Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
77
result(s) for
"Bray, Ross"
Sort by:
Dual GIP and GLP-1 Receptor Agonist Tirzepatide Improves Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes
2021
Abstract
Context
Novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist (RA) tirzepatide demonstrated substantially greater glucose control and weight loss (WL) compared with selective GLP-1RA dulaglutide.
Objective
Explore mechanisms of glucose control by tirzepatide.
Design
Post hoc analyses of fasting biomarkers and multiple linear regression analysis.
Setting
Forty-seven sites in 4 countries.
Patients or other Participants
Three hundred and sixteen subjects with type 2 diabetes.
Interventions
Tirzepatide (1, 5, 10, 15 mg), dulaglutide (1.5 mg), placebo.
Main Outcome Measures
Analyze biomarkers of beta-cell function and insulin resistance (IR) and evaluate WL contributions to IR improvements at 26 weeks.
Results
Homeostatic model assessment (HOMA) 2-B significantly increased with dulaglutide and tirzepatide 5, 10, and 15 mg compared with placebo (P ≤ .02). Proinsulin/insulin and proinsulin/C-peptide ratios significantly decreased with tirzepatide 10 and 15 mg compared with placebo and dulaglutide (P ≤ .007). Tirzepatide 10 and 15 mg significantly decreased fasting insulin (P ≤ .033) and tirzepatide 10 mg significantly decreased HOMA2-IR (P = .004) compared with placebo and dulaglutide. Markers of improved insulin sensitivity (IS) adiponectin, IGFBP-1, and IGFBP-2 significantly increased by 1 or more doses of tirzepatide (P < .05). To determine whether improvements in IR were directly attributable to WL, multiple linear regression analysis with potential confounding variables age, sex, metformin, triglycerides, and glycated hemoglobin A1c was conducted. WL significantly (P ≤ .028) explained only 13% and 21% of improvement in HOMA2-IR with tirzepatide 10 and 15 mg, respectively.
Conclusions
Tirzepatide improved markers of IS and beta-cell function to a greater extent than dulaglutide. IS effects of tirzepatide were only partly attributable to WL, suggesting dual receptor agonism confers distinct mechanisms of glycemic control.
Journal Article
Once-weekly tirzepatide versus once-daily insulin degludec as add-on to metformin with or without SGLT2 inhibitors in patients with type 2 diabetes (SURPASS-3): a randomised, open-label, parallel-group, phase 3 trial
2021
Tirzepatide is a novel dual glucose-dependent insulinotropic polypeptide and GLP-1 receptor agonist under development for the treatment of type 2 diabetes. We aimed to assess the efficacy and safety of tirzepatide versus titrated insulin degludec in people with type 2 diabetes inadequately controlled by metformin with or without SGLT2 inhibitors.
In this open-label, parallel-group, multicentre (122 sites), multinational (13 countries), phase 3 study, eligible participants (aged ≥18 years) had a baseline glycated haemoglobin (HbA1c) of 7·0–10·5%, body-mass index of at least 25 kg/m2, stable weight, and were insulin-naive and treated with metformin alone or in combination with an SGLT2 inhibitor for at least 3 months before screening. Participants were randomly assigned (1:1:1:1), using an interactive web-response system, to once-weekly subcutaneous injection of tirzepatide (5, 10, or 15 mg) or once-daily subcutaneous injection of titrated insulin degludec, and were stratified by country, HbA1c, and concomitant use of oral antihyperglycaemic medications. Tirzepatide was initially given at 2·5 mg and the dose was escalated by 2·5 mg every 4 weeks until the assigned dose was reached. Insulin degludec was initially given at 10 U per day and was titrated once weekly to a fasting self-monitored blood glucose of less than 5·0 mmol/L (<90 mg/dL), following a treat-to-target algorithm, for 52 weeks. The primary efficacy endpoint was non-inferiority of tirzepatide 10 mg or 15 mg, or both, versus insulin degludec in mean change from baseline in HbA1c at week 52. Key secondary efficacy endpoints were non-inferiority of tirzepatide 5 mg versus insulin degludec in mean change from baseline in HbA1c at week 52, superiority of all doses of tirzepatide versus insulin degludec in mean change from baseline in HbA1c and bodyweight, and the proportion of participants achieving HbA1c of less than 7·0% (<53 mmol/mol) at week 52. We used a boundary of 0·3% to establish non-inferiority in HbA1c difference between treatments. Efficacy and safety analyses were assessed in the modified intention-to-treat population (all participants who received at least one dose of study drug). This trial is registered with ClinicalTrials.gov, number NCT03882970, and is complete.
Between April 1 and Nov 15, 2019, we assessed 1947 participants for eligibility, 1444 of whom were randomly assigned to treatment. The modified intention-to-treat population was 1437 participants from the tirzepatide 5 mg (n=358), tirzepatide 10 mg (n=360), tirzepatide 15 mg (n=359), and insulin degludec (n=360) groups. From a mean baseline HbA1c of 8·17% (SD 0·91), the reductions in HbA1c at week 52 were 1·93% (SE 0·05) for tirzepatide 5 mg, 2·20% (0·05) for tirzepatide 10 mg, and 2·37% (0·05) for tirzepatide 15 mg, and 1·34% (0·05) for insulin degludec. The non-inferiority margin of 0·3% was met. The estimated treatment difference (ETD) versus insulin degludec ranged from –0·59% to –1·04% for tirzepatide (p<0·0001 for all tirzepatide doses). The proportion of participants achieving a HbA1c of less than 7·0% (<53 mmol/mol) at week 52 was greater (p<0·0001) in all three tirzepatide groups (82%–93%) versus insulin degludec (61%). At week 52, from a baseline of 94·3 kg (SD 20·1), all three tirzepatide doses decreased bodyweight (–7·5 kg to –12·9 kg), whereas insulin degludec increased bodyweight by 2·3 kg. The ETD versus insulin degludec ranged from –9·8 kg to –15·2 kg for tirzepatide (p<0·0001 for all tirzepatide doses). The most common adverse events in tirzepatide-treated participants were mild to moderate gastrointestinal events that decreased over time. A higher incidence of nausea (12–24%), diarrhoea (15–17%), decreased appetite (6–12%), and vomiting (6–10%) was reported in participants treated with tirzepatide than in those treated with insulin degludec (2%, 4%, 1%, and 1%, respectively). Hypoglycaemia (<54 mg/dL or severe) was reported in five (1%), four (1%), and eight (2%) participants on tirzepatide 5, 10, and 15 mg, respectively, versus 26 (7%) on insulin degludec. Treatment discontinuation due to an adverse event was more common in the tirzepatide groups than in the insulin degludec group. Five participants died during the study; none of the deaths were considered by the investigators to be related to the study treatment.
In patients with type 2 diabetes, tirzepatide (5, 10, and 15 mg) was superior to titrated insulin degludec, with greater reductions in HbA1c and bodyweight at week 52 and a lower risk of hypoglycaemia. Tirzepatide showed a similar safety profile to that of GLP-1 receptor agonists.
Eli Lilly and Company.
Journal Article
Why are not There More Bayesian Clinical Trials? Perceived Barriers and Educational Preferences Among Medical Researchers Involved in Drug Development
by
Wenkert, Deborah
,
Bray, Ross
,
Wang, Fei
in
Analytical Report
,
Bayes Theorem
,
Bayesian analysis
2023
Objective and Background
The clinical trials community has been hesitant to adopt Bayesian statistical methods, which are often more flexible and efficient with more naturally interpretable results than frequentist methods. We aimed to identify self-reported barriers to implementing Bayesian methods and preferences for becoming comfortable with them.
Methods
We developed a 22-question survey submitted to medical researchers (non-statisticians) from industry, academia, and regulatory agencies. Question areas included demographics, experience, comfort levels with Bayesian analyses, perceived barriers to these analyses, and preferences for increasing familiarity with Bayesian methods.
Results
Of the 323 respondents, most were affiliated with pharmaceutical companies (33.4%), clinical research organizations (29.7%), and regulatory agencies (18.6%). The rest represented academia, medical practice, or other. Over 56% of respondents expressed little to no comfort in interpreting Bayesian analyses. “Insufficient knowledge of Bayesian approaches” was ranked the most important perceived barrier to implementing Bayesian methods by a plurality (48%). Of the approaches listed, in-person training was the most preferred for gaining comfort with Bayesian methods.
Conclusions
Based on these survey results, we recommend that introductory level training on Bayesian statistics be presented in an in-person workshop that could also be broadcast online with live Q&A. Other approaches such as online training or collaborative projects may be better suited for higher-level trainings where instructors may assume a baseline understanding of Bayesian statistics. Increased coverage of Bayesian methods at medical conferences and medical school trainings would help improve comfort and overcome the substantial knowledge barriers medical researchers face when implementing these methods.
Journal Article
Patient-Reported Outcomes in People with Type 2 Diabetes Receiving Tirzepatide in the SURPASS Clinical Trial Programme
by
Thieu, Vivian Thuyanh
,
Bray, Ross
,
Landó, Laura Fernández
in
Activities of daily living
,
Antidiabetics
,
Cardiology
2023
Introduction
Tirzepatide, a novel glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1 receptor agonist, is approved for glycaemic control for people with type 2 diabetes (T2D). The SURPASS-1 to -5 clinical trials assessed the efficacy of once weekly tirzepatide (5, 10 and 15 mg) versus placebo or active comparators (semaglutide 1 mg, insulin degludec and insulin glargine) in T2D. We evaluated patient-reported outcomes (PROs) that measured overall quality of life (QoL), treatment satisfaction and weight-related attributes across the five SURPASS studies.
Methods
PRO instruments utilised at baseline and primary timepoint (40 weeks for SURPASS-1, -2 and -5; 52 weeks for SURPASS-3 and -4) or early termination visit were EQ-5D-5L (SURPASS-1 to -5); Impact of Weight on Self-Perceptions (SURPASS-1 to -5); Ability to Perform Physical Activities of Daily Living (SURPASS-1 to -5); Diabetes Treatment Satisfaction Questionnaire (SURPASS-2 to -5); and Impact of Weight on Quality of Life-Lite Clinical Trials Version (SURPASS-2 only).
Results
Across all five studies at week 40/52, tirzepatide improved patients’ QoL measured by general health and weight-related PROs over the comparator. Generally, higher doses of tirzepatide resulted in greater increases in PRO scores.
Conclusion
Overall, tirzepatide produced significant health and weight-related QoL improvements versus comparators in the five SURPASS studies.
Clinical Trial Registration
SURPASS-1: NCT03954834; SURPASS-2: NCT03987919; SURPASS-3: NCT03882970; SURPASS-4: NCT03730662; SURPASS-5: NCT04039503.
Plain Language Summary
Tirzepatide is the first glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1 receptor agonist approved for the treatment of people with type 2 diabetes. The SURPASS-1 to -5 clinical trials evaluated the efficacy and safety of tirzepatide (5, 10 and 15 mg) compared with placebo or active comparators (including semaglutide 1 mg and basal insulins) in people with type 2 diabetes. We evaluated other outcomes reported by patients that measured overall quality of life, treatment satisfaction and weight-related attributes across the five SURPASS studies.
Five validated questionnaires were completed by patients at the beginning and end of the clinical trials, which was after 40 weeks for SURPASS-1, -2 and -5 and after 52 weeks for SURPASS-3 and -4, or when the person left the trial if this was before the official end. These questionnaires were EQ-5D-5L (SURPASS-1 to -5); Impact of Weight on Self-Perceptions (SURPASS-1 to -5); Ability to Perform Physical Activities of Daily Living (SURPASS-1 to -5); Diabetes Treatment Satisfaction Questionnaire (SURPASS-2 to -5); and Impact of Weight on Quality of Life-Lite Clinical Trials Version (SURPASS-2 only).
Across all five studies, treatment with tirzepatide resulted in greater improvements in people’s quality of life at the end of the study compared with placebo or treatment with the comparators. Generally, higher doses of tirzepatide resulted in greater increases in questionnaire scores than lower doses of tirzepatide.
Overall, tirzepatide 5, 10 or 15 mg treatment resulted in significant health- and weight-related quality of life improvements versus comparators in the five SURPASS studies.
Journal Article
Why are There not More Bayesian Clinical Trials? Ability to Interpret Bayesian and Conventional Statistics Among Medical Researchers
2023
Objective and Background
We assessed current understandings in interpretation of Bayesian and traditional statistical results within the clinical researcher (non-statistician) community.
Methods
Within a 22-question survey, including demographics and experience and comfort levels with Bayesian analyses, we included questions on how to interpret both Bayesian and traditional statistical outputs. We also assessed whether Bayesian or traditional interpretations are considered more useful.
Results
Among the 323 respondent clinicians, 42.4% and 36.5% chose the correct interpretations of the posterior probability and 95% credible interval, respectively. Only 11.5% of respondents interpreted the
p
-value correctly and 23.5% interpreted the 95% confidence interval correctly.
Conclusions
Based on these survey results, we conclude that most of these clinicians face uncertainty when attempting to interpret results from both Bayesian and traditional statistical outputs. When presented with accurate interpretations, clinicians generally conclude that Bayesian results are more useful than conventional ones. We believe there is a need for education of clinicians in statistical interpretation in ways that are customized to this audience.
Journal Article
A Bivariate Regression Model with Correlated Mixed Responses
2013
In the dissertation we consider a bivariate model for associated binary and continuous responses such as those in a clinical trial where both safety and efficacy are observed. We designate a marginal and conditional model that allows for the association between the responses by including the marginal response as an additional predictor of the conditional response. We use a Bayesian approach to model the bivariate regression model using a hierarchical prior structure. Simulation studies indicate that the model provides good point and interval estimates of regression parameters across a variety of parameter configurations, with smaller binary event probabilities offering particular challenges. For example, as the probability of an adverse event decreases, we find that the marginal posterior variances increase for the binary safety response regression coefficients, but not for the conditional efficacy response coefficients. Potential problems with induced priors are briefly considered. We implement an asymptotic higher order approximation in order to obtain parameter estimates and confidence intervals via a simulation study. In comparison, the frequentist intervals are slightly more narrow than the Bayesian intervals (using vague priors), but the latter have far superior coverage. Finally, we implement a Bayesian sample size determination method while controlling an operating characteristic of the model, the family-wise error rate. We find that there is a savings in power afforded by use of the multiplicity adjustment when simultaneously testing multiple hypotheses. Simulation results indicate that multiplicity adjustments improve the power of the model when compared to the overly conservative Bonferroni adjustment. We also see an improvement in power through the effective use of prior information.
Dissertation
Anyone for a chukka?
2006
Polo has the image of a pastime for high-flyers and bluebloods. Certainly a sport requiring a minimum of two horses to play a single game is not designed for the financially faint of heart. For those not exposed to the sport from a young age, there are surprisingly few places dedicated to teaching. The Riverlands Polo Club at Richmond near Sydney is recognized as the most advanced in the coaching stakes. It has a summer and winter school, each running over five weeks and costing about $1000. Located south of Cowra, Millamalong is a property owned by the famous Ashton polo family that now operates as a weekend escape. Polocrosse, a combination of polo and lacrosse, is now played around the world, mainly in Commonwealth countries. The game has been designed to be played with one horse (player and horse are rested on alternate chukkas) so it has a lower entry cost.
Trade Publication Article
Human toll mounts as Gaza conflict continues
by
Bray, Ross
2009
If there were, let's investigate, let's find out why this - if it is true - went wrong, even though, as I say, we're 99 per cent it didn't. MARK REGEV, ISRAELI PRIME MINISTER'S SPOKESMAN: Even if their investigation is correct, if someone is sitting immediately outside a UN facility and shooting at Israeli soldiers, isn't that person in this case Hamas, not committing a grave war crime? [Ross Bray]: Israeli officials dismissed the UN statements as biased, saying could have simply bombed the camp and avoided Israeli casualties, but it didn't in order to minimise civilian casualties.
Newspaper Article
Speedway fraternity gears up for Championship
2009
Its heyday was through the '50s, '60s, and '70s; speedway was popular around Australia. [ALEX DAVIES]: Well before the tape drops, you're just thinking- you're just concentrating- fully concentrated, and just thinking about making the start and getting to the first corner first, and after the tape's go up then you just drop the clutch and just go for it. [Terry Poole], SPEEDWAY RACER: You're rivals on the track but when you're off the track we're all pretty good friends.
Newspaper Article
Dire outlook for tourism industry
by
Bray, Ross
2008
Lara Bingle walks along the beach in the \"Where the bloody hell are you\" ad, date unknown.; It is worth about $90 billion to the Australian economy each...
Newspaper Article