Excessive vincristine exposure in a child being treated for acute lymphoblastic leukaemia with underlying Dubin-Johnson syndrome: a case report

BACKGROUND

Dubin-Johnson syndrome is a rare benign autosomal recessive condition that causes an isolated increase of conjugated bilirubin in the serum. Impaired biliary excretion is due to mutation in the multiple drug-resistance protein 2 gene (MRP2).

CASE PRESENTATION

We describe the case of a 4-year-old girl being treated for acute lymphoblastic leukaemia who had a history of conjugated hyperbilirubinaemia and persistently elevated bilirubin levels on initiation of chemotherapy. During treatment for leukaemia, she was diagnosed with Dubin-Johnson syndrome for the underlying condition. Following administration of vincristine at the recommended dose of 1.5 mg/m2, an abnormally high vincristine exposure was observed (AUC > 200 µg/L*h), approximately 3 times higher than previously reported exposures in a comparable clinical setting. Vincristine dose reductions were applied on subsequent cycles of treatment and resulted in markedly reduced drug exposures, within the normal target range.

CONCLUSION

This case provided a rare opportunity to assess the impact of MRP2 mutations associated with Dubin-Johnson syndrome on the pharmacokinetics of vincristine and strongly indicates that a marked dose reduction should be recommended. Clinicians should be made aware of the potential for altered drug disposition for agents such as vincristine in patients with this rare genetic condition.

Pharmacokinetics and Pharmacogenetics of Cyclophosphamide in a Neonate and Infant Childhood Cancer Patient Population

Infants and young children represent an important but much understudied childhood cancer patient population. The pharmacokinetics and pharmacogenetics of the widely used anticancer prodrug cyclophosphamide were investigated in children <2 years of age. Concentrations of cyclophosphamide and selected metabolites were determined in patients administered cyclophosphamide at doses ranging from 100–1500 mg/m² (5–75 mg/kg), with various infusion times as determined by the standard treatment regimen that each patient was receiving. Polymorphisms in genes including CYP2B6 and CYP2C19 were investigated. Data generated for cyclophosphamide were analysed using a previously published population pharmacokinetic model. Cyclophosphamide pharmacokinetics was assessed in 111 samples obtained from 25 patients ranging from 4–23 months of age. The average cyclophosphamide clearance for the patients was 46.6 mL/min/m² (ranging from 9.4–153 mL/min/m²), with marked inter-patient variability observed (CV 41%). No significant differences in cyclophosphamide clearance or exposure (AUC) were observed between patient groups as separated by age or body weight. However, marked differences in drug clearance and metabolism were noted between the current data in children <2 years of age and recently published results from a comparable study conducted by our group in older children, which reported significantly lower cyclophosphamide clearance values and metabolite exposures using the same population pharmacokinetic model for analysis. Whilst this study demonstrates no significant differences in cyclophosphamide clearance in patients <2 years, it highlights large differences in dosing protocols across tumour types. Furthermore, the study suggests marked differences in cyclophosphamide clearance in children less than two years of age as compared to older patients.

Abstract 1406: Are circulating microRNAs (miRNAs) ready for inclusion as biomarkers in breast cancer clinical trials

Background: Circulating miRNAs have potential as surrogate measures of tumor burden to monitor treatment response in clinical trials due to their association with cancer and high stability in blood. Greystoke et al (PMID: 26654130) showed that 10 miRNAs (miRs-200a, 200b, 200c, 141, 429, 95, 195, 210, 335, 375) were elevated in plasma of patients with a range of solid tumors compared to in plasma of healthy volunteers (HVs). The miRNA levels decreased after treatment, especially in patients with larger clinical responses. In the present study, the same 10 miRNAs, and 3 breast cancer (BC) related miRNAs identified in a literature search (miRs-18b, 21, 148b), were analysed to determine if their measurement i) is more sensitive in plasma or serum, ii) distinguishes BC patients from HVs, and iii) changes after surgery or systemic therapy.

Methods: The 13-miRNA panel (13-plex) was analysed by qPCR in plasma and serum from 12 BC patients and 8 HVs, and in plasma from 19 BC patients pre- and 4 hours post-surgery with a multiplex of TaqManTM MiRNA Assays. Expression of the 13-plex was measured with custom TaqManTM Low Density Array (TLDA) cards after pre-amplification, in serum collected at cycle 1, day 1 (C1D1) and day 8 (C1D8) from 44 BC patients starting adjuvant chemotherapy on the B-AHEAD 2 study (ISRCTN04156504). Endogenous miR-16 and exogenous ath-miR-159a provided standards to assess miRNA extraction efficiency. Results are reported as the geometric means of the 40-Ct values for the 13 miRNAs (geomean13).

Results: Expression of the 13-plex was significantly higher in plasma compared to in matched serum. TLDA analysis of 381 miRNAs confirmed that the plasma to serum superiority was a general effect not restricted to the 13-plex. The superiority of plasma was reduced however by pre-amplification; in the 381-miRNA TLDA analysis, detection in serum improved compared to in the multiplex qPCR assay.

The 13-plex was elevated in plasma of BC patients compared to HVs (p = 0.015). There was a trend towards a reduction after surgery, but the difference did not reach statistical significance. However, miR-195, a BC specific marker, was significantly lower after surgery (p = 0.0001). In the B-AHEAD 2 study cohort, the 13-plex was decreased at C1D8 compared to C1D1 (p = 0.0002). The three patients who relapsed within 5 years of diagnosis had geomean13 values at C1D1 of 10.3, 10.6 and 11.8 compared to the median of 10.3 for all patients. Given the low event rate, either a larger patient cohort or a cohort with a higher event rate is required to assess association with clinical outcome.

Conclusions: This study shows that plasma is better than serum for miRNA evaluation but that measures in serum are useful if cDNA is pre-amplified after reverse transcription. The 13-plex is elevated in BC, has a trend towards a fall after surgery and is reduced after chemotherapy. The 13-plex has potential as a biomarker of tumor burden in BC trials.

Citation Format: Edward B. Amankwatia, Alexandra Bennett, David Ou, David Jamieson, Nicola Cresti, Henry Cain, Rosie McNeillis, Jonathan Womack, Sacha Howell, Michelle Harvie, Felicity May, Alastair Greystoke. Are circulating microRNAs (miRNAs) ready for inclusion as biomarkers in breast cancer clinical trials [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1406.

Development of a rapid phenotypic test on a microfluidic device for carbapenemase detection using the chromogenic compound nitrocefin

Routine identification of carbapenemase-producing bacterial isolates is a lengthy process often taking up to 72 h to generate results with standard culture-based tests. Here we describe a rapid test based on the hydrolysis of nitrocefin to identify isolates producing β-lactamase enzymes. A cocktail of inhibitors has been optimized in the reaction mix to provide specificity for carbapenemase enzymes. The developed assay has also been translated to a microfluidic platform with an optical readout (optofluidic chip). The chip has a long absorbance path (25 mm) to provide high sensitivity. A sample-to-answer has been achieved in under 30 min on these chips using colonies from culture plates. The test on this platform has the potential to provide a rapid indicative (presumptive positive) test for carbapenemase producers direct from bacteria isolated from patient samples, to rapidly trigger infection control measures and identify samples that should be prioritized for more specialized carbapenemase diagnostic assays.

Label-Free Leukemia Monitoring by Computer Vision

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. While there are a number of well‐recognized prognostic biomarkers at diagnosis, the most powerful independent prognostic factor is the response of the leukemia to induction chemotherapy (Campana and Pui: Blood 129 (2017) 1913–1918). Given the potential for machine learning to improve precision medicine, we tested its capacity to monitor disease in children undergoing ALL treatment. Diagnostic and on‐treatment bone marrow samples were labeled with an ALL‐discriminating antibody combination and analyzed by imaging flow cytometry. Ignoring the fluorescent markers and using only features extracted from bright‐field and dark‐field cell images, a deep learning model was able to identify ALL cells at an accuracy of >88%. This antibody‐free, single cell method is cheap, quick, and could be adapted to a simple, laser‐free cytometer to allow automated, point‐of‐care testing to detect slow early responders. Adaptation to other types of leukemia is feasible, which would revolutionize residual disease monitoring. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.

Shortening the decade-long gap between adult and paediatric drug formulations: a new framework based on the HIV experience in low- and middle-income countries

Introduction

Despite the coordinated efforts by several stakeholders to speed up access to HIV treatment for children, development of optimal paediatric formulations still lags 8 to 10 years behind that of adults, due mainly to lack of market incentives and technical complexities in manufacturing. The small and fragmented paediatric market also hinders launch and uptake of new formulations. Moreover, the problems affecting HIV similarly affect other disease areas where development and introduction of optimal paediatric formulations is even slower. Therefore, accelerating processes for developing and commercializing optimal paediatric drug formulations for HIV and other disease areas is urgently needed.

Discussion

The Global Accelerator for Paediatric Formulations (GAP‐f) is an innovative collaborative model that will accelerate availability of optimized treatment options for infectious diseases, such as HIV, tuberculosis and viral hepatitis, affecting children in low‐ and middle‐income countries (LMICs). It builds on the HIV experience and existing efforts in paediatric drug development, formalizing collaboration between normative bodies, research networks, regulatory agencies, industry, supply and procurement organizations and funding bodies. Upstream, the GAP‐f will coordinate technical support to companies to design and study optimal paediatric formulations, harmonize efforts with regulators and incentivize manufacturers to conduct formulation development. Downstream, the GAP‐f will reinforce coordinated procurement and communication with suppliers. The GAP‐f will be implemented in a three‐stage process: (1) development of a strategic framework and promotion of key regulatory efficiencies; (2) testing of feasibility and results, building on the work of existing platforms such as the Paediatric HIV Treatment Initiative (PHTI) including innovative approaches to incentivize generic development and (3) launch as a fully functioning structure.

Conclusions

GAP‐f is a key partnership example enhancing North‐South and international cooperation on and access to science and technology and capacity building, responding to Sustainable Development Goal (SDG) 17.6 (technology) and 17.9. (capacity‐building). By promoting access to the most needed paediatric formulations for HIV and high‐burden infectious diseases in low‐and middle‐income countries, GAP‐f will support achievement of SDG 3.2 (infant mortality), 3.3 (end of AIDS and combat other communicable diseases) and 3.8 (access to essential medicines), and be an essential component of meeting the global Start Free, Stay Free, AIDS Free super‐fast‐track targets.

A novel imaging flow cytometry method for the detection of histone H4 acetylation in myeloid cells

BACKGROUND

The histone deacetylase inhibitor (HDACI) valproic acid has been shown to inhibit the growth of multiple paediatric tumour types and is well tolerated in a childhood cancer setting. The current study was designed to develop a novel imaging flow cytometry method for the detection of histone H4 acetylation in white blood cells obtained from childhood cancer patients treated with valproic acid.

MATERIALS AND METHODS

HL-60 cells and whole blood samples from healthy volunteers were incubated with valproic acid (0-8 mM) for 0-24 hours, with additional blood samples collected from ependymoma patients receiving valproic acid on the SIOP Ependymoma II clinical trial. An imaging flow cytometry method was developed using an ImageStream^®χ flow cytometer, collecting 100 000 images per sample following excitation of PE tagged acH4 antibody and DAPI.

RESULTS

The mean percentage of acH4-positive cells increased to a greater extent than increases in mean and median fluorescence intensity following incubation with valproic acid. Comparable results were observed for in vitro and ex vivo experiments, and the assay was shown to be appropriate for clinical sample analysis. Myeloid cells exhibited a smaller proportion of acH4-positive cells than the lymphoid population, but a greater fold increase above basal levels.

CONCLUSIONS

The percentage of acH4-positive myeloid cells has the potential to be used as a robust pharmacodynamic biomarker for the measurement of acH4 for HDACIs. The developed assay is now being utilised in a clinical trial involving the treatment of childhood ependymoma patients with valproic acid.

Abstract 2583: Imaging flow cytometry assay development and validation for the detection of histone H4 acetylation in white blood cells

Introduction: Histone deacetylases have been identified as oncogenes in several cancer types, providing an attractive target for anticancer treatment. In this respect, the histone deacetylase inhibitor valproic acid has been shown to inhibit the growth of multiple paediatric tumor types and is well tolerated in children with refractory solid or CNS tumors.

Objective: The aim of the current study was to develop and validate a novel imaging flow cytometry method for the detection of histone H4 acetylation in lymphoid and myeloid cell populations, and to assess the applicability of the method to a clinical trial setting.

Method: HL-60 cells and whole blood samples from healthy volunteers were incubated with valproic acid (0.5-8 mM) for 0.5-24 hours, followed by RBC lysis for the whole blood samples and fixed with cold methanol. Additional blood samples were collected from patients with ependymoma who were receiving valproic acid as part of the SIOP Ependymoma II clinical trial. An imaging flow cytometry method was developed using an ImageStreamχ flow cytometer, collecting WBCs with excitation of PE conjugated acH4 antibody and DAPI. Data were collected using Inspire™ software and further analysed by Ideas™ software 6.2. Both in vitro and ex vivo experiments were repeated on at least 3 occasions.

Result: In the HL-60 cell line the mean percentage of acH4 positive cells was 1.98% in the vehicle control sample, increasing to 10.9-77.9% when treated with 0.5-8 mM valproic acid for 6 hours, with percentages of 8.7-49.0% observed following incubation with 4 mM valproic acid for 0.5-24 hours. Comparable data were generated in lymphoid and myeloid WBC populations following ex vivo incubation of whole blood samples with valproic acid. Increases in the percentage of acH4 positive cells were observed in samples collected at 4 hours post-administration in patients receiving valproic acid as compared to pre-treatment samples. Myeloid cells appeared to have a smaller proportion of acH4 positive cells than observed in the lymphoid population but a greater fold increase above basal levels.

Conclusion: A new assay for detection of histone H4 acetylation in WBCs by imaging flow cytometry has been developed and optimised. The assay showed increases in acH4 positivity in both in vitro and ex vivo experiments following exposure to valproic acid. The method can be used for the measurement of acH4 as a pharmacodynamic biomarker for histone deacetylase inhibitors in drug development and monitoring of drug efficacy in clinical trials.

Citation Format: Suriyon Uitrakul, Gareth James Veal, Claire Hutton, David Jamieson. Imaging flow cytometry assay development and validation for the detection of histone H4 acetylation in white blood cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2583.

Inhibition of ATR acutely sensitizes acute myeloid leukemia cells to nucleoside analogs that target ribonucleotide reductase

The ataxia telangiectasia and Rad3-related (ATR) protein kinase promotes cancer cell survival by signaling stalled replication forks generated by replication stress, a common feature of many cancers including acute myeloid leukemia (AML). Here we show that the antileukemic activity of the chemotherapeutic nucleoside analogs hydroxyurea and gemcitabine was significantly potentiated by ATR inhibition via a mechanism involving ribonucleotide reductase (RNR) abrogation and inhibition of replication fork progression. When administered in combination with gemcitabine, an inhibitor of the M1 RNR subunit, the ATR inhibitor VX-970, eradicated disseminated leukemia in an orthotopic mouse model, eliciting long-term survival and effective cure. These data identify a synergistic interaction between ATR inhibition and RNR loss that will inform the deployment of small molecule inhibitors for the treatment of AML and other hematologic malignancies.

Neutrophils: driving progression and poor prognosis in hepatocellular carcinoma?

BACKGROUND

Irrespective of the underlying aetiology, 90% of hepatocellular carcinomas arise and progress on a background of chronic inflammation. We have explored the independent prognostic value of circulating inflammatory cells.

METHODS

Peripheral blood count data sets from 583 consecutive patients presenting to a single UK centre (2000-2010) were analysed for associations with tumour stage, liver function, performance status (PST) and survival. Validation was in an independent Hong Kong cohort (585 patients; 2007-2013).

RESULTS

In both UK and Hong Kong cohorts, neutrophils, platelets, lymphocytes, the neutrophil/lymphocyte ratio (NLR) and the Systemic Immune-Inflammation Index (SII) correlated stepwise, either increasing or decreasing (lymphocytes), with tumour node metastasis (TNM) and Childs-Pugh stage, PST and consequently with the combined Barcelona Clinic for Liver Cancer stage. Survival analyses confirmed the NLR and SII as highly significant prognostic biomarkers. Focused on individual cell types, only the neutrophil count was independently associated with both TNM stage and PST, as well as being significantly and independently associated with poorer survival.

CONCLUSIONS

In this study of 1168 patients, neutrophils alone, rather than lymphocytes or platelets, were independently associated with outcome. These data support further characterisation of a potentially distinctive role for neutrophils as facilitators of tumour progression and deteriorating performance.

Gemcitabine and docetaxel versus doxorubicin as first-line treatment in previously untreated advanced unresectable or metastatic soft-tissue sarcomas (GeDDiS): a randomised controlled phase 3 trial

BACKGROUND

For many years, first-line treatment for locally advanced or metastatic soft-tissue sarcoma has been doxorubicin. This study compared gemcitabine and docetaxel versus doxorubicin as first-line treatment for advanced or metastatic soft-tissue sarcoma.

METHODS

The GeDDiS trial was a randomised controlled phase 3 trial done in 24 UK hospitals and one Swiss Group for Clinical Cancer Research (SAKK) hospital. Eligible patients had histologically confirmed locally advanced or metastatic soft-tissue sarcoma of Trojani grade 2 or 3, disease progression before enrolment, and no previous chemotherapy for sarcoma or previous doxorubicin for any cancer. Patients were randomly assigned 1:1 to receive six cycles of intravenous doxorubicin 75 mg/m² on day 1 every 3 weeks, or intravenous gemcitabine 675 mg/m² on days 1 and 8 and intravenous docetaxel 75 mg/m² on day 8 every 3 weeks. Treatment was assigned using a minimisation algorithm incorporating a random element. Randomisation was stratified by age (≤18 years vs >18 years) and histological subtype. The primary endpoint was the proportion of patients alive and progression free at 24 weeks in the intention-to-treat population. Adherence to treatment and toxicity were analysed in the safety population, consisting of all patients who received at least one dose of their randomised treatment. The trial was registered with the European Clinical Trials (EudraCT) database (no 2009-014907-29) and with the International Standard Randomised Controlled Trial registry (ISRCTN07742377), and is now closed to patient entry.

FINDINGS

Between Dec 3, 2010, and Jan 20, 2014, 257 patients were enrolled and randomly assigned to the two treatment groups (129 to doxorubicin and 128 to gemcitabine and docetaxel). Median follow-up was 22 months (IQR 15·7-29·3). The proportion of patients alive and progression free at 24 weeks did not differ between those who received doxorubicin versus those who received gemcitabine and docetaxel (46·3% [95% CI 37·5-54·6] vs 46·4% [37·5-54·8]); median progression-free survival (23·3 weeks [95% CI 19·6-30·4] vs 23·7 weeks [18·1-20·0]; hazard ratio [HR] for progression-free survival 1·28, 95% CI 0·99-1·65, p=0·06). The most common grade 3 and 4 adverse events were neutropenia (32 [25%] of 128 patients who received doxorubicin and 25 [20%] of 126 patients who received gemcitabine and docetaxel), febrile neutropenia (26 [20%] and 15 [12%]), fatigue (eight [6%] and 17 [14%]), oral mucositis (18 [14%] and two [2%]), and pain (ten [8%] and 13 [10%]). The three most common serious adverse events, representing 111 (39%) of all 285 serious adverse events recorded, were febrile neutropenia (27 [17%] of 155 serious adverse events in patients who received doxorubicin and 15 [12%] of 130 serious adverse events in patients who received gemcitabine and docetaxel, fever (18 [12%] and 19 [15%]), and neutropenia (22 [14%] and ten [8%]). 154 (60%) of 257 patients died in the intention-to-treat population: 74 (57%) of 129 patients in the doxorubicin group and 80 (63%) of 128 in the gemcitabine and docetaxel group. No deaths were related to the treatment, but two deaths were due to a combination of disease progression and treatment.

INTERPRETATION

Doxorubicin should remain the standard first-line treatment for most patients with advanced soft-tissue sarcoma. These results provide evidence for clinicians to consider with their patients when selecting first-line treatment for locally advanced or metastatic soft-tissue sarcoma.

FUNDING

Cancer Research UK, Sarcoma UK, and Clinical Trial Unit Kantonsspital St Gallen.

Abstract 5029: Pharmacogenetics of doxorubicin, gemcitabine and docetaxel in the GeDDiS soft tissue sarcoma trial

Introduction

The treatment of locally advanced or metastatic soft tissue sarcoma remains a significant clinical challenge, with overall survival rates of approximately 12 months observed with current first line palliative chemotherapy. A recently completed randomised phase III clinical trial entitled GeDDiS (ISRCTN07742377), was designed to compare first line treatment with gemcitabine in combination with docetaxel (GemDoc) versus current standard treatment with doxorubicin. A pharmacogenetic sub-study was incorporated into the trial to assess potential impact of single nucleotide polymorphisms (SNPs) in genes associated with the pharmacology of the three drugs.

Methods

A total of 240 patients were recruited to the sub-study with 119 on the doxorubicin arm and 121 on the GemDoc arm. A 4 ml blood sample was taken from each participant and genomic DNA extracted. Individual candidate SNPs were assessed by Taqman PCR in 7 genes associated with doxorubicin pharmacology, 7 genes associated with gemcitabine and 5 genes associated with the pharmacology of docetaxel. Association between the SNPs and efficacy and toxicity was assessed.

Results

SNPs within the solute transporter SLC22A16, associated with the intracellular influx of doxorubicin, were associated with worse PFS (HR = 1.72, p=0.04) and decreased frequency of grade 3/4 adverse events (71% vs 48%, p=0.04) in the doxorubicin arm of the study but not in the GemDoc arm.

Conclusions

The association of genetic variants of SLC22A16 with decreased efficacy and decreased incidence of toxicity is consistent with a loss of function in the transporter and previous observation of increased AUC in pharmacokinetic studies assuming that distribution of the drug into target and collateral tissues is restricted.

Citation Format: David Jamieson, Beatrice Seddon, Katja Kuever, Hakim-Moulay Dehbi, Sandra Strauss, Sandy Beare, Gareth Veal. Pharmacogenetics of doxorubicin, gemcitabine and docetaxel in the GeDDiS soft tissue sarcoma trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5029. doi:10.1158/1538-7445.AM2017-5029

Temporary Single-Cell Coating for Bioprocessing with a Cationic Polymer

Temporary single-cell coating is a useful tool for cell processing, allowing manipulation of cells to prevent cell attachment and agglomeration, before re-establishing normal cell function. In this work, a speckled coating method using a known polycation [poly(l-lysine), PLL] is described to induce cell surface electrostatic charges on three different cell types, namely, two bone cancer cell lines and fibroblasts. The morphology of the PLL speckled coating on the cell surface, internalization and metabolization of the polymer, and prevention of cellular aggregations are reported. Polymer concentration was found to be the key parameter controlling both capsule morphology and cell health. This approach allows a temporary cell coating over the course of 1-2 h, with cells exhibiting phenotypically normal behavior after ingesting and metabolizing the polymer. The process offers a fast and efficient alternative to aid single-cell manipulation for bioprocessing applications. Preliminary work on the application of PLL speckled cell coating in enabling reliable bioprinting is also presented.

Pharmacogenetic association of MBL2 and CD95 polymorphisms with grade 3 infection following adjuvant therapy for breast cancer with doxorubicin and cyclophosphamide

Life-threatening infection as an adverse reaction to cytotoxic therapy of cancer remains a major problem, potentially limiting efficacy. Administration of colony-stimulation factors benefits only a minority of patients, and improved stratification guidelines are needed to identify those patients likely to benefit. We investigated single nucleotide polymorphisms (SNPs) in two genes related to immune function to identify associations with severe infection following treatment of breast cancer with doxorubicin and cyclophosphamide. CD95 mediates the extrinsic apoptosis pathway in haematopoietic cells and a CD95 promoter SNP (rs2234767) has been shown to result in reduced expression of the receptor. MBL2 activates the classical complement pathway in the presence of pathogens and independently of antibodies. Numerous SNPs have been described including a promoter SNP (rs7096206) which results in decreased expression of the protein. Homozygotes for the CD95 minor allele were more likely to experience a grade 3 infection than heterozygote and homozygote wild-type patients (29%, 3% and 5%, respectively p=0.048). CD95 minor allele homozygotes also had higher basal white blood cell and neutrophil counts compared with wild-type allele carriers, which was sustained throughout therapy. There was an allele-dose association between the MBL2 SNP and grade 3 infection, with 2, 8 and 17% of wild-type homozygotes, heterozygotes and minor allele homozygotes, respectively, experiencing grade 3 infection (p=0.02). These associations demonstrate the utility of a pharmacogenetic approach to identify individuals more likely to acquire a life-threatening infection during chemotherapy. The apparent association with a CD95 SNP and a mild neutrophilia merits further investigation.

A phase I pharmacokinetic and pharmacodynamic study of the oral mitogen-activated protein kinase kinase (MEK) inhibitor, WX-554, in patients with advanced solid tumours

PURPOSE

We performed a multi-centre phase I study to assess the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of the orally available small molecule mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, WX-554, and to determine the optimal biological dose for subsequent trials.

EXPERIMENTAL DESIGN

Patients with treatment-refractory, advanced solid tumours, with adequate performance status and organ function were recruited to a dose-escalation study in a standard 3 + 3 design. The starting dose was 25 mg orally once weekly with toxicity, PK and PD guided dose-escalation with potential to explore alternative schedules.

RESULTS

Forty-one patients with advanced solid tumours refractory to standard therapies and with adequate organ function were recruited in eight cohorts up to doses of 150 mg once weekly and 75 mg twice weekly. No dose-limiting toxicities were observed during the study, and a maximum tolerated dose (MTD) was not established. The highest dose cohorts demonstrated sustained inhibition of extracellular signal-regulated kinase (ERK) phosphorylation in peripheral blood mononuclear cells following ex-vivo phorbol 12-myristate 13-acetate stimulation. There was a decrease of 70 ± 26% in mean phosphorylated (p)ERK in C1 day 8 tumour biopsies when compared with pre-treatment tumour levels in the 75 mg twice a week cohort. Prolonged stable disease (>6 months) was seen in two patients, one with cervical cancer and one with ampullary carcinoma.

CONCLUSIONS

WX-554 was well tolerated, and an optimal biological dose was established for further investigation in either a once or twice weekly regimens. The recommended phase 2 dose is 75 mg twice weekly.

Condensin II mutation causes T-cell lymphoma through tissue-specific genome instability

Chromosomal instability is a hallmark of cancer, but mitotic regulators are rarely mutated in tumors. Mutations in the condensin complexes, which restructure chromosomes to facilitate segregation during mitosis, are significantly enriched in cancer genomes, but experimental evidence implicating condensin dysfunction in tumorigenesis is lacking. We report that mice inheriting missense mutations in a condensin II subunit (Caph2nes) develop T-cell lymphoma. Before tumors develop, we found that the same Caph2 mutation impairs ploidy maintenance to a different extent in different hematopoietic cell types, with ploidy most severely perturbed at the CD4+CD8+ T-cell stage from which tumors initiate. Premalignant CD4+CD8+ T cells show persistent catenations during chromosome segregation, triggering DNA damage in diploid daughter cells and elevated ploidy. Genome sequencing revealed that Caph2 single-mutant tumors are near diploid but carry deletions spanning tumor suppressor genes, whereas P53 inactivation allowed Caph2 mutant cells with whole-chromosome gains and structural rearrangements to form highly aggressive disease. Together, our data challenge the view that mitotic chromosome formation is an invariant process during development and provide evidence that defective mitotic chromosome structure can promote tumorigenesis.

Imagestream detection and characterisation of circulating tumour cells - A liquid biopsy for hepatocellular carcinoma?

BACKGROUND & AIMS

The lack of progress in developing and delivering new therapies for hepatocellular carcinoma (HCC) is in part attributed to the risk related avoidance of tumour biopsy at diagnosis. Circulating tumour cells (CTCs) are a potential source of tumour tissue that could aid biological or biomarker research, treatment stratification and monitoring.

METHODS

An imaging flow cytometry method, using immunofluorescence of cytokeratin, EpCAM, AFP, glypican-3 and DNA-PK together with analysis of size, morphology and DNA content, for detection of HCC CTCs was developed and applied to 69 patient and 31 control samples. The presence of CTCs as a prognostic indicator was assessed in multivariate analyses encompassing recognised prognostic parameters.

RESULTS

Between 1 and 1642 CTCs were detected in blood samples from 45/69 HCC patients compared to 0/31 controls. CTCs positive for the epithelial markers cytokeratin and EpCAM were detected in 29% and 18% of patients respectively, while an additional 28% of patients had CTCs negative for all markers other than size and evidence of hyperploidy. CTC number correlated significantly with tumour size and portal vein thrombosis (PVT). The median survival of patients with >1 CTC was 7.5months versus >34months for patients with <1 CTC (p<0.001, log-rank), with significance retained in a multivariate analysis (HR 2.34, 95% CI 1.005-5.425, p=0.049) including tumour size and PVT.

CONCLUSIONS

The use of multiple parameters enhanced HCC CTC detection sensitivity, revealing biological associations and predictive biomarker potential that may be able to guide stratified medicine decisions and future research.

LAY SUMMARY

Characteristics of tumour tissues can be used to predict outcomes for individual patients with cancer, as well as help to choose their best treatment. Biopsy of liver cancers carries risks, however, and is usually avoided. Some cancer cells enter the blood, and although they are very rare, we have developed a method of finding and characterising them in patients with liver cancer, which we hope will provide a low risk means of guiding treatment.

Abstract 3942: Increased frequency of proliferating peripheral white blood cells in the blood of hepatocellular carcinoma patients compared with noncancer controls

Introduction

Proliferation of peripheral blood cells, including activated CD8+ T-cells, has been reported in numerous pathologies including haematopoietic cancers and solid tumours. During development of a method to detect and characterise circulating tumour cells by imaging flow cytometry it became apparent that peripheral proliferating lymphocytes, while still rare, are substantially more common than CTCs in all cancer patients and are present in everybody. We investigated the frequency of these cells in patients with hepatocellular carcinoma (HCC) and healthy volunteers, and went on to assess their utility as a surrogate tissue for proof of mechanism studies of anti-proliferative agents.

Methods

Whole blood samples (4ml) from 7 patients with hepatocellular carcinoma and 14 healthy volunteers were collected into EDTA tubes. After RBC lysis and fixation WBCs were stained with fluorochrome conjugated antibodies to Ki67 and CD45 and the nuclei were stained with DAPI to assess relative DNA content. For each sample images of 100,000 cells were collected by imaging flow cytometry. Putative G2 cells were identified as single cells with DNA content equivalent to twice the amount of the majority of cells and the same as images of doublets. The frequency of cells with nuclear localised Ki67 reactivity was assessed independently of DNA content. Whole blood from healthy volunteers was also treated by ex vivo incubation with PMA ± the CDK inhibitor Dinaciclib.

Results

The mean frequency of Ki67 positive G1 peripheral WBCs in blood from patients with HCC was 0.44%, as compared to a frequency of 0.24% in the blood from healthy volunteers (p = 0.007). Incubation of healthy volunteer blood with PMA for 20 minutes at 37°C resulted in a small but reproducible increase in the number of Ki67 positive cells and this increase was abrogated by simultaneous incubation with Dinaciclib (141 ± 41% versus 92 ± 39%, expressed as a percentage of no PMA control, p = 0.0007). Additional staining of the ex vivo samples with an antibody to pMCM2, as a potential proof of mechanism marker for CDC7 inhibitor efficacy, was carried out. Results showed that pMCM2 expression was associated with ki67 and the frequency of pMCM2 positive cells also increased with exposure to PMA

Conclusion

The frequency of proliferating WBCs is increased in patients with HCC. These cells may have utility as a predictive/prognostic biomarker, or possibly in the pharmacodynamic monitoring of anti-proliferative pharmacological agents.

Citation Format: Claire Hutton, Suriyon Uitrakul, Laura F. Ogle, Helen L. Reeves, Alastair Greystoke, Gareth J. Veal, David Jamieson. Increased frequency of proliferating peripheral white blood cells in the blood of hepatocellular carcinoma patients compared with noncancer controls. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3942.

Phase 2 multicentre trial investigating intermittent and continuous dosing schedules of the poly(ADP-ribose) polymerase inhibitor rucaparib in germline BRCA mutation carriers with advanced ovarian and breast cancer

BACKGROUND

Rucaparib is an orally available potent selective small-molecule inhibitor of poly(ADP-ribose) polymerase (PARP) 1 and 2. Rucaparib induces synthetic lethality in cancer cells defective in the homologous recombination repair pathway including BRCA-1/2. We investigated the efficacy and safety of single-agent rucaparib in germline (g) BRCA mutation carriers with advanced breast and ovarian cancers.

METHODS

Phase II, open-label, multicentre trial of rucaparib in proven BRCA-1/2 mutation carriers with advanced breast and or ovarian cancer, WHO PS 0-1 and normal organ function. Intravenous (i.v.) and subsequently oral rucaparib were assessed, using a range of dosing schedules, to determine the safety, tolerability, dose-limiting toxic effects and pharmacodynamic (PD) and pharmacokinetic (PK) profiles.

RESULTS

Rucaparib was well tolerated in patients up to doses of 480 mg per day and is a potent inhibitor of PARP, with sustained inhibition ⩾24 h after single doses. The i.v. rucaparib (intermittent dosing schedule) resulted in an objective response rate (ORR) of only 2% but with 41% (18 out of 44) patients achieved stable disease for ⩾12 weeks and 3 patients maintaining disease stabilisation for >52 weeks. The ORR for oral rucaparib (across all six dose levels) was 15%. In the oral cohorts, 81% (22 out of 27) of the patients had ovarian cancer and 12 out of 13, who were dosed continuously, achieved RECIST complete response/partial response (CR/PR) or stable disease (SD) ⩾12 weeks, with a median duration of response of 179 days (range 84-567 days).

CONCLUSIONS

Rucaparib is well tolerated and results in high levels of PARP inhibition in surrogate tissues even at the lowest dose levels. Rucaparib is active in gBRCA-mutant ovarian cancer and this activity correlates with platinum-free interval. The key lessons learned from this study is that continuous rucaparib dosing is required for optimal response, the recommended phase 2 dose (RP2D) for continuous oral scheduling has not been established and requires further exploration and, thirdly, the use of a PD biomarker to evaluate dose-response has its limitations.

Cyclophosphamide pharmacokinetics and pharmacogenetics in children with B-cell non-Hodgkin's lymphoma

Introduction

Variation in cyclophosphamide pharmacokinetics and metabolism has been highlighted as a factor that may impact on clinical outcome in various tumour types. The current study in children with B-cell non-Hodgkin's lymphoma (NHL) was designed to corroborate previous findings in a large prospective study incorporating genotype for common polymorphisms known to influence cyclophosphamide pharmacology.

Methods

A total of 644 plasma samples collected over a 5 year period, from 49 B-cell NHL patients ≤18 years receiving cyclophosphamide (250 mg/m²), were used to characterise a population pharmacokinetic model. Polymorphisms in genes including CYP2B6 and CYP2C19 were analysed.

Results

A two-compartment model provided the best fit of the population analysis. The mean cyclophosphamide clearance value following dose 1 was significantly lower than following dose 5 (1.83 ± 1.07 versus 3.68 ± 1.43 L/h/m², respectively; mean ± standard deviation from empirical Bayes estimates; P < 0.001). The presence of at least one CYP2B6*6 variant allele was associated with a lower cyclophosphamide clearance following both dose 1 (1.54 ± 0.11 L/h/m² versus 2.20 ± 0.31 L/h/m², P = 0.033) and dose 5 (3.12 ± 0.17 L/h/m² versus 4.35 ± 0.37 L/h/m², P = 0.0028), as compared to homozygous wild-type patients. No pharmacokinetic parameters investigated were shown to have a significant influence on progression free survival.

Conclusion

The results do not support previous findings of a link between cyclophosphamide pharmacokinetics or metabolism and disease recurrence in childhood B-cell NHL. While CYP2B6 genotype was shown to influence pharmacokinetics, there was no clear impact on clinical outcome.

•

The influence of cyclophosphamide clinical pharmacology on childhood cancer outcome has been investigated

•

The presence of at least one CYP2B6*6 variant allele was associated with a lower rate of cyclophosphamide clearance

•

Pharmacokinetic parameters investigated were not shown to have a marked influence on clinical outcome

•

Findings do not support a link between cyclophosphamide metabolism and disease recurrence in B-cell non-Hodgkin's lymphoma

High-resolution imaging for the detection and characterisation of circulating tumour cells from patients with oesophageal, hepatocellular, thyroid and ovarian cancers

Interest has increased in the potential role of circulating tumour cells in cancer management. Most cell‐based studies have been designed to determine the number of circulating tumour cells in a given volume of blood. Ability to understand the biology of the cancer cells would increase the clinical potential. The purpose of this study was to develop and validate a novel, widely applicable method for detection and characterisation of circulating tumour cells. Cells were imaged with an ImageStream^X imaging flow cytometer which allows detection of expression of multiple biomarkers on each cell and produces high‐resolution images. Depletion of haematopoietic cells was by red cell lysis, leukocyte common antigen CD45 depletion and differential centrifugation. Expression of epithelial cell adhesion molecule, cytokeratins, tumour‐type‐specific biomarkers and CD45 was detected by immunofluorescence. Nuclei were identified with DAPI or DRAQ5 and brightfield images of cells were collected. The method is notable for the dearth of cell damage, recoveries greater than 50%, speed and absence of reliance on the expression of a single biomarker by the tumour cells. The high‐quality images obtained ensure confidence in the specificity of the method. Validation of the methodology on samples from patients with oesophageal, hepatocellular, thyroid and ovarian cancers confirms its utility and specificity. Importantly, this adaptable method is applicable to all tumour types including those of nonepithelial origin. The ability to measure simultaneously the expression of multiple biomarkers will facilitate analysis of the cancer cell biology of individual circulating tumour cells.

What's new?

Circulating tumour cells (CTCs) are disseminated malignant cells from which biological and therapeutic information may be obtained non‐invasively. Detection of small CTC populations within the large number of normal blood cells is a challenge. This study describes a novel method for the detection and high‐resolution imaging of CTCs. Unlike most other studies, CTC detection is not reliant upon expression of a single biomarker. The method is applicable to all cancers; the authors present preliminary results from four tumour types. The high quality of the images allows biological characterisation of the tumour cells and increases the clinical potential of the approach.

Antiretroviral procurement and supply chain management

Procurement, the country-level process of ordering antiretrovirals (ARVs), and supply chain management, the mechanism by which they are delivered to health-care facilities, are critical processes required to move ARVs from manufacturers to patients. To provide a glimpse into the ARV procurement and supply chain, the following pages provide an overview of the primary stakeholders, principal operating models, and policies and regulations involved in ARV procurement. Also presented are key challenges that need to be addressed to ensure that the supply chain is not a barrier to the goal of universal coverage. This article will cover the steps necessary to order and distribute ARVs, including different models of delivery, key stakeholders involved, strategic considerations that vary depending on context and policies affecting them. The single drug examples given illustrate the complications inherent in fragmented supply and demand-driven models of procurement and supply chain management, and suggest tools for navigating these hurdles that will ultimately result in more secure and reliable ARV provision. Understanding the dynamics of ARV supply chain is important for the global health community, both to ensure full and efficient treatment of persons living with HIV as well as to inform the supply chain decisions for other public health products.

Identification of dual DNA-PK MDR1 inhibitors for the potentiation of cytotoxic drug activity

Inhibition of DNA repair is an attractive therapeutic approach to enhance the activity of DNA-damaging anticancer chemotherapeutic agents. Similarly, blockade of the multidrug-resistance protein 1 (MDR1) can overcome efflux-mediated resistance. DNA-dependent protein kinase (DNA-PK) is essential for the non-homologous end-joining DNA repair pathway. NU7441 is a potent DNA-PK inhibitor (IC50=14nM) that is used widely to study the effects of DNA-PK inhibition in vitro. In growth inhibition studies, 1μM NU7441 sensitised vincristine-resistant CCRF-CEM VCR/R leukaemia cells (1200-fold resistant) to a range of MDR1 substrates, including doxorubicin (8-fold, p=0.03), vincristine (14-fold, p=0.01) and etoposide (63-fold, p=0.02), compared with 1.4-fold (p=0.02), 2.2-fold (p=0.04) and 3.6-fold (p=0.01) sensitisation, respectively, in parental CCRF-CEM cells. This difference in NU7441 sensitivity was confirmed in another two parental and MDR1-overexpressing cell line pairs. A doxorubicin fluorescence assay showed that in MDR1-overexpressing canine kidney MDCKII-MDR1 cells, 1μM NU7441 increased doxorubicin nuclear fluorescence 16-fold. NU7441 and 3 structurally related compounds (NU7742 (an NU7441 analogue that does not inhibit DNA-PK - IC50>10μM), DRN1 (DNA-PK-inhibitory atropisomeric NU7441 derivative - IC50=2nM) and DRN2 (DNA-PK non-inhibitory atropisomeric NU7441 derivative - IC50=7μM)) all increased intracellular vincristine accumulation in the CCRF-CEM VCR/R cells to a level similar to verapamil, as measured by LC-MS. This paper demonstrates that NU7441 is a dual DNA-PK and MDR1 inhibitor, and this extends the therapeutic potential of the compound when used in combination with MDR substrates.

Abstract 3329: The DNA-PK inhibitor, NU7441, sensitises cancer cells to microtubule-targeting agents and modulates vincristine efflux in multidrug resistant cells

Microtubules are involved in the formation of the mitotic spindle, and correct separation of the sister chromatids at mitosis is essential for maintaining genomic stability. Microtubule-targeting drugs arrest rapidly-dividing cells and are important chemotherapeutic agents, but the development of multidrug-resistance (MDR) is a serious clinical problem. Along with its role in DNA double-strand break repair, DNA-dependent protein kinase (DNA-PK) has also been shown to play an important role in stabilising spindle formation and preventing mitotic catastrophe (Shang et al, Cancer Res. 2010). In light of this novel finding, we hypothesised that inhibition of DNA-PK would sensitise cells to microtubule-targeting agents. Pilot studies showed that inhibition of DNA-PK by the selective inhibitor, NU7441, caused greater sensitisation to vincristine in multidrug-resistant cells compared to parental cells. Here, we further investigate the role of DNA-PK in response to microtubule-targeting drugs using a novel series of NU7441 analogues, and investigate whether these inhibitors interact with the efflux transporter, P-glycoprotein.

In growth inhibition studies, CCRF-CEM leukaemia cells were sensitised 1.4-fold to vincristine by NU7441 (1μM) whereas their vincristine-resistant derivative CCRF-CEM VCR/R cells were sensitised 8-fold to vincristine. DNA-PK-deficient M059J glioblastoma cells were 2-fold more sensitive to docetaxel than DNA-PK-proficient cells, and NU7441 sensitised only DNA-PK-proficient M059J-Fus1 cells to docetaxel. CCRF-CEM VCR/R cells have a higher basal level of autophosphorylation of DNA-PKcs (Western blotting) than the CCRF-CEM cells and autophosphorylation in response to vincristine was abrogated by NU7441.

To investigate the effects of NU7441 on drug transport, a doxorubicin fluorescence assay showed that in P-glycoprotein-overexpressing canine kidney MDCKII-MDR1 cells, 1μM NU7441 increased doxorubicin cellular fluorescence 16-fold by blocking drug efflux via P-glycoprotein. NU7441 and 3 structurally-related compounds (NU7742 (inactive NU7441 analogue), DRN1 (DNA-PK-inhibitory atropisomeric NU7441 derivative) or DRN2 (DNA-PK non-inhibitory atropisomeric NU7441 derivative)) all increased intracellular vincristine accumulation in the CCRF-CEM VCR/R cells to a level similar to verapamil, as measured by LC-MS. However, the non-inhibitory compound NU7742 was 5-fold less effective at sensitising CCRF-CEM VCR/R cells to vincristine than NU7441 (p=0.008).

The novel finding that DNA-PK inhibition sensitises cells to microtubule-targeting agents suggests that along with its function in DNA repair, this enzyme plays a role in the mitotic spindle checkpoint. Additionally, in multidrug-resistant cells, NU7441 is able to block drug efflux via interaction with P-glycoprotein.

Citation Format: Emily Mould, Philip Berry, David Jamieson, Christopher Hill, Niu Tan, Sarah Elliott, Barbara Durkacz, David Newell, Elaine Willmore. The DNA-PK inhibitor, NU7441, sensitises cancer cells to microtubule-targeting agents and modulates vincristine efflux in multidrug resistant cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3329. doi:10.1158/1538-7445.AM2013-3329

Characterisation of the roles of ABCB1, ABCC1, ABCC2 and ABCG2 in the transport and pharmacokinetics of actinomycin D in vitro and in vivo

Actinomycin D plays a key role in the successful treatment of Wilms tumour. However, associated liver toxicities remain a drawback to potentially curative treatment. We have used MDCKII cells over-expressing ABCB1, ABCC1, ABCC2 and ABCG2, alongside knockout mouse models to characterise actinomycin D transport and its impact on pharmacokinetics. Growth inhibition, intracellular accumulation and cellular efflux assays were utilised. A 59-fold difference in GI₅₀ was observed between MDCKII-WT and MDCKII-ABCB1 cells (12.7 nM vs. 745 nM, p < 0.0001). Reduced sensitivity was also seen in MDCKII-ABCC1 and ABCC2 cells (GI₅₀ 25.7 and 40.4 nM respectively, p < 0.0001). Lower intracellular accumulation of actinomycin D was observed in MDCKII-ABCB1 cells as compared to MDCKII-WT (0.98 nM vs. 0.1 nM, p < 0.0001), which was reversed upon ABCB1 inhibition. Lower accumulation was also seen in MDCKII-ABCC1 and ABCC2 cells. Actinomycin D efflux over 2 h was most pronounced in MDCKII-ABCB1 cells, with 5.5-fold lower intracellular levels compared to WT. In vivo studies showed that actinomycin D plasma concentrations were significantly higher in Abcb1a/1b^−/− as compared to WT mice following administration of 0.5 mg/kg actinomycin D (AUC_0–6 h 242 vs. 152 μg/L h respectively). While comparable actinomycin D concentrations were observed in the kidneys and livers of Abcb1a/1b^−/− and Abcc2^−/− mice, concentrations in the brain were significantly higher at 6 h following drug administration in Abcb1a/1b^−/− mice compared to WT. Results confirm actinomycin D as a substrate for ABCB1, ABCC1 and ABCC2, and indicate that Abcb1a/1b and Abcc2 can influence the in vivo disposition of actinomycin D. These data have implications for ongoing clinical pharmacology trials involving children treated with actinomycin D.

Institutional Profile: Pharmacogenomics research at Newcastle University

Newcastle University has been active in the field of pharmacogenomics/pharmacogenetics research since 1988. Research activity is based at the Faculty of Medical Sciences and is led by four professors within two separate research institutes. This article describes the various ongoing research projects and the teams involved together with our teaching activities in the subject.

The impact of retinoic acid treatment on the sensitivity of neuroblastoma cells to fenretinide

Despite the successful introduction of 13-cis retinoic acid (13cisRA) therapy for the treatment of neuroblastoma, approximately 50% patients do not respond or experience relapse. A retinoid analogue, fenretinide [N-(4-hydroxyphenyl) retinamide; 4-HPR] can induce apoptosis in neuroblastoma cell lines and could have clinical use after therapy with 13cisRA. However, there are important questions concerning potential retinoid drug interactions which need to be addressed. The aim of this study was to investigate the influence of retinoic acid pre-treatment on fenretinide-induced apoptosis and fenretinide metabolism in neuroblastoma cell lines. Apoptosis was measured by flow cytometry of propidium iodide-stained neuroblastoma cells and a live-cell imaging assay. Intracellular fenretinide metabolism was determined by HPLC analysis. Pre-treatment of neuroblastoma cell lines with retinoic acid (RA) resulted in a significant decrease in the apoptotic response to fenretinide in three of the four lines tested. Comparison between responsive and non-responsive cell lines suggested that RA sensitivity was required to promote fenretinide resistance, and that this was mediated by up-regulation of Bcl-2 and the inhibition of pro-apoptotic fenretinide signalling pathways. Induction of the oxidative metabolism of fenretinide after RA pre-treatment did not significantly impact on intracellular parent drug levels and is unlikely to explain the decreased apoptotic response observed. The interaction between RA and fenretinide could have important implications for the scheduling of fenretinide in therapeutic protocols for neuroblastoma.

Keratinocyte apoptosis in epidermal remodeling and clearance of psoriasis induced by UV radiation

Psoriasis is a common chronic skin disorder, but the mechanisms involved in the resolution and clearance of plaques remain poorly defined. We investigated the mechanism of action of UVB, which is highly effective in clearing psoriasis and inducing remission, and tested the hypothesis that apoptosis is a key mechanism. To distinguish bystander effects, equal erythemal doses of two UVB wavelengths were compared following in vivo irradiation of psoriatic plaques; one is clinically effective (311 nm) and one has no therapeutic effect on psoriasis (290 nm). Only 311 nm UVB induced significant apoptosis in lesional epidermis, and most apoptotic cells were keratinocytes. To determine clinical relevance, we created a computational model of psoriatic epidermis. Modeling predicted apoptosis would occur in both stem and transit-amplifying cells to account for plaque clearance; this was confirmed and quantified experimentally. The median rate of keratinocyte apoptosis from onset to cell death was 20 minutes. These data were fed back into the model and demonstrated that the observed level of keratinocyte apoptosis was sufficient to explain UVB-induced plaque resolution. Our human studies combined with a systems biology approach demonstrate that keratinocyte apoptosis is a key mechanism in psoriatic plaques clearance, providing the basis for future molecular investigation and therapeutic development.

Use of generic antiretroviral agents and cost savings in PEPFAR treatment programs

CONTEXT

One of the biggest hurdles to the rapid scale-up of antiretroviral therapy in the developing world was the price of antiretroviral drugs (ARVs). Modification of an existing US Food and Drug Administration (FDA) process to expedite review and approval of generic ARVs quickly resulted in a large number of FDA-tentatively approved ARVs available for use by the US President's Emergency Plan for AIDS Relief (PEPFAR).

OBJECTIVE

To evaluate the uptake of generic ARVs among PEPFAR-supported programs in Guyana, Haiti, Vietnam, and 13 countries in Africa, and changes over time in ARV use and costs.

DESIGN, SETTING, AND PARTICIPANTS

An annual survey from 2005 to 2008 of ARVs purchased in 16 countries by PEPFAR implementing and procurement partners (organizations using PEPFAR funding to purchase ARVs).

MAIN OUTCOME MEASURES

Drug expenditures, ARV types and volumes (assessed per pack, a 1-month supply), proportion of generic procurement across years and countries, and cost savings from generic procurement.

RESULTS

ARV expenditures increased from $116.8 million (2005) to $202.2 million (2008); and procurement increased from 6.2 million to 22.1 million monthly packs. The proportion spent on generic ARVs increased from 9.17% (95% confidence interval [CI], 9.17%-9.18%) in 2005 to 76.41% (95% CI, 76.41%-76.42%) in 2008 (P < .001), and the proportion of generic packs procured increased from 14.8% (95% CI, 14.79%-14.84%) in 2005 to 89.33% (95% CI, 89.32%-89.34%) in 2008 (P < .001). In 2008, there were 8 PEPFAR programs that procured at least 90.0% of ARV packs in generic form; South Africa had the lowest generic procurement (24.7%; 95% CI, 24.6%-24.8%). Procurement of generic fixed-dose combinations increased from 33.3% (95% CI, 33.24%-33.43%) in 2005 to 42.73% (95% CI, 42.71%-42.75%) in 2008. Estimated yearly savings generated through generic ARV use were $8,108,444 in 2005, $24,940,014 in 2006, $75,645,816 in 2007, and $214,648,982 in 2008, a total estimated savings of $323,343,256.

CONCLUSION

Among PEPFAR-supported programs in 16 countries, availability of generic ARVs was associated with increased ARV procurement and substantial estimated cost savings.

Abstract 1674: The NQO1 C609T polymorphism is associated with poorer response to AC adjuvant therapy in the treatment of breast cancer

A non-synonymous SNP in the NAD(P)H: Quinone Oxidoreductase 1 gene has previously been implicated in the response of breast cancer patients to anthracycline containing regimens in a retrospective cohort study. NQO2 is 54% homologous to NQO1 at the primary protein structure and, despite the lack of a characterised endogenous electron donating cofactor for NQO2, the two enzymes share numerous substrates. NQO2, in contrast to NQO1, is additionally capable of reducing reactive quinone metabolites of estradiol. The NQO2 gene has a non-synonymous SNP that has previously been shown to result in a lower average NQO2 activity in cohorts of bladder and ovarian cancer patients. It is unknown if the NQO2 SNP impacts on survival in breast cancer.

Genomic DNA samples from 239 women with early breast cancer were genotyped for the NQO1 (rs1800566) and NQO2 (rs1143684) SNPs. All of the participants were recruited from Medical Oncology out-patient clinics within the Newcastle upon Tyne Hospitals NHS Foundation Trust and were treated with an AC adjuvant therapy regimen with curative intent. Median follow up was 78 months and followed a standard protocol. Genotyping was done by the Taqman RT-PCR method.

The NQO1 SNP was associated with a decreased time to progression (HR 2.8, 95%CI 1.4-5.64, p=0.003), decreased overall survival (HR 3.6, 95%CI 1.4-10, p=0.007) and a lower likelihood of having a dose delay, all indicative of NQO1 mediated sensitisation to the effects of doxorubicin. The NQO2 SNP had no impact on the cohort as a whole but was associated with a decreased overall survival (p=0.009, log-rank) and time to progression (p=0.004, log rank) in patients who were oestrogen receptor (ER) negative.

This study confirms the previous observation of NQO1 genotype influencing response to anthracyclines and indicates a potential impact of an NQO2 SNP on the prognosis of ER negative breast cancer. The mechanism by which NQO2 genotype influences breast survival remains to be elucidated.

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 1674.

Influence of pharmacogenetics on response and toxicity in breast cancer patients treated with doxorubicin and cyclophosphamide

Background:

Doxorubicin and cyclophosphamide (AC) therapy is an effective treatment for early-stage breast cancer. Doxorubicin is a substrate for ABCB1 and SLC22A16 transporters. Cyclophosphamide is a prodrug that requires oxidation to 4-hydroxycyclophosphamide, which yields a cytotoxic alkylating agent. The initial oxidation is catalysed by cytochrome P450 enzymes including CYP2B6, CYP2C9, CYP2C19 and CYP3A5. Polymorphic variants of the genes coding for these enzymes and transporters have been identified, which may influence the systemic pharmacology of the two drugs. It is not known whether this genetic variation has an impact on the efficacy or toxicity of AC therapy.

Methods:

Germ line DNA samples from 230 patients with breast cancer on AC therapy were genotyped for the following SNPs: ABCB1 C1236T, G2677T/A and C3435T, SLC22A16 A146G, T312C, T755C and T1226C, CYP2B6^*2, ^*8, ^*9, ^*3, ^*4 and ^*5, CYP2C9^*2 and ^*3, CYP3A5^*3 and CYP2C19^*2. Clinical data on survival, toxicity, demographics and pathology were collated.

Results:

A lower incidence of dose delay, indicative of less toxicity, was seen in carriers of the SLC22A16 A146G, T312C, T755C variants. In contrast, a higher incidence of dose delay was seen in carriers of the SLC22A16 1226C, CYP2B6^*2 and CYP2B6^*5 alleles. The ABCB1 2677A, CYP2B6^*2, CYP 2B6^*8, CYP 2B6^*9, CYP 2B6^*4 alleles were associated with a worse outcome.

Conclusion:

Variant alleles in the ABCB1, SLC22A16 and CYP2B6 genes are associated with response to AC therapy in the treatment of breast cancer.

Acute effects of kava on measures of cognitive performance, physiological function and mood

Volunteer subjects were assigned to receive a mixture of the intoxicating substance, kava, in a mixture with fruit juice, or juice alone. Subjects then undertook tasks of acute cognitive functioning, including reaction time and tracking tasks, and a measure of body sway. Heart rate, respiration rate, blood pressure were recorded and subjects were asked to rate their degree of intoxication and complete a stress/arousal check list. Subjects receiving kava reported feelings of intoxication which peaked approximately one hour after kava ingestion. Compared to the group receiving juice alone, the group receiving kava also had increased body sway. There were no other statistically significant differences between groups, although the mean cognitive performance of the group receiving kava was generally poorer.