Precision medicine and gut dysbiosis

Clostridioides difficile Infection (CDI) is a leading cause of healthcare-associated infections in Canada, affecting the gastrointestinal tract which can lead to fever, abdominal pain, and diarrhea. Effective treatment for patients with Recurrent CDI (rCDI) can be achieved by Fecal Microbiota Transplantation (FMT) by introducing the gut micro-organisms of a healthy person (donor) into the bowel of the affected individual. Research has shown that an increase in the specific bacterial phyla post-FMT may be partly responsible for this gut restoration and elimination of disease. Furthermore, in understanding the key bacteria associated with successful FMT, full treatment plans can be developed for the individual needs of the patient by matching an infected individual with a donor possessing ideal microbiota for the specific patient. This development of precision medicine and more systematic adoption of FMT can be the next step toward more rapid resolution of rCDI.

Nivolumab versus docetaxel in previously treated advanced non-small-cell lung cancer (CheckMate 017 and CheckMate 057): 3-year update and outcomes in patients with liver metastases

Background

Long-term data with immune checkpoint inhibitors in non-small-cell lung cancer (NSCLC) are limited. Two phase III trials demonstrated improved overall survival (OS) and a favorable safety profile with the anti-programmed death-1 antibody nivolumab versus docetaxel in patients with previously treated advanced squamous (CheckMate 017) and nonsquamous (CheckMate 057) NSCLC. We report results from ≥3 years' follow-up, including subgroup analyses of patients with liver metastases, who historically have poorer prognosis among patients with NSCLC.

Patients and methods

Patients were randomized 1 : 1 to nivolumab (3 mg/kg every 2 weeks) or docetaxel (75 mg/m2 every 3 weeks) until progression or discontinuation. The primary end point of each study was OS. Patients with baseline liver metastases were pooled across studies by treatment for subgroup analyses.

Results

After 40.3 months' minimum follow-up in CheckMate 017 and 057, nivolumab continued to show an OS benefit versus docetaxel: estimated 3-year OS rates were 17% [95% confidence interval (CI), 14% to 21%] versus 8% (95% CI, 6% to 11%) in the pooled population with squamous or nonsquamous NSCLC. Nivolumab was generally well tolerated, with no new safety concerns identified. Of 854 randomized patients across both studies, 193 had baseline liver metastases. Nivolumab resulted in improved OS compared with docetaxel in patients with liver metastases (hazard ratio, 0.68; 95% CI, 0.50-0.91), consistent with findings from the overall pooled study population (hazard ratio, 0.70; 95% CI, 0.61-0.81). Rates of treatment-related hepatic adverse events (primarily grade 1-2 liver enzyme elevations) were slightly higher in nivolumab-treated patients with liver metastases (10%) than in the overall pooled population (6%).

Conclusions

After 3 years' minimum follow-up, nivolumab continued to demonstrate an OS benefit versus docetaxel in patients with advanced NSCLC. Similarly, nivolumab demonstrated an OS benefit versus docetaxel in patients with liver metastases, and remained well tolerated.

Clinical trial registration

CheckMate 017: NCT01642004; CheckMate 057: NCT01673867.

Assessing the impact of health and clinical research in British Columbia health authorities

This article describes results of a healthcare research impact survey conducted in two health authorities in British Columbia. A tailored research impact framework formed the basis for the survey created and used to collect quantitative and qualitative data from a sample of employees and academic faculty who had completed research in both health authorities. In all, 178 responses were collected for a combined response rate of 34%. Although there are differences between the two health authorities, the data confirm that the majority of respondents were successful in disseminating their research; 30% of both Island and Fraser Health studies reported improved safety, whether through avoidance of adverse drug effects, or reduced nosocomial infections, and as high as 26% of studies reported a reduction in morbidity or mortality. We conclude with recommendations that build on existing research capacity infrastructure to enhance the generation, implementation, and evaluation of research evidence within healthcare organizations.

Suboptimal Exposure to Anti-TB Drugs in a TBM/HIV+ Population Is Not Related to Antiretroviral Therapy

A placebo-controlled trial that compares the outcomes of immediate vs. deferred initiation of antiretroviral therapy in HIV +ve tuberculous meningitis (TBM) patients was conducted in Vietnam in 2011. Here, the pharmacokinetics of rifampicin, isoniazid, pyrazinamide, and ethambutol were investigated in the presence and absence of anti-HIV treatment in 85 patients. Pharmacokinetic analyses show that HIV therapy has no significant impact on the pharmacokinetics of TB drugs in this cohort. The same population, however, displayed generally low cerebrospinal fluid (CSF) and systemic exposures to rifampicin compared to previously reported HIV -ve cohorts. Elevated CSF concentrations of pyrazinamide, on the other hand, were strongly and independently correlated with increased mortality and neurological toxicity. The findings suggest that the current standard dosing regimens may put the patient at risk of treatment failure from suboptimal rifampicin exposure, and potentially increasing the risk of adverse central nervous system events that are independently correlated with pyrazinamide CSF exposure.

Determination of an optimal dosing schedule for combining Irinophore C™ and temozolomide in an orthotopic model of glioblastoma

Our laboratory reported that Irinophore C™ (IrC™; a lipid-based nanoparticulate formulation of irinotecan) is effective against an orthotopic model of glioblastoma (GBM) and that treatment with IrC™ was associated with vascular normalization within the tumor. Here, the therapeutic effects of IrC™ when used in combination with temozolomide (TMZ) in concurrent and sequential treatment schedules were tested. It was anticipated that IrC™ engendered vascular normalization would increase the delivery of TMZ to the tumor and that this would be reflected by improved treatment outcomes. The approach compared equally efficacious doses of irinotecan (IRN; 50 mg/kg) and IrC™ (25 mg/kg) in order to determine if there was a unique advantage achieved when combining TMZ with IrC™. The TMZ sensitive U251MG(O) cell line (null expression of O-6-methylguanine-DNA methyltransferase (MGMT)) modified to express the fluorescent protein mKate2 was inoculated orthotopically into NOD.CB17-SCID mice and treatment was initiated 14 days later. Our results demonstrated that IrC™ and TMZ administered concurrently resulted in optimal treatment outcomes, with 50% long term survivors (>180 days) in comparison to 17% long term survivors in animals treated with IRN and TMZ or TMZ alone. Indeed, the different treatments resulted in a 353%, 222% and 280% increase in median survival time (MST) compared to untreated animals for, respectively, IrC™ combined with TMZ, IRN combined with TMZ, and TMZ alone. When TMZ was administered after completion of IRN or IrC™ dosing, an increase in median survival time of 167-174% was observed compared to untreated animals and of 67% and 74%, respectively, when IRN (50 mg/kg) and IrC™ (25mg/kg) were given as single agents. We confirmed in these studies that after completion of the Q7D×3 dosing of IrC™, but not IRN, the tumor-associated vascular was normalized as compared to untreated tumors. Specifically, reductions in the fraction of collagen IV-free CD31 staining (p<0.05) and reductions in tumor vessel diameter were observed in tumors from IrC™-treated animals when compared to tumors from untreated or IRN treated animals. Analysis by transmission electron microscopy of the ultra-structure of tumors from IrC™-treated and untreated animals revealed that tumor-associated vessels from treated animals were smaller, more organized and exhibited a morphology comparable to normal blood vessels. In conclusion, optimal treatment outcomes were achieved when IrC™ and TMZ were administered concurrently, whereas IrC™ followed by TMZ treatment given sequentially did not confer any therapeutic advantage.

Pharmacokinetics of anti-TB drugs in Malawian children: reconsidering the role of ethambutol

Background

Current guidelines for dosing of anti-TB drugs in children advocate higher doses for rifampicin and isoniazid despite limited availability of paediatric data on the pharmacokinetics of these drugs, especially from Africa, where the burden of childhood disease remains high.

Methods

Thirty children aged 6 months to 15 years underwent intensive pharmacokinetic sampling for first-line anti-TB drugs at Queen Elizabeth Central Hospital, Blantyre, Malawi. Rifampicin, isoniazid, pyrazinamide and ethambutol were dosed at 10, 5, 25 and 20 mg/kg, respectively. Plasma drug concentrations were determined using sensitive, validated bioanalytical methods and summary pharmacokinetic parameters were estimated using non-compartmental analysis.

Results

The median (IQR) C_max was 2.90 (2.08–3.43), 3.37 (2.55–4.59), 34.60 (32.30–40.90) and 1.20 (0.85–1.68) mg/L while the median (IQR) AUC_0–∞ was 16.92 (11.10–22.74), 11.48 (7.35–18.93), 333.50 (279.50–487.2) and 8.65 (5.96–11.47) mg·h/L for rifampicin, isoniazid, pyrazinamide and ethambutol, respectively. For all drugs, pharmacokinetic parameters relating to drug absorption and exposure were lower than those published for adults, though similar to existing paediatric data from sub-Saharan Africa. Weight and/or dose predicted at least one measure of exposure for all drugs. Age-related decreases in CL/F for rifampicin and pyrazinamide and a biphasic elimination pattern of isoniazid were observed. Predicted AUC_0–∞ for rifampicin dosed at 15 mg/kg was comparable to that of adults while the dose required to achieve ethambutol exposure similar to that in adults was 55 mg/kg or higher.

Conclusions

These data support recently revised WHO recommendations for dosing of anti-TB drugs in children, but dosing of ethambutol in children also appears inadequate by comparison with adult pharmacokinetic data.

Abstract 5261: Irinophore C, a liposomal formulation of irinotecan, has anti-vascular effects in primary tumors of colorectal cancer grown orthotopically in mice

Introduction: Colorectal cancer accounts for ∼10% of cancer deaths in North America. Our group has developed a series of primary tumors from human colorectal cancer tissue obtained during surgery. These tumors are passaged orthotopically in mice and maintain the complexity and heterogeneity of the original patient sample. We have used these tumors to examine the cytotoxic and anti-vascular effects of Irinophore CTM, a liposomal form of irinotecan, which is more efficacious and less toxic than the parent drug. Materials and Methods: Primary tumor tissues from colorectal cancer patients, were validated by a reference pathologist and implanted subcutaneously in SCID mice. Tumors that grew successfully were then passaged orthotopically on the ascending colon of new mice. When these tumors reached ∼200mm3, groups of mice were treated with saline, irinotecan (50mg/kg), or IrinophoreCTM (25mg/kg) once a week for 6 weeks. Separate groups of tumors, A, B and C were harvested on days 3, 21 and 42 after treatment started, respectively. Magnetic resonance imaging (MRI) was used to assess tumor perfusion in mice from group B. Treatment effects on tumor metabolism were assessed with 18F -fluorodeoxyglucose and positron emission tomography (FDG-PET) for groups A and C mice. Immunofluorescence staining was carried out on tumors from all treatment groups to determine levels of cell proliferation, apoptosis, hypoxia, and vessel density. Results: 4 of 14 samples were successfully propagated and maintain their original morphology. Irinophore CTM treatment reduced tumor volume by 54% to 92% compared to the untreated controls depending on the tumor line. No toxic effects were seen with Irinophore CTM. The aggregate data for cell proliferation (Ki67), necrosis (H&E) and cell death (TUNEL) indicate that Irinophore CTM has sustained cytotoxic activity compared to the free drug. Immunostaining data show irinotecan treatment did not change blood vessel density in the tumors; however, Irinophore CTM treatment did reduce vascular density in the tumors. The volume transfer coefficient, Ktrans, derived from MRI, decreased when tumors were treated with irinotecan, but increased with Irinophore CTM treatment. Differences in the metabolic activity of the tumors were also seen. Conclusion: Orthotopic models of colorectal cancer propagated from patient tumors were successfully developed. These models retain the characteristics of the original patient sample and are a good alternative to xenograft models grown from immortalized cell-lines. The anti-tumor activity of Irinophore CTM at lower doses is greater than irinotecan's, and with fewer side effects. Treatment with Irinophore CTM also reduces tumor metabolism and appears to improve vascular function. The data imply that Irinophore CTM has sustained anti-tumor activity and multiple mechanisms of action compared to irinotecan.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5261. doi:1538-7445.AM2012-5261

A low carbohydrate, high protein diet slows tumor growth and prevents cancer initiation

Since cancer cells depend on glucose more than normal cells, we compared the effects of low carbohydrate (CHO) diets to a Western diet on the growth rate of tumors in mice. To avoid caloric restriction-induced effects, we designed the low CHO diets isocaloric with the Western diet by increasing protein rather than fat levels because of the reported tumor-promoting effects of high fat and the immune-stimulating effects of high protein. We found that both murine and human carcinomas grew slower in mice on diets containing low amylose CHO and high protein compared with a Western diet characterized by relatively high CHO and low protein. There was no weight difference between the tumor-bearing mice on the low CHO or Western diets. Additionally, the low CHO-fed mice exhibited lower blood glucose, insulin, and lactate levels. Additive antitumor effects with the low CHO diets were observed with the mTOR inhibitor CCI-779 and especially with the COX-2 inhibitor Celebrex, a potent anti-inflammatory drug. Strikingly, in a genetically engineered mouse model of HER-2/neu-induced mammary cancer, tumor penetrance in mice on a Western diet was nearly 50% by the age of 1 year whereas no tumors were detected in mice on the low CHO diet. This difference was associated with weight gains in mice on the Western diet not observed in mice on the low CHO diet. Moreover, whereas only 1 mouse on the Western diet achieved a normal life span, due to cancer-associated deaths, more than 50% of the mice on the low CHO diet reached or exceeded the normal life span. Taken together, our findings offer a compelling preclinical illustration of the ability of a low CHO diet in not only restricting weight gain but also cancer development and progression.

Validating the use of a luciferase labeled breast cancer cell line, MDA435LCC6, as a means to monitor tumor progression and to assess the therapeutic activity of an established anticancer drug, docetaxel (Dt) alone or in combination with the ILK inhibitor, QLT0267

A significant issue in drug efficacy studies is animal study design. Here we hypothesize that when evaluating new or existing therapeutics for the treatment of cancer, the location of disease burden will influence drug efficacy. To study this, Female NCr nude mice were inoculated with luciferase-positive human breast cancer cells (LCC6WT-luc) orthotopically (o.t.), intraperitoneally (i.p.) or intracardiacly (i.c.) to create localized, ascites or disseminated disease, respectively. Tumor development was monitored using bioluminescence imaging. Docetaxel (Dt) pharmacokinetics and distribution to sites of tumor growth were determined. Disease progression was followed in animals treated with Dt alone and in combination with QLT0267, an Integrin Linked Kinase inhibitor. Tumor related morbidity was most rapid when cells were inoculated i.c., where disease progression was observed in brain, ovaries, adrenal glands, and lungs. Dt pharmacokinetics were comparable regardless of the model used (mean plasma AUC0-24 hrs 482.6 ng/ml*hr), however, Dt levels were lowest in those tissues developing disease following i.c. cell injection. Treatment with low dose Dt (5 mg/kg) increased overall survival and reduced tumor cell growth in all three models but the activity was greatest in mice with orthotopic tumors. Higher doses of Dt (15 mg/kg) was able to prolong survival in animals bearing i.p. tumors but not i.c. tumors. Addition of QLT0267 provided no added benefit above Dt alone in the disseminated model. These studies highlight a need for more comprehensive in vivo efficacy studies designed to assess multiple disease models and multiple endpoints, focusing analysis of drug parameters on the most chemoresistant disease.

Vascular normalization in orthotopic glioblastoma following intravenous treatment with lipid-based nanoparticulate formulations of irinotecan (Irinophore C™), doxorubicin (Caelyx®) or vincristine

Background

Chemotherapy for glioblastoma (GBM) patients is compromised in part by poor perfusion in the tumor. The present study evaluates how treatment with liposomal formulation of irinotecan (Irinophore C™), and other liposomal anticancer drugs, influence the tumor vasculature of GBM models grown either orthotopically or subcutaneously.

Methods

Liposomal vincristine (2 mg/kg), doxorubicin (Caelyx^®; 15 mg/kg) and irinotecan (Irinophore C™; 25 mg/kg) were injected intravenously (i.v.; once weekly for 3 weeks) in Rag2M mice bearing U251MG tumors. Tumor blood vessel function was assessed using the marker Hoechst 33342 and by magnetic resonance imaging-measured changes in vascular permeability/flow (K_trans). Changes in CD31 staining density, basement membrane integrity, pericyte coverage, blood vessel diameter were also assessed.

Results

The three liposomal drugs inhibited tumor growth significantly compared to untreated control (p < 0.05-0.001). The effects on the tumor vasculature were determined 7 days following the last drug dose. There was a 2-3 fold increase in the delivery of Hoechst 33342 observed in subcutaneous tumors (p < 0.001). In contrast there was a 5-10 fold lower level of Hoechst 33342 delivery in the orthotopic model (p < 0.01), with the greatest effect observed following treatment with Irinophore C. Following treatment with Irinophore C, there was a significant reduction in K_trans in the orthotopic tumors (p < 0.05).

Conclusion

The results are consistent with a partial restoration of the blood-brain barrier following treatment. Further, treatment with the selected liposomal drugs gave rise to blood vessels that were morphologically more mature and a vascular network that was more evenly distributed. Taken together the results suggest that treatment can lead to normalization of GBM blood vessel the structure and function. An in vitro assay designed to assess the effects of extended drug exposure on endothelial cells showed that selective cytotoxic activity against proliferating endothelial cells could explain the effects of liposomal formulations on the angiogenic tumor vasculature.

Targeting tumor hypoxia: suppression of breast tumor growth and metastasis by novel carbonic anhydrase IX inhibitors

Carbonic anhydrase IX (CAIX) is a hypoxia and HIF-1-inducible protein that regulates intra- and extracellular pH under hypoxic conditions and promotes tumor cell survival and invasion in hypoxic microenvironments. Interrogation of 3,630 human breast cancers provided definitive evidence of CAIX as an independent poor prognostic biomarker for distant metastases and survival. shRNA-mediated depletion of CAIX expression in 4T1 mouse metastatic breast cancer cells capable of inducing CAIX in hypoxia resulted in regression of orthotopic mammary tumors and inhibition of spontaneous lung metastasis formation. Stable depletion of CAIX in MDA-MB-231 human breast cancer xenografts also resulted in attenuation of primary tumor growth. CAIX depletion in the 4T1 cells led to caspase-independent cell death and reversal of extracellular acidosis under hypoxic conditions in vitro. Treatment of mice harboring CAIX-positive 4T1 mammary tumors with novel CAIX-specific small molecule inhibitors that mimicked the effects of CAIX depletion in vitro resulted in significant inhibition of tumor growth and metastasis formation in both spontaneous and experimental models of metastasis, without inhibitory effects on CAIX-negative tumors. Similar inhibitory effects on primary tumor growth were observed in mice harboring orthotopic tumors comprised of lung metatstatic MDA-MB-231 LM2-4(Luc+) cells. Our findings show that CAIX is vital for growth and metastasis of hypoxic breast tumors and is a specific, targetable biomarker for breast cancer metastasis.

Abstract 3661: Vascular changes and potentiating secondary drug delivery in colorectal cancer with Irinophore C

Introduction: Colorectal cancer is the third most common cancer in the world. The predominant chemotherapeutic treatment in CRC is a combination of 5-fluorouracil (5-FU) and irinotecan (CPT-11). However, the combination is limited by toxicity and resistance. We now report on the effects of 5-FU in combination with a liposomal formulation of CPT-11, Irinophore C, that is more efficacious and less toxic than free CPT-11.

Materials and Methods: 5-FU was used singly and in combination with Irinophore C in a subcutaneous model of colorectal cancer, HT-29, to assess therapeutic efficacy and toxic effects. 5-FU and Irinophore C (40mg/kg) were injected intravenously on a Q7Dx3 schedule, and tumor growth delay was measured. In a subsequent study, a single bolus injection of 14C-spiked 5-FU was delivered at different timepoints during Irinophore C (tritium-labeled) or saline treatment (Q7Dx3), and the accumulation of 5-FU in tumor tissue measured with scintigraphy. Tumors were also harvested and snap-frozen at early (days 1 - 7) and late (days 14 and 21) time points following Irinophore C treatment. Cryosections were subsequently examined for perfusion using the fluorescent dye Hoechst 33342, stained for apoptosis (TUNEL), CD31, CD105, Collagen IV and with H&E to examine changes in vascular function and tissue morphology.

Results: Irinophore C significantly reduced tumour growth (p&lt;0.001) with little or no toxicity compared to saline controls, 5-FU alone and free CPT-11 plus 5-FU. In some cases, tumour growth was completely abolished. When used in combination with 5-FU, there was a slight increase in growth delay. Treatment of the tumours with Irinophore C increased the accumulation of the active lactone form of the drug in the tumour, and also significantly increased the tissue accumulation of a single bolus injection of 5-FU after two (∼50% increase, p&lt;0.001) and three weeks (∼66% increase, p&lt;0.001). Following treatment with Irinophore C, the density of tumor tissue was decreased, and the vascular coverage was increased, leading to increased total perfusion. In addition, apoptotic activity was increased following 1 to 2 weeks of treatment with Irinophore C, compared to controls.

Conclusions: Irinophore C is more efficacious, and less toxic, than free CPT-11. This novel formulation of CPT-11 appears to have a bimodal mechanism of action wherein both endothelial and cancer cells are targeted, and which may improve the delivery of a second drug. We further believe that the dose of Irinophore C used in the combination studies is with 5-FU is overly efficacious and masks the effects of 5-FU. Clinically, Irinophore C with its low toxicity and high efficacy could have advantages over the use of free CPT-11.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3661.

Abstract 455: Hypoxia induced carbonic anhydrase IX is essential for the growth and metastasis of breast tumors

Metastasis of primary malignancies is a multi-step process and remains the principal cause of cancer deaths. Carbonic anhydrase IX (CAIX) is a hypoxia inducible protein and a poor prognostic marker for several types of cancer, including breast cancer. However, the functional role of CAIX in the metastatic progression of breast cancer is unclear. Here, we have investigated its role in the growth and metastasis of breast tumors. Orthotopic mouse mammary tumors derived from metastatic 4T1 and 66cl4 cells or non-metastatic 67NR cells were examined for levels of proliferation (BrdU), hypoxia, (pimonidazole), perfusion (DiOC7), vasculature (CD31), apoptosis (TUNEL) and lymphangiogenesis (LYVE-1). Metastatic 4T1 and 66cl4 tumors expressed a hypoxia gene signature and were characterized as being poorly vascularized, with high levels of hypoxia. Large numbers of apoptotic cells and well developed intratumoral lymphatic vessels were also evident. Inhibition of expression of CAIX in the metastatic 4T1 cells by stable expression of short hairpin RNA (shRNA) resulted in cell death and reversal of extracellular acidosis in hypoxia in vitro, dramatic regression of tumors in vivo, and inhibition of metastasis. These properties were rescued by constitutive expression of human CAIX. Treatment of mice harboring 4T1 tumors with a novel CAIX-specific inhibitor resulted in significant inhibition of tumor growth. Interrogation by immunohistochemistry of a large (3992 patient samples) primary breast tumor tissue microarray showed that CAIX expression was significantly associated with worse distant relapse free survival (p&lt;10−16) and was most prominent in the basal breast cancers (51%). Our data show that CAIX-mediated function is required for the survival and metastasis of hypoxic breast tumors, and suggest that CAIX is a promising therapeutic target for metastatic breast cancer.

This work was supported by the Canadian Breast Cancer Research Alliance, with special funding from the Canadian Breast Cancer Foundation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 455.

Randomized phase III comparison of paclitaxel/carboplatin/etoposide versus gemcitabine/irinotecan, both followed by gefitinib, in patients (pts) with carcinoma of unknown primary site (CUP)

4631

Background: Empiric chemotherapy for pts with CUP has resulted in modest survival improvements. Several regimens have been active in phase II trials, but no randomized comparison of newer regimens have been completed. In this multicenter randomized phase III trial, we compared the efficacy and toxicity of 2 active regimens. Methods: Previously untreated pts with CUP (adenocarcinoma, poorly differentiated adenocarcinoma, poorly differentiated carcinoma, poorly differentiated squamous carcinoma) were eligible. Pts with specific treatable syndromes were excluded. Additional eligibility: ECOG PS 0–2; controlled brain metastases; adequate organ function. Pts were randomized (1:1) to paclitaxel 200mg/m2 day 1/carboplatin AUC 6.0 day 1/etoposide 50mg/100mg alternating po days 1–10 (PCE) or gemcitabine 1000mg IV days 1, 8/irinotecan 100mg/m2 IV days 1, 8 (GI). Both regimens were repeated at 21-day intervals for 4–6 courses. Responding/stable pts then received gefitinib 250mg po qd until tumor progression. The primary endpoint was the 2-year survival rate. Initially, a total of 320 pts were planned, to allow detection of a 50% improvement in 2-year survival (from 20% to 30%). However, due to slow accrual, enrollment was stopped after 198 pts were randomized. Results: Between September 2003 and July 2008, 198 pts were randomized (PCE, 93 patients; GI 105 patients). Pt characteristics were similar in both groups. Median progression-free survival for PCE versus GI was 3.2 months versus 5.3 months, p=0.19. Median overall survivals were 7.4 months (PCE) versus 8.6 months (GI), p=0.34; 2-year survivals were 16% (PCE) and 19% (GI). Response rates were similar (PCE 19%, GI 20%). GI was less toxic, with lower rates of grade 3/4 neutropenia (11% vs. 35%; p< 0.01), febrile neutropenia (0% vs. 9%; p<0.01), thrombocytopenia (3% vs. 8%; p=.05), anemia (3% vs. 9%; p=0.05), and RBC transfusions (10% vs. 24%; p<0.01). Conclusions: The PCE and GI regimens had comparable efficacy in the treatment of CUP, while the GI regimen was better tolerated. The 2-year survival was similar (16%, 19%). Better treatments are needed for pts with CUP.

[Table: see text]

QLT0267, a small molecule inhibitor targeting integrin-linked kinase (ILK), and docetaxel can combine to produce synergistic interactions linked to enhanced cytotoxicity, reductions in P-AKT levels, altered F-actin architecture and improved treatment outcomes in an orthotopic breast cancer model

Introduction

Substantial preclinical evidence has indicated that inhibition of integrin linked-kinase (ILK) correlates with cytotoxic/cytostatic cellular effects, delayed tumor growth in animal models of cancer, and inhibition of angiogenesis. Widely anticipated to represent a very promising therapeutic target in several cancer indications, it is increasingly evident that optimal therapeutic benefits obtained using ILK targeting strategies will only be achieved in combination settings. The purpose of this study was to investigate the therapeutic potential of the ILK small molecule inhibitor, QLT0267 (267), alone or in combination with chemotherapies commonly used to treat breast cancer patients.

Methods

A single end-point metabolic assay was used as an initial screen for 267 interactions with selected chemotherapeutic agents. These in vitro assays were completed with seven breast cancer cell lines including several which over-expressed human epidermal growth factor receptor 2 (Her2). One agent, docetaxel (Dt), consistently produced synergistic interactions when combined with 267. Dt/267 interactions were further characterized by measuring therapeutic endpoints linked to phosphorylated protein kinase B (P-AKT) suppression, inhibition of vascular endothelial growth factor (VEGF) secretion and changes in cytoarchitecture. In vivo efficacy studies were completed in mice bearing orthotopic xenografts where tumor growth was assessed by bioluminescence and calliper methods.

Results

The combination of 267 and Dt resulted in increased cytotoxic activity, as determined using an assay of metabolic activity. Combinations of cisplatin, doxorubicin, vinorelbine, paclitaxel, and trastuzumab produced antagonistic interactions. Further endpoint analysis in cell lines with low Her2 levels revealed that the 267/Dt combinations resulted in: a three-fold decrease in concentration (dose) of 267 required to achieve 50% inhibition of P-AKT; and a dramatic disruption of normal filamentous-actin cellular architecture. In contrast to Her2-positive cell lines, three-fold higher concentrations of 267 were required to achieve 50% inhibition of P-AKT when the drug was used in combination with Dt. In vivo studies focusing on low Her2-expressing breast cancer cells (LCC6) implanted orthotopically demonstrated that treatment with 267/Dt engendered improved therapeutic effects when compared with mice treated with either agent alone.

Conclusions

The findings indicate that the 267/Dt drug combination confers increased (synergistic) therapeutic efficacy towards human breast cancer cells that express low levels of Her2.

Evaluation of osmolality and pH of various concentrations of methotrexate, cytarabine, and thiotepa prepared in normal saline, sterile water for injection, and lactated Ringer's solution for intrathecal administration

Background. Neurotoxicity of intrathecal (IT) chemotherapy has been variously attributed to the preservatives, volume, osmolality, and pH of the preparations. There has been little evaluation of how different drug concentrations or diluents can affect the osmolality and pH of the final solution. We conducted a three-part study: survey of cancer centers regarding the drug concentrations and diluent used in preparing IT chemotherapy; review of the literature on common practice of preparing IT chemotherapy; evaluation of the pH and osmolality of commonly used chemotherapy preparations for IT.

Method. We surveyed selected cancer centers to provide information on their standard volume, drug concentrations, and choice of diluents. MEDLINE was searched for clinical reports using the MeSH terms of `cytarabine,' `methotrexate,' or `thiotepa' with the subheading `Cerebrospinal fluid' and combined with `intrathecal' in all database fields. Data retrieved included the choice of diluent, volume, and/or drug concentration. We evaluated the pH and osmolality of methotrexate (1, 2, 5, and 10 mg/mL), cytarabine (2, 5, 10, and 25 mg/mL), and thiotepa (1, 2, and 5 mg/mL) in normal saline, sterile water for injection (SWFI), and lactated Ringer's solution.

Results. Nine centers were surveyed (seven in Canada, one in Australia, one in United Kingdom). Most centers used 5mL of preservative-free normal saline, irrespective of the drug or drug concentration used. Forty-four reports in the literature were reviewed. Most reported 5 mL of preservative-free normal saline. Most information on drug concentrations was provided for methotrexate, with an average concentration of about 1—2.5 mg/ mL. Cytarabine 0.4—20 mg/mL and thiotepa 1 mg/mL were also reported. In our in vitro evaluation, there was a trend of increased pH associated with increasing concentration of methotrexate and cytarabine. There was no apparent impact of thiotepa concentration on the pH values of the final preparations, irrespective of the diluent used. Except for cytarabine 10 and 25 mg/mL, all the tested solutions have pH within 10% of the physiologic range of CSF. There was a concentration-dependent change in osmolality with methotrexate and cytarabine preparations. Osmolality was increased with increased concentrations in all except methotrexate mixed in SWFI and thiotepa mixed in normal saline and lactated Ringer's solution. Except for some thiotepa solutions, all the tested solutions have osmolality within 10% of the physiologic range of CSF.

Conclusions. There is limited published literature on the potential impact of diluent and drug concentration on the pH and osmolality of IT chemotherapy preparation. Most cancer centers conventionally prepare IT chemotherapy with 5mL of preservative diluent normal saline, irrespective of the specific drug or dose used. The conventional practice means that most methotrexate preparations are likely to have comparable pH and osmolality to CSF. In contrast, cytarabine preparations may show significantly higher pH than the CSF, while thiotepa preparations generally have lower osmolality than the CSF. J Oncol Pharm Practice (2009) 15: 45—52.

A novel liposomal irinotecan formulation with significant anti-tumour activity: use of the divalent cation ionophore A23187 and copper-containing liposomes to improve drug retention

We determined whether the method used to encapsulate irinotecan into 1,2-distearoyl-sn-glycero-phosphocholine/cholesterol (DSPC/Chol; 55:45 mol%) liposomes influenced: (i) irinotecan release rate and (ii) therapeutic efficacy. DSPC/Chol (55:45 mol%) liposomes were prepared with: (i) unbuffered CuSO4; (ii) buffered (pH 7.5) CuSO4; (iii) unbuffered MnSO4 and the ionophore A23187 (exchanges internal metal2+ with external 2H+ to establish and maintain a transmembrane pH gradient); and (iv) unbuffered CuSO4 and ionophore A23187. All formulations exhibited >98% irinotecan encapsulation (0.2 drug-to-lipid molar ratio; 10 min incubation at 50 degrees C). Following a single intravenous injection (100mg/kg irinotecan) into Balb/c mice, the unbuffered CuSO4 plus A23187 formulation mediated a half-life of irinotecan release of 44.4h; a >or=4-fold increase compared to the other liposome formulations. This surprising observation demonstrated that the CuSO4 plus A23187 formulation enhanced irinotecan retention compared to the MnSO4 plus A23187 formulation, indicating the importance of the divalent metal. A single dose of the CuSO4 plus A23187 formulation (50mg/kg irinotecan) mediated an 18-fold increase in median T-C (the difference in days for treated and control subcutaneous human LS 180 adenocarcinoma xenografts to increase their initial volume by 400%) when compared to a comparable dose of Camptosar. Improved irinotecan retention was associated with increased therapeutic activity.

Phase III study of immediate versus delayed docetaxel after induction therapy with gemcitabine plus carboplatin in advanced non-small cell lung cancer: Updated report with survival

LBA7516

Background: Gemcitabine (G) plus carboplatin (C) therapy is active in patients with advanced non-small-cell lung cancer (NSCLC). For nonprogressing patients, optimal timing of second-line therapy with a non-cross-resistant agent is unclear. This Phase III, randomized trial assessed the efficacy and safety of docetaxel (D) administered either immediately after GC induction therapy or upon disease progression (PD). Methods: Patients having either Stage IIIB with pleural effusion or Stage IV NSCLC were enrolled. Prior chemotherapy for NSCLC was not permitted. For GC induction, G 1000 mg/m2 was administered on Days 1, 8 followed by C AUC 5 on Day 1. After four 21-day cycles, nonprogressors were randomized to either the immediate D group (D 75 mg/m2 administered on Day 1 every 21 days, for a maximum of 6 cycles) or the delayed D group (patients given best supportive care after randomization and the same D regimen after first evidence of PD) treatment arms. Primary endpoint was overall survival (OS). Additional analyses included response rates, toxicity and progression-free survival (PFS). Results: Results are summarized in the table below. OS was not statistically different (p=0.071) between the two D arms. However, 31 patients (20.1%) in the delayed D arm and 38 patients (24.8%) in the immediate D arm were censored for OS analysis. PFS analysis (from randomization to first evidence of PD or death) showed a statistically significant (p=<0.0001) improvement in the immediate D arm. D given to NSCLS patients immediately after GC induction did not increase toxicity. Conclusions: Comparison of PFS for each D arm suggests a possible clinical benefit for immediate D therapy. However, even though OS trended in favor of immediate D therapy, the OS result did not reach statistical significance. The implications of these results will be discussed.

[Table: see text] [Table: see text]

Pemetrexed plus cetuximab in patients (pts) with recurrent non-small cell lung cancer (NSCLC): A phase I-IIa dose-ranging study from the Hoosier Oncology Group

7698

Background: Both pemetrexed (P) and cetuximab (C) have single agent activity in NSCLC, non-overlapping toxicities and different mechanisms of action, making the combination of P and C an attractive option to evaluate. This study evaluates the feasibility of combining these agents, and tests the activity and toxicity of this regimen in pts with recurrent NSCLC. Methods: Eligible pts had stage IIIB/IV NSCLC, previously treated ≥ 1 prior platinum containing regimen, PS 0–1. Prior use of EGFR tyrosine kinase inhibitors was permitted. The phase I portion determined the MTD (Bedano Proc ASCO et al., 2006). The primary endpoint of the phase II portion was to estimate TTP using Kaplan-Meier analysis (5% alpha, 80% beta), requiring 25 pts to demonstrate a TTP of ≥ 24 weeks vs. historical control of 12 weeks. Following a loading dose of C at 400 mg/m2 on week 1, pts received P at 750 mg/m2 iv q3wks and C at 250 mg/m2 iv weekly. Cycles were repeated every 21 days. After completing at least 4 cycles, pts with non-progressive disease (PD) were allowed to continue C alone until PD. Results: Eligible and treated phase II pts (n=23) received a median of 4 cycles (range 1–12). Pt characteristics: M:F 57%:43%; median age 64 (range 43–80), stage IIIB: IV 17%:83%; adeno:squamous cell 61%:30%; smoking status: current/former/never: 29%/62%/10%. Prior regimens, median 2 (range 1–6). G3/4/5 toxicities included: 4.3% neutropenia, 13% infection, 4.3% hemorrhage, 22% skin. There were no G3/4 episodes of anemia, TCP, febrile neutropenia, liver toxicity or diarrhea. Response data was available for 18 patients. Partial responses were seen in 2 pts (8.7 %), SD in 8 patients (34.8%). Median TTP was 25 weeks. Conclusion: It is feasible and safe to combine P at 750 mg/m2 every 21 days and C at 400 mg/m2 week 1 and 250 mg/m2 weekly thereafter. This combination resulted in longer TTP when compared with historical controls of P at 500 mg/m2 alone.

No significant financial relationships to disclose.

A parenteral econazole formulation using a novel micelle-to-liposome transfer method: in vitro characterization and tumor growth delay in a breast cancer xenograft model

PURPOSE

The purpose of this study was to develop a parenteral liposomal formulation of econazole, a poorly water-soluble compound not previously available in an intravenous form. We are investigating econazole as an anticancer agent based on its unique mechanism of action to which cancer cells are preferentially sensitive. An intravenous formulation of econazole was desired for preclinical toxicity and efficacy studies of econazole.

METHODS

Liposomal econazole was prepared using a novel micelle exchange technique to incorporate the drug into the lipid bilayer of pre-formed liposomes using a poly(ethylene) glycol-linked phospholipid, distearoyl phosphatidylethanolamine (DSPE-PEG). This method allowed for stable and efficient drug incorporation into DPPC and DMPC liposomes at a final drug:lipid ratio of 0.05 (w/w) and increased solubility in saline from <0.1 to 5 mg/ml.

RESULTS

Stability over 14 days at 4 degrees C in buffer was demonstrated as well as in vitro plasma stability at 37 degrees C. Plasma elimination studies of micelle-loaded liposomal econazole showed a half-life of approximately 35 min and plasma AUC of 281 microg/ml min. In MCF-7 human breast cancer xenografts in Rag2M mice. Liposomal econazole did not induce significant hepatoxicity, renal toxity or weight loss compared to empty liposomes. Tumor growth was slightly delayed in liposomal econazole-treated mice, with approximately 10-day lag time to reach 300 mm(3) compared to vehicle controls.

CONCLUSIONS

The micelle transfer method provided an efficient means of preparing liposomal econazole suitable for intravenous administration. Liposomal econazole was successfully administered to tumor bearing mice at 50 mg/kg, and no significant toxicities attributable to econazole were observed.

Phase II trial of gemcitabine and carboplatin, plus trastuzumab in HER2+ patients as first line therapy in metastatic breast cancer

10590

Background: Gemcitabine (G) and carboplatin (C) demonstrate significant preclinical synergy together as well as in combination with trastuzumab (H) in metastatic breast cancer (MBC) pts. This multicenter phase II trial evaluates the efficacy and safety of G + C with trastuzumab in HER2 + pts as 1st line therapy in MBC. Methods: Eligibility requirements: females > 18 with no prior regimens for MBC, ECOG 0–2, RECIST bidimensional disease, and adequate organ function. FISH HER2 + pts received H with GC. Treatment: G 1,000 mg/m2 D1& 8 with C AUC 5 D1 in the first 20 pts. Following a toxicity assessment revealing significant myelosuppression, C was administered in subsequent pts at AUC 4. 14 HER2+ pts received H 8 mg/kg loading dose followed by 6 mg/kg q21 days. Pts were evaluated for response after 9 weeks; treatment continued until progression or toxicity except in HER2+ pts who received up to 6 cycles GCH followed by single agent H. Results: Between 11/03 & 11/05, 45 pts have been treated: median age 55 for GC, 65 for GCH, ECOG 0/1 22/23. 19 pts were chemonaive. 26 pts received prior adjuvant chemotherapy: 20 pts adjuvant anthracyclines (A) & taxanes (T), 3 only prior A and 3 prior T. 73% had 2 or more metastatic sites of disease. 31 pts received GC & 14 pts received GCH. 18 of 41 evaluable pts (44%) had objective responses (PR 16, CR 2) with 17 pts (42%) exhibiting SD & 6 pts PD (15%). 91% of AT pretreated pts demonstrated SD or better. 9 remain on study. 6 went off study due to heme related toxicities and 9 due to MD discretion [4 max benefit, 3 XRT]. Median # of cycles was 5. Combined G3/4 hematologic toxicity was notable for 66% neutropenia (only 1 FN), 55% thrombocytopenia, and 32% anemia, predominately occurring at the carboplatin AUC 5 dose level. Transfusions of PRBCs and plts were administered in 14 and 8 pts respectively. Nonhematologic toxicity was minimal and remarkable for G3/4 fatigue in 20%. Conclusions: In FISH HER2+ pts, the addition of trastuzumab to GC yielded a 50% RR, with no evident cardiotoxicity. The combination of gemcitabine with carboplatin AUC 4 is active, albeit with moderate hematologic toxicity, warranting further exploration of alternate GC ± H schedules in breast cancer.

[Table: see text]

Updated report of a phase III study of induction therapy with gemcitabine + carboplatin (GC) followed by either delayed vs. immediate second-line therapy with docetaxel (D) in advanced non-small cell lung cancer (NSCLC)

7032

Background: GC is an active regimen in patients with advanced NSCLC. For non-progressors after induction treatment, optimal timing of sequential therapy is unclear. Is it best to sequence immediately to an active non-cross resistant agent or delay the introduction of this agent until time of disease progression (PD)? This trial was designed to answer this question. Methods: Pts with Stage IIIB or IV NSCLC were enrolled. G 1000mg/m2 was administered on day 1,8 followed by C at AUC 5.0 on day 1. After 4 cycles, non-progressers were then randomized to immediate D (75mg/m2 administered on day 1 every 3 wks) or delayed D (pts were observed until first evidence of PD). Conclusions: This study confirms that it is possible to deliver docetaxel immediately following four cycles of GC without significantly increasing toxicity. The response rate of 42.1% and clinical benefit rate (CR+PR+SD) of 88.2% observed in the immediate D arm compares favorably with the rates of 6.1% and 60.6% of the delayed D arm. Additional toxicity and response information will be available at the time of the meeting.

[Table: see text]

[Table: see text]

Substantial increases in idarubicin plasma concentration by liposome encapsulation mediates improved antitumor activity

Idarubicin has been successfully encapsulated in cholesterol-free liposomes, however, little is known about how the rate of drug release from circulating liposomes influences therapeutic activity. The studies described herein assess the attributes of a liposome formulation required to significantly increase the plasma levels of idarubicin and further establish whether increases in the circulation longevity of the drug mediate improved antitumor activity. Pharmacokinetic assessments of 6 different 3[H]-labelled liposome formulations were compared to free idarubicin. The highest idarubicin plasma concentrations were observed with DSPC/DSPE-PEG2000 liposomes formulated with 2 mol% DSPE-PEG2000 and 150 mM (iso-osmotic) internal citrate concentration. It was shown that increased levels of PEG-lipid incorporation augmented IDA release and the optimal liposomal formulation needed to be prepared under iso-osmotic conditions. For efficacy studies in a murine leukemia model, groups of 12-14 mice were treated i.v. with saline or equivalent doses (1, 2, 3 mg/kg) of free or liposomal IDA. Liposomal treatment groups exhibited a higher % increase in life span (ILS) as compared to equivalent doses of free drug. Efficacy studies completed in two drug resistant models, P388/ADR and MDA435LCC6/MDR1, demonstrated that neither the free nor liposomal formulation of idarubicin was therapeutically active. Encapsulation of IDA in liposomes increased antitumor activity in an IDA sensitive model, however, the significant increase in plasma drug levels was not sufficient to overcome multidrug resistance.

Randomized phase III trial comparing cisplatin-etoposide to carboplatin-paclitaxel in advanced or metastatic non-small cell lung cancer

BACKGROUND

The present study was designed to evaluate the efficacy and safety of the regimen of carboplatin plus paclitaxel (investigational arm) versus the reference regimen of cisplatin plus etoposide for the treatment of advanced or metastatic non-small-cell lung cancer.

PATIENTS AND METHODS

A total of 369 patients were enrolled, 179 on arm A (cisplatin 75 mg/m2 and etoposide 100 mg/m2) and 190 on arm B (carboplatin AUC=6 mg/ml min and paclitaxel 225 mg/m2), with cycles repeated every 3 weeks. The arms were well balanced with respect to age, performance status, weight loss, stage of disease and disease measurability. However, significantly more women were randomized to arm A than to arm B (P=0.039).

RESULTS

The objective response rate (ORR) was 15% on arm A compared with 23% on arm B (P=0.061). Median survival time, time to progression and 1-year survival rates for arms A and B were 274 days and 233 days (P=0.086), 111 days and 121 days (P=0.877), and 37% and 32%, respectively. The most prevalent toxicities were neutropenia and leukopenia and they occurred at a higher rate in arm A than in arm B.

CONCLUSION

There was no statistically significant survival advantage for carboplatin-paclitaxel compared with cisplatin-etoposide. However, there was an overall benefit in quality of life with the carboplatin-paclitaxel regimen.

Liposomal irinotecan: formulation development and therapeutic assessment in murine xenograft models of colorectal cancer

PURPOSE

The purpose is to demonstrate whether an appropriately designed liposomal formulation of irinotecan is effective in treating mice with liver-localized colorectal carcinomas.

EXPERIMENTAL DESIGN

Irinotecan was encapsulated in 1,2-distearoyl-sn-glycero-3-phosphocholine/cholesterol (55:45 molar ratio) liposomes using an ionophore (A23187)-generated transmembrane proton gradient. This formulation was evaluated in vivo by measuring plasma elimination of liposomal lipid and drug after i.v. administration. Therapeutic activity was determined in SCID/Rag-2M mice bearing s.c. LS180 tumors or orthotopic LS174T colorectal metastases.

RESULTS

Drug elimination from the plasma was significantly reduced when irinotecan was administered in the liposomal formulation. At 1 hour after i.v. administration, circulating levels of the liposomal drug were 100-fold greater than that of irinotecan given at the same dose. High-performance liquid chromatographic analysis of plasma samples indicated that liposomal irinotecan was protected from inactivating hydrolysis to the carboxylate form. This formulation exhibited substantially improved therapeutic effects. For the LS180 solid tumor model, it was shown that after a single injection of liposomal irinotecan at 50 mg/kg, the time to progress to a 400-mg tumor was 34 days (as compared with 22 days for animals treated with free drug at an equivalent dose). In the model of colorectal liver metastases (LS174T), a median survival time of 79 days was observed after treatment with liposomal irinotecan (50 mg/kg, given every 4 days for a total of three doses). Saline and free drug treated mice survived for 34 and 53 days, respectively.

CONCLUSIONS

These results illustrate that liposomal encapsulation can substantially enhance the therapeutic activity of irinotecan and emphasize the potential for using liposomal irinotecan to treat liver metastases.

Establishment of native and exotic grasses on mine overburden and topsoil in the Hunter Valley, New South Wales

Native grasses have an important role to play in mine rehabilitation throughout Australia, but there have been few scientifically designed studies of field establishment of native grasses from sown seed in this country. Current recommendations for rehabilitation of open-cut coal mines in the Hunter Valley involve the sowing of exotic pasture species to reinstate mined land to Class IV and V under the Rural Land Capability System. Despite the importance of native grasses in the pre-mined landscape, they are currently not widely included in mine rehabilitation. To address this issue a project was conducted between 1994 and 2000 to research the use of native grasses for rehabilitation of open-cut coal mines in the Hunter Valley. This paper reports on 2 mine site experiments that aimed to assess establishment and persistence of a broad range of native and exotic grass species from an autumn sowing in both topsoil and raw spoil over a period of 61 months. The most promising natives in terms of early establishment, persistence and spread over time, included six C3 accessions (five Austrodanthonia spp. and Austrostipa bigeniculata) and one C4 accession (Cynodon dactylon). Persistence of these accessions was better in raw spoil than topsoil, despite initial low numbers, due to a lack of weed competition and their ability to spread by self-seeding. In topsoil, and in the absence of any biomass reduction, native species were mostly out-competed by vigorous exotic perennial grasses which were sown in these experiments and from seed influx from adjacent rehabilitation areas or from the soil seed bank. The effects of climatic conditions and differences in soil physical, chemical and seed bank characteristics at the 2 mine sites are also discussed.

Plasma protein binding, lipoprotein distribution and uptake of free and lipid-associated BCL-2 antisense oligodeoxynucleotides (G3139) in human melanoma cells

The objectives of this study were to determine the protein binding and lipoprotein distribution of G3139 and G3139 lipoplexes following incubation in human plasma, assess complement activation of, and the effect of pre-incubation of G3139 and G3139 lipoplexes in human plasma on in vitro cellular uptake of G3139. Effect of concentration and time on incorporation of free and lipid associated (lipoplexes) [3H]Bcl-2 AO (25-600 ng/ml) into normolipidemic human plasma lipoproteins was determined by density gradient ultracentrifugation after incubation at 37 degrees C for 5, 30, 60 and 120 min. Protein binding in the lipoprotein deficient fractions (LPDP) was determined by equilibrium dialysis. Complement interaction was determined by ELISA after exposure of human plasma to AO+/- liposomes prepared in serial dilution. In vitro uptake of G3139 and G3139 lipoplexes into human melanoma cells was assessed qualitatively by fluorescence microscopy after 4-h exposure to G3139 (free or as lipoplexes) with or without pre-incubation of G3139 in normal human plasma. Analysis of Bcl-2 AO-lipoprotein interaction over time and concentration indicated no significant movement of the compound within the different lipoprotein and LPDP fractions. Majority of drug was recovered within LPDP fraction, and more than 85% of drug recovered within LPDP fraction was protein bound. No significant activation of complement was noted for either free AO or lipoplexes. Pre-incubation of free AO or AO-lipoplexes in human plasma resulted in a greater cellular uptake of AO-lipoplexes compared with plasma free controls. These findings suggest that the majority of [3H]Bcl-2 AO is plasma protein bound with little lipoprotein association and no significant movement between different lipoprotein and LPDP fractions. Plasma protein binding other than lipoprotein binding may be responsible for the difference in cellular uptake of free AO vs. cationic lipoplexes.

Vascular access: a role for a renal nurse clinician

The team approach to the delivery of healthcare is important and has become more so since the boundaries between professional groups have become blurred. Renal replacement therapy requires that patients have adequate access. This could be in the form of an arterio-venous fistula, a graft, or a vascular catheter. Doctors have historically always provided access for patients. Placement of vascular access is a lengthy process often causing long delays and anxiety. Due to the reduction in junior doctors hours and the further demands on senior medical staff, a nurse was nominated and developed the role of vascular access specialist and clinician. Before the development of the nurse clinicians' role, the situation in this centre regarding venous access for haemodialysis was based on an ad hoc arrangement between junior doctors. Historically surgeons and medical staff have always provided vascular access for haemodialysis. However, it was felt that a suitably educated renal nurse would be more suitable to develop this role, and a relevant course, (MSc in Advanced Nursing Practice) had been developed at a nearby university. The access role included the insertion of both short and long-term vascular access catheters. An access referral pathway is now in place, giving a streamlined service. A designated access specialist nurse now inserts vascular access, providing focused individualised care specifically targeted at the renal patients' needs. Because of the success of this role, four more nurses are being supported to undertake the clinical MSc. The aim is to develop other areas of renal provision and to provide a nurse led specialist individualised service in line with the future National Service Framework. The role has also provided scope for nursing career development, giving motivation to experienced clinical nurses who wish to remain clinically involved, improve the care for patients and progress their career.