Shigeki Umemura

A Phase II Trial of Erlotinib Monotherapy in Pretreated Patients with Advanced Non-small Cell Lung Cancer Who Do Not Possess Active EGFR Mutations: Okayama Lung Cancer Study Group Trial 0705

Backgrounds: Efficacy of gefitinib therapy strongly depends on epidermal growth factor receptor (EGFR)-mutation status in Asian patients with non-small cell lung cancer. Recently, the survival advantage of erlotinib, another tyrosine kinase inhibitor, was not affected by EGFR mutation status in a phase III trial, indicating that patients with EGFR-wild-type (EGFR-wt) tumors might also benefit from this tyrosine kinase inhibitor. The aim of this trial was to evaluate the efficacy and toxicity of erlotinib in Japanese patients with EGFR-wt tumors. Methods: The primary end point was an objective response. Patients with EGFR-wt tumors previously receiving one to three chemotherapy regimens were enrolled in this trial. The mutation status was assessed using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. Erlotinib was administered (150 mg/d) until disease progression or unacceptable toxicities occurred. Results: Thirty patients were enrolled between January and December 2008. Objective response was observed in one patient (3.3%), and the disease became stable in 18 patients (60.0%). Skin rash was the most common side effect. Grades 3–4 adverse events included pulmonary embolism, keratitis, and anemia. Two other patients developed interstitial lung disease (grades 1 and 2). Nevertheless, all these events were reversible, resulting in no treatment-related deaths. With a median follow-up time of 10.7 months, the median survival time and median progression-free survival times were 9.2 and 2.1 months, respectively. Conclusion: This is the first prospective biomarker study showing that erlotinib therapy for pretreated patients with EGFR-wt tumors seems to have a modest activity with no irreversible toxicity.

Therapeutic Priority of the PI3K/AKT/mTOR Pathway in Small Cell Lung Cancers as Revealed by a Comprehensive Genomic Analysis

Introduction: The information regarding therapeutically relevant genomic alterations in small cell lung cancer (SCLC) is not well developed. We analyzed the SCLC genome using an integrative approach to stratify the targetable alterations. Methods: We performed whole exon sequencing (n = 51) and copy number analysis (n =47) on surgically resected tumors and matched normal tissue samples from treatment-naive Japanese SCLC patients. Results: The demographics of the 51 patients included in this study were as follows: median age, 67 years (range, 42–86 years); female, 9 (18%); history of smoking, 50 (98%); and pathological stage I/II/III/IV, 28/13/9/1, respectively. The average number of nonsynonymous mutations was 209 (range, 41–639; standard deviation, 130). We repeatedly confirmed the high prevalence of inactivating mutations in TP53 and RB1, and the amplification of MYC family members. In addition, genetic alterations in the PI3K/AKT/mTOR pathway were detected in 36% of the tumors: PIK3CA, 6%; PTEN, 4%; AKT2, 9%; AKT3, 4%; RICTOR, 9%; and mTOR, 4%. Furthermore, the individual changes in this pathway were mutually exclusive. Importantly, the SCLC cells harboring active PIK3CA mutations were potentially targetable with currently available PI3K inhibitors. Conclusions: The PI3K/AKT/mTOR pathway is distinguishable in SCLC genomic alterations. Therefore, a sequencing-based comprehensive analysis could stratify SCLC patients by potential therapeutic targets.

Clinical outcome in patients with leptomeningeal metastasis from non-small cell lung cancer: Okayama Lung Cancer Study Group

OBJECTIVE We examined the prognosis of patients with leptomeningeal metastasis (LM) from non-small cell lung cancer (NSCLC) and that stratified by epidermal growth factor receptor (EGFR) mutation status in LM patients receiving EGFR-tyrosine kinase inhibitors (TKIs). METHODS We retrospectively analyzed a series of 91 consecutive NSCLC patients with LM between 2001 and 2010. RESULTS Most of the LM patients had adenocarcinoma histology and a poor performance status (PS). The median survival time (MST) for all patients was 3.6 months. Adenocarcinoma and TKI treatment were associated with a better prognosis. Among the patients, 51 received EGFR-TKIs. Of these, the EGFR mutation status was assessed in 30 patients; 7 (23%) showed no mutation (group 1), 10 (33%) had a mutation in exon 21 (group 2), and 13 (43%) had deletions in exon 19 (group 3). Interestingly, PS was significantly improved in groups 2 and 3 but not in group 1. The MST in these subgroups was 1.4, 7.1, and 11.0 months in groups 1, 2, and 3, respectively (p<0.001). The median time to progression or symptom deterioration was 0.9, 2.0, and 7.8 months for groups 1, 2, and 3, respectively (p<0.001). A multivariate analysis showed that EGFR-mutant tumors were associated with a better prognosis in patients receiving EGFR-TKIs. CONCLUSIONS The prognosis for patients with LM from NSCLC was still poor. Survival after the initiation of EGFR-TKI treatment differed according to the type of EGFR mutation, suggesting the potential benefit of TKIs for patients with EGFR mutations, even though they suffered from LM.

Comparison of the Incidence and Pattern of Interstitial Lung Disease During Erlotinib and Gefitinib Treatment in Japanese Patients with Non-small Cell Lung Cancer: The Okayama Lung Cancer Study Group Experience

Background: Data comparing the incidence and pattern of interstitial lung disease (ILD) in non-small cell lung cancer patients receiving treatment with gefitinib versus erlotinib, both of which are epidermal growth factor receptor tyrosine kinase inhibitors, are scarce. We investigated the incidence of ILD in Japanese patients treated with gefitinib or erlotinib. Methods: We reviewed the clinical records of 209 patients treated with erlotinib in 2008 (cohort A) and 330 treated with gefitinib between 2000 and 2003 (cohort B). Toxicity within the first month of treatment was investigated. Results: The patients in cohort A had fewer known risk factors for ILD (e.g., poor performance status and prior pulmonary fibrosis). ILD was detected in two patients (1.0%) from cohort A and eight patients (2.4%) from cohort B during the first month of treatment. The events were graded as follows: one patient each in grades 1 and 2 (cohort A), and one, one, and six patients in grades 3, 4, and 5, respectively (cohort B). Multivariate analysis revealed that poor performance status and prior pulmonary fibrosis were significantly correlated with the occurrence of ILD, but the type of epidermal growth factor receptor tyrosine kinase inhibitor administered was not. Conclusion: There was a somewhat lower incidence of ILD with erlotinib therapy than with gefitinib therapy, despite no statistically significant difference. Patient selection based on awareness by Japanese physicians of the risk factors for ILD, rather than the type of agent, may explain the difference in ILD incidence between the two treatments.

Signaling through the Phosphatidylinositol 3-Kinase (PI3K)/Mammalian Target of Rapamycin (mTOR) Axis Is Responsible for Aerobic Glycolysis mediated by Glucose Transporter in Epidermal Growth Factor Receptor (EGFR)-mutated Lung Adenocarcinoma

Background: EGFR signaling maintains aerobic glycolysis, but the molecular mechanism is still undefined. Results: Drug inhibition studies reveal that downstream signaling via the PI3K pathway is critical for glucose transport and metabolism. Conclusion: The PI3K signaling regulates key metabolic activities in EGFR-mutant lung adenocarcinoma. Significance: These data may guide the development of chemotherapeutic options, including targeting of the PI3K pathway and glucose transporter machinery. Oncogenic epidermal growth factor receptor (EGFR) signaling plays an important role in regulating global metabolic pathways, including aerobic glycolysis, the pentose phosphate pathway (PPP), and pyrimidine biosynthesis. However, the molecular mechanism by which EGFR signaling regulates cancer cell metabolism is still unclear. To elucidate how EGFR signaling is linked to metabolic activity, we investigated the involvement of the RAS/MEK/ERK and PI3K/AKT/mammalian target of rapamycin (mTOR) pathways on metabolic alteration in lung adenocarcinoma (LAD) cell lines with activating EGFR mutations. Although MEK inhibition did not alter lactate production and the extracellular acidification rate, PI3K/mTOR inhibitors significantly suppressed glycolysis in EGFR-mutant LAD cells. Moreover, a comprehensive metabolomics analysis revealed that the levels of glucose 6-phosphate and 6-phosphogluconate as early metabolites in glycolysis and PPP were decreased after inhibition of the PI3K/AKT/mTOR pathway, suggesting a link between PI3K signaling and the proper function of glucose transporters or hexokinases in glycolysis. Indeed, PI3K/mTOR inhibition effectively suppressed membrane localization of facilitative glucose transporter 1 (GLUT1), which, instead, accumulated in the cytoplasm. Finally, aerobic glycolysis and cell proliferation were down-regulated when GLUT1 gene expression was suppressed by RNAi. Taken together, these results suggest that PI3K/AKT/mTOR signaling is indispensable for the regulation of aerobic glycolysis in EGFR-mutated LAD cells.

Podoplanin-Positive Cancer-Associated Fibroblasts in the Tumor Microenvironment Induce Primary Resistance to EGFR-TKIs in Lung Adenocarcinoma with EGFR Mutation

Purpose: The biologic characteristics of microenvironmental constituents, especially cancer-associated fibroblasts (CAF), can be key regulators of the cellular sensitivity to molecular-targeted therapy. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) have marked therapeutic effects against non–small cell lung cancer (NSCLC) with EGFR mutations, but some patients have exhibited primary resistance to EGFR-TKIs. We recently reported that podoplanin-positive fibroblasts are associated with a tumor-promoting phenotype of CAFs in lung adenocarcinoma. The aim of this study was to evaluate whether the susceptibility of NSCLC to EGFR-TKIs could be affected by podoplanin-expressing CAFs. Experimental Design: We evaluated the EGFR-TKI sensitivity of EGFR-mutant lung adenocarcinoma cell lines cocultured with podoplanin-expressing CAFs. We also examined the association between the expression of podoplanin in CAFs in surgical specimens and EGFR-TKI response of postoperative recurrent patients with EGFR mutations (N = 106). Results: Lung adenocarcinoma cell lines became more resistant to EGFR-TKI when cocultured with podoplanin-expressing CAFs, compared with control CAFs in vitro. The knockdown of podoplanin expression on CAFs cancelled the resistance to EGFR-TKIs in cancer cells. Compared with control CAFs, the cancer cells that were cocultured with podoplanin-positive CAFs continued to exhibit significantly higher p-ERK levels after treatment with gefitinib. Furthermore, postoperative recurrent patients with podoplanin-positive CAFs had a significantly lower overall response rate to EGFR-TKIs compared with those with podoplanin-negative CAFs (53% vs. 83%; P < 0.01). Conclusions: Podoplanin-positive CAFs play an important role in primary resistance to EGFR-TKIs and may be an ideal therapeutic target for use in combination therapy with EGFR-TKIs. Clin Cancer Res; 21(3); 642–51. ©2014 AACR.

Aberrant DNA methylation profile in pleural fluid for differential diagnosis of malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) usually develops pleural fluid. We investigated the value of DNA methylation in the pleural fluid for differentiating MPM from lung cancer (LC). Pleural fluid was collected from 39 patients with MPM, 46 with LC, 25 with benign asbestos pleurisy (BAP) and 30 with other causes. The methylation of O6‐methylguanine‐DNA methyltransferase (MGMT), p16INK4a, ras association domain family 1A (RASSF1A), death‐associated protein kinase (DAPK), and retinoic acid receptor β (RARβ) was examined using quantitative real‐time PCR. DNA methylation of RASSF1A, p16INK4a, RARβ, MGMT and DAPK was detected in 12 (30.8%), 3 (7.7%), 11 (28.2%), 0 (0.0%) and five patients (12.8%) with MPM, and in 22 (47.8%), 14 (30.4%), 24 (52.2%), 1 (2.2%) and six patients (13.0%) with LC, respectively. The mean methylation ratios of RASSF1A, p16INK4a and RARβ were 0.37 (range 0.0–2.84), 0.11 (0.0–2.67) and 0.44 (0.0–3.32) in MPM, and 0.87 (0.0–3.14), 1.16 (0.0–5.35) and 1.69 (0.0–6.49) in LC, respectively. The methylation ratios for the three genes were significantly higher in LC than in MPM (RASSF1A, P = 0.039; p16INK4a, P = 0.005; and RARβ, P = 0.002). Patients with methylation in at least one gene were 3.51 (95% confidence interval, 1.09–11.34) times more likely to have LC. Hypermethylation seemed no greater with MPM than with BAP. Extended exposure to asbestos (≧30 years) was correlated with an increased methylation frequency (P = 0.020). Hypermethylation of tumor suppressor genes in pleural fluid DNA has the potential to be a valuable marker for differentiating MPM from LC. (Cancer Sci 2012; 103: 510–514)

Aberrant promoter hypermethylation in serum DNA from patients with silicosis

It is well established that patients with silicosis are at high risk for lung cancer; however, it is difficult to detect lung cancer by chest radiography during follow-up treatment of patients with silicosis because of preexisting diffuse pulmonary shadows. The purpose of this study is to evaluate the usefulness of detection of serum DNA methylation for early detection of lung cancer in silicosis. Serum samples from healthy controls (n = 20) and silicosis patients with (n = 11) and without (n = 67) lung cancer were tested for aberrant hypermethylation at the promoters of the DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT), p16(INK4a), ras association domain family 1A (RASSF1A), the apoptosis-related gene death-associated protein kinase (DAPK) and retinoic acid receptor beta (RARbeta) by methylation-specific polymerase chain reaction. Aberrant promoter methylation in at least one of five tumor suppressor genes was detected more frequently in the serum DNA of silicosis patients with lung cancer than in that of patients without it (P = 0.006). Furthermore, the odds ratio of having lung cancer was 9.77 (P = 0.009) for those silicosis patients with methylation of at least one gene. Extended exposure to silica (>30 years) was correlated with an increased methylation frequency (P = 0.017); however, methylation status did not correlate with age, smoking history or radiographic findings of silicosis. These results suggest that testing for aberrant promoter methylation of tumor suppressor genes using serum DNA may facilitate early detection of lung cancer in patients with silicosis.

Protective Effect of Magnesium Preloading on Cisplatin-Induced Nephrotoxicity: A Retrospective Study

OBJECTIVE Magnesium supplementation has been reported to have a nephroprotective effect on cisplatin-induced renal dysfunction, but little evidence exists regarding the effect of magnesium preloading before cisplatin administration. We started to include magnesium preloading (8 mEq) in cisplatin-containing treatment regimens in January 2011. The aim of the present study was to evaluate whether magnesium preloading reduces cisplatin-induced nephrotoxicity. METHODS We retrospectively reviewed 496 thoracic malignancy patients treated with cisplatin (≥60 mg/m²)-containing regimens as a first-time chemotherapy between January 2009 and December 2011. We compared the incidence of Grade ≥2 serum creatinine elevation according to the Common Terminology Criteria for Adverse Events, version 4.0, between magnesium preloading group (n = 161 [32%]) and non-magnesium preloading group (n = 335 [68%]) during the first cycle and all cycles. RESULTS The median number of administered cycles was four in both groups. The incidence of Grade ≥2 serum creatinine elevation in magnesium preloading group was significantly lower during both the first cycle and all cycles than in the non-magnesium preloading group (4.9 versus 19.1% during the first cycle, and 14.2 versus 39.7% during all the cycles). A multivariate analysis indicated that magnesium preloading significantly reduced cisplatin-induced nephrotoxicity throughout the entire period from after the first administration (odds ratio: 0.262, 95% confidence interval: 0.106-0.596 during the first cycle, and odds ratio: 0.234, 95% confidence interval: 0.129-0.414 during all cycles). CONCLUSIONS Magnesium preloading before cisplatin administration significantly reduced cisplatin-induced nephrotoxicity.

Safety and efficacy of gefitinib treatment in elderly patients with non-small-cell lung cancer: Okayama Lung Cancer Study Group Experience

We evaluated the safety and efficacy of gefitinib treatment in elderly patients with non-small-cell lung cancer (NSCLC). We retrospectively compared toxicity, response and survival outcomes for gefitinib in patients aged 75 years or older (elderly group) with the same outcomes in patients aged younger than 75 years. In total, 350 patients were eligible for this analysis, of whom 92 were in the elderly group and 258 in the non-elderly group. In the elderly group, adverse events were generally mild to moderate and grade 3–4 adverse events were observed in 8 (9%) patients. The objective response rate (17 vs. 21% for elderly vs. non-elderly, respectively) and median survival time (7.6 vs. 9.3 months) were also similar in the two groups. Multivariate analysis revealed elderly patients with lower Brinkman index tended to be more sensitive to gefitinib (odds ratio: 4.57, 95% confidence interval: 0.91–22.72, p = 0.0642). In this study, treatment with gefitinib appeared to be as safe and effective in elderly patients (aged 75 or older) with NSCLC as in non-elderly patients.