Favorable therapeutic index of an orally-active small-molecule antagonist of the platelet protease-activated receptor-4, BMS-986141, compared with the P2Y12 antagonist ticagrelor in cynomolgus monkeys

Introduction

BMS-986141 is an orally-active small-molecule platelet thrombin receptor antagonist selective for the protease-activated receptor-4 (PAR4), a human platelet thrombin receptor.

Purpose

This study assessed effects of BMS-986141 vs. the P2Y12 antagonist ticagrelor, a standard of care antiplatelet agent, on arterial thrombosis (AT), mesenteric bleeding time (MBT) and platelet aggregation in monkeys.

Methods

Studies were conducted in models of electrically-mediated carotid artery thrombosis and MBT in anesthetized monkeys. Monkeys were given a single oral dose of BMS-986141 (0.05, 0.1, 0.5 mg/kg) or vehicle (n=8/group). At 2 hr post-dose, in vivo AT, MBT as well as ex vivo platelet aggregation were monitored in the same animal. Ticagrelor was studied as a comparator and given as IV bolus plus infusion at 0.0023+0.017 to 0.075+0.6 (mg/kg+mg/kg/h) (n=5–6/group). Thrombus weight reduction, MBT increase over vehicle, and platelet aggregation inhibition were determined. Peak platelet aggregation responses to activation peptides selective for PAR4 (PAR4-AP, 12.5 μM) and PAR1 (PAR1-AP, 18 μM), to collagen (5 μg/ml) and to ADP (20 μM) were determined by whole blood aggregometry.

Results

BMS-986141 inhibited platelet aggregation induced by PAR4-AP in human and monkey blood in vitro with comparable IC50 of 1.8±0.3 and 1.2±0.3 nM, respectively. BMS-986141 at 0.5 mg/kg completely inhibited platelet aggregation induced by PAR4-AP but not PAR1-AP, ADP and collagen, suggesting PAR4 receptor selectivity. In the AT model, BMS-986141 at 0.05, 0.1 and 0.5 mg/kg reduced thrombus weight by 36±7*, 63±8*, and 88±3%*, respectively (*P<0.05 vs. vehicle). BMS-986141 increased MBT by up to 1.2-fold. In a separate study, ticagrelor at 0.0023+0.017, 0.0068+0.055, 0.0255+0.18 and 0.075+0.6 (mg/kg+mg/kg/h IV) reduced thrombus weight by 19±8, 36±5*, 76±6* and 89±1%*, and increased MBT by respectively by 1.7-, 6.4-*, >10-*, and >10-fold*, respectively (*P<0.05 vs. vehicle).

Conclusion

Comparable antithrombotic efficacy was observed between BMS-986141 and ticagrelor in monkeys. BMS-986141 exhibited lower MBT compared with ticagrelor at equivalent antithrombotic doses. This study suggests that PAR4 antagonism provides a potentially safer antiplatelet therapy.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Research was supported by Bristol-Myers Squibb

Prevalence of hypoxia and correlation with glycolytic metabolism and angiogenic biomarkers in metastatic colorectal carcinoma

PURPOSE

Hypoxia is associated with aggressive tumour behaviour and can influence response to systemic therapy and radiotherapy. The prevalence of hypoxia in metastatic colorectal cancer is poorly understood, and the relationship of hypoxia to patient outcomes has not been clearly established. The aims of the study were to evaluate hypoxia in metastatic colorectal cancer with [¹⁸F]Fluoromisonidazole ([¹⁸F]FMISO PET) and correlate these findings with glycolytic metabolism ([¹⁸F]FDG PET) and angiogenic blood biomarkers and patient outcomes.

METHODS

Patients with metastatic colorectal cancer received routine staging investigations and both [¹⁸F] FMISO PET and [¹⁸F] FDG PET scans. Correlative blood specimens were also obtained at the time of the [¹⁸F] FMISO PET scan. Patient follow-up was performed to establish progression-free survival.

RESULTS

A total of 40 patients were recruited into the trial. [¹⁸F]FMISO and [¹⁸F]FDG PET scans showed a significant correlation of SUV_max (p = 0.003). A significant correlation of progression-free survival and [¹⁸F] FMISO TNR (p = 0.02) and overall survival with [¹⁸F]FMISO TNR (p = 0.003) and [¹⁸F]FDG TGV (p = 0.02) was observed. Serum levels of osteopontin, but not VEGF, correlated with [¹⁸F] FMISO and [¹⁸F]FDG PET scan parameters.

CONCLUSION

[¹⁸F]FMISO PET uptake in metastatic colorectal cancer significantly correlates with glycolytic metabolism and is predictive of progression-free and overall survival. These findings have implications for the assessment and treatment of metastatic colorectal cancer patients with novel therapies which affect tumour angiogenesis and hypoxia.

FRI0354 FACTORS AFFECTING SELF-REPORTED PHYSICAL CTIVITY IN PATIENTS WITH PSORIATIC ARTHRITIS

Background:

Despite the known benefits of exercise1, patients with osteoarthritis (OA) and rheumatoid arthritis (RA) are reported to have low levels of physical activity2. Exercise participation is not well studied in psoriatic arthritis (PsA) cohorts. This study aims to explore which factors predict exercise participation across cohorts and specifically in the PsA cohort.

Objectives:

The primary aim of this study was to determine which clinical factors were predictive of self- reported physical activity levels in patients with PsA. A secondary aim was to explore differences in self-reported physical activity levels amongst patients with PsA, OA and RA.

Methods:

Patients with the diagnosis of PsA, RA or OA are recruited prospectively at two tertiary hospital rheumatology clinics over 12 months. Demographic data is captured by the multi-dimensional health assessment questionnaire, the international physical activity questionnaire short form captures self-reported physical activity and self-efficacy for exercise (SEE) is assessed using the SEE scale. Clinical data including joint count, body mass index and co-morbidities including fibromyalgia are collected for all patients, in addition to PsA specific data including skin and enthesitis indices.

Results:

205 patients (PsA n=62, RA n=83, OA n=60) were recruited across two sites. There was no significant difference in self-reported physical activity between OA, RA and PsA cohorts. Fibromyalgia was present in 30% of each cohort. In patients with PsA, univariate analysis showed that co-existent fibromyalgia, age and self-efficacy for exercise were predictors of physical activity levels. Skin disease and enthesitis were not predictors of physical activity in the PsA cohort.

Table 1.

Univariate Analyses of effect of Clinical Features on Physical Activity levels in PsA

Non-exercisers versus ExercisersOR (95% CI)P-valueLEI1.35 (0.92-1.97)0.127PASI0.8 (0.6-1.07)0.133DLQI1.03 (0.92-1.16)0.589BMI0.97 (0.91-1.04)0.415DAS280.79 (0.55-1.14)0.205Concurrent Fibromyalgia4.46 (1.37-14.49)0.012Age1.05 (1.00-1.10)0.013Self-efficacy for exercise0.97 (0.95-0.99)0.019Pain1.17 (0.99-1.37)0.061Function1.3 (1.02-1.65)0.031Patient global1.14 (0.96-1.34)0.128Depression0.97 (0.51-1.84)0.930Table 2.

Multivariable Analysis on Physical Activity in PsA

Non-exercisers vs ExercisersOR (95% CI)P-valueConcurrent fibromyalgia5.1 (1.44-18.08)0.0117Age1.05 (1.00-1.11)0.0342

Conclusion:

In the PsA cohort, fibromyalgia and age were associated with lower levels of physical activity. DLQI, PASI, LEI did not predict physical activity in PsA. Multivariate analysis showed higher pain levels and lower self-efficacy scores were associated with lower physical activity across arthritis groups.

References:

[1]Der Ananian C, Wilcox S, Watkins K, Saunders RP, Evans AE. (2008). Factors Associated with Exercise Participation in Adults with Arthritis.Journal of Aging and Physical Activity, 16: 125-143

[2]Wilcox S, Der Ananian C, Abbott J, Vrazel J, Ramsey C, Sharpe PA, Brady T. (2006). Perceived Exercise Barriers, Enablers, and Benefits Among Exercising and Nonexercising Adults With Arthritis: Results from a Qualitative Study.Arthritis & Rheumatism, 55(4): 616-627

Acknowledgments:

Joseph Descallar

Dana Georgevsky

Dr Michael Oliffe

Dr Diana Chessman

Department of Rheumatology, Liverpool Hospital NSW Australia

Department of Rheumatology, Westmead Hospital NSW Australia

Disclosure of Interests:

None declared

Comparison of bone structure and microstructure in the metacarpal heads between patients with psoriatic arthritis and healthy controls: an HR-pQCT study

Human cadaveric study has indicated that the metacarpal head (MCH) is intracapsular in location. We hypothesized that exposure to the intra-articular inflammatory milieu in psoriatic arthritis (PsA) will lead to bone loss in the MCH.

INTRODUCTION

To compare the bone structure and microstructure in the MCH between patients with PsA and healthy controls by high-resolution peripheral quantitative CT (HR-pQCT), and to ascertain factors associated with bone loss in PsA patients.

METHODS

Sixty-two PsA patients without joint destruction and 62 age-, gender-, and body mass index-matched healthy subjects underwent HR-pQCT imaging of the second and third MCH (MCH 2&3). The number and volume of bone erosion and enthesiophytes, as well as volumetric bone mineral density (vBMD) and microstructure at the MCH 2&3, were recorded. Correlation analysis and multivariable linear regression models were used to determine the association of demographic and disease-specific variables with compromised bone structure and microstructure in PsA.

RESULTS

At the MCH 2&3, bone erosion (p = 0.003) and enthesiophyte (p = 0.000) volumes in PsA patients were significantly larger than healthy controls. In PsA patients, older age was associated with a larger erosion and enthesiophyte volume. Concerning the mean vBMD and microstructure at the MCH 2&3, PsA patients had significantly lower mean vBMD (average vBMD - 6.9%, trabecular vBMD - 8.8%, peri-trabecular vBMD - 7.7%, meta-trabecular vBMD - 9.8%), trabecular bone volume fraction (- 8.8%), and trabecular thickness (- 8.1%) compared with control subjects. Multivariable regression analysis revealed that older age and a higher C-reactive protein level were associated with trabecular bone loss.

CONCLUSIONS

PsA patients had a higher burden of bone damages (erosions and enthesiophytes) and trabecular bone loss compared with healthy control at the MCH. Inflammation contributed to the deterioration in trabecular microstructure in these patients.

Phlebotomy resulting in controlled hypovolaemia to prevent blood loss in major hepatic resections (PRICE-1): a pilot randomized clinical trial for feasibility

BACKGROUND

Major liver resection is associated with blood loss and transfusion. Observational data suggest that hypovolaemic phlebotomy can reduce these risks. This feasibility RCT compared hypovolaemic phlebotomy with the standard of care, to inform a future multicentre trial.

METHODS

Patients undergoing major liver resections were enrolled between June 2016 and January 2018. Randomization was done during surgery and the surgeons were blinded to the group allocation. For hypovolaemic phlebotomy, 7-10 ml per kg whole blood was removed, without intravenous fluid replacement. Co-primary outcomes were feasibility and estimated blood loss (EBL).

RESULTS

A total of 62 patients were randomized to hypovolaemic phlebotomy (31) or standard care (31), at a rate of 3·1 patients per month, thus meeting the co-primary feasibility endpoint. The median EBL difference was -111 ml (P = 0·456). Among patients at high risk of transfusion, the median EBL difference was -448 ml (P = 0·069). Secondary feasibility endpoints were met: enrolment, blinding and target phlebotomy (mean(s.d.) 7·6(1·9) ml per kg). Blinded surgeons perceived that parenchymal resection was easier with hypovolaemic phlebotomy than standard care (16 of 31 versus 10 of 31 respectively), and guessed that hypovolaemic phlebotomy was being used with an accuracy of 65 per cent (20 of 31). There was no significant difference in overall complications (10 of 31 versus 15 of 31 patients), major complications or transfusion. Among those at high risk, transfusion was required in two of 15 versus three of nine patients (P = 0·326).

CONCLUSION

Endpoints were met successfully, but no difference in EBL was found in this feasibility study. A multicentre trial (PRICE-2) powered to identify a difference in perioperative blood transfusion is justified. Registration number: NCT02548910 ( http://www.clinicaltrials.gov).

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

Major liver surgery in a Jehovah’s Witness patient: challenges for safe surgery

Jehovah’s Witnesses presenting for major surgery run the risk of major bleeding, which is complicated by the refusal to accept blood transfusion. We present a case of a 63-year-old woman, a Jehovah’s Witness, who was diagnosed with hepatocellular carcinoma and advised for curative laparoscopic liver segmentectomy. Due to the risk of significant intraoperative haemorrhage, her perioperative care was coordinated in a multidisciplinary manner. Informed consent requires the physician to advise on the material risks of undertaking major surgery without blood transfusion and the possible alternatives. Conflicting ethical issues of patient autonomy and beneficence related to refusal of blood products also arise. Perioperative strategies to minimise blood loss, maximise haematopoiesis and tolerance of anaemia to facilitate safe surgery in such patients are also presented. Written patient consent obtained.

Trabecular bone score in adults with cerebral palsy

CONTEXT

Bone fragility in cerebral palsy (CP) is secondary to a complex interplay of functional, hormonal, and nutritional factors that affect bone remodelling. A greater understanding of bone microarchitectural changes seen in CP should assist therapeutic decision making.

OBJECTIVE

To examine the relationship between trabecular bone score (TBS), BMD and fractures in adults with CP; the influence of clinical factors and body composition on bone microarchitecture were explored.

DESIGN

Retrospective cross-sectional study.

SETTING AND PARTICIPANTS

43 adults (25 male) with CP of median age 25 years (interquartile range 21.4-33.9) who had evaluable dual-energy X-ray absorptiometry imaging of the lumbar spine from a single tertiary hospital between 2005-March 2018.

RESULTS

24/43 (55.8%) of patients had TBS values indicating intermediate or high risk of fracture (<1.31). TBS correlated with areal BMD at the lumbar spine, femoral neck and total body. TBS was significantly associated with arm and leg lean mass, with adjustment for age, gender and height (adjusted R² = 0.18, p = 0.042 for arm lean mass; adjusted R² = 0.19, p = 0.036 for leg lean mass). There was no difference in TBS when patients were grouped by fracture status, anticonvulsant use, gonadal status or use of PEG feeding. TBS was lower in non-ambulatory patients compared with ambulatory patients (1.28 vs 1.37, p = 0.019).

CONCLUSIONS

Abnormal bone microarchitecture, as measured by TBS, was seen in >50% of young adults with CP. TBS correlated with both areal BMD and appendicular lean mass. Maintaining muscle function is likely to be important for bone health in young adults with CP and needs to be confirmed in further studies.

The Impact of Social Support Networks on Family Resilience in an Australian Intensive Care Unit: A Constructivist Grounded Theory

PURPOSE

This article discusses the findings of a grounded theory of family resilience in an Australian intensive care unit (ICU) with a specific focus on families' experiences of their interactions with other members within their own family, and the families of other patients in the ICU.

DESIGN

A constructivist grounded theory methodology was adopted. Data were collected using in-depth interviews with 25 family members of 21 critically ill patients admitted to a tertiary-level ICU in Australia.

FINDINGS

The core category regaining control represents the families' journey toward resilience when in ICU. The major categories represent facilitators for, and barriers to, regaining control. One of the main facilitators is drawing strength, and it explains the manner with which families receive social support from their own and other family members to help them cope.

CONCLUSIONS

This study offers a framework to improve patient- and family-centered care in the ICU by facilitating families' ability to manage their situation more effectively. Social support offered by family members facilitates the families' ability to regain control. An ICU family resilience theoretical framework, situated within the context of the Australian healthcare system, adds to what is currently known about the families' experiences in the ICU.

CLINICAL RELEVANCE

The relationships that develop between families in the ICU may provide a source of social support; however, not all families welcome interactions with other ICU families, and it may cause further emotional distress. Further research is warranted to determine whether families suffer a secondary stress reaction from incidental interactions with other patients' families in the ICU. Furthermore, when family members pull together and offer social support to each other, they are better able to regain control. This process contributes to an ICU family resilience framework.

Dynamics of the Phanerochaete carnosa transcriptome during growth on aspen and spruce

BACKGROUND

The basidiomycete Phanerochaete carnosa is a white-rot species that has been mainly isolated from coniferous softwood. Given the particular recalcitrance of softwoods to bioconversion, we conducted a comparative transcriptomic analysis of P. carnosa following growth on wood powder from one softwood (spruce; Picea glauca) and one hardwood (aspen; Populus tremuloides). P. carnosa was grown on each substrate for over one month, and mycelia were harvested at five time points for total RNA sequencing. Residual wood powder was also analyzed for total sugar and lignin composition.

RESULTS

Following a slightly longer lag phase of growth on spruce, radial expansion of the P. carnosa colony was similar on spruce and aspen. Consistent with this observation, the pattern of gene expression by P. carnosa on each substrate converged following the initial adaptation. On both substrates, highest transcript abundances were attributed to genes predicted to encode manganese peroxidases (MnP), along with auxiliary activities from carbohydrate-active enzyme (CAZy) families AA3 and AA5. In addition, a lytic polysaccharide monooxygenase from family AA9 was steadily expressed throughout growth on both substrates. P450 sequences from clans CPY52 and CYP64 accounted for 50% or more of the most highly expressed P450s, which were also the P450 clans that were expanded in the P. carnosa genome relative to other white-rot fungi.

CONCLUSIONS

The inclusion of five growth points and two wood substrates was important to revealing differences in the expression profiles of specific sequences within large glycoside hydrolase families (e.g., GH5 and GH16), and permitted co-expression analyses that identified new targets for study, including non-catalytic proteins and proteins with unknown function.

Searching for meaning: A grounded theory of family resilience in adult ICU

AIM

To explore families' experiences of their interactions in an Australian adult intensive care unit (ICU) to develop a grounded theory that can be used by critical care nurses to improve patient- and family-centred care (PFCC).

BACKGROUND

Families in ICU play an important role in the patient's recovery and outcomes. However, families are at risk of significant psychological morbidity due to their experiences in ICU. Although many ICU patients can make their own decisions, a large proportion are unconscious or chemically sedated and unable to contribute to decisions about their care, leaving the decision-making role to the family. Therefore, the families' psychosocial and emotional well-being must be supported by implementing evidence-based interventions that align with a PFCC approach. This study describes the findings of a grounded theory of family resilience in ICU, of which the core category is Regaining control. The focus of this paper is on the major category: Searching for meaning.

METHODS

We adopted a constructivist grounded theory method. Twenty-five adult family members (n = 25) of 21 patients admitted unexpectedly to an ICU in metropolitan Australia were recruited. In-depth interviews were used to collect the data, and the analytical processes of constructivist grounded theory underpinned the development of a core category and related subcategories.

RESULTS

When adult family members experience the unexpected admission of a relative to ICU, they move towards a state of being beyond emotional adversity and regaining control when facilitated to search for meaning in their situation. When families were able to make sense of their situation and find a purpose by contributing to their relative's recovery, it encouraged them to cope and be resilient.

CONCLUSIONS

Our findings can be used to promote PFCC in ICU, which considers a collaborative approach to meet the patient's needs while providing emotional and psychosocial support to their families.

An explanation of the reversal of erythrocyte echinocytosis by incubation and storage by serum albumin

It is proposed that the specific reversal by serum albumin of the erythrocyte echinocytosis in an inorganic phosphate buffer saline or in a saline, either after 24 h in blood or after a storage of 6-7 weeks in SGAM or PAGGSM media, is due to a cell dehydration by a decrease of the total NaCl and KCl concentrations favoring the stomatocytogenic slow outward transport of inorganic phosphate with a hydrogen ion by band 3 anion exchanger, which was previously proposed to control the erythrocyte shape. This proposal would indicate that the opposition of the erythrocyte echinocytosis by serum albumin is not limited to binding to echinocytogenic amphiphiles, supported by the ability of the band 3-based mechanism of control of the erythrocyte shape to explain a variety of observations on the erythrocyte shape. It would also imply that this mechanism is a determinant of the erythrocyte rheological properties since influenced by cell shape and volume. It is shown that the above process of stomatocytosis can explain stomatocytoses by different agents as well as a knizocytosis induced in vitro and occurring in acquired and inherited disorders and other situations. Lastly, it can also explain the opposition of hemolysis by mannitol in SGAM and PAGGSM media.