Update on Anti-EGFR Therapy

Editoria

Tumor marker analyses from the phase III, placebo-controlled, FASTACT-2 study of intercalated erlotinib with gemcitabine/platinum in the first-line treatment of advanced non-small-cell lung cancer

AbstractObjectivesThe FASTACT-2 study of intercalated erlotinib with chemotherapy in Asian patients found that EGFR mutations were the main driver behind the significant progression-free survival (PFS) benefit noted in the overall population. Further exploratory biomarker analyses were conducted to provide additional insight.Materials and methodsThis multicenter, randomized, placebo-controlled, double-blind, phase III study investigated intercalated first-line erlotinib or placebo with gemcitabine/platinum, followed by maintenance erlotinib or placebo, for patients with stage IIIB/IV non-small cell lung cancer (NSCLC). Provision of samples for biomarker analysis was encouraged but not mandatory. The following biomarkers were analyzed (in order of priority): EGFR mutation by cobas® test, KRAS mutation by cobas® KRAS test, HER2 by immunohistochemistry (IHC), HER3 by IHC, ERCC1 by IHC, EGFR gene copy number by fluorescence in-situ hybridization (FISH) and EGFR by IHC. All subgroups were assessed for PFS (primary endpoint), overall survival (OS), non-progression rate and objective response rate.ResultsOverall, 256 patients provided samples for analysis. Considerable overlap was noted among biomarkers, except for EGFR and KRAS mutations, which are mutually exclusive. Other than EGFR mutations (p<0.0001), no other biomarkers were significantly predictive of outcomes in a treatment-by-biomarker interaction test, although ERCC1 IHC-positive status was predictive of improved OS for the erlotinib arm versus placebo in EGFR wild-type patients (median 18.4 vs 9.5 months; hazard ratio [HR] HR=0.32, 95% confidence intervals [CI]: 0.14–0.69, p=0.0024).ConclusionActivating EGFR mutations were predictive for improved treatment outcomes with a first-line intercalated regimen of chemotherapy and erlotinib in NSCLC. ERCC1 status may have some predictive value in EGFR wild-type disease, but requires further investigation

Health-Related Quality-of-Life in a Randomized Phase Iii First-Line Study of Gefitinib Versus Carboplatin/Paclitaxel in Clinically Selected Patients from Asia with Advanced Nsclc (Ipass)

Introduction: Evaluation of health-related quality-of-life ( HRQoL) and symptom improvement were preplanned secondary objectives for the overall population and posthoc analyses for epidermal growth factor receptor (EGFR ) mutation- positive/negative subgroups in IPASS. Methods: HRQoL was assessed using the Functional Assessment of Cancer Therapy- Lung (FACT-L) and Trial Outcome Index (TOI); symptom improvement by the Lung Cancer Subscale (LCS). Improvements defined as: 6 or more (FACT-L; TOI), 2 or more (LCS) points increase maintained for 21 or more days. Results: Overall (n = 1151/1217 evaluable), HRQoL improvement rates were significantly greater with gefitinib versus carboplatin/ paclitaxel; symptom improvement rates were similar for both treatments. Significantly more patients recorded improvements in HRQoL and symptoms with gefitinib in the EGFR mutation-positive subgroup (n = 259; FACT-L 70.2% versus 44.5% ; odds ratio, 3.01 [95% confidence interval, 1. 79-5.07]; p < 0.001; TOI 70.2% versus 38.3%; 3.96 [2.33-6.71 ]; p < 0.001; LCS 75.6% versus 53.9%; 2.70 [1.58-4.62]; p < 0.001), and with carboplatin/paclitaxel in the EGFR mutation -negative subgroup (n = 169; FACT-L 14.6% versus 36.3%; odds ratio, 0.31 [0.15-0.65]; p = 0.002; TOI 12.4% versus 28.8%; 0.35 [0.16-0. 79]; p = 0.011; LCS 20.2% versus 47.5%; 0.28 [ 0.14-0.55]; p < 0.001). Median time-to-worsening (months) FACT-L score was longer with gefitinib versus carboplatin/ paclitaxel for the overall population (8.3 versus 2.5) and EGFR mutation-positive subgroup (15.6 versus 3.0), and similar for both treatments in the EGFR mutation-negative subgroup (1.4 versus 1.4). Median time-to-improvement with gefitinib was 8 days in patients with EGFR mutation-positive tumors who improved. Conclusions: HRQoL and symptom endpoints were consistent with efficacy outcomes in IPASS and favored gefitinib in patients with EGFR mutation- positive tumors and carboplatin/ paclitaxel in patients with EGFR mutation-negative tumors