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Purpose: Oral aprepitant has a large interindividual variation in clinical responses in advanced cancer. This study aimed to characterize plasma aprepitant and its N-dealkylated metabolite (ND-AP) based on the cachexia status and clinical responses in head and neck cancer patients., Methods: Fifty-three head and neck cancer patients receiving cisplatin-based chemotherapy with oral aprepitant were enrolled. Plasma concentrations of total and free aprepitant and ND-AP were determined at 24 h after a 3-day aprepitant treatment. The clinical responses to aprepitant and degrees of cachexia status were assessed using a questionnaire and Glasgow Prognostic Score (GPS)., Results: Serum albumin level was negatively correlated with the plasma concentrations of total and free aprepitant but not ND-AP. The serum albumin level had a negative correlation with the metabolic ratio of aprepitant. The patients with GPS 1 or 2 had higher plasma concentrations of total and free aprepitant than those with GPS 0. No difference was observed in the plasma concentration of ND-AP between the GPS classifications. The plasma interleukin-6 level was higher in patients with GPS 1 or 2 than 0. The absolute plasma concentration of free ND-AP was higher in patients without the delayed nausea, and its concentration to determine the occurrence was 18.9 ng/mL. The occurrence of delayed nausea had no relation with absolute plasma aprepitant., Conclusion: Cancer patients with a lower serum albumin and progressive cachectic condition had a higher plasma aprepitant level. In contrast, plasma free ND-AP but not aprepitant was related to the antiemetic efficacy of oral aprepitant., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that has exhibited efficacy in patients with EGFR-mutant non-small cell lung cancer (NSCLC). Interstitial lung disease (ILD) is a fatal adverse event of osimertinib treatment, and it requires treatment discontinuation. There are few reports regarding the safety and efficacy of osimertinib re-challenge in patients who experienced osimertinib-induced ILD. This retrospective study assessed this treatment option. We retrospectively collected data for patients treated with osimertinib who developed ILD at Shizuoka Cancer Center from April 2016 to March 2020. ILD was diagnosed by two doctors based on imaging tests and blood tests to exclude other causes. Among 215 patients treated with osimertinib, 28 developed ILD. The median age of patients with ILD was 69.5 years (range, 39.0-80.0). In addition, 29% of patients were men, and 46% had a history of smoking. Eleven patients were re-administered EGFR TKIs, including eight patients treated with osimertinib and three patients treated with alternative EGFR TKIs. Among patients re-challenged with osimertinib, none who previously experienced grade 1 ILD exhibited ILD relapse, even with the same osimertinib dose and without the concurrent administration of systemic steroids. Meanwhile, one of the four patients who previously exhibited grade 2 ILD experienced despite a dose reduction for osimertinib and systemic steroid administration. For patients with EGFR-mutant NSCLC who experience grade 1 ILD during osimertinib therapy, osimertinib re-challenge may be suitable when no other treatments are available.

Major issues in anaplastic lymphoma kinase-positive non-small cell lung carcinoma are acquired resistance against anaplastic lymphoma kinase inhibitors and control of central nervous system metastasis. The development of these inhibitors has changed therapeutic strategy in patients with advanced anaplastic lymphoma kinase-positive non-small cell lung carcinoma. Brigatinib and lorlatinib were designed to penetrate the blood-brain barrier and to inhibit resistant mutations against anaplastic lymphoma kinase inhibitors. We review the clinical data supporting treatment of advanced anaplastic lymphoma kinase-positive non-small cell lung carcinoma with brigatinib and lorlatinib. Brigatinib has shown promising antitumour activity, including substantial activity against central nervous system metastases, in crizotinib-treated (ALTA trial) patients and crizotinib-naïve (ALTA-1L trial) patients with anaplastic lymphoma kinase-positive non-small cell lung carcinoma. In addition, brigatinib improved progression-free survival compared with crizotinib in anaplastic lymphoma kinase inhibitor-naïve patients with anaplastic lymphoma kinase-positive non-small cell lung carcinoma. Lorlatinib has demonstrated clinical antitumour activity against both intracranial and extracranial lesions in patients with anaplastic lymphoma kinase- or c-ros oncogene 1 (ROS1)-positive non-small cell lung carcinoma. Ongoing trials and further studies of these agents' biological and clinical properties would provide insight into the optimal therapeutic strategy for administering them to achieve the best survival benefit., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: Severe hepatotoxicity induced by the standard dose of gefitinib (250 mg daily) often becomes manageable by dose reduction to 250 mg every other day. Thus, we hypothesized that systemic exposure of standard-dose gefitinib in patients with experience of severe hepatotoxicity might be higher than that in patients without severe hepatotoxicity., Methods: Patients with advanced epidermal growth factor receptor-mutated non-small cell lung cancer who were receiving gefitinib either at a reduced dose (250 mg every other day) because of intolerable severe toxicity or at a standard dose (250 mg daily) were enrolled. A series of blood samples were collected to estimate pharmacokinetic parameters and calculate systemic exposure of standard-dose gefitinib (area under the concentration-time curve from 0 to 24 h at steady state, AUC 0-24,ss ). Systemic exposure of unbound gefitinib (fu·AUC 0-24,ss ) was also assessed, because gefitinib is extensively bound to serum proteins., Results: Of the 38 enrolled patients, 34 (23 patients without experience of severe hepatotoxicity, 11 patients with experience of severe hepatotoxicity) were evaluable. There was no significant differences in total AUC 0-24,ss or unbound fu·AUC 0-24,ss between patients with and without experience of severe hepatotoxicity. Analysis of the time to severe hepatotoxicity indicated no difference between patients with a high AUC 0-24,ss and those with a low AUC 0-24,ss of either total or unbound gefitinib., Conclusion: This study suggests that reversible severe hepatotoxicity is not caused by high systemic exposure of gefitinib.

3rd-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), including osimertinib, have reasonable efficacy in non-small-cell lung cancers (NSCLC) with EGFR mutations. However, the efficacy of osimertinib in NSCLC patients with fluids, such as pleural, pericardial and abdominal effusions, is unclear. We evaluated the efficacy of osimertinib in this specific setting. NSCLC patients harboring EGFR T790 M mutations who experienced progressive disease after first EGFR-TKI treatment and started osimertinib treatment between April 2016 and August 2018 were retrospectively screened. In particular, we assessed the efficacy of osimertinib for NSCLC with EGFR T790 M mutations in patients who were diagnosed with EGFR T790 M mutation by malignant effusion. Among 90 patients with EGFR T790 M mutation who started osimertinib treatment after EGFR-TKI failure, 21 were diagnosed from malignant effusions excluding cerebrospinal fluid (F group) and 69 using other methods including tissue biopsies (NF group). Patient characteristics were well-balanced between the two groups. Overall response was 50%, and significantly worse in the F group (29%) than the NF group (57%; P = 0.025). Median progression-free survival with osimertinib treatment in the F group (7.1 months, 95% confidence interval [CI]: 2.3-14.0) was significantly shorter than that in the NF group (11.9 months, 95% CI: 9.5-16.0; P = 0.046)). Median drainage-free time was 10.9 months (95% CI: 1.4 months- not reached). The present study showed that the efficacy of osimertinib for NSCLC in which EGFR T790 M mutation is detected by malignant effusion may be less than in EGFR T790 M-mutated NSCLC detected by other methods.

Crizotinib is a receptor tyrosine kinase inhibitor that has several targets, including c-ros oncogene 1 and the MET proto-oncogene. Considering its known cardiac toxicity, bradycardia is often investigated following treatment with crizotinib. Our patients had bradycardia, QT prolongation, ventricular rhythm, ventricular fibrillation, and pericarditis simultaneously. The cardiotoxicity of crizotinib can sometimes be simultaneous; thus, intensive observation is needed.

Background and Objective: Patients with advanced non-small cell lung cancer (NSCLC) and interstitial lung disease (ILD) are commonly excluded from most clinical trials because of acute exacerbation (AE) of ILD triggered by chemotherapy. Data on the efficacy and feasibility of chemotherapy are limited in this patient population. Recently, the ILD-GAP index and staging system was reported as a clinical prognostic factor associated with mortality in patients with ILD. Therefore, we evaluated the incidence of ILD-AE during the surveillance term in this study and the prognosis in patients with NSCLC and ILD using a modified ILD-GAP (ILD-NSCLC-GAP) index scoring system., Materials and Methods: The medical records of patients with NSCLC and ILD who underwent a pulmonary function test before initiation of platinum-based chemotherapy as first-line treatment at the Shizuoka Cancer Center between September 2002 and December 2014 were reviewed retrospectively. Among these patients, we compared the incidence of ILD-AE, one-year survival rate, and overall survival (OS) between the ILD-NSCLC-GAP index scores and stages., Results: Of the 78 patients included, 21 (27%; 95% confidence interval [CI], 18%-38%) had ILD-AE during the surveillance term in this study. The one-year survival and median OS rates were 49% and 11.3 months, respectively. The incidence of ILD-AE increased gradually and the one-year survival and median OS rates decreased gradually with increasing ILD-NSCLC-GAP index scores and stages., Conclusion: The ILD-NSCLC-GAP index scoring and staging system may be a useful tool to calculate a prediction of the incidence of ILD-AE and its prognosis for patients with NSCLC and ILD., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: T790M, a secondary epidermal growth factor receptor (EGFR) mutation, accounts for approximately 50% of acquired resistance to EGFR-tyrosine kinase inhibitors (TKIs). To facilitate the use of third-generation EGFR-TKIs to potentially overcome T790M-mediated resistance, we evaluated the clinical factors influencing the incidence of T790M mutation., Patients and Methods: We retrospectively screened patients with non-small-cell lung cancer harboring EGFR mutations with progressive disease who were rebiopsied between January 2013 and December 2016. Factors influencing T790M status were evaluated by univariate and multivariate analysis., Results: Among 131 rebiopsied patients for whom EGFR mutation status was available, 58 (44%) had T790M mutations. Patient characteristics at rebiopsy were not significantly different between T790M-positive and -negative groups, except for surgical history (postsurgery recurrence). Total duration of EGFR-TKI treatment before rebiopsy, TKI-free interval, EGFR-TKI treatment history immediately before rebiopsy, continuation of initial EGFR-TKI beyond progressive disease, progression-free survival after initial TKI treatment, and rebiopsy site (other than fluid samples) significantly influenced T790M status. The incidence of T790M mutation was shown by multivariate analysis to be significantly higher in patients with postsurgery recurrence and total duration of EGFR-TKI treatment ≥ 1 year before rebiopsy (odds ratio, 4.2; 95% confidence interval, 1.3-15.7 and odds ratio, 4.4; 95% confidence interval, 1.1-19.8, respectively)., Conclusion: Postsurgery recurrence and longer total duration of EGFR-TKI treatment before rebiopsy may represent useful predictive markers for T790M detection. In patients with these clinical factors, rebiopsies are more recommended to detect T790M mutation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Cancer cachexia in elderly patients may substantially impact physical function and medical dependency. The aim of this study was to estimate the impact of cachexia on activity of daily living (ADL), length of hospital stay, and inpatient medical costs among elderly patients with advanced non-small-cell lung cancer (NSCLC) receiving chemotherapy., Methods: Thirty patients aged ≥70 years with advanced NSCLC (stage III-IV) scheduled to receive first-line chemotherapy were prospectively enrolled between January 2013 and November 2014. ADL was assessed using the Barthel index. The disability-free survival time (DFS) was calculated as the time between the date of study entry and the date of onset of a disabling event, which was defined as a 10-point decrease in the Barthel index from that at baseline. The mean cumulative function of the length of hospital stay and inpatient medical costs (¥, Japanese yen) was calculated., Results: The study patients comprised 11 women and 19 men, with a median age of 74 (range, 70-82) years. Cachexia was diagnosed in 19 (63%) patients. Cachectic patients had a shorter DFS (7.5 vs. 17.1 months, p < 0.05). During the first year from study entry, cachectic patients had longer cumulative lengths of hospital stay (80.7 vs. 38.5 days/person, p < 0.05), more frequent unplanned hospital visits or hospitalizations (4.2 vs. 1.7 times/person, p < 0.05), and higher inpatient medical costs (¥3.5 vs. ¥2.1 million/person, p < 0.05) than non-cachectic patients., Conclusions: Elderly NSCLC patients with cachexia showed higher risks for disability, prolonged hospitalizations, and higher inpatient medical costs while receiving chemotherapy than patients without cachexia. Our results might indicate that there is a potential need for an early intervention to minimize progression to or development of cachexia, improve functional prognosis, and reduce healthcare resource burden in this population., Trial Registration: Trial registration number: UMIN000009768 . Name of registry: UMIN (University hospital Medical Information Network). Date of registration: 14 January 2013. Date of enrolment of the first participant to the trial: 23 January 2013.

Antibodies to programmed cell death-1 (PD-1), such as nivolumab, have shown promising clinical activity in patients with advanced non-small-cell lung cancer (NSCLC), but their efficacy appears to be less pronounced in patients with such tumors harboring epidermal growth factor receptor gene (EGFR) mutations. Recent findings suggest that patients with EGFR mutation-positive NSCLC who develop resistance to tyrosine kinase inhibitors (TKIs) due to mechanisms other than acquisition of the secondary T790M mutation of EGFR are more likely to benefit from nivolumab treatment, possibly as a result of a higher level of expression of the PD-1 ligand PD-L1, than are patients who are T790M-positive. The WJOG8515L study (UMIN ID: 000021133) is a randomized phase II trial to compare nivolumab with the combination of carboplatin and pemetrexed in patients with EGFR mutation-positive nonsquamous NSCLC who have developed resistance to EGFR-TKIs due to mechanisms other than T790M. Eligible patients are those with stage IV or recurrent EGFR mutation-positive NSCLC who experience disease progression after therapy with more than 1 EGFR-TKI, including gefitinib, erlotinib, or afatinib; they must show no evidence of the T790M mutation on analysis of a tumor biopsy specimen obtained after progression on such EGFR-TKI therapy, or, if T790M is detected, they must again experience progression on subsequent treatment with a third-generation EGFR-TKI. The primary endpoint is progression-free survival (PFS), and secondary end points include overall survival (OS), objective response rate, duration of response, safety, and OS and PFS according to PD-L1 expression level. Recruitment started in May 2016 and is ongoing., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: Despite the efficacy of postoperative adjuvant cisplatin (CDDP)-based chemotherapy for patients who have undergone surgical resection of non-small cell lung cancer (NSCLC), few reports have presented survival data for Asian patients treated with adjuvant chemotherapy involving a combination of CDDP and vinorelbine (VNR). This study was performed to evaluate the survival of patients with NSCLC who received postoperative adjuvant chemotherapy comprising CDDP + VNR., Methods: We retrospectively evaluated patients with NSCLC who received adjuvant chemotherapy comprising CDDP + VNR at the Shizuoka Cancer Center between February 2006 and October 2011., Results: One hundred patients who underwent surgical resection of NSCLC were included in this study. The patients' characteristics were as follows: median age 63 years (range 36-74 years), female 34%, never-smokers 20%, and non-squamous NSCLC 73%. Pathological stages IIA, IIB, and IIIA were observed in 31, 22, and 47% of patients, respectively. The 5- and 2-year overall survival rates were 73 and 93%, respectively. The 5- and 2-year relapse-free survival rates were 53 and 62%, respectively. Univariate analysis of prognostic factors showed that patient characteristics (sex, histology, and pathological stage) and CDDP dose intensity were not significantly associated with survival. In 48 patients who developed NSCLC recurrence, the 5-year survival rate after recurrence was 29%, and the median survival time after recurrence was 37 months., Conclusions: Our results suggest that the prognosis after surgical resection of NSCLC and adjuvant chemotherapy comprising CDDP + VNR might be improving compared with previous survival data of adjuvant chemotherapy for NSCLC.

Background: Currently, no markers predictive of response to nivolumab monotherapy in patients with advanced non-small cell lung cancer (NSCLC) are currently recognized in Japan. The present study was undertaken to identify such markers., Materials and Methods: Medical records of 50 patients with advanced NSCLC and treated with nivolumab monotherapy at Shizuoka Cancer Center between December 2015 and April 2016 were retrospectively reviewed. The parameters studied were age, sex, Eastern Cooperative Oncology Group performance status, smoking history, histological diagnosis, epidermal growth factor receptor or anaplastic lymphoma kinase status, therapeutic line of nivolumab, efficacy of treatment immediately before nivolumab monotherapy, and time since previous therapy., Results: The objective response rate to nivolumab monotherapy was 18% [95% confidence interval (CI) 10-31]. Multivariate logistic regression identified "squamous histology" [odds ratio (OR) 0.00054; 95% CI 0-0.27] and "response to the treatment immediately before nivolumab monotherapy" (OR 0.0011; 95% CI 0-0.092) as independently associated with response to nivolumab monotherapy., Conclusion: "Response to the treatment immediately before nivolumab monotherapy" might be a predictive marker of response to nivolumab in patients with advanced NSCLC.

Background: The majority of non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation eventually develop resistance to EGFR tyrosine kinase inhibitors (TKIs). Minimal information exists regarding genetic alterations in rebiopsy samples from Asian NSCLC patients who develop acquired resistance to EGFR-TKIs., Methods: We retrospectively reviewed the medical records of patients with NSCLC harboring EGFR mutations who had undergone rebiopsies after developing acquired resistance to EGFR-TKIs. We analyzed 27 practicable samples using a tumor genotyping panel to assess 23 hot-spot sites of genetic alterations in nine genes (EGFR, KRAS, BRAF, PIK3CA, NRAS, MEK1, AKT1, PTEN, and HER2), gene copy number of EGFR, MET, PIK3CA, FGFR1, and FGFR2, and ALK, ROS1, and RET fusions. Additionally, 34 samples were analyzed by commercially available EGFR mutation tests., Results: Sixty-one patients underwent rebiopsy. Twenty-seven samples were analyzed using our tumor genotyping panel, and 34 samples were analyzed for EGFR mutations only by commercial clinical laboratories. Twenty-one patients (34 %) had EGFR T790M mutation. Using our tumor genotyping panel, MET gene copy number gain was observed in two of 27 (7 %) samples. Twenty patients received continuous treatment with EGFR-TKIs even after disease progression, and 11 of these patients had T790M mutation in rebiopsy samples. In contrast, only 10 of 41 patients who finished EGFR-TKI treatment at disease progression had T790M mutation. The frequency of T790M mutation in patients who received continuous treatment with EGFR-TKIs after disease progression was significantly higher than that in patients who finished EGFR-TKI treatment at disease progression (55 % versus 24 %, p = 0.018)., Conclusions: The frequency of T790M mutation in this study was lower than that in previous reports examining western patients. These results suggest that continuous treatment with EGFR-TKI after disease progression may enhance the frequency of EGFR T790M mutation in rebiopsy samples.

A 57-year-old male current smoker was diagnosed with an aggressive variant of ALK-rearranged inflammatory myofibroblastic tumor (IMT) arising in the pleural cavity. First line treatment with ASP3026 was initiated at a dose of 125mg once daily. A follow-up CT scan revealed drastic regression of the pleural lesion. After disease progression with ASP3026 treatment, LDK378 (ceritinib) was initiated at a dose of 750mg once daily. A follow-up CT scan revealed a second drastic regression of the pleural lesion. Furthermore, it is noteworthy that this case represents the use of serum hyaluronan levels to assist in monitoring of treatment efficacy in an IMT. Herein, we present the first case of a patient with a highly aggressive ALK-rearranged IMT arising in the pleural cavity, who showed both initial and subsequent drastic response to two ALK inhibitors while being monitored for serum hyaluronan., (Copyright © 2016 The Author(s). Published by Elsevier Ireland Ltd.. All rights reserved.)

Background: Patients undergoing imatinib therapy for gastrointestinal stromal tumors (GISTs) show drug resistance during treatment in the late stages. The aims of this study were to determine survival after the appearance of imatinib secondary resistance (ISR) and to identify the prognostic factors., Methods: Eligible were patients with unresectable and metastatic GISTs who were diagnosed with ISR and/or underwent treatment for ISR in our institution between 2001 and 2012. A total of 48 patients were enrolled and overall survival was retrospectively analyzed. The Cox proportional hazards model was used to identify the independent prognostic factors. Median follow-up time was 58 months., Results: As of the cutoff date, 41 of the 48 patients with ISR had died, of which 39 died of GISTs. The overall 1-, 3-, and 5-year survival rates of the 48 patients were 64.6, 32.8, and 20.4 %, respectively, and median survival time was 22 months. The favorable independent prognostic factors identified were long progression-free survival in first-line imatinib therapy (P = 0.04), small diameter of progressive disease (PD) (P = 0.02), and surgical resection of PD (P = 0.01)., Conclusion: Surgical resection of PD in selected cases could improve prognosis in ISR patients undergoing GIST treatment.

Background: It is unclear whether there is a difference in the effect of gefitinib treatment between patients with postoperative recurrent non-small cell lung cancer (NSCLC) and those with stage IV NSCLC harboring mutations in the epidermal growth factor receptor (EGFR)., Methods: We retrospectively reviewed the medical records of consecutive patients with postoperative recurrent NSCLC (postoperative group) or stage IV NSCLC (stage IV group) harboring EGFR mutations who were treated with gefitinib at the Shizuoka Cancer Center between September 2002 and March 2012 to compare the effect of gefitinib on survival from treatment initiation., Results: A total of 168 patients were treated with gefitinib (postoperative group, 49 patients; stage IV group, 119 patients). The response rate of gefitinib treatment in the postoperative group was similar to that in the stage IV group (58 vs. 61 %, p = 0.613). In contrast, median progression-free survival (PFS; 15.8 vs. 9.8 months, p < 0.001) and median overall survival (OS; 51.1 vs. 22.2 months, p < 0.001) were significantly longer in the postoperative group. In addition, postoperative recurrent disease, performance status (0-1), and a single metastatic organ were independent favorable prognostic factors in the multivariate analysis of survival., Conclusions: PFS and OS were superior in patients with postoperative recurrent NSCLC harboring EGFR mutations treated by gefitinib than in those with stage IV disease. These results suggest that postoperative recurrent disease may be considered a stratification factor in clinical trials for NSCLC with EGFR mutations.

Background: Gene mutations in the pathway downstream of epidermal growth factor receptor (EGFR) are considered to induce resistance to anti-EGFR therapy in colorectal cancer (CRC). We recently reported that microRNA-31 (miR-31)-5p may regulate BRAF activation and play a role in the signaling pathway downstream of EGFR in CRC. Therefore, we hypothesized that miR-31-5p can be a useful biomarker for anti-EGFR therapy in CRC., Methods: We evaluated miR-31-5p expression and gene mutations [KRAS (codon 61 or 146), NRAS (codon 12, 13, or 61), and BRAF (V600E)] in the EGFR downstream pathway in 102 CRC patients harboring KRAS (codon 12 or 13) wild-type who were treated with anti-EGFR therapeutics. Progression-free survival (PFS) and overall survival (OS) were evaluated., Results: KRAS (codon 61 or 146), NRAS, and BRAF mutations were detected in 6.9, 6.9, and 5.9 % patients, respectively. Compared with CRCs with at least one mutation (n = 20), significantly better PFS (P = 0.0003) but insignificantly better OS were observed in CRCs harboring all wild-type genes (KRAS, NRAS, and BRAF). High miR-31-5p expression was identified in 11 % (n = 11) patients and was significantly associated with shorter PFS (P = 0.003). In CRCs carrying all wild-type genes, high miR-31-5p was associated with shorter PFS (P = 0.027)., Conclusions: High miR-31-5p expression was associated with shorter PFS in patients with CRC treated with anti-EGFR therapeutics. Moreover, in CRCs carrying all wild-type genes, high miR-31-5p was associated with shorter PFS, suggesting that it may be a useful and additional prognostic biomarker for anti-EGFR therapy.

This study developed a method for the simultaneous determination of erlotinib and its isomeric major metabolites, OSI-413 and OSI-420, in human plasma using an isocratic liquid chromatography-tandem mass spectrometry. Plasma specimens deproteinized with acetonitrile were separated using a 3-µm particle size octadecylsilyl column. The m/z values of the precursor and product ions for the analytes were as follows: erlotinib, 394.2/278.2; and OSI-413 and OSI-420, 380.2/278.2. The total run time was 21 min and no peaks interfering with the analytes and internal standard (d6 -erlotinib) in human plasma were observed. The calibration curves of erlotinib, OSI-413 and OSI-420 were linear over the concentration ranges of 10-3000, 2-500 and 2-100 ng/mL, respectively. The pretreatment recovery ratios were >86.1%. The intra- and inter-assay precisions and accuracies were <12.7 and 89.0-108.9% for all analytes. This validated method was applied to the determination of plasma samples in lung cancer patients receiving 150 mg of oral erlotinib. The plasma concentration ranges of erlotinib, OSI-413 and OSI-420 were 373-2354, 15.7-379 and 2.5-43.6 ng/mL, respectively. In conclusion, the present method can be helpful for evaluating the plasma exposures of erlotinib and its major isomeric metabolites in clinical settings., (Copyright © 2014 John Wiley & Sons, Ltd.)

Objectives: To evaluate the efficacy of rechallenge with current induction regimens for sensitive-relapse small cell lung cancer (SCLC) patients., Methods: We defined sensitive relapse as treatment-free interval (TFI≥90 d). Sensitive-relapse SCLC patients who received second-line chemotherapy were separated into those treated with rechallenge chemotherapy (rechallenge group) and those treated with other regimens (other group). The endpoints were overall survival (OS), progression-free survival, and toxicity., Results: Sixty-five patients (19 rechallenge group and 46 other group) were assessable for efficacy and safety evaluation. No significant differences in age, sex, ECOG performance status at relapse, disease extent at diagnosis, or response to first-line treatment were found between the 2 groups, but TFI was significantly longer in the rechallenge group. Twenty-one patients of the other group received amrubicin. There was no significant difference in OS between the 2 groups (median survival time [MST]: rechallenge group, 14.4 mo; other group, 13.1 mo; P=0.51). In the patients treated with amrubicin, MST was 12.6 months. Comparing the rechallenge group with the patients treated with amrubicin, there was also no significant difference in OS (P=0.38). Both the rechallenge and other group included 11 patients with ex-sensitive relapse (TFI≥180 d). There was no significant difference in OS between the 2 groups (MST 15.7 vs. 26.9 mo, P=0.46)., Conclusions: Rechallenge chemotherapy did not prove superior to other chemotherapies, suggesting that monotherapy, such as amrubicin, might be reasonable as second-line chemotherapy for sensitive-relapse SCLC patients.

Background: Gefitinib and erlotinib are used to treat advanced non-small cell lung cancer (NSCLC). Gefitinib is a common first-line treatment, but most patients develop resistance. This phase II study evaluated the efficacy of erlotinib after acquired resistance to gefitinib., Patients and Methods: Between January 2008 and September 2009, we enrolled 50 patients with advanced NSCLC who had received one or more chemotherapy regimens, including gefitinib monotherapy to which they had partial responses (PR) or stable disease (SD). Erlotinib (150 mg) was administered until disease progression or unacceptable toxicity. Patients were 11 males, 39 females; median age 65 years (range=36-81 years); 46 with adenocarcinoma; performance status 0/1/2: 24/19/7; and smoking status, never/former/current: 33/15/2. Prior gefitinib response, PR/SD: 36/14. Median duration of prior gefitinib therapy was 419 days (range=63-1,540 days). Median interval after gefitinib therapy was 29 days (range=13-1,198 days)., Results: Of 47 patients on erlotinib, four showed PR and 29 showed SD [response rate, 8.5%; disease control rate (DCR), 70.2%]. DCR for patients who continued gefitinib treatment for more than one year was significantly higher (81.5%) than for patients who could not continue (57.1%; p=0.018); but was not affected by prior gefitinib response or treatment interval. Median tiMETo treatment failure: 100 days (95% confidence interval=90-110 days); median overall survival: 342 days (95% confidence interval=242-442 days). Rash (78%) and diarrhea (68%) were the most common adverse reactions; grade 5 pneumonitis occurred in one patient (2%)., Conclusion: Erlotinib treatment after gefitinib failure may prolong the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors treatment.

The anti-HER2 antibody trastuzumab has led to an era of personalized therapy in gastric cancer (GC). As a result, HER2 expression has become a major concern in GC. HER2 overexpression is seen in 7-34% of GC cases. Trastuzumab is an antibody that targets the HER2 extracellular domain and induces antibody-dependent cellular cytotoxicity and inhibition of the HER2 downstream signals. Mechanisms of resistance to trastuzumab have been reported in breast cancer. There are various mechanisms underlying trastuzumab resistance, such as alterations of HER2 structure or surroundings, dysregulation of HER2 downstream signal effectors and interaction of HER2 with other membrane receptors. The PI3K-Akt pathway is one of the main downstream signaling pathways of HER2. It is well known that PIK3CA mutations and phosphate and tensin homolog (PTEN) inactivation cause over-activation of the downstream signal without an upstream signal activation. Frequencies of PIK3CA mutations and PTEN inactivation have been reported to be 4-25 and 16-77%, respectively. However, little is known about the association between HER2 expression and PI3K-Akt pathway alterations in GC. We have found that HER2 over-expression was significantly correlated with pAkt expression in GC tissues. Furthermore, pAkt expression was correlated with poor prognosis. These results suggest that the PI3K-Akt pathway plays an important role in HER2-positive GC. Moreover, PIK3CA mutations and/or PTEN inactivation might affect the effectiveness of HER2-targeting therapy. Hence, it is necessary to clarify not only HER2 alterations but also PI3K-Akt pathway alterations for HER2-targeting therapy in GC. This review will introduce recent investigations and consider the current status of HER2-targeted therapy for treatment of GC.

Tivozanib is a potent and selective inhibitor of vascular endothelial growth factor receptor (VEGFR) tyrosine kinases. A previous clinical trial in the EU and USA indicated that tivozanib at the maximum tolerated dose of 1.5 mg/day showed an antitumor activity in patients with renal cell carcinoma. This Japanese phase I study was designed to determine the recommended phase II dose of tivozanib for Japanese patients; secondary objectives included pharmacokinetic/pharmacodynamic profiles and preliminary efficacy. Daily treatment with tivozanib in a 3-weeks-on/1-week-off cycle was examined in nine Japanese patients with advanced solid tumors in the 3 + 3 design (Level 1, 1.0 mg; Level 2, 1.5 mg). No dose-limiting toxicity was observed throughout the study, and the maximum tolerated dose was not reached. The most commonly observed drug-related adverse events were diarrhea, dysphonia, rash, thyroid stimulating hormone increase, and with severity grade ≥3, hand-foot skin reaction, hypertension, and proteinuria. Those adverse events were generally well-manageable and mostly resolved within the tolerability evaluation period. Serum exposure to tivozanib resulted in t1/2 of more than >60 h. Increase of plasma VEGF and decrease of plasma VEGFR-1 and VEGFR-2 were observed 1-3 weeks after tivozanib treatment. Although no complete or partial response was observed, long-term stable disease continuing more than 170 days was observed in three renal cell carcinoma patients who had failed prior VEGFR inhibitors. In conclusion, 1.5 mg/day of tivozanib in a 3-weeks-on/1-week-off setting was tolerable in Japanese patients, and was recommended for further clinical trials in the Japanese population. Clinical trial Registration No: JapicCTI-090854., (© 2013 Japanese Cancer Association.)

The pharmacokinetics of aprepitant, a neurokinin-1 receptor antagonist, have not been fully evaluated in clinical settings. The aim of this study was to characterize the plasma pharmacokinetics of aprepitant and reveal their influence of laboratory tests and cytochrome P450 (CYP) 3A5 gene polymorphisms in cancer patients. Forty-four Japanese cancer patients receiving cisplatin-based chemotherapy for the first time following oral aprepitant (125 mg on day 1 and 80 mg on days 2 and 3) were enrolled. The patients did not have gastrointestinal disease and the clinical laboratory values were within their normal reference levels. The plasma concentrations of aprepitant 24 (day 2 predose), 72, and 120 h after the first aprepitant administration were determined using LC-MS/MS. The relationships between plasma exposure to aprepitant and body weight, clinical laboratory values, age, gender, or CYP3A5*3 were investigated. The median and interquartile ranges of the 120-h area under the plasma concentration time curve (AUC)(0-120) of aprepitant were 73215 and 55518-91121 ng h/mL. The coefficient of variation value for aprepitant AUC(0-120) was 53%. The AUC(0-120) of aprepitant was correlated with the levels of total bilirubin and serum albumin, respectively (r=0.454, p<0.01 and r=0.287, p=0.06), but not with other non-genetic factors and CYP3A5 genetic variants in a univariate analysis. The AUC(0-120) of aprepitant was significantly correlated with the level of total bilirubin (adjusted R(2)=0.187, p<0.01) in a multivariate analysis. In conclusion, the plasma pharmacokinetics of aprepitant varied markedly in cancer patients receiving cisplatin-based chemotherapy for the first time and were correlated with the level of total bilirubin.

Background: There is no standard therapy for relapsed patients who have received postoperative platinum-based adjuvant chemotherapy for resected non-small-cell lung cancer (NSCLC). We investigated the efficacy and safety of platinum combination chemotherapy re-challenge for such patients., Methods: Medical records from 3 institutes from April 2005 to July 2012 were retrospectively reviewed. Patients who underwent complete surgical resection were eligible if they received postoperative adjuvant chemotherapy consisting of cisplatin plus vinorelbine once and then re-challenge with platinum combination chemotherapy., Results: Sixteen patients were enrolled in this study. After re-challenge with platinum combination chemotherapy, we observed an overall response rate of 31.2% (5/16) and a disease control rate of 81.2% (13/16). Median progression-free survival and overall survival from the start of the re-administration of platinum combination chemotherapy were 6.5 and 28.0 months, respectively. Frequently observed severe adverse events (≥grade 3) included neutropenia (31.2%), thrombocytopenia (31.2%), leukopenia (12.5%) and hyponatremia (12.5%). Frequently observed non-hematological toxicities (≥grade 2) were anorexia (37.5%) and nausea (37.5%)., Conclusion: Re-challenge with platinum combination chemotherapy was effective and safe; therefore, this therapy should be considered as a treatment option for relapsed patients after postoperative cisplatin-based adjuvant chemotherapy for resected NSCLC., (© 2014 S. Karger AG, Basel.)

Background: Dacomitinib (PF-00299804) is an oral, irreversible, small molecule inhibitor of human epidermal growth factor receptor-1, -2, and -4 tyrosine kinases., Methods: This phase I, open-label, dose-escalation study (clinicaltrials.gov: NCT00783328) primarily evaluated the safety and tolerability of dacomitinib by dose-limiting toxicity (DLT), and determined the clinically recommended phase II dose (RP2D) in Japanese patients with advanced solid tumors. Dacomitinib was administered orally at three dose levels (15, 30, or 45 mg once daily [QD]). Patients initially received a single dose, and after 9 days of follow-up, continuously QD in 21-day cycles. Endpoints included pharmacokinetics (PK) and antitumor activity., Results: Thirteen patients were assigned to the three dose levels (15 mg cohort: n = 3; 30 mg cohort: n = 3; 45 mg cohort: n = 7) according to a traditional '3 + 3' design. None of the treated patients experienced a DLT. Toxicities were manageable and similar in type to those observed in other studies. PK concentration parameters increased with dose over the range evaluated, with no evidence of accumulation over time. Of 13 evaluable patients, one with NSCLC (adenocarcinoma) had a partial response and nine patients had stable disease., Conclusions: Dacomitinib 45 mg QD was defined as the RP2D and demonstrated preliminary activity in Japanese patients with advanced solid tumors.

Contamination of the external surface of anticancer drug vials supplied to hospital pharmacies has been recognized as a potential health hazard. The aim of this study was to investigate the levels of contamination on the exterior surface of vials containing platinum anticancer drugs in Japan. Platinum contamination on the exterior surface of vials containing cisplatin or carboplatin was examined using products commercially available in Japan. Cisplatin vials from 42 batches (2 drug contents, 10 products and 5 manufacturers) and carboplatin vials from 28 batches (3 drug contents, 7 products and 3 manufacturers) were used. Five vials were randomly sampled from each batch. Exterior contamination levels of 0.070-144 ng/vial as cisplatin and 0.21-1630 ng/vial as carboplatin were detected. Significant differences in the levels of contamination among the batch numbers were observed in 6 of 10 cisplatin products and 6 of 7 carboplatin products. Significant differences in the levels of contamination were observed in 3 cisplatin products with different contents of drug within the vials and 1 carboplatin product with different contents of drug within the vials. Significant differences in the contamination levels among the cisplatin manufacturers but not carboplatin manufacturers were observed. The degree of contamination of the carboplatin products was significantly higher than that of the cisplatin products. In conclusion, external contamination was confirmed in all cisplatin and carboplatin vials tested. The degree of contamination was different among different batch numbers, drug contents, manufacturers, and platinum anticancer drug.

The efficacy of gefitinib for patients with non-adenocarcinoma non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations is unclear, because only a small percentage of patients enrolled in the clinical trials to evaluate the efficacy of gefitinib for tumors harboring EGFR mutation were non-adenocarcinoma NSCLC. A pooled analysis was conducted to clarify the efficacy of gefitinib for non-adenocarcinoma NSCLC patients harboring EGFR mutations. A systematic search of the PUBMED databases was conducted to identify all clinical reports that contained advanced non-adenocarcinoma NSCLC patients harboring EGFR mutations and treated with gefitinib. The selected patients were advanced non-adenocarcinoma NSCLC patients harboring EGFR mutations who were treated with gefitinib and described in reports containing the data of the histology, status of EGFR mutations and response to gefitinib. This study selected 33 patients from 15 reports. Twenty-seven and three of the 33 patients were squamous cell carcinoma and adenosquamous cell carcinoma, respectively. One patient each had large-cell carcinoma, pleomorphic carcinoma and spindle cell carcinoma. Twenty-one patients (64%) had sensitive EGFR mutations. The response rate (RR), disease control rate (DCR) and median progression-free survival (mPFS) was 27%, 67-70% and 3.0 months, respectively. These factors were statistically significantly inferior in the non-adenocarcinoma NSCLC patients harboring EGFR mutations to adenocarcinoma patients harboring EGFR mutations selected from the same published reports (RR: 27%vs 66%, P = 0.000028; DCR: 67-70%vs 92-93%, P = 0.000014; mPFS: 3.0 vs 9.4 months, P = 0.0001, respectively). Gefitinib is less effective in non-adenocarcinoma NSCLC harboring EGFR mutations than adenocarcinoma harboring EGFR mutations., (© 2011 Japanese Cancer Association.)

Background: The standard therapy for young patients with advanced non-small cell lung cancer (NSCLC) is platinum doublet therapy, whereas that for elderly patients with NSCLC is single-agent therapy. However, there is limited information about the platinum-based treatment for elderly patients., Purpose: The aim of this study is to examine the efficacy and safety of platinum-doublet therapy for elderly patients, retrospectively., Methods: There were 76 patients 75 years old or more with advanced NSCLC for whom chemotherapy was performed between June, 2008 and January, 2005. Among them, 65 patients except for 11 who underwent first-line gefitinib therapy were retrospectively reviewed., Results: Median age: 77 years old (range 75-83 years old), gender: male/female; 51/14, stage: III B/ IV ; 15/50, pathology: adeno/squamous/other; 41/13/11, PS: 0/1/2; 14/44/7 patients. Fifty-three patients received single-agent (S), whereas 12 patients received platinum-doublet (D). Even in the analysis of patients with PS 0-1, similar results were obtained. Progression-free survival (PFS)was 107 versus 85 days, and overall survival(OS)was 270 versus 262 days between S and D, in patients with PS 0-1. In addition, we did not recognize a large difference in toxicity between S and D., Conclusion: In this examination, we could not show a large difference in efficacy and toxicity between platinum-doublet therapy and single-agent therapy. Further study would be needed to confirm our results.

Gefitinib and erlotinib are commercially available epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) that are widely used for the treatment of non-small-cell lung cancer (NSCLC). Acute severe liver injury, although rare, has been observed in patients receiving these EGFR-TKIs. Some studies have reported that erlotinib treatment does not cause severe liver toxicity in patients with NSCLC who previously presented with severe liver injury during the course of gefitinib treatment. We retrospectively assessed the occurrence of liver toxicity in patients with NSCLC who were receiving erlotinib and had previously presented with severe gefitinib-induced liver injury.Severe liver injury occurred in only 1 of the 8 patients receiving erlotinib treatment. In this case, erlotinib was discontinued because of the onset of grade 3 skin rash and liver injury. After liver function was restored, erlotinib (100 mg) was administered at a lower dose; nonetheless, grade 4 liver injury occurred. Our findings suggest that it is necessary not only to explain the early symptoms of liver toxicity to patients who are receiving erlotinib treatment and have previously experienced gefitinib-induced severe liver injury but also to more closely monitor liver function.

Purpose: The use of erlotinib after gefitinib failure in patients with non-small cell lung cancer (NSCLC) is not clearly clarified in clinical practice. We sought to compile the available clinical reports to better understand the effectiveness of erlotinib after failure of gefitinib., Methods: We searched published reports including erlotinib and gefitinib. Eleven reports were identified (published between November 2004 and December 2008). Advanced NSCLC who documented progressive disease (PD) for gefitinib 250 mg/day, received erlotinib 150 mg once daily., Results: A total of 106 patients were pooled from these studies. Asian was observed in 70.8%, women in 72.6%, adenocarcinoma in 85.1%, never smoker in 75.3%. In erlotinib therapy, there was observed in 9.9% in partial response (PR), 18.9% in stable disease (SD) and 70.8% in PD. Disease control (DC) rate for gefitinib and erlotinib was 71.7% and 29.2%, respectively. No significant difference of disease control rate (37.5% vs 21.7%, p=0.1503) and response rate (6.3% vs 8.7%, p=1.000) was observed between patients with EGFR mutations and those with wild type EGFR. The significantly different response on erlotinib therapy was observed in patients who had shown SD for gefitinib therapy (p=0.0095) and those who had a PFS of more than 6 months during gefitinib treatment (p=0.0261). The common toxicities were skin rash and diarrhea., Conclusion: Erlotinib may produce clinical benefits in patients who had shown long SD on prior gefitinib therapy. Moreover, EGFR mutations were not positive predictors for erlotinib response after gefitinib failure., (Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.)

Background: The aim of this study is to evaluate the rate of long-term survival of more than 5 years in advanced non-small cell lung cancer (NSCLC)., Methods: One-hundred and twenty-four patients with advanced NSCLC treated with chemotherapy from September 2002 to October 2003 were reviewed., Results: Ten (8%) patients survived for more than 5 years. The median survival time (MST) for the 10 patients was 61.5 months, ranging from 60.1 to 81.0 months. All of the 10 patients had performance status (PS) 0 or 1 and adenocarcinoma. As the initial treatment, 9 patients were treated with a platinum-containing chemotherapy [median progressive free survival (PFS), 10.7 months] and 8 patients received gefitinib as the second or third line chemotherapy (median PFS, 28.7 months). Nine patients received cytotoxic agents after first line chemotherapy (median duration of the chemotherapy, 22.4 months). A mean regimen of chemotherapy was three (range, 1-8). Re-challenge of gefitinib was performed in 2 patients, and surgical resection of solitary brain metastasis was performed as the initial treatment in 2 patients., Conclusion: Our results suggest that good performance status, adenocarcinoma and EGFR-TKI therapy play an important role in the long-term survivors of more than 5 years.

1-(3-C-Ethynyl-beta-D-ribo-pentofuranosyl)cytosine (3'-Ethynylcytidine; ECyd), a ribonucleoside analog, has a potent cytotoxic activity against cancer cells. We have investigated the cancer-cell death induced by ECyd, focusing on its molecular mechanisms. In ECyd-treated cells, RNase L is activated and involved in c-jun NH(2)-terminal kinase (JNK) phosphorylation, followed by induction of mitochondria-dependent apoptosis. The mechanism of JNK phophorylation by RNase L was unknown. To investigate the mechanism, we performed the identification of RNase L-binding partners by proteomic approach using co-immunoprecipitation and mass spectrometry. We found that RNase L was associated with a protein (we named it Protein-190). At the same time, we observed that Protein-190 was amply phosphorylated. Furthermore, the participation of Protein-190 in the ECyd-induced apoptosis was supported by a knockdown experiment using small interfering RNA (siRNA). Thus, the number of ECyd-induced apoptotic cells was drastically decreased when Protein-190 was knocked-down. These results indicated Protein-190 as a regulator in apoptosis, and provide the possibility for a new clinical target in cancer chemotherapy.

RNase L functions as a tumor suppressor protein due to its role in apoptosis during viral infections and various agents treatment. RNase L-mediated apoptosis is accompanied by cytochrome c release from mitochondria and requires caspase-3 activity. It was reported that RNase L is involved in JNK activation during viral infections, and that JNK is essential for apoptosis in response to RNase L activation. However, the proximal signals of RNase L that trigger JNK activation have not as yet been identified, and it is possible that the interactions between RNase L and other proteins play an important role in the RNase L-JNK apoptotic signal pathway. To investigate this hypothesis, we attempted to identify the proteins associated with RNase L using coimmunoprecipitation. In this study, we found that RNase L was associated with other proteins. Here we identified the protein X by LC-MS/MS analysis. We demonstrated that this association was increased in the presence of activated RNase L. Moreover, Protein X was phosphorylated during the activation of RNase L by treatment with cytotoxic agent, ECyd, 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) cytosine and 2-5A. To reveal the role of protein X in RNase L-mediated apoptosis, we decreased the level of protein X by a small interfering RNA (siRNA). As a result, protein X deficient cells became resistant to the apoptosis mediated by RNase L, suggesting that protein X is related to RNase L-mediated apoptosis following JNK activation. Therefore, in this study, we report the identification of a novel protein, protein X that transduces between RNase L and JNK signals.

RNase L is an endoribonuclease that requires 2'-5' oligoadenylate to cleave single-stranded RNA. Although the antiviral effects of RNase L are well known because of its viral RNA degradation activity recently but it has been suggested that RNase L is concerned in mitochondrial-caspase dependent apoptotic signaling pathway induced by a number of anticancer agents. Moreover, it has variety of functions including translation and transcription of proteins. In this report, we found that 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) cytosine (ECyd), which inhibits RNA synthesis through competitive inhibition of RNA polymerase I induced 28S rRNA fragmentation. The cleavage pattern of rRNA induced by ECyd was similar and the cleavage sites were identical to those cleaved by RNase L. Additionaly, apoptosis induced by ECyd was elevated following the protein expression of RNase L in the tumor cells when treated with IFN-alpha2a which was known to induce RNase L expression. To identify the role of RNase L in apoptosis induced by ECyd, we detected the decreased level of RNase L by several folds in the tumor cell lines through a small interfering RNA (siRNA). These results indicated that RNase L might integrate apoptotic signals induced by ECyd and provide the possibility to be a novel clinical target for cancer chemotherapy.

We investigated the molecular mechanisms of cell death induced by 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd, TAS-106), a potent inhibitor of RNA synthesis, using mouse mammary tumor FM3A cells and human fibrosarcoma HT1080 cells. ECyd induced the characteristics of apoptosis on these cells, such as morphological changes, DNA fragmentations and caspase-3-like protease activation. General caspases inhibitor, Z-Asp-CH2-DCB inhibited cell death. Interestingly, we also found that ECyd induced rRNA fragmentation. The cleavage pattern of rRNA resembled in that mediated by RNase L. On the other hands, it was suggested that caspase-1, 3, 8 and 9 concerned with ECyd-induced apoptosis through mitochondria. ECyd-induced rRNA fragmentation was inhibited by general caspases inhibitor (Z-Asp-CH2-DCB) and caspase-5 inhibitor (Z-WEHD-fmk). So it is clear that caspase-5 (ICErel III/TY), member of ICE (Interleukin-1 beta-converting enzyme) protease, activated pathway concerned with ECyd-induced rRNA fragmentation. These results indicate that antitumor mechanisms of ECyd are involved in caspase-dependent activation of RNase L. rRNA fragmentation may occur one of the death events, as a result of inhibition of RNA synthesis and play an important role in the antitumor activity of ECyd.

The antitumor ribonucleoside analogue 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine (ECyd), synthesized in 1995, has strong antitumor activity. In mouse mammary tumor FM3A cells, ECyd was rapidly phosphorylated to ECyd-triphosphate (ECTP) as the final product, strongly inhibiting RNA synthesis. The ultimate metabolite of ECyd, ECTP, is stable in cultured FM3A cells with a half-life of 21 hr; ECyd is on a "closed" metabolic pathway to ECTP. Deaminated ECyd derivatives were minor metabolites in the cells treated with Ecyd; therefore cytidine forms probably were not converted to uridine forms at the nucleoside or nucleotide stage. The characteristics of ECyd may be important for the antitumor activity. RNA polymerase in the nucleus was inhibited competitively by ECTP; the ki value was 21 nM. ECyd induced DNA and 28S ribosomal RNA fragnetations. The cleavage pattern of rRNA resembled in that mediated by RNase L. The results suggested that RNase L related mechanisms might be involved in the antitumor activity of ECyd.

The 2''-O-, 3''-O- and 2'',3''-di-O-substituted derivatives (4a--p) of etoposide were prepared by nucleophilic substitution of 4'-O-benzyloxycarbonyletoposide (2) followed by deprotection. Controlled reaction (a limited amount of reagents and low temperature) was required for preparing the mono-O-substituted derivatives. In terms of ED125 values, doses which show 125% of T/C against P388 leukemia in mice, both the 2''-O-acetate (4a, ED125 = 0.18 mg/kg) and 3''-O-acetate (4b, 0.23 mg/kg) were nearly as active as etoposide (1, 0.19 mg/kg), while the 2'',3''-di-O-acetate (4c, 1.9 mg/kg) was somewhat less potent. In the replacement with other substituents, antitumor activity of the 2''-O-substituted derivatives was affected much more by the difference of the substituents as compared with that of the corresponding 3''-O-substituted derivatives. In the 2'',3''-di-O-substituted derivatives, the activity was decreased additively on the substituents.