Epithelial Transfer of the Tyrosine Kinase Inhibitors Erlotinib, Gefitinib, Afatinib, Crizotinib, Sorafenib, Sunitinib, and Dasatinib: Implications for Clinical Resistance.

Background: tyrosine kinase inhibitors (TKIs) inhibit phosphorylation of signaling proteins. TKIs often show large variations in the clinic due to poor pharmacology, possibly leading to resistance. We compared gut absorption of inhibitors of epidermal growth factor receptor (erlotinib, gefitinib, and afatinib), ALK-cMET (crizotinib), PDGFR/BCR-Abl (dasatinib), and multikinase inhibitors (sunitinib and sorafenib). In clinical samples, we measured the disposition of each compound within various blood compartments. Methods: we used an optimized CaCo2 gut epithelial model to characterize 20 µM TKI absorption. The apical/basolateral transfer is considered to represent the gut/blood transfer. Drugs were measured using LC-MS/MS. Results: sorafenib and sunitinib showed the highest apical/basolateral transfer (Papp 14.1 and 7.7 × 10-6 cm/s, respectively), followed by dasatinib (3.4), afatinib (1.5), gefitinib (0.38), erlotinib (0.13), and crizotinib (n.d.). However, the net absorptions for dasatinib, afatinib, crizotinib, and erlotinib were highly negative (efflux ratios >5) or neutral/negative, sorafenib (0.86), gefitinib (1.0), and sunitinib (1.6). A high negative absorption may result in resistance because of a poor exposure of tissues to the drug. Accumulation of the TKIs at the end of the transfer period (A->B) was not detectable for erlotinib, very low for afatinib 0.45 pmol/µg protein), followed by gefitinib (0.79), dasatinib (1.1), sorafenib (1.65), and crizotinib (2.11), being highest for sunitinib (11.9). A similar pattern was found for accumulation of these drugs in other colon cell lines, WiDr and HT29. In clinical samples, drugs accumulated consistently in red blood cells; blood to plasma ratios were all > 3 (sorafenib) or over 30 for erlotinib. Conclusions: TKIs are consistently poorly absorbed, but accumulation in red blood cells seems to compensate for this.

Phase I Dose-Escalation Study of Once Weekly or Once Every Two Weeks Administration of High-Dose Sunitinib in Patients With Refractory Solid Tumors.

PURPOSE: Dose and schedule optimization of treatment with tyrosine kinase inhibitors is of utmost importance. On the basis of preclinical data, a phase I clinical trial of once weekly or once every 2 weeks administration of high-dose sunitinib in patients with refractory solid malignancies was conducted. PATIENTS AND METHODS: Patients with advanced cancer refractory to standard treatment were eligible. With use of a standard 3 + 3 phase I design, patients received escalating doses of sunitinib, in 100 mg increments, starting at 200 mg once weekly. In both the once weekly and once every 2 weeks cohorts, 10 more patients were included at the maximum tolerated dose level. Primary end points were safety and tolerability. RESULTS: Sixty-nine patients with advanced cancer, predominantly colorectal cancer (42%), were treated with this alternative dosing regimen. Maximum tolerated dose was established at 300 mg once weekly and 700 mg once every 2 weeks, resulting in nine- and 18-fold higher maximum plasma concentrations compared with standard dose, respectively. Treatment was well tolerated, with fatigue (81%), nausea (48%), and anorexia (33%) being the most frequent adverse events. The only grade 3 or 4 treatment-related adverse event in 5% or more of patients was fatigue (6%). Sixty-three percent of patients had significant clinical benefit, with a 30% progression-free survival of 5 months or more. CONCLUSION: Sunitinib administered once weekly at 300 mg or once every 2 weeks at 700 mg is feasible, with comparable tolerability as daily administration. Administration of 700 mg once every 2 weeks can be considered as the most optimal schedule because of the highest maximum plasma concentration being reached. The promising preliminary antitumor activity of this alternative schedule in heavily pretreated patients warrants further clinical evaluation and might ultimately indicate a class characteristic of tyrosine kinase inhibitors.

Development of bioluminescent chick chorioallantoic membrane (CAM) models for primary pancreatic cancer cells: a platform for drug testing.

The aim of the present study was to develop chick-embryo chorioallantoic membrane (CAM) bioluminescent tumor models employing low passage cell cultures obtained from primary pancreatic ductal adenocarcinoma (PDAC) cells. Primary PDAC cells transduced with lentivirus expressing Firefly-luciferase (Fluc) were established and inoculated onto the CAM membrane, with >80% engraftment. Fluc signal reliably correlated with tumor growth. Tumor features were evaluated by immunohistochemistry and genetic analyses, including analysis of mutations and mRNA expression of PDAC pivotal genes, as well as microRNA (miRNA) profiling. These studies showed that CAM tumors had histopathological and genetic characteristic comparable to the original tumors. We subsequently tested the modulation of key miRNAs and the activity of gemcitabine and crizotinib on CAM tumors, showing that combination treatment resulted in 63% inhibition of tumor growth as compared to control (p < 0.01). These results were associated with reduced expression of miR-21 and increased expression of miR-155. Our study provides the first evidence that transduced primary PDAC cells can form tumors on the CAM, retaining several histopathological and (epi)genetic characteristics of original tumors. Moreover, our results support the use of these models for drug testing, providing insights on molecular mechanisms underlying antitumor activity of new drugs/combinations.

Alternative scheduling of pulsatile, high dose sunitinib efficiently suppresses tumor growth.

BACKGROUND: Increased exposure to multitargeted kinase inhibitor sunitinib is associated with improved outcome, emphasizing the importance of maintaining adequate dosing and drug levels. The currently approved schedule (50 mg daily, four weeks on, two weeks off) precludes further dose-intensification. Recent data suggest that sunitinib, although initially developed as an antiangiogenic agent, has direct antitumor activity. METHODS: In this study, we tested whether a chemotherapy-like schedule of pulsatile high dose sunitinib would result in improved antitumor activity. RESULTS: In vitro, a single exposure to 20 µM sunitinib for 6-9 h resulted in complete inhibition of tumor cell growth and cell death conveyed through activation of caspases and autophagy upregulation. Notably, repeated exposure of tumor cells to pulses of high concentrations of sunitinib did not induce resistance. In vivo, once-weekly treatment with high dose sunitinib of tumors growing on the chorioallantoic membrane (CAM) of the chicken embryo significantly impaired tumor growth by 57 % compared to vehicle, outperforming the daily, standard scheduling. CONCLUSIONS: These results prompted the initiation of a phase I clinical trial, where intermittent, high dose sunitinib is being investigated in patients with advanced solid tumors (registration number and date: NCT02058901, 30 September 2013, respectively). The trial is actively recruiting patients and promising preliminary indications of antitumor activity have been observed.

Response and toxicity prediction by MALDI-TOF-MS serum peptide profiling in patients with non-small cell lung cancer.

PURPOSE: We validated a previously reported proteomic signature, associated with treatment outcome, in an independent cohort of patients with non-small cell lung cancer (NSCLC). A novel peptide signature was developed to predict toxicity. EXPERIMENTAL DESIGN: Using automated magnetic C18 bead-assisted serum peptide capture coupled to MALDI-TOF MS, we conducted serum peptide profiling of 50 NCSLC patients participating in a phase II trial of erlotinib and sorafenib. On the obtained peptide mass profiles, we applied a previously described proteomic classification algorithm. Additionally, associations between observed side effects and peptide profiles were investigated. RESULTS: Application of the previously acquired algorithm successfully classified the new cohort of patients in groups significantly associated with the outcome. The "poor" group exhibited shorter median progression-free survival (PFS) and overall survival (OS) of 1.35 and 1.98 months (with p = 0.00677 and p = 0.00002, respectively) while the "good" group had significantly longer PFS and OS (10.63 and 14.4 months with p = 0.00142 and p = 0.00002, respectively), compared to average OS and PFS. Two specific peptides were detected in the sera of all patients that developed severe toxicity. CONCLUSIONS AND CLINICAL RELEVANCE: Our results provide an algorithm that, following prospective validation in larger cohorts, could assist treatment selection of patients with NSCLC in the first line setting.

Cross-resistance to clinically used tyrosine kinase inhibitors sunitinib, sorafenib and pazopanib.

PURPOSE: When during cancer treatment resistance to a tyrosine kinase inhibitor (TKI) occurs, switching to another TKI is often considered as a reasonable option. Previously, we reported that resistance to sunitinib may be caused by increased lysosomal sequestration, leading to increased intracellular lysosomal storage and, thereby, inactivity. Here, we studied the effect of several other TKIs on the development of (cross-) resistance. METHODS: TKI resistance was induced by continuous exposure of cancer cell lines to increasing TKI concentrations for 3-4 months. (Cross-) resistance was evaluated using MTT cell proliferation assays. Intracellular TKI concentrations were measured using LC-MS/MS. Western blotting was used to detect lysosome-associated membrane protein-1 and -2 (LAMP1/2) expression. RESULTS: The previously generated sunitinib-resistant (SUN) renal cancer cells (786-O) and colorectal cancer cells (HT-29) were found to be cross-resistant to pazopanib, erlotinib and lapatinib, but not sorafenib. Exposure of 786-O and HT-29 cells to sorafenib, pazopanib or erlotinib for 3-4 months induced drug resistance to pazopanib and erlotinib, but not sorafenib. Intracellular drug accumulation was found to be increased in pazopanib- and erlotinib-, but not in sorafenib-exposed cells. Lysosomal capacity, reflected by LAMP1/2 expression, was found to be increased in resistant cells and, in addition, to be transient. No cross-resistance to the mTOR inhibitor everolimus was detected. CONCLUSIONS: Our data indicate that tumor cells can develop (cross-) resistance to TKIs, and that such resistance includes increased intracellular drug accumulation accompanied by increased lysosomal storage. Transient (cross-) resistance was found to occur for several of the TKIs tested, but not for everolimus, indicating that switching from a TKI to a mTOR inhibitor may be an attractive therapeutic option.

A phase II study of metronomic oral vinorelbine administered in the second line and beyond in non-small cell lung cancer (NSCLC): a phase II study of the Hellenic Oncology Research Group.

INTRODUCTION: Frequent administration of low doses of cytotoxic drugs (metronomic chemotherapy) has been suggested to suppress tumour growth possibly by inhibiting angiogenesis. We evaluated a metronomic regimen of oral vinorelbine in pre-treated patients with advanced non-small cell lung cancer (NSCLC). METHODS: Forty-six pre-treated NSCLC patients received oral vinorelbine at a fixed dose of 50 mg three times a week. RESULTS: Treatment was administered as second-line in 12 (26·1%) patients and as third- or further-line in 34 (73·9%). Grade 3-4 neutropenia was observed in 23·9% and febrile neutropenia in 10·9%. Grade 3 fatigue was the most common severe non-hematologic toxicity (10·9%). Response rate was 10·9%; 19·6% achieved disease stabilization. Median tumour progression (TTP) was 2·2 months, median overall survival 9·4 months and the 1-year survival rate was 30·1%. CONCLUSION: The administration of metronomic oral vinorelbine is feasible and results in acceptable clinical efficacy associated with manageable toxicity in a population consisting mostly of heavily pre-treated NSCLC patients.

A multicenter phase I trial of metronomic oral vinorelbine plus cisplatin in patients with NSCLC.

The purpose of the present study was to determine the maximum-tolerated doses (MTDs) and the dose-limiting toxicities of a metronomic administration of oral vinorelbine and cisplatin in patients with advanced/metastatic NSCLC. Twenty-six patients with advanced/metastatic NSCLC were enrolled. Escalating doses of vinorelbine (40-70 mg p.o./trice per week) and cisplatin (70-85 mg/m(2) intravenous infusion) were administered on day 1 every 3 weeks. ΜΤDs were reached at 60 mg thrice/week p.o. for vinorelbine and 85 mg/m(2) for cisplatin. Grade 4 neutropenia, febrile neutropenia and grade 4 diarrhea were the dose-limiting events during the first cycle of chemotherapy. The most common grade III-IV hematologic toxicity was neutropenia occurring in seven (27%) patients, while non-hematological toxicities were relatively infrequent and mostly of grade I or II. Objective responses were observed in 20.8% of patients with measurable disease. The regimen of metronomic administration and cisplatin is feasible and active in patients with NSCLC.

Second-line chemotherapy with capecitabine (Xeloda) and docetaxel (Taxotere) in previously treated, unresectable adenocarcinoma of pancreas: the final results of a phase II trial.

PURPOSE: To investigate the efficacy and toxicity of the docetaxel and capecitabine combination in patients with previously treated, unresectable adenocarcinoma of the pancreas. PATIENTS AND METHODS: Patients with pancreatic adenocarcinoma, pre-treated with gemcitabine-based chemotherapy, were treated with capecitabine (800 mg/m(2) orally, twice a day for 14 days) and docetaxel (75 mg/m(2) i.v, on day 1), every 3 weeks. The primary end-point was overall response rate (RR). RESULTS: Thirty-one patients were enrolled in the study; 93.6% of them had a performance status (PS) of 0-1 and 96.8% had stage IV disease. Patients received a median of 4 cycles/patient, and the main reason for treatment discontinuation was disease progression. Partial response was observed in three (9.7%) patients, stable disease in seven (22.6%) (disease control rate: 32.3%, 95% CI: 15.80-48.71%) and disease progression in 21 (67.6%). The median progression-free survival (PFS) was 2.4 months (95% CI: 1.6-3.13) and the median overall survival (OS) was 6.3 months (95% CI: 3.38-9.23); the estimated 1-year survival rate was 14.7%. Grade III/IV neutropenia occurred in 10 (32.2%) patients and febrile neutropenia in one patient. Other severe non-hematologic toxicities were mild and manageable. After 2 chemotherapy cycles, pain control occurred in 20% of patients and stabilization of body weight in 40%. CONCLUSION: The combination of docetaxel/capecitabine may confer good disease control associated with improvement of quality of life as second-line chemotherapy in patients with metastatic pancreatic cancer.