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Background: Activation of the phosphoinisitide-3 kinase (PI3K) pathway through mutation and constitutive upregulation has been described in renal cell carcinoma (RCC), making it an attractive target for therapeutic intervention. We performed a randomized phase II study in vascular endothelial growth factor (VEGF) therapy refractory patients to determine whether MK-2206, an allosteric inhibitor of AKT, was more efficacious than the mammalian target of rapamycin inhibitor everolimus., Patients and Methods: A total of 43 patients were randomized in a 2:1 distribution, with 29 patients assigned to the MK-2206 arm and 14 to the everolimus arm. Progression-free survival (PFS) was the primary endpoint., Results: The trial was closed at the first futility analysis with an observed PFS of 3.68 months in the MK-2206 arm and 5.98 months in the everolimus arm. Dichotomous response rate profiles were seen in the MK-2206 arm with one complete response and three partial responses in the MK-2206 arm versus none in the everolimus arm. On the other hand, progressive disease was best response in 44.8% of MK2206 versus 14.3% of everolimus-treated patients. MK-2206 induced significantly more rash and pruritis than everolimus, and dose reduction occurred in 37.9% of MK-2206 versus 21.4% of everolimus-treated patients. Genomic analysis revealed that 57.1% of the patients in the PD group had either deleterious TP53 mutations or ATM mutations or deletions. In contrast, none of the patients in the non-PD group had TP53 or ATM defects. No predictive marker for response was observed in this small dataset., Conclusions: Dichotomous outcomes are observed when VEGF therapy refractory patients are treated with MK-2206, and MK-2206 does not demonstrate superiority to everolimus. Additionally, mutations in DNA repair genes are associated with early disease progression, indicating that dysregulation of DNA repair is associated with a more aggressive tumor phenotype in RCC., (© The Author 2017. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Cellular resistance to the antifolate methotrexate (MTX) is often caused by target amplification, uptake defects, or alterations in polyglutamylation. Here we have examined MTX cross-resistance in a human breast carcinoma cell line (MCF7/MX) selected in the presence of mitoxantrone, an anticancer agent associated with the multidrug resistance (MDR) phenotype. Examination of protein expression and enzyme activities showed that MCF7/MX cells displayed none of the classical mechanisms of MTX resistance. They did, however, exhibit an ATP-sensitive accumulation defect accompanied by reduced polyglutamylation. Although the kinetics of drug uptake was similar between parental and resistant cells, the resistant cells exhibited increased energy-dependent drug efflux. This suggested the involvement of an ATP-binding cassette (ABC) transporter. However, cells transfected with the breast cancer resistance protein (BCRP)-the ABC transporter known to be highly overexpressed in MCF7/MX cells and to confer mitoxantrone resistance (D. D. Ross et al., J. Natl. Cancer Inst. 91: 429-433, 1999)-were not MTX resistant, which suggested that this transporter is not involved in MTX cross-resistance. Moreover, members of the MRP protein family of transport proteins, which had previously been implicated in MTX resistance, were not found to be overexpressed in the MCF7/MX cells. Thus, our data suggest that a novel MTX-specific efflux pump may be involved in this unusual cross-resistance phenotype.

Background: Human cancer cell lines grown in the presence of the cytotoxic agent mitoxantrone frequently develop resistance associated with a reduction in intracellular drug accumulation without increased expression of the known drug resistance transporters P-glycoprotein and multidrug resistance protein (also known as multidrug resistance-associated protein). Breast cancer resistance protein (BCRP) is a recently described adenosine triphosphate-binding cassette transporter associated with resistance to mitoxantrone and anthracyclines. This study was undertaken to test the prevalence of BCRP overexpression in cell lines selected for growth in the presence of mitoxantrone., Methods: Total cellular RNA or poly A+ RNA and genomic DNA were isolated from parental and drug-selected cell lines. Expression of BCRP messenger RNA (mRNA) and amplification of the BCRP gene were analyzed by northern and Southern blot hybridization, respectively., Results: A variety of drug-resistant human cancer cell lines derived by selection with mitoxantrone markedly overexpressed BCRP mRNA; these cell lines included sublines of human breast carcinoma (MCF-7), colon carcinoma (S1 and HT29), gastric carcinoma (EPG85-257), fibrosarcoma (EPF86-079), and myeloma (8226) origins. Analysis of genomic DNA from BCRP-overexpressing MCF-7/MX cells demonstrated that the BCRP gene was also amplified in these cells., Conclusions: Overexpression of BCRP mRNA is frequently observed in multidrug-resistant cell lines selected with mitoxantrone, suggesting that BCRP is likely to be a major cellular defense mechanism elicited in response to exposure to this drug. It is likely that BCRP is the putative "mitoxantrone transporter" hypothesized to be present in these cell lines.

MCF-7/AdrVp is a multidrug-resistant human breast cancer subline that displays an ATP-dependent reduction in the intracellular accumulation of anthracycline anticancer drugs in the absence of overexpression of known multidrug resistance transporters such as P glycoprotein or the multidrug resistance protein. RNA fingerprinting led to the identification of a 2.4-kb mRNA that is overexpressed in MCF-7/AdrVp cells relative to parental MCF-7 cells. The mRNA encodes a 655-aa [corrected] member of the ATP-binding cassette superfamily of transporters that we term breast cancer resistance protein (BCRP). Enforced expression of the full-length BCRP cDNA in MCF-7 breast cancer cells confers resistance to mitoxantrone, doxorubicin, and daunorubicin, reduces daunorubicin accumulation and retention, and causes an ATP-dependent enhancement of the efflux of rhodamine 123 in the cloned transfected cells. BCRP is a xenobiotic transporter that appears to play a major role in the multidrug resistance phenotype of MCF-7/AdrVp human breast cancer cells.

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 microM 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.

PurposeThe clinical relevance of targeting the RAS/RAF/MEK/ERK pathway, activated in 70% to 80% of patients with acute myelogenous leukemia (AML), is unknown.Experimental designSelumetinib is an oral small-molecule inhibitor of MAP-ERK kinase (MEK)-1/2. Forty-seven patients with relapsed/refractory AML or 60 years old or more with untreated AML were enrolled on a phase II study. Patients were stratified by FLT3 ITD mutation status. The primary endpoint was response rate (complete, partial, and minor). Leukemia cells were analyzed for extracellular signal-regulated kinase (ERK) and mTOR phosphorylation.ResultsCommon drug-related toxicities were grade 1-2 diarrhea, fatigue, nausea, vomiting, and skin rash. In the FLT3 wild-type cohort, six of 36 (17%) patients had a response [one partial response, three minor responses, two unconfirmed minor responses (uMR)]. No patient with FLT3 ITD responded. NRAS and KRAS mutations were detected in 7% and 2% of patients, respectively. The sole patient with KRAS mutation had uMR with hematologic improvement in platelets. Baseline p-ERK activation was observed in 85% of patients analyzed but did not correlate with a response. A single-nucleotide polymorphism (SNP) rs3733542 in exon 18 of the KIT gene was detected in significantly higher number of patients with response/stable disease compared with nonresponders (60% vs. 23%; P = 0.027).ConclusionsSelumetinib is associated with modest single-agent antileukemic activity in advanced AML. However, given its favorable toxicity profile, combination with drugs that target other signaling pathways in AML should be considered. The potential association of SNP rs3733542 in exon 18 of the KIT gene with antileukemic activity of selumetinib is intriguing, but will require validation in larger trials.

Summary: Purpose. Targeting the vascular endothelial growth factor (VEGF) pathway improves progression free survival in multiple advanced malignancies but durable responses are uncommon. Inhibition of the VEGF pathway at multiple levels of signal transduction may improve clinical outcomes. Preclinical data with cediranib, an inhibitor of all 3 VEGF receptors, in combination with selumetinib, an inhibitor of MEK 1/2, demonstrated improved tumor control experimentally. This phase I trial was designed to test the two agents in combination to evaluate the tolerability, safety and assess disease response. Methods. Patients with advanced solid malignancies were enrolled into this phase I trial. Cediranib and selumetinib were dosed using a toxicity-adaptive isotonic design for the dose escalation/de-escalation of each agent. Both cediranib and selumetinib were administered daily and continuously. Cycles were 28 days in length. Results. Eighteen patients were enrolled. At all dose levels, dose limiting toxicities (DLT) were observed, which limited dose escalation and further evaluation. The maximum tolerated dose of cediranib and selumetinib in combination could not be determined. The best response of stable disease was observed in eight patients. Conclusions. Cediranib and selumetinib in combination on a continuous schedule was not tolerable, with patients experiencing cardiovascular and other DLTs. Intermittent schedules may be needed to establish a safe and tolerable combination of cediranib and selumetinib. [ABSTRACT FROM AUTHOR]

Purpose PI3K/AKT/mTOR and RAS/RAF/MEK pathways are frequently dysregulated in colorectal cancer (CRC). We conducted a biomarker-driven trial of the combination of MK-2206, an allosteric AKT 1/2/3 inhibitor, and selumetinib, a MEK 1/2 inhibitor, in patients with CRC to evaluate inhibition of phosphorylated ERK (pERK) and AKT (pAKT) in paired tumor biopsies. Patients and Methods Adult patients with advanced CRC were enrolled in successive cohorts stratified by KRAS mutation status. Initially, 12 patients received oral MK-2206 90 mg weekly with oral selumetinib 75 mg daily in 28-day cycles. Following an interim analysis, the doses of MK-2206 and selumetinib were increased to 135 mg weekly and 100 mg daily, respectively. Paired tumor biopsies were evaluated for target modulation. Results Common toxicities were gastrointestinal, hepatic, dermatologic, and hematologic. Of 21 patients enrolled, there were no objective responses. Target modulation did not achieve the pre-specified criteria of dual 70 % inhibition of pERK and pAKT levels in paired tumor biopsies. Conclusion Despite strong scientific rationale and preclinical data, clinical activity was not observed. The desired level of target inhibition was not achieved. Overlapping toxicities limited the ability to dose escalate to achieve exposures likely needed for clinical activity, highlighting the challenges in developing optimal combinations of targeted agents. [ABSTRACT FROM AUTHOR]

Background:Eribulin mesylate is a synthetic macrocyclic ketone analogue of Halichondrin B that has demonstrated high antitumor activity in preclinical and clinical settings. This phase I study aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics in combination with cisplatin (CP) in patients with advanced solid tumours.Methods:Thirty-six patients with advanced solid tumours received eribulin mesylate 0.7-1.4 mg m−2 and CP 60-75 mg m−2. Eribulin mesylate was administered on days 1, 8, and 15 in combination with CP day 1 every 28-day cycle. The protocol was amended after dose level 4 (eribulin mesylate 1.4 mg m−2, CP 60 mg m−2) when it was not feasible to administer eribulin mesylate on day 15 because of neutropenia; the treatment schedule was changed to eribulin mesylate on days 1 and 8 and CP on day 1 every 21 days.Results:On the 28-day schedule, three patients had DLT during the first cycle: grade (G) 4 febrile neutropenia (1.0 mg m−2, 60 mg m−2); G 3 anorexia/fatigue/hypokalemia (1.2 mg m−2, 60 mg m−2); and G 3 stomatitis/nausea/vomiting/fatigue (1.4 mg m−2, 60 mg m−2). On the 21-day schedule, three patients had DLT during the first cycle: G 3 hypokalemia/hyponatremia (1.4 mg m−2, 60 mg m−2); G 4 mucositis (1.4 mg m−2, 60 mg m−2); and G 3 hypokalemia (1.2 mg m−2, 75 mg m−2). The MTD and recommended phase II dose was determined as eribulin mesylate 1.2 mg m−2 (days 1, 8) and CP 75 mg m−2 (day 1), on a 21-day cycle. Two patients had unconfirmed partial responses (PR) (pancreatic and breast cancers) and two had PR (oesophageal and bladder cancers).Conclusions:On the 21-day cycle, eribulin mesylate 1.2 mg m−2, administered on days 1 and 8, in combination with CP 75 mg m−2, administered on day 1 is well tolerated and showed preliminary anticancer activity. [ABSTRACT FROM AUTHOR]

Background: Human cancer cell lines grown in the presence of the cytotoxic agent mitoxantrone frequently develop resistance associated with a reduction in intracellular drug accumulation without increased expression of the known drug resistance transporters P-glycoprotein and multidrug resistance protein (also known as multidrug resistance-associated protein). Breast cancer resistance protein (BCRP) is a recently described adenosine triphosphate-binding cassette transporter associated with resistance to mitoxantrone and anthracyclines. This study was undertaken to test the prevalence of BCRP overexpression in cell lines selected for growth in the presence of mitoxantrone.Methods: Total cellular RNA or poly A+ RNA and genomic DNA were isolated from parental and drug-selected cell lines. Expression of BCRP messenger RNA (mRNA) and amplification of the BCRP gene were analyzed by northern and Southern blot hybridization, respectively.Results: A variety of drug-resistant human cancer cell lines derived by selection with mitoxantrone markedly overexpressed BCRP mRNA; these cell lines included sublines of human breast carcinoma (MCF-7), colon carcinoma (S1 and HT29), gastric carcinoma (EPG85-257), fibrosarcoma (EPF86-079), and myeloma (8226) origins. Analysis of genomic DNA from BCRP-overexpressing MCF-7/MX cells demonstrated that the BCRP gene was also amplified in these cells.Conclusions: Overexpression of BCRP mRNA is frequently observed in multidrug-resistant cell lines selected with mitoxantrone, suggesting that BCRP is likely to be a major cellular defense mechanism elicited in response to exposure to this drug. It is likely that BCRP is the putative "mitoxantrone transporter" hypothesized to be present in these cell lines. [ABSTRACT FROM AUTHOR]

Purpose: Both docetaxel (DOC), a promoter and stabilizer of microtubule assembly, and topotecan (TOPO), a topoisomerase I inhibitor, have shown antitumor activity in a variety of solid tumor malignancies. This phase I trial was conducted to determine the overall and dose-limiting toxicities (DLT), the maximum tolerated dose (MTD) and the pharmacokinetics of the combination of DOC and TOPO in patients with advanced solid tumor malignancies. Methods: DOC was administered first at 60 mg/m2 without G-CSF and at 60, 70, and 80 mg/m2 with G-CSF by 1-h infusion on day 1 of the odd-numbered cycles (1, 3, 5, etc.) and on day 4 of the even-numbered cycles (2, 4, 6, etc.). TOPO 0.75 mg/m2 was administered as a 30-min infusion on days 1, 2, 3 and 4 of each cycle. G-CSF 300 μg was administered subcutaneously (s.c.) on days 5–14. Cycles were repeated every 21 days. All patients were premedicated with dexamethasone 8 mg orally every 12 h for a total of six doses starting on the day before DOC infusion. Results: A total of 22 patients were treated. Six patients were treated in cohort I with DOC and TOPO doses of 60 and 0.75 mg/m2, respectively, without G-CSF, and two patients developed DLT (febrile neutropenia). Four patients were treated in cohort II with DOC and TOPO doses of 60 and 0.75 mg/m2, respectively, with G-CSF, and no DLT was observed. Four patients were treated in cohort III with DOC and TOPO doses of 80 and 0.75 mg/m2, respectively, with G-CSF, and three developed DLT (febrile neutropenia). DOC was then de-escalated to 70 mg/m2 and delivered with TOPO 0.75 mg/m2 and G-CSF (cohort IV). Eight patients were treated at this dose level, and one DLT (febrile neutropenia) was observed. Two patients developed a severe hypersensitivity reaction shortly after the DOC infusion was started, one in cycle 1 and one in cycle 2. Both patients were removed from the study. Two patients developed severe dyspnea in the presence of progressive pulmonary metastases. Other nonhematological toxicities were mild. One patient with extensively pretreated ovarian carcinoma had a partial response, and eight patients with various solid tumor malignancies had stable disease with a median time to progression of 12 weeks (range 9–18 weeks). Administration of TOPO on days 1–4 and DOC on day 4 resulted in increased neutropenia. Conclusions: DOC 80 mg/m2 given first as a 1-h infusion on day 1 with TOPO 0.75 mg/m2 given as a 0.5-h infusion on days 1, 2, 3 and 4 with G-CSF was considered the MTD. The recommended phase II dose for DOC given on day 1 is 70 mg/m2 with TOPO 0.75 mg/m2 given on days 1, 2, 3 and 4 every 21 days with G-CSF 300 μg s.c. on days 5–14. The alternative schedule with DOC given on day 4 and TOPO on days 1–4 is not recommended. [ABSTRACT FROM AUTHOR]

Purpose: To determine the feasibility and toxicity of the addition of cetuximab with paclitaxel, carboplatin, and radiation for patients with esophagogastric cancer on a Phase II study. Methods and Materials: Patients with locoregional esophageal and proximal gastric cancer without distant organ metastases were eligible. All patients received cetuximab, paclitaxel, and carboplatin weekly for 6 weeks with 50.4 Gy radiation. Results: Sixty patients were enrolled, 57 with esophageal cancer and 3 with gastric cancer. Forty-eight had adenocarcinoma and 12 had squamous cell cancer. Fourteen of 60 patients (23%) had Grade 3 dermatologic toxicity consisting of a painful, pruritic acneiform rash on the face outside of the radiation field. The rates of Grades 3 and 4 esophagitis were 12% and 3%, respectively. Three patients had Grade 3/4 cetuximab hypersensitivity reactions and were not assessable for response. Forty of 57 patients (70%) had a complete clinical response after chemoradiation. Conclusion: Cetuximab can be safely administered with chemoradiation for esophageal cancer. Dermatologic toxicity and hypersensitivity reactions were associated with the addition of cetuximab. There was no increase in esophagitis or other radiation-enhanced toxicity. [Copyright &y& Elsevier]