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Dive into the research topics where Kentaro Okuda is active.

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Featured researches published by Kentaro Okuda.


Oncology Research | 2012

Relationship of circulating tumor cells to the effectiveness of cytotoxic chemotherapy in patients with metastatic non-small-cell lung cancer.

Takashi Hirose; Yasunori Murata; Yasunari Oki; Tomohide Sugiyama; Sojiro Kusumoto; Hiroo Ishida; Takao Shirai; Masano Nakashima; Toshimitsu Yamaoka; Kentaro Okuda; Tsukasa Ohnishi; Tohru Ohmori

The aim of this study was to investigate the relationship of the number of circulating tumor cells (CTCs) with the effectiveness of cytotoxic chemotherapy in patients with metastatic non-small-cell lung cancer (NSCLC). We prospectively evaluated CTCs in the peripheral blood of patients with previously untreated metastatic NSCLC. From May 2008 through August 2010, 33 patients (23 men and 10 women; median age, 64 years; range, 46-74 years) were enrolled. All patients received combination chemotherapy with gemcitabine and carboplatin. The CTCs were captured from samples of peripheral blood with a semiautomated system using an antibody against epithelial cell adhesion molecule. Blood samples with one or more CTC per 7.5 ml were defined as positive. Of total 33 patients, 12 (36.4%) had positive CTCs and 5 (15.2%) had five or more CTCs before chemotherapy. There were no differences in response rates to cytotoxic chemotherapy between CTC-positive patients and CTC-negative patients. On the other hand, the rate of progressive disease in cytotoxic chemotherapy was significantly higher in CTC-positive patients (66.7%) than in CTC-negative patients (23.8%, p = 0.02). In conclusion, the number of CTCs could be a useful predictive factor for the effectiveness of cytotoxic chemotherapy in patients with metastatic NSCLC.


Clinical Cancer Research | 2005

Enhancement of sensitivity to tumor necrosis factor α in non-small cell lung cancer cells with acquired resistance to gefitinib

Koichi Ando; Tohru Ohmori; Fumiko Inoue; Tsuyoki Kadofuku; Takamichi Hosaka; Hiroo Ishida; Takao Shirai; Kentaro Okuda; Takashi Hirose; Naoya Horichi; Kazuto Nishio; Nagahiro Saijo; Mitsuru Adachi; Toshio Kuroki

Tumor cells that have acquired resistance to gefitinib through continuous drug administration may complicate future treatment. To investigate the mechanisms of acquired resistance, we established PC-9/ZD2001, a non-small-cell lung cancer cell line resistant to gefitinib, by continuous exposure of the parental cell line PC-9 to gefitinib. After 6 months of culture in gefitinib-free conditions, PC-9/ZD2001 cells reacquired sensitivity to gefitinib and were established as a revertant cell line, PC-9/ZD2001R. PC-9/ZD2001 cells showed collateral sensitivity to several anticancer drugs (vinorelbine, paclitaxel, camptothecin, and 5-fluorouracil) and to tumor necrosis factor α (TNF-α). Compared with PC-9 cells, PC-9/ZD2001 cells were 67-fold more sensitive to TNF-α and PC-9/ZD2001R cells were 1.3-fold more sensitive. Therefore, collateral sensitivity to TNF-α was correlated with gefitinib resistance. PC-9/ZD2001 cells expressed a lower level of epidermal growth factor receptor (EGFR) than did PC-9 cells; this down-regulation was partially reversed in PC-9/ZD2001R cells. TNF-α-induced autophosphorylation of EGFR (cross-talk signaling) was detected in all three cell lines. However, TNF-α-induced Akt phosphorylation and IκB degradation were observed much less often in PC-9/ZD2001 cells than in PC-9 cells or PC-9/ZD2001R cells. Expression of the inhibitor of apoptosis proteins c-IAP1 and c-IAP2 was induced by TNF-α in PC-9 and PC-9/ZD2001R cells but not in PC-9/ZD2001 cells. This weak effect of EGFR on Akt pathway might contribute to the TNF-α sensitivity of PC-9/ZD2001 cells. These results suggest that therapy with TNF-α would be effective in some cases of non-small-cell lung cancer that have acquired resistance to gefitinib.


Lung Cancer | 2011

Are levels of pro-gastrin-releasing peptide or neuron-specific enolase at relapse prognostic factors after relapse in patients with small-cell lung cancer?

Takashi Hirose; Kentaro Okuda; Toshimitsu Yamaoka; Koko Ishida; Sojiro Kusumoto; Tomohide Sugiyama; Takao Shirai; Tsukasa Ohnshi; Tohru Ohmori; Mitsuru Adachi

The purposes of this study were to assess the relationship of serum levels of pro-gastrin-releasing protein (ProGRP) and neuron-specific enolase (NSE) at relapse with survival after relapse and the response to salvage therapy and to assess whether serum levels of ProGRP and NSE at relapse are useful markers for detecting relapse earlier than are symptoms or radiographic findings in patients with small-cell lung cancer (SCLC). The subjects of this study were 103 patients with SCLC who had achieved a complete response (CR) or partial response (PR) to first-line chemotherapy. We retrospectively evaluated whether ProGRP or NSE increased earlier than symptoms or radiographic findings appeared, and the association between response to salvage therapy and levels of ProGRP or NSE at relapse. In addition, we evaluated the association between survival after relapse and clinical and demographic factors at relapse, including age, sex, response to first-line treatment, sensitivity to first-line treatment, stage, performance status (PS), and serum levels of ProGRP, NSE, and lactate dehydrogenase. At relapse, 69.3% of patients had elevated serum levels of ProGRP, 60.2% had elevated serum levels of NSE, and 81.3% had elevated serum levels of either ProGRP or NSE. However, almost all asymptomatic relapses were detected with radiographic studies. The rate of CR to salvage chemotherapy was significantly lower in patients with elevated levels of NSE (2.2%) than in patients without (26.7%; p=0.001). Univariate analysis showed that sensitivity to first-line treatment, serum levels of NSE, stage, and PS at relapse were prognostic factors for survival after relapse. Multivariate analysis showed that sensitivity to first-line treatment, serum levels of NSE, and PS at relapse were independent prognostic factors after relapse. In conclusion, serum levels of ProGRP and NSE at relapse are not useful markers for detecting relapse earlier than are symptoms or radiographic findings. On the other hand, the serum level of NSE at relapse is a useful predictive marker for CR to salvage chemotherapy and a useful prognostic factor after relapse in patients with SCLC who have achieved a CR or PR to first-line chemotherapy.


Respirology | 2008

Patient satisfaction with sedation for flexible bronchoscopy

Takashi Hirose; Kentaro Okuda; Hiroo Ishida; Tomohide Sugiyama; Sojiro Kusumoto; Masanao Nakashima; Toshimitsu Yamaoka; Mitsuru Adachi

Background and objective:  Patient satisfaction with health care has increasingly been recognized as an important health outcome, but few studies have examined patient satisfaction with flexible bronchoscopy (FB). The purpose of this study was to assess patient satisfaction with FB conducted under conscious sedation and to identify the aspects of the procedure related to patient satisfaction.


Psycho-oncology | 2009

Patient willingness to undergo chemotherapy and thoracic radiotherapy for locally advanced non-small cell lung cancer

Takashi Hirose; Toshimitsu Yamaoka; Tsukasa Ohnishi; Tomohide Sugiyama; Sojiro Kusumoto; Takao Shirai; Kentaro Okuda; Tohru Ohmori; Mitsuru Adachi

Objectives: To determine how Japanese patients with lung cancer weigh the chance of cure and potential survival against the potential toxicity of different treatment strategies for locally advanced non‐small cell lung cancer (NSCLC).


Oncology Research | 2009

The UGT1A1*28 genotype and the toxicity of low-dose irinotecan in patients with advanced lung cancer.

Tomohide Sugiyama; Takashi Hirose; Sojiro Kusumoto; Takao Shirai; Toshimitsu Yamaoka; Kentaro Okuda; Tsukasa Ohnishi; Tohru Ohmori; Mitsuru Adachi

The association between the UGT1A1*28 genotype and the severe toxicity of low-dose irinotecan has been controversial, and few studies have examined this association in patients with lung cancer. The aim of this study was to assess the association between the UGT1A1*28 genotype and the severe toxicity of low-dose irinotecan in Japanese patients with lung cancer. From December 2005 through July 2008, 53 Japanese patients with advanced lung cancer who underwent chemotherapy that included low-dose irinotecan (50 or 60 mg/m2) as a single agent or in combination chemotherapy were retrospectively analyzed. Genomic DNA was extracted from peripheral blood. Genotypes for the UGT1A1*28 were denoted as wild-type for 6/6, heterozygous for 6/7, or homozygous for 7/7 depending on the number of TA repeats found in each allele. Of the 53 patients, 42 (79.2%) were wild-type, 9 (17.0%) were heterozygous, and 2 (3.7%) were homozygous for the UGT1A1*28 genotype. The UGT1A1*28 genotype was not associated with grade 3 or 4 neutropenia, thrombocytopia, diarrhea, or febrile neutropenia. The frequency of dose reduction of irinotecan did not differ between wild-type and heterozygous or homozygous for the UGT1A1*28 genotype. In addition, there were no significant differences in response rates and survival between wild-type and heterozygous or homozygous for the UGT1A1*28 genotype. In conclusion, the UGT1A1*28 genotype did not predict the severe toxicity of low-dose irinotecan in patients with lung cancer. Therefore, low-dose irinotecan could be administered without reducing starting dose in patients with UGT1A1*28 genotype.


European Journal of Cancer | 2011

Phase II trial of the combination of carboplatin and irinotecan in elderly patients with small-cell lung cancer

Yasunori Murata; Takashi Hirose; Toshimitsu Yamaoka; Takao Shirai; Kentaro Okuda; Tomohide Sugiyama; Sojiro Kusumoto; Masanao Nakashima; Tohru Ohmori; Mitsuru Adachi

AIM The aim of the present phase II study was to assess the antitumour activity and safety of the combination of irinotecan and carboplatin in elderly patients with small-cell lung cancer (SCLC). MATERIAL AND METHODS Patients with previously untreated SCLC were eligible if they had a performance status of 0-2, were 70 years or older, and had adequate organ function. Patients were treated with carboplatin at an area under the plasma concentration versus time curve of 5 min/ml on day 1 and with irinotecan at 50mg/m(2) on days 1 and 8 every 3 weeks. RESULTS Thirty patients (26 men and 4 women; median age, 76 years; age range, 70-86 years) were enrolled. Eight patients had limited disease (LD) and 22 patients had extensive disease (ED). The overall response rate was 83.3% (95% confidence interval: 65.3-94.4%). Response rates did not differ significantly between patients with LD (87.5%) and those with ED (81.8%; p=0.71). The median survival time was 14 months overall and was significantly longer in patients with LD (26 months) than in patients with ED (11 months; p=0.025). The median progression free survival time was 6 months overall and was significantly longer in patients with LD (12 months) than in patients with ED (6 months; p=0.016). Grade 3-4 toxicities included neutropenia in 83% of patients, thrombocytopenia in 47%, anaemia in 60%, infection in 23%, and diarrhoea in 20%. There were no treatment-related deaths. CONCLUSIONS This chemotherapy is safe and effective for elderly patients with SCLC.


Lung Cancer | 2011

Phase II trial of amrubicin and carboplatin in patients with sensitive or refractory relapsed small-cell lung cancer.

Takashi Hirose; Masanao Nakashima; Takao Shirai; Sojiro Kusumoto; Tomohide Sugiyama; Toshimitsu Yamaoka; Kentaro Okuda; Tsukasa Ohnishi; Tohru Ohmori; Mitsuru Adachi

Amrubicin is a novel, totally synthesized anthracycline derivative, and has antitumor activity against several human tumor xenografts. The combination of amrubicin with platinum derivative showed additive effect against a human small-cell lung cancer (SCLC) cell line. Until now, the combination of amrubicin plus carboplatin has not been studied in patients with previously treated SCLC. Therefore, we examined the safety and efficacy of the combination of amrubicin plus carboplatin in patients with sensitive or refractory relapsed SCLC. Patients with previously treated SCLC were eligible if they had a performance status of 2 or less, were 75 years or younger, and had adequate organ function. Twenty-five patients were enrolled (21 men and 4 women; median age, 65 years; age range 55-73 years). Patients received the combination of amrubicin (30 mg/m(2) on days 1-3) plus carboplatin (with a target area under the concentration-versus-time curve of 4 mg min/ml using the Calvert formula on day 1) every 3 weeks. The overall response rate was 36.0% (95% confidence interval [CI], 18.0-57.5%). Response rates differed significantly between patients with sensitive relapse (58.3%; 95% CI, 27.7-84.8%) and those with refractory relapse (15.4%; 95% CI, 1.9-15.4%; p=0.03). The median survival time (MST) from the start of this treatment was 7 months (range: 1-42 months); the MST of patients with sensitive relapse (10 months) was significantly longer than that of patients with refractory relapse (5 months: p=0.004). The median progression-free survival (PFS) time was 3 months (range: 1-14 months): the median PFS time of patients with sensitive relapse (5 months) was significantly longer than that of patients with refractory relapse (2 months; p=0.01). The most frequent grade 3-4 toxicity was myelosuppression, especially neutropenia, which developed in 88% of patients. Grade 3-4 thrombocytopenia developed in 44% of patients, and anemia developed in 56%. Nonhematologic toxicities were generally mild to moderately severe and temporary. None of the patients had cardiotoxicity. In conclusion, this therapy is effective and well tolerated for previously treated SCLC.


Lung Cancer | 2016

Association of pharmacokinetics and pharmacogenomics with safety and efficacy of gefitinib in patients with EGFR mutation positive advanced non-small cell lung cancer.

Takashi Hirose; Ken-ichi Fujita; Sojiro Kusumoto; Yasunari Oki; Yasunori Murata; Tomohide Sugiyama; Hiroo Ishida; Takao Shirai; Masanao Nakashima; Toshimitsu Yamaoka; Kentaro Okuda; Tohru Ohmori; Yasutsuna Sasaki

OBJECTIVES Gefitinib is a potent epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor and is a key drug for patients with EGFR mutation-positive advanced non-small cell lung cancer (NSCLC). The pharmacokinetics of orally administered gefitinib varies greatly among patients. We prospectively evaluated the association of pharmacokinetics and pharmacogenomics with the safety and efficacy of gefitinib in patients with EGFR mutation-positive advanced NSCLC. PATIENTS AND METHODS Pharmacokinetics was evaluated with samples of peripheral blood obtained on day 1 before treatment and 1, 3, 5, 8, and 24h after gefitinib (250 mg per day) was administered and on days 8 and 15 as the trough values. The plasma concentration of gefitinib was analyzed with high-performance liquid chromatography. The genotypes of ABCG2, ABCB1, CYP3A4, CYP3A5, and CYP2D6 genes were analyzed with direct sequencing. RESULTS The subjects were 35 patients (21 women; median age, 72 years; range, 53 to 90 years) with stage IV adenocarcinoma harboring EGFR mutations. The median peak plasma concentration (Cmax) was 377 (range, 168-781)ng/mL. The median area under the curve (AUC) of the plasma concentration of gefitinib from 0 to 24h was 4893 (range, 698-13991) ng/mL h. The common adverse events were skin toxicity (68% of patients), diarrhea (46%), and liver injury (63%). One patient died of drug-induced interstitial lung disease (ILD). The overall response rate was 82.9% (95% confidence interval, 66.4%-93.4%). The median progression-free survival time was 10 months, and the median survival time was 25 months. The pharmacokinetics and pharmacogenomics were not associated with significantly different toxicities, response rates, or survival times with gefitinib. However, the AUC and Cmax were highest and the trough value on day 8 was the second highest in one patient who died of drug-induced ILD. CONCLUSION Elevated gefitinib exposure might be associated with drug-induced ILD.


Oncology | 2011

Evaluation of the Efficacy and Safety of the Combination of Gemcitabine and Nedaplatin for Elderly Patients with Advanced Non-Small-Cell Lung Cancer

Tomohide Sugiyama; Takashi Hirose; Masanao Nakashima; Koko Ishida; Yasunari Oki; Yasunori Murata; Sojiro Kusumoto; Takao Shirai; Toshimitsu Yamaoka; Kentaro Okuda; Tsukasa Ohnishi; Tohru Ohmori; Mitsuru Adachi

Objective: The aim of the present study was to retrospectively assess the safety and efficacy of the combination of gemcitabine and nedaplatin in elderly patients with advanced non-small-cell lung cancer (NSCLC). Methods: Patients ≧75 years with previously untreated NSCLC who underwent chemotherapy consisting of gemcitabine (800 mg/m2 on days 1 and 8) and nedaplatin (80 mg/m2 on day 1) every 3 weeks were retrospectively analyzed. Results: Of the 35 patients, 28 were men and 7 were women, with a mean age of 78 years (range 75–87); 10 patients had stage IIIB disease and 25 patients had stage IV disease. The overall response rate was 45.7% (95% confidence interval 28.8–63.4). The median survival time was 14 months (range 3–44). Grade 3–4 toxicities included neutropenia in 74.3%, thrombocytopenia in 48.6%, anemia in 34.3%, hepatic dysfunction in 11.4%, and infection in 2.9%. There were no treatment-related deaths. There were no differences in response rate and survival between patients aged 75–79 years and patients ≧80 years, although grade 3–4 thrombocytopenia and anemia were significantly more frequent in patients ≧80 years. Conclusion: Our results suggest that the combination of gemcitabine and nedaplatin is effective and well tolerated for selected elderly patients with advanced NSCLC.

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Mitsuru Adachi

International University of Health and Welfare

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