The LeVe CPAP System for Oxygen-Efficient CPAP Respiratory Support: Development and Pilot Evaluation

Background: The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has placed a significant demand on healthcare providers (HCPs) to provide respiratory support for patients with moderate to severe symptoms. Continuous Positive Airway Pressure (CPAP) non-invasive ventilation can help patients with moderate symptoms to avoid the need for invasive ventilation in intensive care. However, existing CPAP systems can be complex (and thus expensive) or require high levels of oxygen, limiting their use in resource-stretched environments. Technical Development + Testing: The LeVe ("Light") CPAP system was developed using principles of frugal innovation to produce a solution of low complexity and high resource efficiency. The LeVe system exploits the air flow dynamics of electric fan blowers which are inherently suited to delivery of positive pressure at appropriate flow rates for CPAP. Laboratory evaluation demonstrated that performance of the LeVe system was equivalent to other commercially available systems used to deliver CPAP, achieving a 10 cm H2O target pressure within 2.4% RMS error and 50-70% FiO2 dependent with 10 L/min oxygen from a commercial concentrator. Pilot Evaluation: The LeVe CPAP system was tested to evaluate safety and acceptability in a group of ten healthy volunteers at Mengo Hospital in Kampala, Uganda. The study demonstrated that the system can be used safely without inducing hypoxia or hypercapnia and that its use was well-tolerated by users, with no adverse events reported. Conclusions: To provide respiratory support for the high patient numbers associated with the COVID-19 pandemic, healthcare providers require resource efficient solutions. We have shown that this can be achieved through frugal engineering of a CPAP ventilation system, in a system which is safe for use and well-tolerated in healthy volunteers. This approach may also benefit other respiratory conditions which often go unaddressed in Low and Middle Income Countries (LMICs) for want of context-appropriate technology designed for the limited oxygen resources available.

MEK1/2 inhibitor withdrawal reverses acquired resistance driven by BRAFV600E amplification whereas KRASG13D amplification promotes EMT-chemoresistance

Acquired resistance to MEK1/2 inhibitors (MEKi) arises through amplification of BRAFV600E or KRASG13D to reinstate ERK1/2 signalling. Here we show that BRAFV600E amplification and MEKi resistance are reversible following drug withdrawal. Cells with BRAFV600E amplification are addicted to MEKi to maintain a precise level of ERK1/2 signalling that is optimal for cell proliferation and survival, and tumour growth in vivo. Robust ERK1/2 activation following MEKi withdrawal drives a p57KIP2-dependent G1 cell cycle arrest and senescence or expression of NOXA and cell death, selecting against those cells with amplified BRAFV600E. p57KIP2 expression is required for loss of BRAFV600E amplification and reversal of MEKi resistance. Thus, BRAFV600E amplification confers a selective disadvantage during drug withdrawal, validating intermittent dosing to forestall resistance. In contrast, resistance driven by KRASG13D amplification is not reversible; rather ERK1/2 hyperactivation drives ZEB1-dependent epithelial-to-mesenchymal transition and chemoresistance, arguing strongly against the use of drug holidays in cases of KRASG13D amplification.

Modeling Dose and Schedule Effects of AZD2811 Nanoparticles Targeting Aurora B Kinase for Treatment of Diffuse Large B-cell Lymphoma

Barasertib (AZD1152), a pro-drug of the highly potent and selective Aurora B kinase inhibitor AZD2811, showed promising clinical activity in relapsed/refractory diffuse large B-cell lymphoma (DLBCL) patients administered as a 4-day infusion. To improve potential therapeutic benefit of Aurora B kinase inhibition, a nanoparticle formulation of AZD2811 has been developed to address limitations of repeated intravenous infusion. One of the challenges with the use of nanoparticles for chronic treatment of tumors is optimizing dose and schedule required to enable repeat administration to sustain tumor growth inhibition. AZD2811 gives potent cell growth inhibition across a range of DLBCL cells lines in vitro In vivo, repeat administration of the AZD2811 nanoparticle gave antitumor activity at half the dose intensity of AZD1152. Compared with AZD1152, a single dose of AZD2811 nanoparticle gave less reduction in pHH3, but increased apoptosis and reduction of cells in G1 and G₂-M, albeit at later time points, suggesting that duration and depth of target inhibition influence the nature of the tumor cell response to drug. Further exploration of the influence of dose and schedule on efficacy revealed that AZD2811 nanoparticle can be used flexibly with repeat administration of 25 mg/kg administered up to 7 days apart being sufficient to maintain equivalent tumor control. Timing of repeat administration could be varied with 50 mg/kg every 2 weeks controlling tumor control as effectively as 25 mg/kg every week. AZD2811 nanoparticle can be administered with very different doses and schedules to inhibit DLBCL tumor growth, although maximal tumor growth inhibition was achieved with the highest dose intensities.

Cells Lacking the RB1 Tumor Suppressor Gene Are Hyperdependent on Aurora B Kinase for Survival

Small cell lung cancer (SCLC) accounts for 15% of lung cancers and is almost always linked to inactivating RB1 and TP53 mutations. SCLC frequently responds, albeit briefly, to chemotherapy. The canonical function of the RB1 gene product RB1 is to repress the E2F transcription factor family. RB1 also plays both E2F-dependent and E2F-independent mitotic roles. We performed a synthetic lethal CRISPR/Cas9 screen in an RB1 -/- SCLC cell line that conditionally expresses RB1 to identify dependencies that are caused by RB1 loss and discovered that RB1 -/- SCLC cell lines are hyperdependent on multiple proteins linked to chromosomal segregation, including Aurora B kinase. Moreover, we show that an Aurora B kinase inhibitor is efficacious in multiple preclinical SCLC models at concentrations that are well tolerated in mice. These results suggest that RB1 loss is a predictive biomarker for sensitivity to Aurora B kinase inhibitors in SCLC and perhaps other RB1 -/- cancers. SIGNIFICANCE: SCLC is rarely associated with actionable protooncogene mutations. We did a CRISPR/Cas9-based screen that showed that RB1 -/- SCLC are hyperdependent on AURKB, likely because both genes control mitotic fidelity, and confirmed that Aurora B kinase inhibitors are efficacious against RB1 -/- SCLC tumors in mice at nontoxic doses.See related commentary by Dick and Li, p. 169.This article is highlighted in the In This Issue feature, p. 151.

Abstract 311: Development of AZD2811, an aurora kinase B inhibitor, incorporated into an AccurinTM nanoparticle for use in haematological and solid cancers

A nanoparticle formulation of AZD2811, a selective aurora kinase B inhibitor, is currently under clinical development for the treatment of both haematological and solid tumour disease. AZD2811 is the active derivative of the prodrug Barasertib (AZD1152) which gave promising clinical activity in elderly AML patients delivered as a 7-day infusion (Kantarjian et al, Cancer, 119, 2611-2619, 2013). To address the limitations associated with the clinical utility of Barasertib and other cell cycle inhibitors in the clinic, AZD2811 has been incorporated into an AccurinTM nanoparticle using a pamoic acid ion pairing approach to optimise drug release rate (Song et al, Journal of Controlled Release, 229, 106-119, 2016), improve the drug exposure to tumour and reduce the duration of administration. A proof of principle formulation of AZD2811 as an AccurinTM nanoparticle established the principle that anti-tumour activity and improved therapeutic index could be achieved (Ashton et al, Science Translational Medicine, 325, 1-10, 2016). The clinical nanoparticle formulation of AZD2811 has been optimised for drug loading and release rate. In pre-clinical models, the clinical formulation can be used flexibly to optimise drug delivery for use in both haematological disease such as AML, or in solid tumour settings. Anti-tumour activity in solid tumours can be achieved at doses where bone marrow toxicity is reduced compared to Barasertib. In sensitive xenograft and PDX solid tumour models greater than 90% tumour regression is observed after a total dose of 50mg/kg with no tumour progression for greater than 40 days. In contrast, for AML, increasing the dose intensity by 2-4 fold leads to neutropenia and to complete tumour regression in a range of AML xenograft models for greater than 60 days. These data establish the concept that drug delivery using nanoparticles is able to resolve therapeutic index challenges, and is able to do so across different disease types. AZD2811 is currently in Phase 1 clinical trial (D6130C0000). The current pre-clinical and clinical data with this novel approach to inhibition of the cell cycle will be discussed.

Citation Format: Susan Ashton, Nicholas Floch, Paula Taylor, Colin Howes, Doug Ferguson, Matthew Ling, Maureen Hattersley, Shenghua Wen, Kim Maratea, Adina Hughes, Sean Redmond, Wolfram Brugger, Simon Smith, Alexander MacDonald, Keith Parry, Howard Burris, Young-Ho Song, Jim Nolan, Elizabeth Pease, Simon T. Barry. Development of AZD2811, an aurora kinase B inhibitor, incorporated into an AccurinTM nanoparticle for use in haematological and solid cancers [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 311. doi:10.1158/1538-7445.AM2017-311

Abstract 2079: Osimertinib, an irreversible mutant selective EGFR tyrosine kinase inhibitor, exerts anti tumor activity in NSCLC harbouring exon 20 insertion mutant-EGFR

EGFR exon 20 insertion (Ex20Ins) mutations represent a combination of in-frame insertions and/or duplications that account for 4-10% of all EGFR mutants in non-small cell lung cancer (NSCLC). To date, more than one hundred different Ex20Ins mutations have been identified. With the notable exception of the rare A763_Y764insFQEA insertion (<1%), EGFR Ex20Ins mutations are clinically unresponsive to early generation EGFR inhibitors, the standard of care for NSCLC patients with EGFR Ex20Ins mutations is chemotherapy. Therefore, a significant unmet need remains requiring the development of an EGFR TKI agent that can more effectively target NSCLC with EGFR Ex20Ins mutations. Osimertinib is a newly developed EGFR TKI approved for the treatment of advanced NSCLC with EGFR T790M tumors. This work describes the potential of osimertinib and AZ5104, a circulating metabolite of osimertinib, in Ex20Ins tumours.

Using CRISPR-Cas 9 genome editing technology, we engineered cellular disease relevant models carrying the most prevalent Ex20Ins mutations, namely Ex20Ins D770_N771InsSVD (22%) or Ex20Ins V769_D770InsASV (17%).

Using these models, we show that osimertinib and AZ5104 inhibit signalling pathways and cellular growth of Ex20Ins CRISPR-Cas9 engineered cell lines in vitro. This translates into sustained tumor growth inhibition in vivo in both the Ex20Ins SVD (65%, p<0.001 & 95%, p<0.001 respectively at day 14) and Ex20Ins ASV (82%, p<0.001 & 95%, p<0.001 respectively at day 14) xenograft models when compared to the control group. Importantly in vivo osimertinib was dosed at exposures consistent with the 80 mg osimertinib clinical dose. Moreover, a dual EGFR blockade strategy combining osimertinib or AZ5104 with cetuximab (an EGFR antibody) improved the anti tumor effect further. We also describe the anti-tumor activity of osimertinib and AZ5104 using a series of patient derived xenograft models harbouring the rarer Ex20Ins H773-V774insNPH and M766-A767insASV mutations. In addition, we performed pharmacodynamic studies to explore the relationship between efficacy and target/pathway modulation. These studies establish a clear relationship between depth and duration of phospho-EGFR inhibition and anti tumor efficacy. Interestingly, we observed that downstream signalling molecules displayed a more transient inhibition than the phospho

EGFR signal. Two patients from the AURA Phase 2 osimertinib trials with plasma positive Ex20Ins (concurrent with Ex19del and T790M) had durable PFS responses of 6.4 and 13.9 months, supporting the premise that osimertinib has the potential to be clinically beneficial in tumors harboring Ex20Ins.

The work presented herein demonstrates that osimertinib has the potential to improve upon the current treatment options for NSCLC patients whose tumors harbour an Ex20Ins mutation, and warrants its further clinical investigation.

Citation Format: Nicolas Floc'h, Susan Ashton, Ambra Bianco, Nicola Colclough, Darren AE Cross, Maria Emanuela Cuomo, M. Raymond V. Finlay, Matthew J Martin, Ludovic Menard, Darren McKerrecher, Daniel J O'Neill, Jonathan P Orme, Anna D Staniszewska, Richard A Ward, James W T Yates. Osimertinib, an irreversible mutant selective EGFR tyrosine kinase inhibitor, exerts anti tumor activity in NSCLC harbouring exon 20 insertion mutant-EGFR [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 2079. doi:10.1158/1538-7445.AM2017-2079

Abstract PD4-02: A study to determine the optimal method of detection and threshold for lymphoedema intervention: A multi-centre prospective study

Introduction

Lymphoedema, a complication of nodal surgery in 30-40% of patients, reduces quality of life for sufferers. This prospective, multi-centre study compared multi-frequency bioimpedance spectroscopy (BIS, ImpediMed) with a validated perometer method to determine which test is more sensitive for detecting lymphoedema after axillary clearance and identify the factors predicting lymphoedema development.

Material and methods

Participants (n = 629) undergoing axillary clearance at 9 UK centres underwent pre-operative and arm volume measurements post-surgery (1, 3, 6, 9 & 12 months, then 6 monthly) by arm perometry, BIS measurements (L-Dex) and recorded self-reported symptoms via questionnaires. Follow-up was a minimum of two years from surgery. Change in arm volume was calculated using relative arm volume change (RAVC) with >10% increase defined as lymphoedema. The predictors of lymphoedema development and optimal method for its detection were assessed using Cox Regression, Log Rank and Kaplan-Meier survival analyses.

Results

In total, 629 women underwent axillary surgery, with a median age of 56 (range 22 to 90) years; 80% were ER positive and received endocrine therapy, 78% received radiotherapy and 65% received chemotherapy. Lymphoedema was detected by 24 months in 124 (20%) women by perometry. Using the LDex >10 cut-off score, bioimpedance sensitivity was 71% and specificity was 89% (PPV 47%) compared to RAVC changes. Women who had an RAVC >5%-<10% at six months developed lymphoedema in 44% of cases by two years, whereas those who had less than 3% RAVC developed lymphoedema in 9% of cases (p=>0.000001). Twenty-six per cent of ER negative patients developed lymphoedema compared to 19% ER positive cancer patients.

The type (taxane versus no taxane) and whether chemotherapy was neo-adjuvant or adjuvant did not predict lymphoedema development.

Univariate analysis revealed BMI (p=0.003), ER negativity (p=<0.010), absence of endocrine therapy (p=0.034), number of nodes involved (p=0.001) and an increase in RAVC >5%-<10% (p<0.005) all predicted lymphoedema development by two years. On multivariate analysis, RAVC >5%-<10% after six months (HR 5.51 95% CI 3.05 – 9.94) along with number of nodes involved (HR 1.06 95% CI 1.03 – 1.09) and BMI HR 1.04 (1.04 – 1.09) were included in the model for predicting lymphoedema development at two years.

Conclusions

This is the first report; ER negative cancer is associated with an increased risk of lymphoedema after axillary node clearance. Arm measurements should be taken from baseline in all patients undergoing axillary surgery and increases greater than 3% should lead to further surveillance to prevent lymphoedema development. Perometer measurement is the optimal technique for measuring and predicting the development of lymphoedema.

A threshold RAVC of >5%-<10% after six months predicts lymphoedema in 44% of patients by two years.

(Funded by NIHR Programme Grant).

Citation Format: Bundred NJ, Ashton S, Riches K, Ashcroft L, Evans A, Todd C, Bramley M, Hodgkiss T, Purushotham A, Keeley V. A study to determine the optimal method of detection and threshold for lymphoedema intervention: A multi-centre prospective study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD4-02.

Aurora kinase inhibitor nanoparticles target tumors with favorable therapeutic index in vivo

Efforts to apply nanotechnology in cancer have focused almost exclusively on the delivery of cytotoxic drugs to improve therapeutic index. There has been little consideration of molecularly targeted agents, in particular kinase inhibitors, which can also present considerable therapeutic index limitations. We describe the development of Accurin polymeric nanoparticles that encapsulate the clinical candidate AZD2811, an Aurora B kinase inhibitor, using an ion pairing approach. Accurins increase biodistribution to tumor sites and provide extended release of encapsulated drug payloads. AZD2811 nanoparticles containing pharmaceutically acceptable organic acids as ion pairing agents displayed continuous drug release for more than 1 week in vitro and a corresponding extended pharmacodynamic reduction of tumor phosphorylated histone H3 levels in vivo for up to 96 hours after a single administration. A specific AZD2811 nanoparticle formulation profile showed accumulation and retention in tumors with minimal impact on bone marrow pathology, and resulted in lower toxicity and increased efficacy in multiple tumor models at half the dose intensity of AZD1152, a water-soluble prodrug of AZD2811. These studies demonstrate that AZD2811 can be formulated in nanoparticles using ion pairing agents to give improved efficacy and tolerability in preclinical models with less frequent dosing. Accurins specifically, and nanotechnology in general, can increase the therapeutic index of molecularly targeted agents, including kinase inhibitors targeting cell cycle and oncogenic signal transduction pathways, which have to date proved toxic in humans.

Utilization of Structure-Based Design to Identify Novel, Irreversible Inhibitors of EGFR Harboring the T790M Mutation

A novel series of covalent inhibitors of EGFR (epidermal growth factor receptor) kinase was discovered through a combination of subset screening and structure-based design. These compounds preferentially inhibit mutant forms of EGFR (activating mutant and T790M mutant) over wild-type EGFR in cellular assays measuring EGFR autophosphorylation and proliferation, suggesting an improved therapeutic index in non-small cell lung cancer patients would be achievable relative to established EGFR inhibitors. We describe our design approaches, resulting in the identification of the lead compound 5, and our efforts to develop an understanding of the structure-activity relationships within this series. In addition, strategies to overcome challenges around metabolic stability and aqueous solubility are discussed. Despite limitations in its physical properties, 5 is orally bioavailable in mice and demonstrates pronounced antitumor activity in in vivo models of mutant EGFR-driven cancers.

PDGFR Inhibition Results in Pericyte Depletion and Hemorrhage into the Corpus Luteum of the Rat Ovary

The growth plate, ovary, adrenal gland, and rodent incisor tooth are sentinel organs for antiangiogenic effects since they respond reliably, quantitatively, and sensitively to inhibition of the vascular endothelial growth factor receptor (VEGFR). Here we report that treatment of rats with platelet-derived growth factor receptor beta (PDGFRβ) inhibitors that target pericytes results in severe ovarian hemorrhage with degeneration and eventual rupture of the corpus luteum. Evaluation of the growth plate, adrenal gland, and incisor tooth that are typical target organs for antiangiogenic treatment in the rodent revealed no abnormalities. Histologically, the changes in the ovary were characterized by sinusoidal dilatation, increased vessel fragility, and hemorrhage into the corpus luteum. Immunocytochemical staining of vessels with alpha smooth muscle actin and CD31 that recognize pericytes and vascular endothelium, respectively, demonstrated that this effect was due to selective pericyte deficiency within corpora lutea. Further experiments in which rats were treated concurrently with both PDGFRβ and VEGFR inhibitors ablated the hemorrhagic response, resulting instead in corpus luteum necrosis. These changes are consistent with the notion that selective pericyte loss in the primitive capillary network resulted in increased vessel fragility and hemorrhage, whereas concomitant VEGFR inhibition resulted in vessel regression and reduced vascular perfusion that restricted development of the hemorrhagic vessels. These results also highlight the utility of the rodent ovary to respond differentially to VEGFR and PDGFR inhibitors, which may provide useful information during routine safety assessment for determining target organ toxicity.

Abstract 3678: Imaging AZD1152HQPA Accurin™ nanoparticle accumulation in preclinical tumors

AZD1152HQPA Accurin is a passively targeted nanoparticle containing the active metabolite of the Aurora B kinase prodrug AZD1152. In preclinical studies, AZD1152HQPA Accurin displays reduced bone marrow toxicity associated with AZD1152 together with increases in anti-tumour activity. Nanoparticles are proposed to enable delivery and retention of drug to the tumour thereby increasing efficacy and modifying therapeutic index. While it is possible to demonstrate increased duration of modulation of pharmacodynamic biomarkers and drug exposure by nanoparticle delivery, directly demonstrating that nanoparticles accumulate in the tumour is challenging. To investigate the intra tumoural distribution of AZD1152HQPA Accurin nanoparticles we have employed mass spectrometry techniques to image samples derived from human colorectal cancer SW620 studies in rats. We have separately identified the nanoparticle itself, drug encapsulated in nanoparticle, and drug released from nanoparticle; the latter by detecting a metabolite that is only generated from released drug. First MALDI (matrix assisted laser desorption ionization) which offers 20 μm spatial resolution, was used to detect AZD1152-hQPA (released and encapsulated). Second LESA (liquid extraction surface analysis), which offers 1000 μm spatial resolution, was used to detect drug and metabolite, enabling co-distribution to be demonstrated. Finally DESI (desorption electrospray ionization) which offers 100 μm spatial resolution was used to detect drug, metabolite and nanoparticle constituent showing the co-distribution in more detail. Using this combination of approaches it is possible to demonstrate the presence of nanoparticle-delivered AZD1152HQPA metabolite in the tumour at extended timepoints; co-located with nanoparticle and unchanged (encapsulated) drug. At these time points no drug remains if delivered as a simple IV infusion. Collectively this imaging mass spectrometry analysis demonstrates AZD1152HQPA Accurin accumulation in pre-clinical tumours and confirms that the Accurin accesses the tumour and achieves sustained drug release within the tumour.

Citation Format: Richard Goodwin, John Swales, Anna Nilsson, Per Andren, Nicola Strittmatter, Zoltan Takats, Colin Howes, Paula Taylor, Susan Ashton, Philip Jewsbury, Simon T. Barry. Imaging AZD1152HQPA Accurin™ nanoparticle accumulation in preclinical tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3678. doi:10.1158/1538-7445.AM2015-3678

Abstract 761: Changing the paradigm for treating drug resistance in NSCLC: Novel combinations of AZD6094, a selective MET inhibitor, and an irreversible, selective (EGFRm/T790M) EGFRTKI, AZD9291

Aberrant receptor tyrosine kinase (RTK) signaling is a well-documented driver of disease onset and progression across myriad cancer types, where the MET RTK contributes to tumor progression, maintenance and resistance to targeted therapies. Here we explore the therapeutic potential of AZD6094, a highly potent and selective MET inhibitor, in EGFR mutant (EGFRm) non-small cell lung cancer (NSCLC). Although many EGFRm NSCLC patients receiving first-line EGFR Tyrosine Kinase Inhibitors (TKI) benefit from therapy initially, the majority of patients will acquire resistance in 9-14 months1,2. Of this patient population, ∼10-15% of patients with emerging resistance to early generation EGFRm-TKI will have MET amplification3. Using xenograft models (HCC827) of resistance to erlotinib or gefitinib, both first-generation EGFRm-TKI, we assessed the efficacy of AZD6094 in models with varying copy number gain for MET. We demonstrate that the combination of AZD6094 with gefitinib, or AZD9291, an irreversible, selective (EGFRm/T790M) EGFR TKI, results in tumor growth inhibition (TGI) of >100% in 3 models (HCC827-ER1, PCS030 clone 1 and 2)4, suggesting that the combination is necessary and sufficient to address acquired resistance due to MET gene amplification. Moreover, we explore efficacy of AZD6094 in models representative of resistance to first-line treatment with EGFRm-TKIs, harboring MET amplification and T790M EGFR mutations. In NCI-H820 xenografts (EGFRm/T790M/MET), we demonstrate for the first time that combining MET and EGFRm/T790M TKIs (AZD6094 with AZD9291) induces tumor regressions (TGI% >100%, 94% regressions) and the loss of palpable tumors in 5/7 animals as compared to AZD9291 (TGI 48%) or AZD6094 treatment alone (TGI >100%). Pharmacodynamic analysis of tumor lysates demonstrated potent and durable inhibition of pMET in all AZD6094 treatment groups. Due to the clinical importance of understanding acquired resistance to targeted TKIs, we then generated a model of resistance to AZD6094 in MET-amplified NSCLC NCI-H1993 cells and analyzed several resistant clones (H1993R). Interestingly, MET phosphorylation remains strongly inhibited in AZD6094-treated H1993R cells, while EGFR protein expression is upregulated and leads to co-dependency between both pathways. Enhanced expression and phosphorylation of EGFR, as well as AKT, MEK and ERK activation were commonly observed in H1993R cells. Taken together, our data support the potential of AZD6094 as a novel combination therapy for MET-driven NSCLC in the context of EGFRm TKI resistance, and highlight the clinical relevance of EGFR and MET signaling in the context of emerging TKI resistance mechanisms and coordinated pathways.

1. Mok et al. N Engl J Med 2009;361:947-957.

2. Rosell et al. Lancet Oncol 2012;13:239-246.

3. Engelman et al. Science 2007;316:1039-1043.

4. Models from Precos Ltd

Citation Format: Celina D'Cruz, Evan Barry, Ryan Henry, Lillian Castriotta, Alwin Schuller, Garry Beran, Susan Ashton, Cath Eberlein, Corinne Reimer, Melanie Frigault, Michael Zinda, Darren Cross, Stephen Fawell. Changing the paradigm for treating drug resistance in NSCLC: Novel combinations of AZD6094, a selective MET inhibitor, and an irreversible, selective (EGFRm/T790M) EGFRTKI, AZD9291. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 761. doi:10.1158/1538-7445.AM2015-761

Abstract 3102: AZD1152HQPA Accurin™ nanoparticles inhibit growth of diffuse large B-cell lymphomas and small cell lung cancer

Inhibitors of the Aurora Kinases have been developed to treat both liquid and solid tumours. The prodrug AZD1152 is an inhibitor of Aurora kinase B that is clinically active in acute myeloid leukaemia. Despite this clinical proof-of-concept, the broader clinical utility of AZD1152 is limited by the requirement for continuous IV infusion, and the mechanism-related dose-limiting toxicities seen with this class of inhibitors, in particular bone marrow toxicity.   To address these challenges and maximise the clinical utility, an Accurin nanoparticle containing AZD1152HQPA, the active metabolite of AZD1152, has been developed. In preclinical models, the AZD1152HQPA Accurin shows increased efficacy without the bone marrow toxicity seen with the prodrug formulation.  In preclinical studies, models of Diffuse Large B Cell Lymphoma (DLBCL) and Small Cell Lung Cancer (SCLC) show sensitivity to monotherapy Aurora B kinase inhibitors.  Consistent with this, AZD1152 inhibits the growth of subsets of DLBCL and SCLC cells lines in vitro, while in vivo, AZD1152HQPA Accurin consistently reduces the growth of DLBCL and SCLC models.  When given at 25mg/kg on days 1 and 3, AZD1152HQPA Accurin gave either equivalent or superior activity to AZD1152 delivered at 25mg/kg on days 1, 2, 3 and 4. When the dose-schedule was explored, increasing the dose intensity increases the anti-tumour effect, while modifying the timing and dose intensity of each dose cycle also influenced the anti-tumour activity. In a DLBCL model, low dose AZD1152HQPA Accurin (25mg/kg delivered as a fractionated dose on day 1 and 3) gave tumour stasis or partial regression, while a higher dose (50mg/kg delivered weekly) gave increased tumour response, which was durable on repeated dosing. The timing of AZD1152HQPA Accurin doses had significant impact on the shape of the tumour response, indicating that optimal scheduling is important to maximize the benefits of sustained release and enhanced tumour accumulation of Accurin nanoparticles. Collectively the preclinical data indicate that the AZD1152HQPA Accurin has the potential for activity in SCLC and DLBCL; is able to be used flexibly; and has an improved therapeutic index.

Citation Format: Susan Ashton, Paula Taylor, Nicola Curtis, James Pilling, Thierry Dorval, Jeff Hrkach, Philip J. Jewsbury, Simon T. Barry. AZD1152HQPA Accurin™ nanoparticles inhibit growth of diffuse large B-cell lymphomas and small cell lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3102. doi:10.1158/1538-7445.AM2015-3102

Abstract 4744: Structure-based development of covalent inhibitors of the activating and T790M gatekeeper mutant forms of the epidermal growth factor receptor (EGFR) leading to the discovery of AZD9291

Small molecule inhibitors of the Epidermal Growth Factor Receptor (EGFR) tyrosine kinase such as gefitinib and erlotinib have been employed successfully in the treatment of non-small cell lung cancer (NSCLC) patients harboring an activating mutation (EGFRm+). However, resistance to these inhibitors in the form of additional mutations such as T790M, (mutation of the gatekeeper residue), is recognized as a clinical issue. This presentation will describe the discovery and evolution of one of our novel chemical series, leading ultimately to the identification of AZD9291, an orally bioavailable, covalent EGFR inhibitor of both the resistance (NCI-H1975, cell phosphorylation IC50 <0.025 uM) and activating mutations (PC9, cell phosphorylation IC50<0.025 uM) that spares inhibition of the wild type form of the receptor (A431, cell phosphorylation IC50>0.5 uM). Wild type EGFR inhibition is believed to drive the observed dose limiting toxicities (such as skin rash and diarrhea) for these first generation therapies in the clinic. New data will be presented for the first time including a broader description of the medicinal chemistry program that led to the identification of AZD9291. We shall also present previously undisclosed work on the identification of additional distinct chemical series and an update of recent data from ongoing AZD9291 Phase I clinical studies in NSCLC patients.

L858R/T790M Double Mutant (resistance) cell IC50 uMEGFRm+ Single Mutant (activating) cell IC50 uMEGFR Wild Type cell IC50 uMAqueous solubility, (salt) (pH=6.8, ug/mL)L858R/T790M Double Mutant efficacy (% TGI at 5mpk PO QD for 14 days)<0.025<0.025>0.5>490119

Citation Format: Richard A. Ward, Susan Ashton, Mark Anderton, Pete G. Ballard, Rob H. Bradbury, Sam Butterworth, Nicola Colclough, Darren A E Cross, M Ray V. Finlay, Heather L. McFarland, Martine Mellor, Mike J. Waring. Structure-based development of covalent inhibitors of the activating and T790M gatekeeper mutant forms of the epidermal growth factor receptor (EGFR) leading to the discovery of AZD9291. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4744. doi:10.1158/1538-7445.AM2014-4744

Abstract 5409: AZD1152-hQPA Accurins: Nanoparticle formulations showing extended release and the potential for improved therapeutic index

The prodrug, Barasertib (AZD1152) is a potent selective inhibitor of the Aurora B kinase which plays a pivotal role in chromosomal segregation during the cell cycle. In a Phase 2 randomised study in elderly AML patients unfit for intensive therapy, Barasertib showed a statistically significant improvement in Overall Complete Response Rate and a trend for improved Overall Survival as a continuous infusion over 7 days (Kantarjian et al, Cancer 2013;119:2611-2619) . The Dose Limiting Toxicities were neutropenia and stomatitis. AccurinTM nanoparticle formulations of the active metabolite, AZD1152-hQPA, have been developed utilizing medicinal nanoengineering to optimize critical nanoparticle properties such that a short infusion has the potential for extended target cover and an improved therapeutic index from increased biodistribution to the tumour site. In nude rats bearing SW620 tumours, AZD1152-hQPA Accurins gave extended target cover leading to sustained pharmacodynamic (PD) inhibition of phospho-histone H3 in the tumour relative to Barasertib at the same dose. Interestingly the Accurins gave a differentiated PD profile with maximal PD seen at later time points. This profile led to improved anti-tumour effects when AZD1152-hQPA Accurins were dosed intravenously at 25mg/kg on day 1 and 3, compared to Barasertib dosed at 25mg/kg on days 1, 2, 3, 4. Significantly, one of the AZD1152-hQPA Accurins had minimal impact on bone marrow pathology, demonstrating the potential for increased efficacy and lower toxicity at half the dose intensity of Barasertib in this preclinical model. The impact on efficacy of different dose intensities and schedules with this AZD1152-hQPA Accurin has also been explored in the equivalent nude mouse SW620 model. Together these studies demonstrate that by careful selection of formulation parameters, AZD1152-hQPA can be formulated with an extended release profile able to deliver improved efficacy and tolerability in pre-clinical models. AZD1152-hQPA Accurins offer the potential to overcome the therapeutic index challenges which previously limited the clinical development of agents in the class.

Citation Format: Simon T. Barry, Elaine Cadogan, Rajesh Odedra, Susan Ashton, John Foster, Young Ho Song, Susan Low, Paula Taylor, Rebecca Ellston, Urszula Polanska, Joanne Wilson, Colin Howes, Dawn Trueman, Mike Walker, David De Witt, Marianne Ashford, Jeff Hrkach, Phil Jewsbury. AZD1152-hQPA Accurins: Nanoparticle formulations showing extended release and the potential for improved therapeutic index. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5409. doi:10.1158/1538-7445.AM2014-5409

Researcher or nurse? Difficulties of undertaking semi-structured interviews on sensitive topics

AIM

To reflect on the author's personal and professional journey when undertaking semi-structured interviews on sensitive topics with potentially vulnerable people.

BACKGROUND

When discussing care at the end of life, researchers must accept that some participants may become distressed or emotional, depending on their previous experiences. Interviews that involve sensitive topics require careful planning.

DATA SOURCES

The semi-structured interviews were conducted as part of the author's PhD study examining the experiences of advance care planning among family caregivers of people with advanced dementia.

REVIEW METHODS

A reflection on my personal and professional journey when undertaking semi-structured interviews on sensitive topics with potentially vulnerable people.

DISCUSSION

The frustration and tragedy of dementia, as experienced by the family caregivers, were powerful and required the author to exert self-control to avoid being overly sympathetic and offering words of reassurance, agreement and comfort.

CONCLUSION

This blurring of roles between researcher and nurse has implications for all nurse researchers who undertake qualitative interviews, particularly when an intense emotional response is likely.

IMPLICATIONS FOR RESEARCH/PRACTICE

Nurse researchers should plan and prepare for potential blurring of roles during emotional interviews and should never automatically assume that they are sufficiently prepared as a result of their previous experience and nurse training.

Abstract 912: Targeting HER family signaling in low HER2-expressing breast cancer: activity of the selective and equipotent EGFR, HER2 and HER3 signaling inhibitor, AZD8931, in models of low HER2-expressing disease

Effective therapies for women with low-HER2 expressing breast cancer remain a significant unmet clinical need. We have detected significant phosphorylated-HER and HER2:HER3 dimer expression in clinical breast cancer samples without HER2 amplification suggesting that HER signaling may play a role in these tumors. It is our hypothesis that ligand-driven signaling is the major route of HER family activation in the absence of HER2 amplification.

AZD8931 is an orally bioavailable and highly selective small molecule inhibitor of EGFR, HER2 and HER3 signaling, which shows greatest potency when HER signaling is ligand-driven(1). In a range of low HER2 breast cancer cell lines, AZD8931 inhibited heregulin-driven proliferation (GI50 range 0.05 to 0.38μM) HER2:HER3 signaling, HER3:PI3K interaction and downstream signaling. In vivo, twice-daily oral dosing of AZD8931 showed significant monotherapy anti-tumor efficacy in a xenograft model of low HER2 breast cancer (MDA-MB-175VII) at well-tolerated doses (90% TGI at 12.5 mg/kg/bid).

We further evaluated the activity of AZD8931 in combination with paclitaxel, a commonly used standard of care chemotherapy for patients with advanced breast cancer expressing low levels of HER2. Pre-clinically, the combination of AZD8931 with paclitaxel showed at least additive activity in vitro in a range of breast cell lines and additive efficacy in vivo in a BT474 (high HER2) xenograft model at well tolerated doses (AZD8931 12.5 mg/kg/bid TGI 63%; paclitaxel 7.5mg/kg/qw TGI 41%; combination TGI 95%). Combination work in the low HER2 xenograft model is ongoing.

These data demonstrate that AZD8931 inhibits ligand-driven HER family receptor activation, receptor dimerization, PI3K interaction and downstream signaling leading to anti-tumor activity in vivo. These data also support the potential clinical utility of AZD8931 for the therapeutic treatment of low HER2 expressing breast cancers in combination with paclitaxel.

1 Hickinson et al. Clin.Cancer Res (2010) 16:1159-69.

Citation Format: Gayle Marshall, Susan Ashton, Georgina Speake, Celina D'Cruz, Michael Grondine, Cath Trigwell, Graham Bigley, Garry Beran, Katy Lynaugh, Teresa C. Klinowska. Targeting HER family signaling in low HER2-expressing breast cancer: activity of the selective and equipotent EGFR, HER2 and HER3 signaling inhibitor, AZD8931, in models of low HER2-expressing disease. [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 912. doi:10.1158/1538-7445.AM2013-912

Abstract 1564: Investigating the interaction of tumor xenografts with their microenvironment by combining human- and mouse- specific assays with high throughput RT-qPCR

Tumour growth is governed by the interaction with its microenvironment through pathways that regulate tumour cell function, angiogenesis, and recruitment of associated stromal cells and immune infiltrate. These complicated biological networks can be studied in tumour xenografts using a combination of gene expression, protein and histological analysis. The majority of gene expression studies either probe expression of specific transcripts by RT-qPCR, or use broad Affymetrix microarrays to examine 1000s of genes. RT-PCR experiments may be too focussed studying the interaction of a small number of pathways, while Affymetrix is often not sensitive enough to detect low abundance transcripts, or is limited by species specificity of the probe sets. For example studying tumour stromal and endothelial cells can be challenging because these cells comprise only a small proportion of the tumour. In this study we have used high throughput RT-qPCR to specifically analyse 180 human and mouse genes (or orthologues) thought to regulate key stromal/tumour interactions in a broad xenograft panel. This approach enabled us to determine the expression patterns of potential angiogenic, migratory and survival drives of a diverse range of tumour xenograft models. Across the xenograft panel these genes distinguished tumours with an Epithelial and Mesenchymal phenotype. Interestingly we find that the transcript profile of the supporting stroma (all murine transcripts) is similar between models and key genes cluster with physiological characteristics such vessel, stromal or inflammatory phenotypes. We also used this approach to assess pharmacodynamic changes in gene expression in the tumour and host compartments in response to a VEGF signalling inhibitor. Surprisingly there was little modulation in the expression of genes in the tumour cell compartment. However, there was a clear down regulation of transcripts corresponding to endothelial cells with a concomitant reduction in the tumour vasculature. This approach has enabled us to gain insight into pre-clinical models and the response to a host targetted therapy. The data provides information that enhances understanding that can be derived using histological analysis and standard protein expression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1564. doi:10.1158/1538-7445.AM2011-1564

Inhibition of neutrophil infiltration into A549 lung tumors in vitro and in vivo using a CXCR2-specific antagonist is associated with reduced tumor growth

Neutrophils are important innate immune cells that are involved in microbial clearance at sites of infection and in wound healing. The microenvironment of tumors often resembles that of chronic inflammation and increased numbers of neutrophils have been observed in several tumors and, in some cases, these positively correlate with poor prognosis. Neutrophil recruitment into tumors appears to be dependent on chemokines that bind to CXCR1 and CXCR2 expressed by neutrophils. In our study, we used lung adenocarcinoma A549 multicellular tumor spheroids and A549 tumor xenografts along with a CXCR2-specific small molecule inhibitor (AZ10397767) to investigate the recruitment and function of human neutrophils in tumors. We found that A549 spheroids constitutively secrete high levels of CXCL chemokines and that neutrophil recruitment into A549 tumors in vitro and in vivo is largely dependent on CXCR2 activation. AZ10397767 significantly reduced the numbers of infiltrating neutrophils into both in vitro and in vivo tumor models, which was associated with slower growing tumors. Neutrophil infiltration into A549 tumor spheroids increased their size compared to noninfiltrated spheroids and neutrophil-derived factors increased the proliferation of A549 tumor cells and induced endothelial cell tubule formation in vitro. In contrast, we saw no reduction in microvascular density in AZ10397767-treated A549 tumors or in tumors grown in CXCR2(-/-) mice, suggesting that angiogenesis in these tumors is CXCR2-independent. Our data show that neutrophils can contribute to lung tumor growth and that CXCR2 antagonists may be a useful therapeutic agent in the treatment of lung carcinomas.

Distribution of radioactivity and metabolite profiling in tumour and plasma following intravenous administration of a colchicine derivative (14C-ZD6126) to tumour-bearing mice

The main aim of the study was to investigate the distribution of radioactivity in the tissues and tumours using quantitative whole-body autoradiography (QWBA), together with a more detailed investigation of plasma and tumour samples, following administration of a single intravenous dose at 200 mg kg(-1) of 14C-ZD6126 to mice bearing subcutaneous Hras5 tumour xenografts. The study also included an assessment of tumour necrosis following administration of a single intravenous dose of non-labelled ZD6126 at 200 mgkg(-1). QWBA analysis showed that drug-related material was widely distributed to the tissues and tumour. In the majority of tissues, concentrations of radioactivity were highest at 15 min and declined rapidly thereafter. The tumour-to-plasma ratio was 0.6:1 at 0.25 h and increased to 6:1 at 48 h, indicating that drug-related material persisted in the tumour longer than in plasma. ZD6126, a phosphate ester, is rapidly hydrolysed to ZD6126 phenol, the active metabolite. The major metabolite in plasma (36% of the sample radioactivity) and all tumour samples (58-83% of the sample radioactivity) was confirmed as ZD6126 phenol. Extensive tumour necrosis was noted by 24h, which was still evident at 48 h, although there was some evidence of tumour regrowth.

Understanding behavior change for women experiencing intimate partner violence: mapping the ups and downs using the stages of change

OBJECTIVE

For women who are experiencing intimate partner violence (IPV), making changes toward safety is often a gradual process. When providing counseling and support, health care providers may benefit from better understanding of where women are in their readiness to change. Our objective was to apply the transtheoretical model's stages of change to the experiences of women who experienced IPV and map their experiences of change as they moved toward increased safety.

METHODS

A multi-disciplinary team designed a qualitative interview process with 20 women who had current or past histories of IPV in order to explore their experiences.

RESULTS

The women in our study (1) moved through stages of readiness generally in a nonlinear fashion, with varying rates of progression between safe and nonsafe situations, (2) were able to identify a "turning-point" in their situations, (3) attempted multiple "action" steps and (4) were influenced by internal and external factors.

CONCLUSIONS

Our study suggests that focusing on the transtheoretical model to develop stage-based interventions for IPV may not be the most appropriate given the nonsequential movement between stages and influence of external factors.

PRACTICE IMPLICATIONS

The "change mapping" technique can be used as an educational and counseling tool with patients, as well as a training tool for health care providers.

Effect of cross-tolerance between endotoxin and TNF-alpha or IL-1beta on cellular signaling and mediator production

Endotoxin [lipopolysaccharide (LPS)] tolerance suppresses macrophage/monocyte proinflammatory-mediator production. This phenomenon also confers cross-tolerance to other stimuli including tumor necrosis factor (TNF) alpha and interleukin (IL)-1beta. Post-receptor convergence of signal transduction pathways might occur after LPS, IL-1beta, and TNF-alpha stimulation. Therefore, it was hypothesized that down-regulation of common signaling molecules induces cross-tolerance among these stimuli. LPS tolerance and cross-tolerance were examined in THP-1 cells. Phosphorylation of MAP kinases and degradation of inhibitor kappaBalpha (IkappaBalpha) DNA binding of nuclear factor-kappaB (NF-kappaB), and mediator production were examined. In naive cells, LPS, TNF-alpha, and IL-1beta induced IkappaBalpha degradation, kinase phosphorylation, and NF-kappaB DNA binding. LPS stimulation induced production of TNF-alpha or TxB2 and degradation of IRAK. However, neither TNF-alpha nor IL-1beta induced IRAK degradation or stimulated TNF-alpha or TxB2 production in naive cells. Pretreatment with each stimulus induced homologous tolerance to restimulation with the same agonist. LPS tolerance also suppressed LPS-induced TxB2 and TNF-alpha production. LPS pretreatment induced cross-tolerance to TNF-alpha or IL-1beta stimulation. Pretreatment with TNF-alpha induced cross-tolerance to LPS-induced signaling events and TxB2 production. Although pretreatment with IL-1beta did not induce cross-tolerance to LPS-induced signaling events, it strongly inhibited LPS TNF-alpha and TxB2 production. These data demonstrate that IL-1beta induces cross-tolerance to LPS-induced mediator production without suppressing LPS-induced signaling to MAP kinases or NF-kappaB activation.

A twin study of chronic fatigue

OBJECTIVE

The etiology of chronic fatigue syndrome is unknown, but genetic influences may be important in its expression. Our objective was to assess the role of genetic and environmental factors in unexplained chronic fatigue.

METHODS

A classic twin study was conducted using 146 female-female twin pairs, of whom at least one member reported > or =6 months of fatigue. After completing questionnaires on symptoms, zygosity, physical health, and a psychiatric interview, twins were classified using three increasingly stringent definitions: 1) chronic fatigue for > or =6 months, 2) chronic fatigue not explained by exclusionary medical conditions, and 3) idiopathic chronic fatigue not explained by medical or psychiatric exclusionary criteria of the chronic fatigue syndrome case definition. Concordance rates in monozygotic and dizygotic twins were calculated for each fatigue definition along with estimates of the relative magnitude of genetic and environmental influences on chronic fatigue.

RESULTS

The concordance rate was higher in monozygotic than dizygotic twins for each definition of chronic fatigue. For idiopathic chronic fatigue, the concordance rates were 55% in monozygotic and 19% in dizygotic twins (p =.042). The estimated heritability in liability was 19% (95% confidence interval = 0-56) for chronic fatigue > or =6 months, 30% (95% confidence interval = 0-81) for chronic fatigue not explained by medical conditions, and 51% (95% confidence interval = 7-96) for idiopathic chronic fatigue.

CONCLUSIONS

These results provide evidence supporting the familial aggregation of fatigue and suggest that genes may play a role in the etiology of chronic fatigue syndrome.

Cognitive compromise following exercise in monozygotic twins discordant for chronic fatigue syndrome: fact or artifact?

This study examined the effects of exhaustive exercise on cognitive functioning among 21 monozygotic twin pairs discordant for chronic fatigue syndrome (CFS). The co-twin control design adjusts for genetic and family environmental factors not generally accounted for in more traditional research designs of neuropsychological function. Participants pedaled a cycle ergometer to exhaustion; maximum oxygen output capacity (VO2max) as well as perceived exertion were recorded. Neuropsychological tests of brief attention and concentration, speed of visual motor information processing, verbal learning and recognition memory, and word and category fluency were administered with alternate forms to participants pre- and postexercise. The preexercise neuropsychological test performance of CFS twins tended to be slightly below that of the healthy twin controls on all measures. However, twins with CFS did not demonstrate differential decrements in neuropsychological functioning after exercise relative to their healthy co-twins. Because exercise does not appear to diminish cognitive function, rehabilitative treatment approaches incorporating exercise are not contraindicated in CFS.

Monozygotic twins discordant for chronic fatigue syndrome: regional cerebral blood flow SPECT

PURPOSE

To evaluate the relationship between regional cerebral blood flow (rCBF) and chronic fatigue syndrome (CFS) in monozygotic twins discordant for CFS.

MATERIALS AND METHODS

The authors conducted a co-twin control study of 22 monozygotic twins in which one twin met criteria for CFS and the other was healthy. Twins underwent a structured psychiatric interview and resting technetium 99m-hexamethyl-propyleneamine oxime single photon emission computed tomography of the brain. They also rated their mental status before the procedure. Scans were interpreted independently by two physicians blinded to illness status and then at a blinded consensus reading. Imaging fusion software with automated three-dimensional matching of rCBF images was used to coregister and quantify results. Outcomes were the number and distribution of abnormalities at both reader consensus and automated quantification. Mean rCBF levels were compared by using random effects regression models to account for the effects of twin matching and potential confounding factors.

RESULTS

The twins with and those without CFS were similar in mean number of visually detected abnormalities and in mean differences quantified by using image registration software. These results were unaltered with adjustments for fitness level, depression, and mood before imaging.

CONCLUSION

The study results did not provide evidence of a distinctive pattern of resting rCBF abnormalities associated with CFS. The described method highlights the importance of selecting well-matched control subjects.

Comorbid clinical conditions in chronic fatigue: a co-twin control study

OBJECTIVES

Chronically fatiguing illness, defined as fatigue for at least 6 months, has been associated with various physical health conditions. Our objective was to determine whether there is a significant relationship between chronically fatiguing illness and 10 clinical conditions that frequently appear to be associated with fatigue, adjusting for the potentially confounding effects of psychiatric illness.

DESIGN

A co-twin control study controlling for genetic and many environmental factors by comparing chronically fatigued twins with their nonfatigued co-twins.

SETTING

A nationally distributed volunteer twin registry.

PARTICIPANTS

The study included 127 twin pairs in which one member of the pair experienced fatigue of at least 6 months' duration and the co-twin was healthy and denied chronic fatigue. Fatigued twins were classified into 3 levels using increasingly stringent diagnostic criteria.

MEASUREMENTS AND MAIN RESULTS

Twins reported on a history of fibromyalgia, irritable bowel syndrome, multiple chemical sensitivities, temporomandibular disorder, interstitial cystitis, postconcussion syndrome, tension headache, chronic low back pain, chronic pelvic pain (women), and chronic nonbacterial prostatitis (men). The prevalence of these comorbid clinical conditions was significantly higher in the fatigued twins compared to their nonfatigued co-twins. Most notably, compared to their nonfatigued co-twins, the chronically fatigued twins had higher rates of fibromyalgia (> 70% vs < 10%) and irritable bowel syndrome (> 50% vs < 5%). The strongest associations were observed between chronic fatigue and fibromyalgia (odds ratios > 20), irritable bowel syndrome, chronic pelvic pain, multiple chemical sensitivities, and temporomandibular disorder (all with odds ratios > or = 4). Regression analysis suggested that the number of comorbid clinical conditions associated with chronic fatigue could not be attributed solely to psychiatric illness.

CONCLUSIONS

Chronically fatiguing illnesses were associated with high rates of many other clinical conditions. Thus, patients with chronic fatigue may present a complex clinical picture that poses diagnostic and management challenges. Nonetheless, clinicians should assess such patients for the presence of comorbid clinical conditions. Future research should provide a better understanding of the temporal relationship of the onset of fatigue and these conditions, and develop strategies for early intervention.

Preventive care of older urban American Indians and Alaska natives in primary care

Little is known about prevention among elderly or urban American Indian/Alaska Native (AI/AN) populations. We reviewed the medical records of 550 older urban AI/AN primary care patients to evaluate how frequently preventive measures were received. Adherence to guidelines was examined by a culturally appropriate (> or =50 years) and standard age threshold (> or =65 years), and by performance of preventive measures at any time ("ever") and in the past year. Lifetime performance was inadequate for the many measures, including mammograms (56%), fecal occult blood testing (37%), audiometry (33%), visual acuity testing (50%), smoking cessation counseling (50%), and pneumococcal (22%) and influenza (49%) vaccinations. Performance of the measures was less frequent in the prior year, but did not differ by age threshold. Predictors of adherence included female gender, having insurance, and having more health problems and medications. Nonadherence infrequently resulted from patients' failure to comply with recommendations. We conclude that use of most preventive services among elderly urban AI/ANs is suboptimal and should be improved.

Comorbid clinical conditions in chronic fatigue: a co-twin control study

OBJECTIVES

Chronically fatiguing illness, defined as fatigue for at least 6 months, has been associated with various physical health conditions. Our objective was to determine whether there is a significant relationship between chronically fatiguing illness and 10 clinical conditions that frequently appear to be associated with fatigue, adjusting for the potentially confounding effects of psychiatric illness.

DESIGN

A co-twin control study controlling for genetic and many environmental factors by comparing chronically fatigued twins with their nonfatigued co-twins.

SETTING

A nationally distributed volunteer twin registry.

PARTICIPANTS

The study included 127 twin pairs in which one member of the pair experienced fatigue of at least 6 months' duration and the co-twin was healthy and denied chronic fatigue. Fatigued twins were classified into 3 levels using increasingly stringent diagnostic criteria.

MEASUREMENTS AND MAIN RESULTS

Twins reported on a history of fibromyalgia, irritable bowel syndrome, multiple chemical sensitivities, temporomandibular disorder, interstitial cystitis, postconcussion syndrome, tension headache, chronic low back pain, chronic pelvic pain (women), and chronic nonbacterial prostatitis (men). The prevalence of these comorbid clinical conditions was significantly higher in the fatigued twins compared to their nonfatigued co-twins. Most notably, compared to their nonfatigued co-twins, the chronically fatigued twins had higher rates of fibromyalgia (> 70% vs < 10%) and irritable bowel syndrome (> 50% vs < 5%). The strongest associations were observed between chronic fatigue and fibromyalgia (odds ratios > 20), irritable bowel syndrome, chronic pelvic pain, multiple chemical sensitivities, and temporomandibular disorder (all with odds ratios > or = 4). Regression analysis suggested that the number of comorbid clinical conditions associated with chronic fatigue could not be attributed solely to psychiatric illness.

CONCLUSIONS

Chronically fatiguing illnesses were associated with high rates of many other clinical conditions. Thus, patients with chronic fatigue may present a complex clinical picture that poses diagnostic and management challenges. Nonetheless, clinicians should assess such patients for the presence of comorbid clinical conditions. Future research should provide a better understanding of the temporal relationship of the onset of fatigue and these conditions, and develop strategies for early intervention.

Comorbid clinical conditions in chronic fatigue: a co-twin control study

OBJECTIVES

Chronically fatiguing illness, defined as fatigue for at least 6 months, has been associated with various physical health conditions. Our objective was to determine whether there is a significant relationship between chronically fatiguing illness and 10 clinical conditions that frequently appear to be associated with fatigue, adjusting for the potentially confounding effects of psychiatric illness.

DESIGN

A co-twin control study controlling for genetic and many environmental factors by comparing chronically fatigued twins with their nonfatigued co-twins.

SETTING

A nationally distributed volunteer twin registry.

PARTICIPANTS

The study included 127 twin pairs in which one member of the pair experienced fatigue of at least 6 months' duration and the co-twin was healthy and denied chronic fatigue. Fatigued twins were classified into 3 levels using increasingly stringent diagnostic criteria.

MEASUREMENTS AND MAIN RESULTS

Twins reported on a history of fibromyalgia, irritable bowel syndrome, multiple chemical sensitivities, temporomandibular disorder, interstitial cystitis, postconcussion syndrome, tension headache, chronic low back pain, chronic pelvic pain (women), and chronic nonbacterial prostatitis (men). The prevalence of these comorbid clinical conditions was significantly higher in the fatigued twins compared to their nonfatigued co-twins. Most notably, compared to their nonfatigued co-twins, the chronically fatigued twins had higher rates of fibromyalgia (> 70% vs < 10%) and irritable bowel syndrome (> 50% vs < 5%). The strongest associations were observed between chronic fatigue and fibromyalgia (odds ratios > 20), irritable bowel syndrome, chronic pelvic pain, multiple chemical sensitivities, and temporomandibular disorder (all with odds ratios > or = 4). Regression analysis suggested that the number of comorbid clinical conditions associated with chronic fatigue could not be attributed solely to psychiatric illness.

CONCLUSIONS

Chronically fatiguing illnesses were associated with high rates of many other clinical conditions. Thus, patients with chronic fatigue may present a complex clinical picture that poses diagnostic and management challenges. Nonetheless, clinicians should assess such patients for the presence of comorbid clinical conditions. Future research should provide a better understanding of the temporal relationship of the onset of fatigue and these conditions, and develop strategies for early intervention.

Results of isoproterenol tilt table testing in monozygotic twins discordant for chronic fatigue syndrome

BACKGROUND

The pathogenesis of chronic fatigue syndrome (CFS) is unknown. Neurally mediated hypotension (NMH) has been suggested as a common comorbid condition or a potential underlying cause.

METHODS

We conducted a cotwin control study of 21 monozygotic twins who were discordant for CFS. One twin met the 1994 Centers for Disease Control and Prevention criteria for CFS, and the other twin was healthy and denied chronic fatigue. The twins were selected from a volunteer twin registry in which at least 1 member reported persistent fatigue. As part of a 7-day clinical evaluation, all 21 twin pairs were evaluated with a 3-stage tilt table test with isoproterenol hydrochloride for the assessment of NMH. The presence of NMH was defined as syncope or presyncope associated with a decrease of 25 mm Hg in blood pressure and no associated increase in heart rate.

RESULTS

A positive tilt table test result was observed in 4 twins with CFS (19%) and in 4 healthy twins (19%). This difference was not statistically significant (matched pair odds ratio, 1.0; 95% confidence interval, 0.2-5.4; P>.90). Compared with the healthy twins, the twins with CFS reported more severe symptoms of CFS and NMH both in the week before and during the tilt table test.

CONCLUSIONS

These results do not support a major role for NMH in CFS. They highlight the importance of selecting well-matched control subjects, as well as the unique value of the monozygotic cotwin control design in the study of this illness. Arch Intern Med. 2000;160:3461-3468.

Use of alternative treatments by chronic fatigue syndrome discordant twins

Background: Patients with chronic fatigue syndrome (CFS) have been faced with difficulties in diagnosis and lack of effective treatments. Anecdotal evidence suggests that use of alternative treatments may be common in these patients. Our primary objective was to compare the prevalence and patterns of alternative medicine use among twins who met the Centers for Disease Control and Prevention (CDC) CFS criteria to that of their non-CFS co-twins. Secondary goals were to assess how often alternative medicine use was discussed with physicians and the perceived benefit of these therapies. Methods: Sixty-three twin pairs discordant for CFS completed a survey about their use of 22 alternative therapies. Matched pair odds ratios and 95% confidence intervals were used to examine differences in the use between CFS twins and their non-CFS co-twins. Results: 91% of twins with CFS and 71% of non-CFS twins had used at least 1 alternative treatment in their lifetime. Twins with CFS were more likely to use homeopathy, mega-vitamins, herbal therapies, biofeedback, relaxation/meditation, guided imagery, massage therapy, energy healing, religious healing by others, and self-help groups than their non-CFS counterparts. A large proportion of all twins found alternative therapies helpful; however, only 42% of those with CFS and 23% of those without CFS discussed their use of alternative medicine with a physician. Conclusions: Individuals with CFS frequently used alternative medical treatments yet rarely communicated this use to their medical doctor. Future research should ascertain the usefulness of alternative practices in the management of CFS.

The Chronic Fatigue Twin Registry: method of construction, composition, and zygosity assignment

Chronic fatigue syndrome (CFS) and the symptom of chronic fatigue are conditions of unknown etiology. The Centers for Disease Control and Prevention (CDC) define CFS as an illness characterized by > or = 6 months of disabling fatigue associated with muscle pain, pharyngitis, and alterations in mood, sleep and neurocognition. We constructed a registry of twins with chronic fatigue to facilitate research on the impact of illness, the associated medical and psychosocial factors, and the heterogeneous proposed mechanisms for these conditions. We have recruited 204 twin pairs in which one or both members reported persistent fatigue through patient support group newsletters (60%), clinicians/researchers familiar with CFS (12%), notices placed on electronic bulletin boards for CFS (11%), twin organizations and researchers (6%), relatives and friends (3%) and other sources (8%). Complete data are available for 177 pairs (87%). Twins completed an extensive questionnaire booklet that included measures of physical and mental health, functional status, and psychosocial factors; a structured psychiatric interview was also conducted by telephone. Twins were classified using three increasingly more stringent diagnostic criteria for chronic fatigue: 1) > or = 6 months of fatigue (115 discordant and 61 concordant pairs); 2) chronic fatigue with additional symptoms and application of the medial exclusions of the CDC CFS case definition as obtained by self-report (92 discordant and 41 concordant pairs) and; 3) chronic fatigue with additional symptoms unexplained by self-reported medical conditions and psychiatric diagnoses as determined by the structured interview (69 discordant pairs and 25 concordant pairs). Despite the limitations of a volunteer registry, the Chronic Fatigue Twin Registry promises to be an important resource for research on CFS and chronic fatigue.

Tolerance to LPS decreases macrophage G protein content

The effects of tolerizing doses of LPS on mRNA and protein levels of three different G protein subunits were investigated to understand the mechanism(s) responsible for the reduction in Gialpha protein content in LPS tolerance. Tolerance was induced in rats using Salmonella enteritidis LPS (intraperitoneal route) with a single dose of 100 microg/kg. Peritoneal macrophages were harvested 6 and 24 h later. In some studies, a second dose of LPS 500 microg/kg was given on the following day, and peritoneal macrophages were harvested 5 days after the first injection. Macrophage RNA or a crude membrane fraction was prepared from macrophages, and the mRNA level or the protein content for Gialpha3, Gialpha2, and Gsalpha was analyzed using Northern or Western blots, respectively. Compared with the control levels, the message for Gialpha3 was reduced (p < .025) at 6 and 24 h and 5 day time periods after LPS treatment. The Gialpha2 mRNA was increased relative to the control levels (p < .05) at 6 h and 5 days after LPS treatment, respectively, and Gsalpha message was not significantly changed. The half-life of Gialpha3 mRNA was not significantly different in control versus tolerant macrophages. The Gialpha3 mRNA and membrane protein were not significantly changed by incubation with LPS for intervals up to 6 h in vitro. Macrophage membrane Gialpha3 and Gialpha1 and 2 protein content from tolerant rats were reduced compared with the controls at 6 and 24 h, respectively (p < .05). These studies are consistent with our previous observations of selective changes in macrophage Gialpha protein content in LPS tolerance and raise the possibility that this may affect signal transduction events in these cells.

Suppressed thromboxane production in endotoxin-desensitized THP-1 cells is not a result of decreased prostaglandin H synthase activity

Pre-exposure of THP-1 cells to low concentrations of endotoxin (lipopolysaccharide, LPS) down-regulates thromboxane (Tx) A2, an arachidonic acid (AA) metabolite, production in response to a subsequent LPS stimulation. To further delineate the mechanisms of LPS-induced down-regulation of TxA2, we examined expression of prostaglandin H synthase (PGHS)-2 mRNA, changes in PGHS activity, and content of PGHS-1 and -2. Pre-exposure to LPS (1 microg/mL for 18 h to desensitize cells) inhibits production of TxB2, the stable metabolite of TxA2, in response to secondary stimulation of LPS (10 microg/mL), when compared with LPS-stimulated naive cells (p < .05, n=5). LPS (10 microg/mL) induced expression of PGHS-2 mRNA at 1 and 2 h in naive cells, but this expression was decreased in the LPS-desensitized cells. However, exogenous AA (16 microM) or phorbol myristic acid (PMA), 3 microM) stimulated greater TxB2 production in the LPS-desensitized cells than in the naive cells (p < .05). Protein content of PGHS-1 and -2 were examined by Western blot analysis, using antibodies specific for PGHS-1 and PGHS-2. Densitometric analysis demonstrated a significant increase in PGHS-2 induction in LPS-stimulated naive cells (405+/-174%) over its respective basal group (p < .05, n=5). PGHS-1 was constitutively present, but there was no significant difference in quantity between naive and LPS-desensitized basal or LPS-stimulated groups. Thus, despite the reduction in expression of PGHS-2 mRNA, these composite data demonstrate that down-regulation of PGHS activity (assessed with exogenous AA or PMA) cannot be responsible for the inhibition of AA metabolism observed in LPS desensitization.

Transforming growth factor beta 1 alters rat peritoneal macrophage mediator production and improves survival during endotoxic shock

Transforming Growth Factor beta 1 (TGF-beta 1) is a potent anti-inflammatory cytokine involved in wound healing. Because of its anti-inflammatory actions, the effects of TGF-beta 1 were studied in vitro on rat macrophage inflammatory mediator production and in vivo on Salmonella enteritidis endotoxin (LPS) induced lethality. TGF-beta 1's effect on stimulated rat peritoneal macrophage (MO) production of prostacyclin and nitric oxide were assessed via measurement of their stable metabolites, 6-keto-PGF-1 alpha and nitrite, respectively. TGF-beta 1 (10 ng/ml) pretreatment (3 hours) resulted in significant reductions (p < 0.05) of LPS (50 micrograms/ml) stimulated, lipid A (1 and 10 micrograms/ml) stimulated, arachidonic acid (16 microM) stimulated, and Ca++ ionophore (10 microM) stimulated MO 6-keto-PGF 1 alpha production. These data suggest that TGF-beta 1 inhibits LPS stimulated MO 6-keto-PGF-1 alpha production by acting at, or distally to, phospholipase A2, possibly at the level of cyclooxygenase in the arachidonic acid cascade. In a similar study, TGF-beta 1 pretreatment led to a significant (p < 0.05) reduction of LPS stimulated MO nitrite production. In subsequent studies, the effects of TGF-beta 1 were studied in vivo on rats challenged with lethal doses of LPS. Rats pretreated with TGF-beta 1 (250 ng/rat i.v.) exhibited a significant increase (p < 0.01, n = 15 rats/group) in mean survival time compared to control rats. The increased survival time of TGF-beta 1 pretreated rats with LPS shock may be due, in part, to altered production of MO mediators.