Imatinib Mesylate Inhibits Platelet-Derived Growth Factor Receptor Phosphorylation of Melanoma Cells But Does Not Affect Tumorigenicity In Vivo

Platelet-derived growth factor (PDGF) and its cognate receptor are widely expressed on melanomas. Coexpression of the growth factor and receptor suggests their role in autocrine or paracrine growth mechanisms. Imatinib mesylate was previously reported to have specific activity in inhibiting select tyrosine kinase receptors, including PDGF and c-Kit. Melanoma cells express abundant levels of the PDGF receptor (PDGFR). Nevertheless, c-Kit expression is progressively lost as the cells take on a more highly metastatic phenotype. To investigate the potential of imatinib mesylate as a therapy for melanoma, we studied its effect on the growth of melanoma cells using an in vivo mouse model. Melanoma cells with high malignant potential (PDGFR-positive, c-Kit-negative) or low malignant potential (PDGFR-positive, c-Kit-positive) were injected subcutaneously into athymic nude mice. Mice were treated with imatinib mesylate (100 mg/kg three times weekly) or with phosphate-buffered saline for 4 to 6 wk. PDGFR-α and -β were expressed on all melanoma cell lines tested. The level of PDGFR expression correlated with the metastatic potential of the melanoma cells: higher levels of PDGFR-α were expressed on cells with higher metastatic potential, and higher levels of PDGFR-β were expressed on cells with lower metastatic potential. There was no significant difference in tumor size between treated and control mice. Immunohistochemical studies demonstrated inhibition of PDGFR phosphorylation on the tumors from mice treated with imatinib mesylate but not from control mice, suggesting that the receptors were functional and that the concentration of drug used was appropriate. Our data demonstrated that imatinib mesylate blocked both PDGFR-α and PDGFR-βin vivo. It did not, however, affect the growth of melanoma cells expressing PDGFR, regardless of whether the cells expressed c-Kit

Effect of visceral metastases on the efficacy and safety of everolimus in postmenopausal women with advanced breast cancer: Subgroup analysis from the BOLERO-2 study

AbstractBackgroundEverolimus (EVE; an inhibitor of mammalian target of rapamycin [mTOR]) enhances treatment options for postmenopausal women with hormone-receptor-positive (HR+), human epidermal growth factor receptor-2-negative (HER2–) advanced breast cancer (ABC) who progress on a non-steroidal aromatase inhibitor (NSAI). This is especially true for patients with visceral disease, which is associated with poor prognosis. The BOLERO-2 (Breast cancer trial of OraL EveROlimus-2) trial showed that combination treatment with EVE and exemestane (EXE) versus placebo (PBO)+EXE prolonged progression-free survival (PFS) by both investigator (7.8 versus 3.2months, respectively) and independent (11.0 versus 4.1months, respectively) central assessment in postmenopausal women with HR+, HER2– ABC recurring/progressing during/after NSAI therapy. The BOLERO-2 trial included a substantial proportion of patients with visceral metastases (56%).MethodsPrespecified exploratory subgroup analysis conducted to evaluate the efficacy and safety of EVE+EXE versus PBO+EXE in a prospectively defined subgroup of patients with visceral metastases.FindingsAt a median follow-up of 18months, EVE+EXE significantly prolonged median PFS compared with PBO+EXE both in patients with visceral metastases (N=406; 6.8 versus 2.8months) and in those without visceral metastases (N=318; 9.9 versus 4.2months). Improvements in PFS with EVE+EXE versus PBO+EXE were also observed in patients with visceral metastases regardless of Eastern Cooperative Oncology Group performance status (ECOG PS). Patients with visceral metastases and ECOG PS 0 had a median PFS of 6.8months with EVE+EXE versus 2.8months with PBO+EXE. Among patients with visceral metastases and ECOG PS ⩾1, EVE+EXE treatment more than tripled median PFS compared with PBO+EXE (6.8 versus 1.5months).InterpretationAdding EVE to EXE markedly extended PFS by ⩾4months among patients with HR+ HER2– ABC regardless of the presence of visceral metastases.FundingNovartis

Everolimus plus exemestane for hormone-receptor-positive, human epidermal growth factor receptor-2-negative advanced breast cancer: overall survival results from BOLERO-2†.

The BOLERO-2 study previously demonstrated that adding everolimus (EVE) to exemestane (EXE) significantly improved progression-free survival (PFS) by more than twofold in patients with hormone-receptor-positive (HR(+)), HER2-negative advanced breast cancer that recurred or progressed during/after treatment with nonsteroidal aromatase inhibitors (NSAIs). The overall survival (OS) analysis is presented here.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Dacomitinib versus erlotinib in patients with advanced-stage, previously treated non-small-cell lung cancer (ARCHER 1009): A randomised, double-blind, phase 3 trial

Background: Dacomitinib is an irreversible pan-EGFR family tyrosine kinase inhibitor. Findings from a phase 2 study in non-small cell lung cancer showed favourable efficacy for dacomitinib compared with erlotinib. We aimed to compare dacomitinib with erlotinib in a phase 3 study. Methods: In a randomised, multicentre, double-blind phase 3 trial in 134 centres in 23 countries, we enrolled patients who had locally advanced or metastatic non-small-cell lung cancer, progression after one or two previous regimens of chemotherapy, Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, and presence of measurable disease. We randomly assigned patients in a 1:1 ratio to dacomitinib (45 mg/day) or erlotinib (150 mg/day) with matching placebo. Treatment allocation was masked to the investigator, patient, and study funder. Randomisation was stratified by histology (adenocarcinoma vs non-adenocarcinoma), ethnic origin (Asian vs non-Asian and Indian sub-continent), performance status (0-1 vs 2), and smoking status (never-smoker vs ever-smoker). The coprimary endpoints were progression-free survival per independent review for all randomly assigned patients, and for all randomly assigned patients with KRAS wild-type tumours. The study has completed accrual and is registered with ClinicalTrials.gov, number NCT01360554. Findings: Between June 22, 2011, and March 12, 2013, we enrolled 878 patients and randomly assigned 439 to dacomitinib (256 KRAS wild type) and 439 (263 KRAS wild type) to erlotinib. Median progression-free survival was 2.6 months (95% CI 1.9-2.8) in both the dacomitinib group and the erlotinib group (stratified hazard ratio [HR] 0.941, 95% CI 0.802-1.104, one-sided log-rank p=0.229). For patients with wild-type KRAS, median progression-free survival was 2.6 months for dacomitinib (95% CI 1.9-2.9) and erlotinib (95% CI 1.9-3.0; stratified HR 1.022, 95% CI 0.834-1.253, one-sided p=0.587). In patients who received at least one dose of study drug, the most frequent grade 3-4 adverse events were diarrhoea (47 [11%] patients in the dacomitinib group vs ten [2%] patients in the erlotinib group), rash (29 [7%] vs 12 [3%]), and stomatitis (15 [3%] vs two [Interpretation: Irreversible EGFR inhibition with dacomitinib was not superior to erlotinib in an unselected patient population with advanced non-small-cell lung cancer or in patients with KRAS wild-type tumours. Further study of irreversible EGFR inhibitors should be restricted to patients with activating EGFR mutations. Funding: Pfizer.</p