Hiroshi Takatani

The Multidrug Resistance‐associated Protein Gene Confers Drug Resistance in Human Gastric and Colon Cancers

To determine the expression of multidrug resistance‐associated protein (MRP) gene and its role in gastric and colon cancers, we analyzed 10 gastric and 10 colon non‐drug‐selected cell lines and a similar number of tissue samples of these cancers. We compared the expression of MRP and mdr1 mRNA in cell lines and tissues using reverse‐transcriptase polymerase chain reaction. In mdr1‐negative cells, the relationship between the level of MRP gene expression and sensitivity to anticancer drugs was examined. The effect of verapamil, an MRP‐modulating agent, was also examined in these cells. The expression of MRP gene in gastric cancer cell lines varied from a low to a high level, but mdr1 was not detected in any of these cell lines. Colon cancer cell lines expressed low to intermediate levels of MRP gene, and half of the cells co‐expressed low to high levels of mdr1. In tissue samples, the expression pattern of the two multidrug resistance (MDR) genes was broadly similar to that described for the cell lines, except that most of the gastric cancer tissue samples did express low levels of mdr1. No significant correlation was observed between the level of MRP gene expression and sensitivity to anticancer drugs in gastric and colon cell lines. However, verapamil significantly increased the sensitivity to etoposide, doxorubicin and vincristine in cells highly expressing MRP gene. Our results indicate that MRP gene may be important in conferring MDR in gastric and colon cancer cells.

A novel quinoline derivative, MS-209, overcomes drug resistance of human lung cancer cells expressing the multidrug resistance-associated protein (MRP) gene

Purpose and methods: MS-209 is a newly synthesized quinoline compound used orally to overcome human P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). The multidrug resistance-associated protein (MRP) gene is thought to play an important role in MDR in lung cancer. To investigate whether MS-209 could also overcome MRP-mediated MDR, we examined the effect of the compound using a cytotoxicity assay on MDR1 gene-negative drug-selected MDR and wildtype lung cancer cells with various levels of MRP gene expression. The effects of MS-209 were compared with those of verapamil (VER) and cyclosporin A (CsA). The level of MRP gene expression in the cells was evaluated semiquantitatively by RT-PCR. For vincristine (VCR), intracellular accumulation of [3H]-VCR was measured with or without MS-209. Results: In MDR UMCC-1/VP small-cell lung carcinoma cell line, 5 μM of MS-209 and VER enhanced the cytotoxicity of etoposide, doxorubicin (DOX) and VCR more than twofold, and completely reversed the resistance to VCR. The mean reversing effects of MS-209 on DOX and VCR were significantly stronger than those of VER and CsA. In wildtype non-small-cell lung carcinoma cells, the effects of MS-209 were almost equal to those of VER and CsA. The effect of these three agents correlated with the level of MRP gene expression. The MS-209-induced increase in intracellular accumulation of VCR was proportional to the level of MRP gene expression in these cells. Conclusion: Our results indicate that MS-209 is a potentially useful drug that can overcome MRP-mediated intrinsic and acquired MDR in human lung cancer.

Pharmacokinetics of gefitinib predicts antitumor activity for advanced non-small cell lung cancer.

Introduction: We assessed the relationship between the plasma concentration of gefitinib and its efficacy in Japanese patients with advanced non-small cell lung cancer (NSCLC). Methods: Plasma trough levels of gefitinib were measured on days 3 (D3) and 8 (D8) by high-performance liquid chromatography in 44 patients with advanced NSCLC treated with 250 mg gefitinib daily. Eligibility criteria included performance status ≤3, age ≤ 80 years, and stages IIIB–IV cancer. Epidermal growth factor receptor mutations in 23 patients were analyzed retrospectively. Results: The median plasma gefitinib values were 662 ng/ml on D3 and 1064 ng/ml on D8, and the D8/D3 ratio was 1.587. The median progression-free survival (PFS) was 71 days, and the median overall survival was 224 days. Adenocarcinoma, never smoking, and high D8/D3 ratio were associated with better PFS. Multivariate analysis showed that PFS was associated with never smoking and high D8/D3 ratio. Never-smokers with a high D8/D3 ratio showed the best PFS. Overall survival was not associated with the D8/D3 ratio. Epidermal growth factor receptor mutation analysis of 23 patients showed that 15 patients had exon 19 deletion and/or exon 21 point mutation. Median PFS was similar between mutation-positive and mutation-negative individuals in the high D8/D3 group, whereas mutation-negative individuals in the low D8/D3 group showed the worst median PFS. Conclusions: A high D8/D3 ratio was independently associated with better PFS in patients with NSCLC treated with gefitinib. Our findings suggest that the pharmacokinetics of gefitinib may be involved in its antitumor activity.

Gene Mutation Analysis and Quantitation of DNA Topoisomerase I in Previously Untreated Non-small Cell Lung Carcinomas

To elucidate whether gene alterations of topoisomerase I (topo I) exist in untreated non‐small cell lung carcinomas (NSCLC), polymerase chain reaction‐single strand conformation polymorphism analysis was performed in forty‐four NSCLC tissue samples. Gene alterations of topo I were sought in three regions, near codons 361 and 363, 533, and 722 and 729, where point mutations have been found in resistant tumor cell lines selected by chronic camptothecin exposure. In addition, nuclear topo I contents were determined by immunoblotting. No mobility shifts were observed compared to the pattern observed in a normal control at any of the three regions in any sample, whereas topo I levels showed an approximately 12‐fold variation. The variation is remarkably large compared to those seen in previous in vitro and in vivo studies. The results suggest that mutations of topo I may not contribute to intrinsic resistance of NSCLC to camptothecins, but low topo I levels may account, at least in part, for the resistance.

Phase I study of irinotecan and cisplatin with concurrent split-course radiotherapy in limited-disease small-cell lung cancer.

We conducted a phase I study of irinotecan (CPT-11) and cisplatin with concurrent split-course radiotherapy in limited-disease small-cell lung cancer (LD-SCLC). This study aimed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of this therapy. Four chemotherapy cycles of CPT-11 (days 1, 8 and 15) and cisplatin (day 1) were repeated every 28 days. Radiotherapy of 2 Gy/day commenced on day 2 of each chemotherapy cycle with 20 Gy administered from the first to the third cycles (a total of 60 Gy). 17 patients were enrolled at three dose levels (CPT-11/cisplatin: 40/60, 50/60 and 60/60 mg/m(2)), and 16 were evaluable for toxicity and outcome. 2 of 4 patients at 60/60 mg/m(2) refused continuation of therapy because of general fatigue, and the relative dose intensity of CPT-11 at 50/60 mg/m(2) was approximately 50%. These levels were considered as the MTD. Tumour responses included four complete responses (CR), 11 partial responses (PR) and one no change (NC), and the overall response rate was 93.8% (95% confidence interval: (CI) 71.7-98.9%). This combined modality is tolerable, and CPT-11/cisplatin of 40/60 mg/m(2) in this modality is recommended for phase II study.

Randomized Phase II Trial of Irinotecan with Paclitaxel or Gemcitabine for Non-small Cell Lung Cancer Association of UGT1A1*6 and UGT1A1*27 with Severe Neutropenia

Hypothesis: Irinotecan-containing regimens are known to be active and tolerable in patients with non-small cell lung cancer (NSCLC). A randomized phase II trial was conducted to evaluate the efficacy of irinotecan plus paclitaxel or gemcitabine for previously untreated stage IIIB or stage IV NSCLC. Patients and Methods: Previously untreated patients with adequate organ function who gave written informed consent were randomly assigned to receive irinotecan (50 mg/m2 on days 1, 8, and 15) plus paclitaxel (180 mg/m2 on day 1) every 4 weeks (IP group) or irinotecan (100 mg/m2 on days 1 and 8) plus gemcitabine (1000 mg/m2 on days 1 and 8) every 3 weeks (IG group). The primary endpoint was the response rate. We also evaluated the relationship of response and toxicity to polymorphisms of the uridine diphosphate glucuronosyltransferase (UGT) gene. Results: Eighty patients were enrolled, and 78 patients were eligible (38 in the IP group and 40 in the IG group). The response rate was 31.6% (95% confidence interval: 17.5–48.7%) in the IP group and 20.0% (9.1–35.6%) in the IG group. The median progression-free survival time was 86 days and 145 days, respectively. Both regimens were well tolerated. The most common severe adverse event was grade 4 neutropenia (36.8% and 10.0%, respectively), which was associated with UGT1A1*6 and UGT1A1*27. UGT polymorphisms did not correlate with response. Conclusions: Irinotecan plus paclitaxel may be more active against NSCLC than irinotecan plus gemcitabine. The UGT1A1*6 and UGT1A1*27 genotypes might be useful predictors of grade 4 neutropenia in patients who receive irinotecan-based chemotherapy.

Irinotecan and cisplatin with concurrent split-course radiotherapy in locally advanced nonsmall-cell lung cancer : A multiinstitutional phase 2 study

The purpose was to determine the efficacy and toxicity of irinotecan and cisplatin with concurrent split‐course thoracic radiotherapy (TRT) in locally advanced nonsmall‐cell lung cancer.

Phase I and pharmacokinetic study of paclitaxel and irinotecan for patients with advanced non-small cell lung cancer.

We conducted a phase I study of paclitaxel and irinotecan (CPT-11) in advanced non-small cell lung cancer (NSCLC). This study aimed to determine the maximum tolerated doses (MTD). The pharmacokinetics of CPT-11 and its major active metabolite, SN-38, were also analysed. Patients received paclitaxel (day 1) followed by CPT-11 (days 1, 8 and 15), in a 4-week cycle, and paclitaxel and CPT-11 were escalated from 120 and 40 mg/m(2), respectively. 28 patients were enrolled, who were evaluated for toxicity. 2 of 6 patients at 210 mg/m(2) paclitaxel and 50 mg/m(2) CPT-11, and 2 of 4 at 180 and 60 mg/m(2) developed dose-limiting toxicity (DLT) (neutropenia, fever, neurotoxicity and diarrhoea). The area under the plasma concentration-time curve (AUC) of CPT-11 on day 1 was significantly higher than that on days 8 or 15 at each dose level (P=0.002). The AUC of SN-38 on day 1 was significantly increased using paclitaxel doses >or=150 mg/m(2). A preceding paclitaxel administration changed the pharmacokinetics of CPT-11 and SN-38. However, the toxicity was tolerable. Paclitaxel 180 mg/m(2) and CPT-11 50 mg/m(2) were the recommended doses for further phase II study of this combination.

Phase I study of irinotecan and cisplatin with concurrent split-course radiotherapy in unresectable and locally advanced non-small cell lung cancer

We conducted a phase I study of irinotecan (CPT-11) and cisplatin with concurrent split-course radiotherapy in locally advanced stage III non-small cell lung cancer (NSCLC). This study aimed to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of this therapy. Two chemotherapy cycles of CPT-11 (days 1, 8 and 15) and cisplatin (day 1) were repeated with a 28-day interval. Radiotherapy of 2 Gy/day commenced on day 2 of each chemotherapy cycle, with 24 Gy and 36 Gy administered for the first and second cycle, respectively. 24 eligible patients were enrolled at five dose levels (CPT-11/cisplatin: 40/60, 50/60, 60/60, 60/70 and 60/80 mg/m(2)), and 23 patients were evaluated for toxicity and clinical outcome. Only 1 patient experienced a DLT with neutropenia and diarrhoea at 60/60 mg/m(2). Dose escalation was limited to 60/80 mg/m(2) which was the recommended dose for CPT-11/cisplatin alone in NSCLC. Tumour responses included one complete response (CR), 15 partial response (PR), and 7 no change (NC), and the overall response rate was 69.6% (95% confidence interval (CI) 47.1-86.8%). This combined modality is tolerable, and CPT-11/cisplatin of 60/80 mg/m(2) in this modality is recommended for phase II study.

A Phase I Study of Amrubicin and Carboplatin for Previously Untreated Patients with Extensive-Disease Small Cell Lung Cancer

Background: Amrubicin and cisplatin are active in the treatment of small cell lung cancer (SCLC), and carboplatin is an analogue of cisplatin with less nonhematological toxicity. The appropriate dose of amrubicin and carboplatin combination chemotherapy for previously untreated patients with extensive-disease (ED) SCLC has not been established. Purpose: To determine the maximum-tolerated dose and dose-limiting toxicity (DLT) of amrubicin and carboplatin in ED-SCLC. Patients and methods: Eligibility criteria were chemotherapy-naive ED-SCLC patients, performance status 0–1, age ≤75, and adequate hematological, hepatic, and renal function. Patients received escalating amrubicin doses under a fixed target area under the curve (AUC) 5 of carboplatin (Chatelut formula). Amrubicin and carboplatin were administered by intravenous (IV) infusion on days 1, 2, and 3, and day 1, respectively. The initial dose of amrubicin was 30 mg/m2, and the dose was escalated to 35 and 40 mg/m2. Results: Sixteen patients were enrolled and 15 eligible patients were evaluated. One of six patients in level 1, one of six in level 2, and three of three in level 3 experienced DLTs. The presentation of DLTs included neutropenia, leukopenia, thrombocytopenia, febrile neutropenia, and liver dysfunction. Evaluation of responses were two complete response, nine partial response, three stable disease, and one progressive disease (response rate 73%), and the median survival time was 13.6 months. The maximum-tolerated doses of amrubicin and carboplatin were determined as 40 mg/m2 and AUC 5. A dose of 35 mg/m2 amrubicin and carboplatin AUC 5 was recommended in this regimen. Conclusions: This regimen is associated with an acceptable tolerability profile, and warrants evaluation in the phase II setting.