Chih-Hsin Yang

Gefitinib or Carboplatin–Paclitaxel in Pulmonary Adenocarcinoma

BACKGROUND Previous, uncontrolled studies have suggested that first-line treatment with gefitinib would be efficacious in selected patients with non-small-cell lung cancer. METHODS In this phase 3, open-label study, we randomly assigned previously untreated patients in East Asia who had advanced pulmonary adenocarcinoma and who were nonsmokers or former light smokers to receive gefitinib (250 mg per day) (609 patients) or carboplatin (at a dose calculated to produce an area under the curve of 5 or 6 mg per milliliter per minute) plus paclitaxel (200 mg per square meter of body-surface area) (608 patients). The primary end point was progression-free survival. RESULTS The 12-month rates of progression-free survival were 24.9% with gefitinib and 6.7% with carboplatin-paclitaxel. The study met its primary objective of showing the noninferiority of gefitinib and also showed its superiority, as compared with carboplatin-paclitaxel, with respect to progression-free survival in the intention-to-treat population (hazard ratio for progression or death, 0.74; 95% confidence interval [CI], 0.65 to 0.85; P<0.001). In the subgroup of 261 patients who were positive for the epidermal growth factor receptor gene (EGFR) mutation, progression-free survival was significantly longer among those who received gefitinib than among those who received carboplatin-paclitaxel (hazard ratio for progression or death, 0.48; 95% CI, 0.36 to 0.64; P<0.001), whereas in the subgroup of 176 patients who were negative for the mutation, progression-free survival was significantly longer among those who received carboplatin-paclitaxel (hazard ratio for progression or death with gefitinib, 2.85; 95% CI, 2.05 to 3.98; P<0.001). The most common adverse events were rash or acne (in 66.2% of patients) and diarrhea (46.6%) in the gefitinib group and neurotoxic effects (69.9%), neutropenia (67.1%), and alopecia (58.4%) in the carboplatin-paclitaxel group. CONCLUSIONS Gefitinib is superior to carboplatin-paclitaxel as an initial treatment for pulmonary adenocarcinoma among nonsmokers or former light smokers in East Asia. The presence in the tumor of a mutation of the EGFR gene is a strong predictor of a better outcome with gefitinib. (ClinicalTrials.gov number, NCT00322452.)

MET amplification occurs with or without T790M mutations in EGFR mutant lung tumors with acquired resistance to gefitinib or erlotinib

In human lung adenocarcinomas harboring EGFR mutations, a second-site point mutation that substitutes methionine for threonine at position 790 (T790M) is associated with approximately half of cases of acquired resistance to the EGFR kinase inhibitors, gefitinib and erlotinib. To identify other potential mechanisms that contribute to disease progression, we used array-based comparative genomic hybridization (aCGH) to compare genomic profiles of EGFR mutant tumors from untreated patients with those from patients with acquired resistance. Among three loci demonstrating recurrent copy number alterations (CNAs) specific to the acquired resistance set, one contained the MET proto-oncogene. Collectively, analysis of tumor samples from multiple independent patient cohorts revealed that MET was amplified in tumors from 9 of 43 (21%) patients with acquired resistance but in only two tumors from 62 untreated patients (3%) (P = 0.007, Fishers Exact test). Among 10 resistant tumors from the nine patients with MET amplification, 4 also harbored the EGFRT790M mutation. We also found that an existing EGFR mutant lung adenocarcinoma cell line, NCI-H820, harbors MET amplification in addition to a drug-sensitive EGFR mutation and the T790M change. Growth inhibition studies demonstrate that these cells are resistant to both erlotinib and an irreversible EGFR inhibitor (CL-387,785) but sensitive to a multikinase inhibitor (XL880) with potent activity against MET. Taken together, these data suggest that MET amplification occurs independently of EGFRT790M mutations and that MET may be a clinically relevant therapeutic target for some patients with acquired resistance to gefitinib or erlotinib.

Vandetanib Plus Pemetrexed for the Second-Line Treatment of Advanced Non–Small-Cell Lung Cancer: A Randomized, Double-Blind Phase III Trial

PURPOSE Vandetanib is a once-daily oral inhibitor of vascular endothelial growth factor receptor and epidermal growth factor receptor signaling. This randomized, placebo-controlled phase III study assessed the efficacy of vandetanib plus pemetrexed as second-line therapy in advanced non-small-cell lung cancer. PATIENTS AND METHODS Patients (N = 534) were randomly assigned to receive vandetanib 100 mg/d plus pemetrexed 500 mg/m(2) every 21 days (n = 256) or placebo plus pemetrexed (n = 278). Progression-free survival (PFS) was the primary end point; overall survival, objective response rate, disease control rate, time to deterioration of symptoms, and safety were secondary assessments. RESULTS There was no significant difference in PFS between treatment arms (hazard ratio [HR], 0.86; 97.58% CI, 0.69 to 1.06; P = .108). Overall survival was also not significantly different (HR, 0.86; 97.54% CI, 0.65 to 1.13; P = .219). Statistically significant improvements in objective response rate (19% v 8%; P < .001) and time to deterioration of symptoms (HR, 0.71; P = .0052; median, 18.1 weeks for vandetanib and 12.1 weeks for placebo) were observed in patients receiving vandetanib. Adding vandetanib to pemetrexed increased the incidence of some adverse events, including rash, diarrhea, and hypertension, while showing a reduced incidence of nausea, vomiting, anemia, fatigue, and asthenia with no reduction in the dose intensity of pemetrexed. CONCLUSION This study did not meet the primary end point of statistically significant PFS prolongation with vandetanib plus pemetrexed versus placebo plus pemetrexed. The vandetanib combination showed a significantly higher objective response rate and a significant delay in the time to worsening of lung cancer symptoms versus the placebo arm as well as an acceptable safety profile in this patient population.

Specific EGFR Mutations Predict Treatment Outcome of Stage IIIB/IV Patients With Chemotherapy-Naive Non–Small-Cell Lung Cancer Receiving First-Line Gefitinib Monotherapy

PURPOSE To explore predictive factors for time to treatment failure (TTF) in chemotherapy-naive non-small-cell lung cancer (NSCLC) patients receiving gefitinib treatment. PATIENTS AND METHODS We designed a phase II study to test gefitinib antitumor efficacy in advanced-stage, chemotherapy-naive NSCLC patients. Patients were treated with gefitinib 250 mg/d. Tumor assessments were performed every 2 months. Responding or stable patients were treated until progression or unacceptable toxicity. All scans were reviewed independently. EGFR exons 18-21 sequence, K-ras exon 2 sequence, and MET gene copy numbers were examined in available samples. Clinical or molecular predictors of TTF were examined by multivariate analysis. RESULTS One hundred six patients were enrolled. Ninety patients had tumor samples for biomarker tests. Overall response rate was 50.9% (95% CI, 41.4% to 60.4%). Median TTF was 5.5 months, and median overall survival (OS) was 22.4 months. The response rate and median TTF of the patients with exon 19 deletion (n = 20) were 95.0% and 8.9 months, for exon 21 L858R mutation (n = 23) were 73.9% and 9.1 month, and for other types of EGFR mutations (N = 12) were 16.7% and 2.3 months, respectively. In multivariate analysis, the presence of EGFR deletion exon 19 or L858R EGFR mutations in adenocarcinoma patients predicted longer TTF. High copy number of MET seemed to correlate with shorter TTF in patients with gefitinib-sensitive activating EGFR mutations. CONCLUSION In this prospective study, EGFR exon 19 deletion or L858R mutations in adenocarcinoma were the best predictors for longer TTF in stage IIIB/IV chemotherapy-naive NSCLC patients receiving first-line gefitinib monotherapy.

Lung Cancer with Epidermal Growth Factor Receptor Exon 20 Mutations Is Associated with Poor Gefitinib Treatment Response

Purpose: Clinical reports about responsiveness to gefitinib treatment in patients of non-small cell lung cancer (NSCLC) with mutations in exon 20 of epidermal growth factor receptor (EGFR) are limited. To increase understanding of the influence of exon 20 mutations on NSCLC treatment with gefitinib, we investigated the clinical features of lung cancer in patients with exon 20 mutations and analyzed the gefitinib treatment response. Experimental Design: We surveyed the clinical data and mutational studies of NSCLC patients with EGFR exon 20 mutations in the National Taiwan University Hospital and reviewed the literature reports about EGFR exon 20 mutations and the gefitinib treatment response. Results: Twenty-three patients with mutations in exon 20 were identified. Nine (39%) had coexisting mutations in EGFR exons other than exon 20. Sixteen patients received gefitinib treatment, and a response was noted in 4 patients. The gefitinib response rate of NSCLC with exon 20 mutations was 25%, far lower than those with deletions in exon 19 and L858R mutations. Interestingly, different exon 20 mutations and coexisting mutations seemed to have a different influence on gefitinib response. Conclusions: EGFR exon 20 mutations of NSCLC patients result in poorer responsiveness to gefitinib treatment, but variability exists between different individuals.

Effectiveness of Tyrosine Kinase Inhibitors on “Uncommon” Epidermal Growth Factor Receptor Mutations of Unknown Clinical Significance in Non–Small Cell Lung Cancer

Purpose: Clinical features of epidermal growth factor receptor (EGFR) mutations, L858R, deletions in exon 19, T790M, and insertions in exon 20, in non–small cell lung cancer (NSCLC) are well known. The clinical significance of other uncommon EGFR mutations, such as their association with the effectiveness of EGFR tyrosine kinase inhibitors (TKI), is not well understood. This study aimed to improve the understanding of these uncommon EGFR mutations of unknown clinical significance. Patients and Methods: Specimens from 1,261 patients were tested for EGFR mutations. We surveyed the clinical data and the effectiveness of gefitinib and erlotinib in NSCLC patients with uncommon EGFR mutations. Results: Of the 1,261 patients, 627 (49.8%) had EGFR mutations. This included 258 patients with deletions in exon 19, 260 patients with L858R, 25 patients with insertions or duplications in exon 20, 6 patients with de novo T790M, and 78 (12.4%) patients with uncommon mutations. Of the 78 patients, 62 received either gefitinib or erlotinib treatment. The response rate of TKIs treatment was 48.4%, and the median progression-free survival (PFS) was 5.0 months. Mutations on G719 and L861 composed a major part (28 of 62) of uncommon mutations, and were associated with a favorable effectiveness of EGFR TKIs (response rate, 57.1%; median PFS, 6.0 months). Mutations other than G719 and L861 led to a worse response to EGFR TKIs (response rate, 20.0%; median PFS, 1.6 months). Conclusions: Uncommon EGFR mutations constituted a distinct part of the whole group of EGFR mutations. Their composition was heterogeneous, and their associations with EGFR TKIs differed. Clin Cancer Res; 17(11); 3812–21. ©2011 AACR.

Gefitinib (IRESSA) in Patients of Asian Origin with Refractory Advanced Non-small Cell Lung Cancer: Subset Analysis from the ISEL Study

Introduction: The IRESSA Survival Evaluation in Lung Cancer (ISEL) phase III study compared the efficacy of gefitinib (IRESSA) versus placebo in patients with refractory advanced non-small cell lung cancer (NSCLC). Although a statistically significant difference in survival was not seen between gefitinib and placebo in the overall ISEL population, preplanned subset analyses demonstrated a significant survival benefit in patients who had never smoked and in patients of Asian origin. Methods: In ISEL, 1692 patients who were refractory to or intolerant of their latest chemotherapy were randomized to receive either gefitinib (250 mg/day) or placebo, plus best supportive care. Preplanned subgroup analyses included an assessment of patients who were of Asian origin (n = 342). Results: Two hundred thirty-five patients of Asian origin received gefitinib, and 107 received placebo. In these patients, treatment with gefitinib significantly improved survival compared with placebo (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.48, 0.91; p = 0.010; median survival, 9.5 versus 5.5 months). Patients of Asian origin also experienced statistically significant improvements in time to treatment failure with gefitinib compared with placebo (HR, 0.69; 95% CI, 0.52, 0.91; p = 0.0084; 4.4 versus 2.2 months), and objective response rates were higher with gefitinib than with placebo (12 versus 2%). Gefitinib was generally well tolerated in patients of Asian origin, with rash and diarrhea being the most common adverse events. No unexpected adverse events were observed. Conclusions: Treatment with gefitinib was associated with a significant improvement in survival in a subgroup of patients of Asian origin with previously treated refractory advanced NSCLC.

Comparison of epidermal growth factor receptor mutations between primary and corresponding metastatic tumors in tyrosine kinase inhibitor-naive non-small-cell lung cancer

BACKGROUND Mutations of the epidermal growth factor receptor (EGFR) gene in non-small-cell lung cancer (NSCLC) patients predict the patients who will respond to EGFR tyrosine kinase inhibitor (TKI) treatment. A recent study has suggested that 33% of NSCLC showed primary tumor/metastasis discordance of EGFR expression by immunohistochemistry analysis. We intended to find out whether the EGFR mutations of primary lung cancers are concordant to that of corresponding metastatic tumors. MATERIALS AND METHODS We analyzed EGFR exons 18-21 from paired primary and metastatic tumors in 67 lung cancer patients who had not received TKI before tissues were sampled. RESULTS Using the direct sequencing method, 9 of 18 (50%) patients with EGFR mutation-positive primary lung tumors had lost the mutations in metastases. For 26 patients who were EGFR mutation positive in the metastatic tumors, 17 (65%) were negative in the primary tumors. We analyzed these paired tissues with discrepant EGFR mutations by the Scorpion Amplified Refractory Mutation System assay. Finally, the discordant rate reached 27% (18 of 67 cases). CONCLUSION EGFR mutations in primary lung tumors do not always reflect the same situation in metastases. Analysis of EGFR mutations in the primary lung tumor would be inadequate for planning the use of TKI for advanced NSCLC.

Radiotherapy in Lung Adenocarcinoma with Brain Metastases: Effects of Activating Epidermal Growth Factor Receptor Mutations on Clinical Response

Purpose: Whole-brain radiation therapy (WBRT) has been applied to inoperable brain metastases in lung adenocarcinoma. Recently, an in vitro study showed reduced clonogenic survival of mutant epidermal growth factor receptor (EGFR) lung cancer cell lines in response to ionizing radiation compared with that of the wild type. To elucidate the role of EGFR mutations in radiation treatment, we evaluated the clinical response to WBRT and survival of lung adenocarcinoma patients with brain metastases. Experimental Design: This was a retrospective analysis of 63 patients with brain metastases from lung adenocarcinoma who were treated with WBRT. Demographic data, EGFR mutation status, response to WBRT, and survival data were collected. Clinical response was assessed 1 month after the start of WBRT. Univariate and logistic regression models were used to test potential predictive factors associated with clinical response. Log-rank test and Cox regression were analyzed to identify factors that affected survival. Results: Clinical response to WBRT was observed in 29 patients (46%), with 34 nonresponder patients (54%). Patients with EGFR mutations had higher response rates to WBRT compared with those with the wild-type (54% versus 24%; P = 0.045). Both the administration of EGFR tyrosine kinase inhibitor (P = 0.034) and EGFR mutation (P = 0.029) were independently associated with response to WBRT. In Cox regression analysis, WBRT responder (P = 0.010) and absence of extracranial metastases (P = 0.002) were associated with better survival. Conclusions: Both the EGFR mutations and the administration of EGFR TKI during WBRT were independent predictors of response to WBRT in brain metastases of lung adenocarcinoma.

BCRP/MXR/ABCP expression in topotecan-resistant human breast carcinoma cells

We have previously described a mitoxantrone-resistant MCF7 cell line that is cross-resistant to topotecan, 7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxy-camptothecin (CPT-11), and 9-aminocamptothecin, but not to camptothecin. A novel mechanism that resulted in decreased topotecan accumulation in MCF7/MX cells was proposed (Yang et al. Cancer Res 55: 4004-4009, 1995). We now have developed a topotecan-resistant cancer cell line from wild-type MCF7 cells. MCF7/TPT300 cells were 68.9-fold resistant to topotecan, 68.3-fold to 10-hydroxy-7-ethylcamptothecin (SN-38), and 116-fold to mitoxantrone, but only 4.1-fold to camptothecin. Topotecan efflux was increased in MCF7/TPT300 cells compared with MCF7/WT cells, and this increase was reversed upon ATP depletion by sodium azide, suggesting an energy-dependent drug efflux mechanism. However, MCF7/TPT300 cells did not overexpress P-glycoprotein or the multidrug resistance-associated protein (MRP1). In contrast, overexpression of the breast cancer resistance protein (BCRP/MXR/ABCP) was observed in MCF7/TPT300 cells as well as DNA topoisomerase I down-regulation. Our data suggest that enhanced topotecan efflux contributes partly to topotecan resistance in MCF7/TPT300 cells, possibly mediated by BCRP/MXR/ABCP.