Dose Of Gemcitabine Research Articles

A novel assay revealed that ribonucleotide reductase is functionally important for interstrand DNA crosslink repair

Cells have evolved complex biochemical pathways for DNA interstrand crosslink (ICL) removal. Despite the chemotherapeutic importance of ICL repair, there have been few attempts to identify which mechanistic DNA repair inhibitor actually inhibits ICL repair. To identify such compounds, a new and robust ICL repair assay was developed using a novel plasmid that contains synthetic ICLs between a CMV promoter region that drives transcription and a luciferase reporter gene, and an SV40 origin of replication and the large T antigen (LgT) gene that enables self-replication in mammalian cells. In a screen against compounds that are classified as inhibitors of DNA repair or synthesis, the reporter generation was exquisitely sensitive to ribonucleotide reductase (RNR) inhibitors such as gemcitabine and clofarabine, but not to inhibitors of PARP, ATR, ATM, Chk1, and others. The effect was observed also by siRNA downregulation of RNR. Moreover, the reporter generation was also particularly sensitive to 3-AP, a non-nucleoside RNR inhibitor, but not significantly sensitive to DNA replication stressors, suggesting that the involvement of RNR in ICL repair is independent of incorporation of a nucleotide RNR inhibitor into DNA to induce replication stress. The reporter generation from a modified version of the plasmid that lacks the LgT-SV40ori motif was also adversely affected by RNR inhibitors, further indicating a role for RNR in ICL repair that is independent of DNA replication. Intriguingly, unhooking of cisplatin-ICL from nuclear DNA was significantly inhibited by low doses of gemcitabine, suggesting an unidentified functional role for RNR in the process of ICL unhooking. The assay approach could identify other molecules essential for ICLR in quantitative and flexible manner.

Concurrent pelvic radiation with weekly low-dose cisplatin and gemcitabine as primary treatment of locally advanced cervical cancer: A phase II study

Purpose: This study was done to evaluate response, compliance and survival of weekly low dose cisplatin (20 mg/m 2 ) and gemcitabine (125 mg/m 2 ) concurrently with pelvic radiation as primary treatment of stage IIB-IIIB cervical cancer. Methods: External radiation consisted of 50 Gy/25 fractions using 6-10 MV photon followed by 600 cGy boost to parametrium if it was still felt thickened. Then, intracavitary radiotherapy to deliver 60 Gy at point A. Chemotherapy consisted of gemcitabine at a dose of 125 mg/ m 2 was given by i.v infusion over 30 minutes immediately after cisplatin 20 mg/ m 2 weekly for 5 weeks during EBRT. Forty–five eligible patients received the treatment protocol. Results: Toxicity was tolerable and manageable. No grade 4 toxicity while grade 3 was recorded in hematologic one only. In order of frequency; diarrhea, nausea and vomiting, and anemia (50%, 40%, 35.5%) were most common adverse events. Overall clinical response rate was 93.4% with pathological complete response of 62.2%. After median follow-up of 20 months, 2-year survival and progression-free survival rates were 90.5% and 81% respectively. Conclusion: Weekly combination of low- dose cisplatin and gemcitabine given concurrently with pelvic radiotherapy in primary treatment of locally advanced cervical cancer resulted in a high response rate with a good compliance. Further exploration is needed for the use of this approach prior to incorporating it into routine clinical care through phase III clinical trial.

Tolerability of Gemcitabine Plus Cisplatin for Treatment of Urothelial Cancer in the Elderly Population

BackgroundGemcitabine plus cisplatin is the standard of care for metastatic urothelial cancer and is frequently used in the neoadjuvant and adjuvant setting as well. However, the optimal dose and schedule for patients aged ≥ 65 years is not clear. Patients and MethodsWe performed a retrospective study to determine the tolerability of gemcitabine plus cisplatin for treatment of urothelial cancer in the elderly population. A total of 28 patients aged ≥ 65 years with urothelial cancer treated with gemcitabine plus cisplatin on a 21-day schedule from January 1, 2008 to August 31, 2013 were included in the present study. ResultsOf the 28 patients, 16 (57.1%) received gemcitabine plus cisplatin in the neoadjuvant setting. The most common dosing regimen was gemcitabine 1250 mg/m2 given on days 1 and 8 plus cisplatin 70 mg/m2 on day 1 every 21 days, with some receiving gemcitabine at a dose of 1000 mg/m2. The primary reason behind the dose modifications and treatment delays with the higher gemcitabine dose was hematologic toxicity. Two patients discontinued treatment because of renal dysfunction, with one developing a grade 4 elevation in serum creatinine. One patient developed febrile neutropenia; however, this patient did not receive growth factor support for primary prophylaxis of febrile neutropenia. ConclusionGemcitabine plus cisplatin overall is a reasonably well-tolerated treatment regimen for patients aged ≥ 65 years. The results of the present study support the use of a lower gemcitabine dose of 1000 mg/m2, because it was better tolerated.

Voltage/pH-Driven Mechanized Silica Nanoparticles for the Multimodal Controlled Release of Drugs.

The major challenges of current drug delivery systems for combination chemotherapy focus on how to efficiently transport drugs to target sites and release multiple drugs in a programmed manner. Herein, we report a novel multidrug delivery system, MSNPs 1, based on mechanized silica nanoparticles, which were constructed through functionalization of mesoporous silica nanoparticles with the acid-cleavable intermediate linkages and the monoferrocene functionalized β-cyclodextrin (Fc-β-CD) as supramolecular nanovalves. MSNPs 1 achieved zero premature release in the physiological pH solution and realized two different release modalities. In modality 1, MSNPs 1 released the encapsulated drugs gemcitabine (GEM) and doxorubicin (DOX) in sequence when they were successively applied to voltage and acid stimuli. The release time and dosage of GEM were precisely controlled via external voltage. The subsequent acid-triggered release of DOX was attributed to breakage of the intermediate linkages containing ketal groups. Modality 2 is the concurrent release of these two drugs directly upon acid exposure. Furthermore, the cell viability experiments demonstrated that MSNPs 1 had an improved cytotoxicity to MCF7 cells in comparison with single DOX- or GEM-loaded mechanized silica nanoparticles. We envisage that MSNPs 1 will play an important role in research and development for a new generation of controlled-release drug delivery system.

Evaluation of low-dose fractionated radiation therapy as a chemopotentiator of gemcitabine in advanced pancreatic cancer: results from an international multi-institutional phase II trial

Potentiation of systemic dosing of gemcitabine using very low-dose fractionated radiotherapy may improve its effect in advanced pancreatic cancer without additional toxicity as suggested by the results of our multi-institutional phase II study. Future regimens combining low-dose fractionated radiotherapy (RT) with systemic chemotherapy should be assessed for improving the chemotherapeutic benefit. Until recently, gemcitabine was considered the standard treatment for advanced pancreatic cancer despite low response rates. Efforts to improve response rates by combination therapies have had limited success and have involved using sub-systemic dosing of gemcitabine as a sensitizer for radiation. A novel paradigm, utilizing low-dose fractionated radiotherapy (LDFRT) as a potentiator of full-dose gemcitabine instead, was explored to assess safety and efficacy in treating advanced pancreatic cancer. Patients with locally advanced and metastatic pancreatic cancer were treated with 4 cycles of gemcitabine and LDFRT in a multi-institutional phase II study. Gemcitabine (1250 mg/m2 over 2 h) was administered on days 1 and 8 of a 21-day cycle. LDFRT fields included the upper abdomen from the diaphragm to the iliac crest and were administered at 60 cGy per fraction twice daily on days 1, 2, 8, and 9, with the morning fraction being delivered prior to gemcitabine infusion on days 1 and 8. Primary endpoint was objective response rate by Response Evaluation Criteria in Solid Tumors (RECIST). Thirty-eight patients were enrolled in the trial, of which 23 had metastatic disease at time of enrollment. Objective response rate (CR + PR) was 8 %, and 61 % had at least stable disease. Overall median survival was 13 months and 1-year survival was 37 %. Patients with non-metastatic disease had a 1-year survival of 60 %. The most significant toxicity was hematologic, and only 3 patients were withdrawn from protocol due to toxicity. There was no reported febrile neutropenia. The use of LDFRT with systemic gemcitabine is safe, tolerable, and potentially effective. In advanced pancreatic cancer, where response rates with single-agent gemcitabine have been low, this chemopotentiation paradigm may improve survival among a poor prognostic patient cohort.

Abstract 3316: The role of high mobility group box 1 in the combination therapy of gemcitabine and radiation in muscle invasive bladder cancer

Abstract Purpose: Radical cystectomy is the gold standard treatment for muscle invasive bladder cancer. However, it causes a serious impact in the quality of life of the patients. Radiation therapy when combined with radio-sensitizing chemotherapy is an attractive alternative as it offers bladder preservation allowing for normal urinary and sexual functions. However, lack of local control and dose dependent toxicity are the main drawbacks of the combination therapy. As HMGB1 has been found to be associated with DNA damage response and chronic inflammation pathways of radiation resistance, we sought to investigate the role of HMGB1 in the response to radiation in bladder cancer. Methods: The expression of HMGB1 among different bladder cancer cell lines was analyzed by mRNA and Protein quantification. The mean growth inhibition to Gemcitabine was assessed by colorimetric assays of cellular viability. Knock down of HMGB1 was done using lentiviral shRNA system. To assess the effect of the combination therapy, Clonogenic assay was done. Cells were exposed to the mean growth inhibition dose of gemcitabine for 6 hours followed by varying doses of radiation (2-8 Gy). Analysis of cell cycle was done by Flow Cytometry. Western blot was utilized to assess pathways involved in cellular survival. In vivo, athymic mice were subcutaneously injected with two bladder cancer cell lines. Treatment consisted of either placebo or combined gemcitabine (1 g/m2, 6 hours prior to radiation) and fractionated IR (total 6Gy = 3Gy×2) in cells with scramble vs knockdown of HMGB1. Mice were followed over 3 weeks. Tumor weight was measured at experimental endpoint. Results: HMGB1 expression was analyzed in eight urothelial carcinoma cell lines. Amongst all, UM-UC3 and UM-UC5 had the highest expression while 253J-BV had the lowest expression of HMGB1. There was a significant correlation between the levels of HMGB1 and resistance to radiation (P value <0.0001). Our results from clonogenic assays post combined treatment shows that knockdown of HMGB1 resulted in a dose modifying factor (DMF) of 2.95 for a survival fraction of 0.5. Moreover, western blot analysis revealed that high expression of HMGB1 was associated with increased and sustained activation of ERK pathway. Also, cell cycle analysis showed that upon HMGB1 knockdown, cell cycle arrest was induced at S phase post gemcitabine treatment and at G2 phase post radiation and combination therapy. To validate these results, subcutaneous tumors were induced in athymic mice and underwent two fractions of the combined treatment. Significant sensitization effect upon HMGB1 knockdown was observed, evident by tumor volume (P value <0.0001) and weight (P value <0.05). Conclusion: Our in vitro and in vivo results strongly suggest that investigating HMGB1 increases efficacy of combination therapy of gemcitabine and radiation. Baseline of HMGB1 could be a good marker to predict response to such therapy. Citation Format: Jose J. Mansure, Wael S. Almajed, Sanhita Shrivastava, Fabio Cury, Gerardo Ferbeyre, Marija Popovic, Jan Seuntjens, Wassim Kassouf. The role of high mobility group box 1 in the combination therapy of gemcitabine and radiation in muscle invasive bladder cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3316. doi:10.1158/1538-7445.AM2015-3316

Progression of Large Lymphoma Is Significantly Impeded with a Combination of Gemcitabine Chemotherapy and Dendritic Cells Intra-Tumor Vaccination.

Relapsed, refractory lymphoma remains to be a challenge and lacks efficient treatment. Some tumor cells escape from treatment, become resistant to chemotherapeutic agents, and rapidly regenerate into large tumors. Lymphoma cells induce accumulation of Gr-1+CD11b+ myeloid derived suppressor cells (MDSCs) in lymphatic organs and their vicinity. MDSCs enable tumor cells to escape from immune cells mediated surveillance and attack. Gemcitabine is a chemotherapeutic agent that eliminates both tumor cells and MDSCs, improving the immune environment favorable for subsequent treatment. We evaluated the effects of low dose gemcitabine combined with intra-tumorally delivered dendritic cells (DCs) for the treatment of A20 large-size lymphoma. We showed that MDSCs increased markedly in lymphoma-bearing mice, and that gemcitabine significantly increased the apoptosis of MDSCs. Treatment of lymphoma with either gemcitabine or intra-tumoral DCs alone could not inhibit tumor growth or rescue lymphoma-bearing mice. Treatment of lymphoma with small dose gemcitabine followed by intra-tumorally injected DCs significantly improved the efficacy of either individual treatment by reducing MDSCs, inducing onsite DCs maturation, eliminating tumor cells, inhibiting tumor growth and relapse, and extending the survival of the lymphoma-bearing mice, partly through the induction of the IFNγ secreting cells and the activation of cytotoxic lymphocytes. We showed that NK cells and CD8+ T cells were the major effectors to mediate the inhibition of tumor growth. Thus, the observation that gemcitabine synergizes DCs mediated immunotherapy to improve the efficacy of large size lymphoma treatment provides an experimental basis for the combination of chemotherapy and immunotherapy for the efficient treatment of relapsed or refractory lymphoma.

90Y-clivatuzumab tetraxetan with or without low-dose gemcitabine: A phase Ib study in patients with metastatic pancreatic cancer after two or more prior therapies

BackgroundFor patients with metastatic pancreatic adenocarcinoma, there are no approved or established treatments beyond the 2nd line. A Phase Ib study of fractionated radioimmunotherapy was undertaken in this setting, administering 90Y-clivatuzumab tetraxetan (yttrium-90-radiolabelled humanised antibody targeting pancreatic adenocarcinoma mucin) with or without low radiosensitising doses of gemcitabine. MethodsFifty-eight patients with three (2–7) median prior treatments were treated on Arm A (N=29, 90Y-clivatuzumab tetraxetan, weekly 6.5mCi/m2doses×3, plus gemcitabine, weekly 200mg/m2 doses×4 starting 1week earlier) or Arm B (N=29, 90Y-clivatuzumab tetraxetan alone, weekly 6.5mCi/m2doses×3), repeating cycles after 4-week delays. Safety was the primary endpoint; efficacy was also evaluated. ResultsCytopaenias (predominantly transient thrombocytopenia) were the only significant toxicities. Fifty-three patients (27 Arm A, 26 Arm B, 91% overall) completed ⩾1 full treatment cycles, with 23 (12 Arm A, 11 Arm B; 40%) receiving multiple cycles, including seven (6 Arm A, 1 Arm B; 12%) given 3–9 cycles. Two patients in Arm A had partial responses by RECIST criteria. Kaplan–Meier overall survival (OS) appeared improved in Arm A versus B (hazard ratio [HR] 0.55, 95% CI: 0.29–0.86; P=0.017, log-rank) and the median OS for Arm A versus Arm B increased to 7.9 versus 3.4months with multiple cycles (HR 0.32, P=0.004), including three patients in Arm A surviving >1year. ConclusionsClinical studies of 90Y-clivatuzumab tetraxetan combined with low-dose gemcitabine appear feasible in metastatic pancreatic cancer patients beyond 2nd line and a Phase III trial of this combination is now underway in this setting.

Abstract IA28: BRCA-mutated pancreas adenocarcinoma: Emerging therapeutic implications

Abstract Germline BRCA mutations, in particular BRCA 2, incur an increased risk of developing pancreas adenocarcinoma. BRCA mutations occur in 5-7% of an unselected pancreas adenocarcinoma population. In patients with Ashkenazi Jewish heritage and pancreas adenocarcinoma the frequency of BRCA mutations may be significantly higher at 12-15%. In patients with familial pancreatic cancer, defined as having at least one first degree relative with pancreas adenocarcinoma, the frequency of BRCA 1 or 2 mutation carriers is estimated at 11-17%. PALB2 (partner and localizer to BRCA2) mutations occur in a smaller fraction of patients with pancreas adenocarcinoma. The PALB2 protein stabilizes the BRCA 2 protein and anchors it to the nucleus, allowing it to carry out its DNA repair function. More recently, PALB2 has been shown to associate with the BRCA 1 protein, providing a linkage between BRCA 1 and 2 in homologous recombination repair of double-stranded DNA breaks. Preclinical data has demonstrated hypersensitivity of BRCA 2 deficient pancreatic cell lines to DNA cross-linking agents mitomycin and cisplatin and more recently to the novel agents, poly (ADP-ribose) polymerases (PARP) inhibitors. We and others have reported increased sensitivity to DNA damaging agents in patients with pancreas adenocarcinoma arising on a background of a known BRCA 1 or 2 germline mutation. Poly ADP ribose polymerases are a family of enzymes, two of which, PARP1 and 2, are key components of the DNA repair mechanism for cells with single-strand breaks and nucleoside base damage. PARP inhibition has particular application in tumors with pre-existing defects in homologous recombination, such as BRCA 1 or 2 deficient cells. Inhibition of PARP in these cells leads to transformation of single-strand breaks into double-strand breaks (DSB), which are cytotoxic in cells, which are unable to repair DSBs by homologous repair. This effect of synthetic lethality provides the therapeutic rationale for development of PARP inhibitors for BRCA 1 or 2 mutation associated pancreas adenocarcinoma. Veliparib (ABT-888) is an orally available, small molecule inhibitor of polyADP-ribose polymerase. Three trials are evaluating the role of role of veliparib in combination with cisplatin-based therapy in patients with BRCA or PALB2 mutated pancreas adenocarcinoma. Data will be presented on the first of these trials, which is a phase IB study designed to determine the recommended phase II dose of veliparib in combination with cisplatin and gemcitabine for patients with a either a known BRCA or PALB2 mutation or a very strong personal or family history of malignancy. Between 02/12 and 10/13, 33 patients were screened and 17 enrolled. Male = 10, Female = 7. Median age = 60 years (range 42- 72). BRCA = 9. Non-BRCA = 8. Four dose levels of veliparib were evaluated; Two dose-limiting toxicities of veliparib were observed at an 80mg daily continuous dosing schedule (neutropenia, thrombocytopenia). Overall grade 3-4 toxicities: Hematologic, fatigue and one fatal bowel perforation tumor/diverticulitis. For N= 9 BRCA patients tumor response: 5 (56%) partial responses and 4 (44%) stable disease. No objective responses were seen in the non-BRCA patients. The recommended phase II dose of Veliparib is 80 mg PO BID day 1-12 q 3 weeks with fixed dose cisplatin and gemcitabine. The triplet combination of cisplatin, gemcitabine and veliparib shows high activity in BRCA-related pancreas adenocarcinoma. A randomized phase II trial evaluating cisplatin/gemcitabine +/- veliparib is underway in BRCA/PALB2-mutated pancreas adenocarcinoma (NCT01585805). In addition to the clinical trials, there are a series of correlative science questions focused around: (1) characterization of the molecular phenotype of BRCA/PALB2 mutated pancreas adenocarcinoma, (2) mechanisms of resistance to platinum and PARP inhibition, (3) evaluation of assays for homologous repair, (4) evaluation of loss of heterozygosity at BRCA 1, 2 loci in tumor, and other considerations.

Abstract B98: Final results of a randomized phase Ib study of fractionated 90Y-clivatuzumab tetraxetan in patients with metastatic pancreatic cancer having at least two prior therapies

Abstract Background: Prior clinical studies in the first and second line setting showed radioimmunotherapy (RAIT) is a promising therapy for pancreatic cancer that avoids the side effects of further chemotherapy. This multicenter study evaluated the contribution of low radiosensitizing doses of gemcitabine (GEM) to fractionated doses of 90Y-clivatuzumab tetraxetan in patients with metastatic pancreatic ductal cancer after having received at least 2 prior systemic therapies. Methods: Fifty-eight patients (33 males, 25 females; median age 63.5 years), 1.6 median years from diagnosis and with a median of 3 (2-7) prior treatments, were randomized to Arm A (N=29, 4-week cycles: 200 mg/m2 GEM, weekly, combined with 6.5 mCi/m2 90Y-clivatuzumab tetraxetan, weekly the last 3 weeks) or Arm B (N=29, 3-week cycles: 6.5 mCi/m2 90Y-clivatuzumab tetraxetan alone, once-weekly), repeating cycles after 4-week delays. Safety and efficacy were evaluated. Results: None of the patients had infusion reactions, and as expected, cytopenias (predominantly thrombocytopenia) were the only significant toxicities, but mostly transient and manageable with infrequent hematologic support and little evidence of increased infection or bleeding. Patients terminated treatment cycles due to disease progression or clinical deterioration, not treatment toxicity. Fifty-three patients (27 Arm A, 26 Arm B, 91% overall) completed ≥1 full treatment cycle and thus were evaluable for efficacy, with 23 (12 Arm A, 11 Arm B; 40%) receiving multiple cycles, including 7 (6 Arm A, 1 Arm B; 12%) given 3-7 cycles. Two patients in Arm A had PRs by RECIST criteria. Karnofsky performance status (90-100 v 70-80), number of prior therapies, and tumor burden estimates (summed length of index lesions, serum CA 19-9 levels) correlated with overall survival (OS), but appear balanced between arms. Kaplan-Meier median OS was 3.9 months (1.0-16.7) in Arm A v 2.8 months (0.9-9.4) in Arm B (hazard ratio 0.54, 95% CI: 0.27-0.87; P=0.020, log-rank). The median OS for Arm A v Arm B increased to 7.9 v 3.4 months with multiple cycles (P= 0.004) and 3 patients in Arm A still being observed (11 – 17 months). Conclusions: This randomized trial demonstrated the feasibility of performing clinical studies in metastatic pancreatic cancer patients after having at least 2 prior therapies (3rd line and beyond). With significant survival advantage and favorable safety profile, fractionated RAIT with 90Y-clivatuzumab tetraxetan and low-dose GEM appears promising in this difficult population, supporting Phase 3 studies of this combination now being initiated. Citation Format: Vincent J. Picozzi, Ramesh K. Ramanathan, Maeve A. Lowery, Allyson J. Ocean, Edith P. Mitchell, Bert H. O'Neil, Michael J. Guarino, Paul R. Conkling, Steven J. Cohen, Nathan Bahary, Richard C. Frank, Tomislav Dragovich, Benjamin B. Bridges, Marie Lee, Ronald L. Korn, Neeta Pandit-Taskar, Stanley J. Goldsmith, Charles M. Intenzo, Arif Sheikh, Timothy C. Manzone, Michael L. Miller, Michael Yu, Judith M. Joyce, Edward B. Strauss, Susan Passalaqua, Ronald V. Dorn, III, Michael J. Anderson, Michael Holt, Fadi S. Braiteh, Fa-Chyi Lee, Thomas E. Gribbin, Donald A. Richards, Alexander N. Starodub, Wegener A. William, Eileen M. O'Reilly, Daniel D. Von Hoff, David M. Goldenberg. Final results of a randomized phase Ib study of fractionated 90Y-clivatuzumab tetraxetan in patients with metastatic pancreatic cancer having at least two prior therapies. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr B98.

Abstract A53: Chemotherapy treated pancreatic cancer tumor-associated fibroblasts are protumorigenic

Abstract Introduction: The dense tumor-associated stroma (TAS) characteristic of pancreatic ductal adenocarcinoma (PDAC) plays an important role in disease progression and treatment resistance. PDAC tumor-associated fibroblasts (TAFs), the predominant cell type of the TAS, enhance tumor growth, invasion, metastasis, and chemoresistance. However, the impact of cytotoxic chemotherapy on TAF biology has not yet been reported. Methods: Immortalized human TAFs were grown in either standard media or media containing IC50 doses of gemcitabine (GEM) for 4 weeks to generate chemotherapy-naïve and chemotherapy-resistant lines. Conditioned media (CM) was produced from both naïve and resistant TAFs. MTT assay was used to assess tumor cell (TC) viability in naïve versus resistant CM. TC migration and invasion as well as endothelial cell migration were assessed using modified Boyden chambers with naïve or resistant CM. For in vivo studies, TCs were subcutaneously co-implanted with naïve or resistant TAFs in immunodeficient mice. Gene expression microarray analysis was performed to compare naïve and chemoresistant TAFs. Expression of selected targets was confirmed by qRT-PCR and/or antibody-based cytokine array. IL-8 expression was quantified by ELISA. Expression of phospo- and total forms of ATM, AKT, and S6 were assessed by immunofluorescence and/or Western blot. Results:TCs (Miapaca-2 and Panc1) demonstrated increased viability when grown in the presence of resistant as compared to naïve TAF CM (p<0.001). TCs also showed increased migration (Miapaca-2, p<0.001 and Panc1, p=0.002) and invasion (Panc-1, p<0.001) in the presence of resistant CM. In addition, resistant TAF CM increased endothelial cell migration (p=0.01). In vivo, TCs (Miapaca-2) implanted along with chemoresistant TAFs grew larger tumors compared to those implanted with naïve TAFs (p<0.05). Microarray analysis demonstrated that TAFs undergo a large number of molecular changes in response to GEM. Molecules involved in important TAF functions such as stellate cell activation, cellular movement, extracellular matrix production and remodeling, and cytokine signaling were altered. Of note, the expression of multiple protumorigenic inflammatory molecules was increased. Cytokine array and qRT-PCR confirmed elevated levels of multiple inflammatory cytokines (IL-6, IL-8, CXCL-1, SPP1) in chemoresistant TAFs. Furthermore, ELISA demonstrated that IL-8 concentration was 6-fold higher in chemoresistant TAF CM compared to naïve TAF CM. TAFs activated a DNA damage response (DDR) upon treatment with GEM as evidence by phosphorylation of ATM. Treatment with NVP-BEZ235, a pan-PI3K related kinase (PIKK) inhibitor that inhibits the DDR effector kinases ATM and ATR as well as PI3K and mTOR, attenuated the induction of inflammatory factors by GEM. Conclusions: Chemotherapy treated TAFs support tumorigenesis and angiogenesis in vitro and in vivo via paracrine signaling. After treatment with GEM, TAFs activate a DDR and manifest a pro-inflammatory gene expression signature. Inhibition of PIKK attenuates this inflammatory response to chemotherapy in TAFs. Citation Format: Paul A. Toste, Andrew H. Nguyen, Brian E. Kadera, Mindy Duong, Luyi Li, Timothy R. Donahue. Chemotherapy treated pancreatic cancer tumor-associated fibroblasts are protumorigenic. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A53.

Preclinical results of gemcitabinebased regimens for preoperative chemotherapy of spontaneous feline breast cancer

Comparative preclinical study of chemotherapy regimen doxorubicin (DOX) + gemcitabine (GEM) for preoperative chemotherapy of spontaneous feline breast cancer and standard monochemotherapy with DOX alone was performed on transplantable murine mammary adenocarcinoma Ca55 in BDF1 hybrid mice model. The total GEM doses of 100 and 200 mg/kg for the triple course in combination with the single injection of 7.5 mg/kg of DOX were chosen to treat the established Ca755 tumor of 595.5 mm 3 average volume (preoperative treatment modeling). The combined chemotherapy showed an advantage of DOX + GEM regimen with GEM course dose of 200 mg/kg (70, 70 and 60 mg/kg, accordingly) as compared to other groups in terms of Tumor Growth Inhibition (TGI max=100% versus 96%; number of complete remissions (CR) 30% versus 0%, and enhanced Life Expectancy (LE) 163% versus 84-85%). The most effective regimen demonstrated dose-dependent therapeutic pathomorphism of grade II-III with 1.5-fold decrease of cell polymorphism and increase of cell differentiation. At the same time, the number of cells in mitosis decreased in 3-4 times and the number of apoptotic cells increased in 5-10 times. The results suggest that DOX + GEM combination with the unchanged components doses ratio has good potential for preoperative chemotherapy of locally advanced feline breast cancer and may be recommended for clinical study of this disease.

Impact of renal function of patients with advanced urothelial cancer on eligibility for first-line chemotherapy and treatment outcomes.

The aim of the study is to clarify the clinical effects of first-line chemotherapy regimens for advanced urothelial cancer on clinical responses and survival of patients grouped by renal function. In this multicenter retrospective cohort study, 345 urothelial cancer patients received systemic chemotherapy for metastatic or unresectable disease in 17 centers (2004-10). Two hundred and forty-one patients were treated with methotrexate, vinblastine, doxorubicin and cisplatin/methotrexate, epirubicin and cisplatin (n = 136) or gemcitabine and cisplatin (n = 105) followed by carboplatin-based treatments, non-platinum treatments or other regimens. After 2008, gemcitabine and cisplatin was the most frequently used regimen in patients with an estimated glomerular filtration rate < 60 ml/min/1.73 m(2) and in those with estimated glomerular filtration rate ≥ 60 ml/min/1.73 m(2). The gemcitabine and cisplatin patients' complete response rate was 10.5% and their response rate was 52.4%, which was highest among all regimens. Gemcitabine and cisplatin demonstrated a better 3-year overall survival when the estimated glomerular filtration rate was ≥ 60 ml/min/1.73 m(2) (31.4%), but it tended to be worse when the estimated glomerular filtration rate was < 60 ml/min/1.73 m(2) (14.1%). In the latter cases, the dose reduction rate of gemcitabine and cisplatin was high (43.9%). Among the patients with estimated glomerular filtration rate < 60 ml/min/1.73 m(2), the 1-year overall survival of the patients treated with a reduced dose of gemcitabine and cisplatin was significantly lower than that of those treated with standard-dose gemcitabine and cisplatin (26.2 vs. 60.3%, respectively, P = 0.0108). Gemcitabine and cisplatin provided favorable responses and survival in patients with estimated glomerular filtration rate ≥ 60 ml/min/1.73 m(2) but unsatisfactory oncological outcomes in patients with estimated glomerular filtration rate < 60 ml/min/1.73 m(2), especially when treated with a reduced dose. Alternative regimens might be optimal rather than reduced-dose gemcitabine and cisplatin in patients with estimated glomerular filtration rate < 60 ml/min/1.73 m(2).

Gemcitabine Plus Cisplatin for Advanced Biliary Tract Cancer: A Systematic Review.

Evidence suggests that combined gemcitabine-cisplatin chemotherapy extends survival in patients with advanced biliary tract cancer (BTC). We conducted a systematic review in order to collate this evidence and assess whether gemcitabine-cisplatin efficacy is influenced by primary tumor site, disease stage, or geographic region, and whether associated toxicities are related to regimen. MEDLINE (1946-search date), EMBASE (1966-search date), ClinicalTrials. gov (2008-search date), and abstracts from major oncology conferences (2009- search date) were searched (5 Dec 2013) using terms for BTC, gemcitabine, and cisplatin. All study types reporting efficacy (survival, response rates) or safety (toxicities) outcomes of gemcitabine-cisplatin in BTC were eligible for inclusion; efficacy data were extracted from prospective studies only. Evidence retrieved from one meta-analysis (abstract), four randomized controlled trials, 12 nonrandomized prospective studies, and three retrospective studies supported the efficacy and safety of gemcitabine-cisplatin for BTC. Median overall survival ranged from 4.6 to 11.7 months, and response rate ranged from 17.1% to 36.6%. Toxicities were generally acceptable and manageable. Heterogeneity in study designs and data collected prevented formal meta-analysis, however exploratory assessments suggested that efficacy did not vary with primary tumor site (gallbladder vs. others), disease stage (metastatic vs. locally advanced), or geographic origin (Asia vs. other). Incidence of grade 3/4 toxicities was not related to gemcitabine dose or cisplatin frequency. Despite individual variation in study designs, the evidence presented suggests that gemcitabine-cisplatin is effective in patients from a diverse range of countries and with heterogeneous disease characteristics. No substantial differences in toxicity were observed among the different dosing schedules of gemcitabine and cisplatin.

CCR9-mediated signaling through β-catenin and identification of a novel CCR9 antagonist

Elevated levels of chemokine receptor CCR9 expression in solid tumors may contribute to poor patient prognosis. In this study, we characterized a novel CCR9-mediated pathway that promotes pancreatic cancer cell invasion and drug resistance, indicating that CCR9 may play a critical role in cancer progression through activation of β-catenin. We noted that the CCL25/CCR9 axis in pancreatic cancer cells induced the activation of β-catenin, which enhanced cell proliferation, invasion, and drug resistance. CCR9-mediated activation of β-catenin and the resulting downstream effects were effectively inhibited by blockade of the PI3K/AKT pathway, but not by antagonism of Wnt. Importantly, we discovered that CCR9/CCL25 increased the lethal dose of gemcitabine, suggesting decreased efficacy of anti-cancer drugs with CCR9 signaling. Through in silico computational modeling, we identified candidate CCR9 antagonists and tested their effects on CCR9/β-catenin regulation of cell signaling and drug sensitivity. When combined with gemcitabine, it resulted in synergistic cytotoxicity. Our results show that CCR9/β-catenin signaling enhances pancreatic cancer invasiveness and chemoresistance, and may be a highly novel therapeutic target.

Use of a Lipid-Coated Mesoporous Silica Nanoparticle Platform for Synergistic Gemcitabine and Paclitaxel Delivery to Human Pancreatic Cancer in Mice

Recently, a commercial albumin-bound paclitaxel (PTX) nanocarrier (Abraxane) was approved as the first new drug for pancreatic ductal adenocarcinoma in almost a decade. PTX improves the pharmaceutical efficacy of the first-line pancreatic cancer drug, gemcitabine (GEM), through suppression of the tumor stroma and inhibiting the expression of the GEM-inactivating enzyme, cytidine deaminase (CDA). We asked, therefore, whether it was possible to develop a mesoporous silica nanoparticle (MSNP) carrier for pancreatic cancer to co-deliver a synergistic GEM/PTX combination. High drug loading was achieved by a custom-designed coated lipid film technique to encapsulate a calculated dose of GEM (40 wt %) by using a supported lipid bilayer (LB). The uniform coating of the 65 nm nanoparticles by a lipid membrane allowed incorporation of a sublethal amount of hydrophobic PTX, which could be co-delivered with GEM in pancreatic cells and tumors. We demonstrate that ratiometric PTX incorporation and delivery by our LB-MSNP could suppress CDA expression, contemporaneous with induction of oxidative stress as the operating principle for PTX synergy. To demonstrate the in vivo efficacy, mice carrying subcutaneous PANC-1 xenografts received intravenous (IV) injection of PTX/GEM-loaded LB-MSNP. Drug co-delivery provided more effective tumor shrinkage than GEM-loaded LB-MSNP, free GEM, or free GEM plus Abraxane. Comparable tumor shrinkage required coadministration of 12 times the amount of free Abraxane. High-performance liquid chromatography analysis of tumor-associated GEM metabolites confirmed that, compared to free GEM, MSNP co-delivery increased the phosphorylated DNA-interactive GEM metabolite 13-fold and decreased the inactivated and deaminated metabolite 4-fold. IV injection of MSNP-delivered PTX/GEM in a PANC-1 orthotopic model effectively inhibited primary tumor growth and eliminated metastatic foci. The enhanced in vivo efficacy of the dual delivery carrier could be achieved with no evidence of local or systemic toxicity. In summary, we demonstrate the development of an effective LB-MSNP nanocarrier for synergistic PTX/GEM delivery in pancreatic cancer.

P1.06 - Phase I study of the combination of alisertib (MLN8237) and gemcitabine in advanced solid tumors

ABSTRACT Background: This phase I study evaluated the safety and tolerability of a combination of gemcitabine and an oral Aurora Kinase A (AKA) inhibitor, alisertib (MLN8237). The primary goal of this study was to determine the maximally tolerated dose (MTD) of alisertib in combination with gemcitabine. Methods: Eligible adult patients (pts) had refractory solid tumors that had progressed on standard therapy; ECOG performance status (PS) 0-2; adequate organ function. Pts received 28-day cycles of gemcitabine on days 1, 8, 15 and alisertib twice daily on days 1-3, 8-10, and 15-17. Gemcitabine was given at a standard dose of 1000mg/m2. Dose level (DL) 1 for alisertib was 20mg BID. Dose escalation: 30mg BID (DL2), 40mg BID (DL3), and 50mg BID (DL4); 3 + 3 design. Formalin-fixed paraffin embedded tumor samples were requested in all cases. Secondary endpoints were objective response, progression-free survival, and safety. Results: Twenty-one pts were treated. Baseline characteristics: median age 57 years (range, 42-75); 10 males and 11 females; PS 0 (7 pts), 1 (13 pts), or 2 (1 pt); median prior therapies was 2 (range 0-7); cancer dx (#pts): NSCLC (7); colorectal (3); poorly differentiated neuroendocrine (3); small cell lung carcinoma (2); head and neck carcinoma (2); 1 each of pancreatic adenocarcinoma, gallbladder, small bowel, mesothelioma. A median of 4 cycles (range, 1-13) were administered. Two pts experienced DLT: 1 pt at DL3 had grade 3 urinary tract infection; 1 pt at DL4 developed grade 3 oral mucositis, hyponatremia, and dehydration. The maximum administered dose (DL4) achieved 900 mg alisertib per cycle and was tolerated (1 DLT in 6 pts). Grade 3–4 hematologic toxicities observed included (%pts): anemia (24%), leukopenia (48%), neutropenia (57%), thrombocytopenia (14%). Hyponatremia (19%) was the only non-hematologic toxicity observed in >10% of the pts. Ten of 14 evaluable pts (71%) had stable disease as their best response with remaining pts having disease progression. Conclusions: Alisertib can be safely administered at 50 mg PO BID on days 1-3. 8-10, and 15-17 in combination with full dose gemcitabine. A pre-planned expansion is ongoing in pts with pancreatic adenocarcinoma. Tumor tissue is being characterized for baseline expression level of AKA.

Identifying factors impacting subsequent gemcitabine dose intensity in patients undergoing chemoradiation for locally advanced pancreatic cancer.

455 Background: Systemic therapy is a critical part of the management of locally advanced pancreatic cancer (LAPC) due to the risk of distant failure. In the clinic, anecdotal evidence suggests that maintaining dose intensity of chemotherapy is more challenging after prior chemoradiotherapy (CRT). We thus evaluated whether treatment or patient factors limit the amount of systemic therapy received in LAPC patients receiving CRT. Methods: Following IRB approval, we retrospectively reviewed all patients diagnosed with LAPC undergoing CRT between 2006 and 2012. Exclusion criteria included receipt of non-gemcitabine chemotherapy or chemotherapy prior to CRT. Patient and treatment factors were evaluated for their relationship to total gemcitabine dose received during CRT and within the first three months post-CRT. Statistical analysis was performed using regression models. Results: A total of 76 patients met the inclusion criteria with a median age of 69 (range 44-89) and a median follow-up of 13.2 months (range 3-68). The median gemcitabine dose received during CRT was 3,000 mg/m2 of a planned 3,600 mg/m2 and post-CRT was 5000 mg/m2 of a planned 9,000 mg/m2. Patients receiving a higher percentage of the desired chemotherapy dose during CRT received a lower percentage of desired chemotherapy dose post-CRT (p&lt;0.01). Patients who underwent subsequent surgical resection (p&lt;0.01) or received a higher radiation dose (p=0.03) were more likely to have received a higher total post-CRT chemotherapy dose. There were no variables correlated to chemotherapy dose received during CRT. Conclusions: Our analysis suggests that chemotherapy dosing during CRT rather than radiation dose impacts subsequent gemcitabine dose intensity. As a number of different CRT regimens are utilized in practice, this finding warrants further confirmation in a larger database.

Neoadjuvant chemoradiation therapy for cholangiocarcinoma to improve R0 resection rate: The first report of phase II study.

402 Background: With the much-improved surgical techniques of hepatic lobectomy, but the long-term survival of patients undergoing such surgery remains far from satisfactory. Then, to improve the prognosis of cholangiocarcinoma patients, we have applied neoadjuvant chemoradiation therapy followed by conventional resection for possibly resectable cholangiocarcinoma, named NACRAC. Here, we analyzed and evaluated the Phase II (P-2) study. Methods: Patients with histologically or cytologically confirmed adenocarcinoma of the extra- and hilar cholangiocarcinoma were enrolled from 2008 to 2013 at Department Surgery, Tohoku University Hospital. The dose of gemcitabine was determined 600mg/m2 of gemcitabine with external beam radiation therapy (1.8-Gy daily fractions to a total dose of 45 Gy) ( Hepatogastroenterology. 2011;58(112):1866-72.). The primary endpoint of P-2 is R0-resection rate. We hypothesized that R0-resection rate become from 60% to 80%. Results: Total numbers of enrolled patients were 25 cases. 22 cases were operated, and 20 cases were resected. After chemoradiation, 3 cases were not operated by liver metastases, tumor progression, and heart failure. 2 cases were not resected by peritoneal carcinomatosis. One case was diagnosed as pancreatic cancer at the final pathological diagnosis. R0-resectinn cases were 17 cases. R0 resection rate was 89.6% (17/19) among operated cases. In recruited 24 cases (A pancreatic cancer was not included), R0 resection rate was 70.8% (17/24). Grade 3 and 4 adverse events (AE) were neutropenia, leukocytopenia, and Thrombocytopenia. No grade 5 AE and no fatal AE in this P-2 study. Conclusions: Neoadjuvant chemoradiation therapy with conventional resections appears to be effective and well tolerated. After both disease free survival and overall survival are going to be fixed, we will decide a proper indication of neoadjuvant therapy for cholangiocarcinoma. Trial Registration: UMIN Clinical Trials Registry (UMIN-CTR) UMIN UMIN000000992 and UMIN000001754 Clinical trial information: 000001754.

Histopathological effects of preoperative chemoradiotherapy for pancreatic cancer: An analysis for the impact of radiation and gemcitabine doses

Background and purposeHistopathological findings of patients who underwent resection for pancreatic adenocarcinoma (PC) after preoperative chemoradiotherapy (CRT) reportedly showed beneficial effects. The purpose of our study was to evaluate the correlation between histopathological effects (HE) of preoperative CRT and treatment parameters [radiation and gemcitabine (GEM) doses]. Material and methodsHE of CRT were assessed on 158 primary lesions of 157 patients with PC who underwent pancreatic resection after preoperative CRT with GEM between January 2006 and December 2011. The radiation dose delivered to the primary tumor site and surrounding regional nodal areas was 50Gy until September 2009 followed by the dose escalation of a 10Gy boost added for delivery with the field-in-field technique to the roots of the celiac and superior mesenteric arteries. Intravenous administration of GEM (1000mg/m2) was initiated concurrently on days 1, 8, and 15, every 4weeks and generally repeated for 3 cycles. HE of CRT on the primary tumor were categorized based on the number of tumor cells destroyed. ResultsThe median overall survival time was 74.5months and 3-year and 5-year survival rates were 64.3% and 54.5%, respectively. Dose-volume parameters of radiation such as D33 with a cut-off value of 51.6Gy were correlated significantly with HE (p=.0230). Lesions having received GEM>7625mg/m2 before surgical resection more frequently showed positive HE (p=.0002). Multivariate logistic regression analysis demonstrated that both D33 and cumulative GEM dose were significant predictors of definite HE (p=.0110 and <.0001, respectively). ConclusionsOur retrospective analysis showed that dose intensity of radiation and GEM is significantly related to HE of preoperative CRT for PC.