, the exon 20 S768I mutation, and the exon 21 G836S mutation appeared to confer a good outcome with erlotinib treatment, whereas exon 18 S720I showed a particularly poor outcome. Owing to the small number of patients with each mutation, however, it is difficult to confirm whether these rare mutations do indeed confer sensitivity or resistance to erlotinib. CONCLUSIONS: Erlotinib can have different efficacy depending on the specific EGFR mutation. More research is needed to create a central database such as the My Cancer Genome database of rare mutations to definitively confirm whether these mutations are activating, resistant, or neutral.

BEYOND: A Randomized, Double-Blind, Placebo-Controlled, Multicenter, Phase III Study of First-Line Carboplatin/Paclitaxel Plus Bevacizumab or Placebo in Chinese Patients With Advanced or Recurrent Nonsquamous Non-Small-Cell Lung Cancer.

PURPOSE: The phase III BEYOND trial was undertaken to confirm in a Chinese patient population the efficacy seen with first-line bevacizumab plus platinum doublet chemotherapy in globally conducted studies. PATIENTS AND METHODS: Patients age ≥ 18 years with locally advanced, metastatic, or recurrent advanced nonsquamous non-small-cell lung cancer (NSCLC) were randomly assigned to receive carboplatin (area under the curve, 6) intravenously and paclitaxel (175 mg/m(2)) intravenously (CP) on day 1 of each 3-week cycle, for ≤ six cycles, plus placebo (Pl+CP) or bevacizumab (B+CP) 15 mg/kg intravenously, on day 1 of each cycle, until progression, unacceptable toxicity, or death. The primary end point was progression-free survival (PFS); secondary end points were objective response rate, overall survival, exploratory biomarkers, safety. RESULTS: A total of 276 patients were randomly assigned, 138 to each arm. PFS was prolonged with B+CP versus Pl+CP (median, 9.2 v 6.5 months, respectively; hazard ratio [HR], 0.40; 95% CI, 0.29 to 0.54; P < .001). Objective response rate was improved with B+CP compared with Pl+CP (54% v 26%, respectively). Overall survival was also prolonged with B+CP compared with Pl+CP (median, 24.3 v 17.7 months, respectively; HR, 0.68; 95% CI, 0.50 to 0.93; P = .0154). Median PFS was 12.4 months with B+CP and 7.9 months with Pl+CP (HR, 0.27; 95% CI, 0.12 to 0.63) in EGFR mutation-positive tumors and 8.3 and 5.6 months, respectively (HR, 0.33; 95% CI, 0.21 to 0.53), in wild-type tumors. Safety was similar to previous studies of B+CP in NSCLC; no new safety signals were observed. CONCLUSION: The addition to bevacizumab to carboplatin/paclitaxel was well tolerated and resulted in a clinically meaningful treatment benefit in Chinese patients with advanced nonsquamous NSCLC.