Enrichment Benefits of Risk Algorithms for Pulmonary Arterial Hypertension Clinical Trials

Prognostic factors associated with venous thromboembolism following traumatic injury: A systematic review and meta-analysis

INTRODUCTION

Trauma patients are at increased risk of venous thromboembolism (VTE), including deep venous thrombosis and/or pulmonary embolism. We conducted a systematic review and meta-analysis summarizing the association between prognostic factors and the occurrence of VTE following traumatic injury.

METHODS

We searched the Embase and Medline databases from inception to August 2023. We identified studies reporting confounding adjusted associations between patient, injury, or postinjury care factors and risk of VTE. We performed meta-analyses of odds ratios using the random-effects method and assessed individual study risk of bias using the Quality in Prognosis Studies tool.

RESULTS

We included 31 studies involving 1,981,946 patients. Studies were predominantly observational cohorts from North America. Factors with moderate or higher certainty of association with increased risk of VTE include older age, obesity, male sex, higher Injury Severity Score, pelvic injury, lower extremity injury, spinal injury, delayed VTE prophylaxis, need for surgery, and tranexamic acid use. After accounting for other important contributing prognostic variables, a delay in the delivery of appropriate pharmacologic prophylaxis for as little as 24 to 48 hours independently confers a clinically meaningful twofold increase in incidence of VTE.

CONCLUSION

These findings highlight the contribution of patient predisposition, the importance of injury pattern, and the impact of potentially modifiable postinjury care on risk of VTE after traumatic injury. These factors should be incorporated into a risk stratification framework to individualize VTE risk assessment and support clinical and academic efforts to reduce thromboembolic events among trauma patients.

LEVEL OF EVIDENCE

Systematic Review and Meta-Analysis; Level III.

The Imperative to Enhance Cost-Effectiveness for Cardiovascular Therapeutic Development

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Therapeutic agents, such as those that lower low-density lipoprotein cholesterol, have been a critical factor in mitigating CVD event risk and demonstrate the important role that drug discovery plays in reducing morbidity and mortality. However, rapidly rising development costs, diminishing returns, and an increasingly challenging regulatory environment have all contributed to a declining number of cardiovascular (CV) therapeutic agents entering the health care marketplace. For pharmaceutical companies, a traditional cardiovascular outcomes trial (CVOT) can be a major financial burden and impediment to CV agent development. They can take as long as a decade to conduct, delaying potential investment return while carrying risk of failure. For patients, lengthy CVOTs delay drug accessibility. Without cost-effective CVOTs, drug innovation may be compromised, with CV patients bearing the consequences. This paper reviews potential approaches for making CV drug development more cost-effective.

Prognostic Value of Serial Risk Stratification in Adult and Pediatric Pulmonary Arterial Hypertension: A Systematic Review

BACKGROUND

In pulmonary arterial hypertension, it is recommended to base therapeutic decisions on risk stratification. This systematic review aims to report the prognostic value of serial risk stratification in adult and pediatric pulmonary arterial hypertension and to explore the usability of serial risk stratification as treatment target.

METHODS AND RESULTS

Electronic databases PubMed, Embase, and Web of Science were searched up to January 30, 2023, using terms associated with pulmonary arterial hypertension, pediatric pulmonary hypertension, and risk stratification. Observational studies and clinical trials describing risk stratification at both baseline and follow-up were included. Sixty five studies were eligible for inclusion, including only 2 studies in a pediatric population. C-statistic range at baseline was 0.31 to 0.77 and improved to 0.30 to 0.91 at follow-up. In 53% of patients, risk status changed (42% improved, 12% worsened) over 168 days (interquartile range, 137-327 days; n=22 studies). The average proportion of low-risk patients increased from 18% at baseline to 36% at a median follow-up of 244 days (interquartile range, 140-365 days; n=40 studies). In placebo-controlled drug studies, risk statuses of the intervention groups improved more and worsened less compared with the placebo groups. Furthermore, a low-risk status, but also an improved risk status, at follow-up was associated with a better outcome. Similar results were found in the 2 pediatric studies.

CONCLUSIONS

Follow-up risk stratification has improved prognostic value compared with baseline risk stratification, and change in risk status between baseline and follow-up corresponded to a change in survival. These data support the use of serial risk stratification as treatment target in pulmonary arterial hypertension.

Seralutinib in adults with pulmonary arterial hypertension (TORREY): a randomised, double-blind, placebo-controlled phase 2 trial

BACKGROUND

Morbidity and mortality in pulmonary arterial hypertension (PAH) remain high. Activation of platelet-derived growth factor receptor, colony stimulating factor 1 receptor, and mast or stem cell growth factor receptor kinases stimulates inflammatory, proliferative, and fibrotic pathways driving pulmonary vascular remodelling in PAH. Seralutinib, an inhaled kinase inhibitor, targets these pathways. We aimed to evaluate the efficacy and safety of seralutinib in patients with PAH receiving standard background therapy.

METHODS

The TORREY trial was a phase 2, randomised, multicentre, multinational, double-blind, placebo-controlled study. Patients with PAH from 40 hospital and community sites were randomly assigned 1:1 via interactive response technologies to receive seralutinib (60 mg twice daily for 2 weeks, then increased to 90 mg twice daily as tolerated) or placebo by dry powder inhaler twice daily for 24 weeks. Randomisation was stratified by baseline pulmonary vascular resistance (PVR; <800 dyne·s/cm5 and ≥800 dyne·s/cm5). Patients were eligible if classified as WHO Group 1 PH (PAH), WHO Functional Class II or III, with a PVR of 400 dyne·s/cm5 or more, and a 6 min walk distance of between 150 m and 550 m. The primary endpoint was change in PVR from baseline to 24 weeks. Analyses for efficacy endpoints were conducted in randomly assigned patients (intention-to-treat population). Safety analyses included all patients who received the study drug. TORREY was registered with ClinicalTrials.gov (NCT04456998) and EudraCT (2019-002669-37) and is completed.

FINDINGS

From Nov 12, 2020, to April 20, 2022, 151 patients were screened for eligibility, and following exclusions, 86 adults receiving PAH background therapy were randomly assigned to seralutinib (n=44; four male, 40 female) or placebo (n=42; four male, 38 female), and comprised the intention-to-treat population. At baseline, treatment groups were balanced except for a higher representation of WHO Functional Class II patients in the seralutinib group. The least squares mean change from baseline to week 24 in PVR was 21·2 dyne·s/cm5 (95% CI -37·4 to 79·8) for the placebo group and -74·9 dyne·s/cm5 (-139·7 to -10·2) for the seralutinib group. The least squares mean difference between the seralutinib and placebo groups for change in PVR was -96·1 dyne·s/cm5 (95% CI -183·5 to -8·8; p=0·03). The most common treatment-emergent adverse event in both treatment groups was cough: 16 (38%) of 42 patients in the placebo group; 19 (43%) of 44 patients in the seralutinib group.

INTERPRETATION

Treatment with inhaled seralutinib significantly decreased PVR, meeting the primary endpoint of the study among patients receiving background therapy for PAH.

FUNDING

Gossamer Bio.

Development and External Validation of Models to Predict Persistent Hypoxemic Respiratory Failure for Clinical Trial Enrichment

OBJECTIVES

Improving the efficiency of clinical trials in acute hypoxemic respiratory failure (HRF) depends on enrichment strategies that minimize enrollment of patients who quickly resolve with existing care and focus on patients at high risk for persistent HRF. We aimed to develop parsimonious models predicting risk of persistent HRF using routine data from ICU admission and select research immune biomarkers.

DESIGN

Prospective cohorts for derivation ( n = 630) and external validation ( n = 511).

SETTING

Medical and surgical ICUs at two U.S. medical centers.

PATIENTS

Adults with acute HRF defined as new invasive mechanical ventilation (IMV) and hypoxemia on the first calendar day after ICU admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We evaluated discrimination, calibration, and practical utility of models predicting persistent HRF risk (defined as ongoing IMV and hypoxemia on the third calendar day after admission): 1) a clinical model with least absolute shrinkage and selection operator (LASSO) selecting Pa o2 /F io2 , vasopressors, mean arterial pressure, bicarbonate, and acute respiratory distress syndrome as predictors; 2) a model adding interleukin-6 (IL-6) to clinical predictors; and 3) a comparator model with Pa o2 /F io2 alone, representing an existing strategy for enrichment. Forty-nine percent and 69% of patients had persistent HRF in derivation and validation sets, respectively. In validation, both LASSO (area under the receiver operating characteristic curve, 0.68; 95% CI, 0.64-0.73) and LASSO + IL-6 (0.71; 95% CI, 0.66-0.76) models had better discrimination than Pa o2 /F io2 (0.64; 95% CI, 0.59-0.69). Both models underestimated risk in lower risk deciles, but exhibited better calibration at relevant risk thresholds. Evaluating practical utility, both LASSO and LASSO + IL-6 models exhibited greater net benefit in decision curve analysis, and greater sample size savings in enrichment analysis, compared with Pa o2 /F io2 . The added utility of LASSO + IL-6 model over LASSO was modest.

CONCLUSIONS

Parsimonious, interpretable models that predict persistent HRF may improve enrichment of trials testing HRF-targeted therapies and warrant future validation.

Prognostic factors associated with risk of stroke following blunt cerebrovascular injury: A systematic review and meta-analysis

BACKGROUND & OBJECTIVES

Blunt cerebrovascular injury (BCVI) includes carotid and/or vertebral artery injury following trauma, and conveys an increased stroke risk. We conducted a systematic review and meta-analysis to provide a comprehensive summary of prognostic factors associated with risk of stroke following BCVI.

METHODS

We searched the EMBASE and MEDLINE databases from January 1946 to June 2023. We identified studies reporting associations between patient or injury factors and risk of stroke following BCVI. We performed meta-analyses of odds ratios (ORs) using the random effects method and assessed individual study risk of bias using the QUIPS tool. We separately pooled adjusted and unadjusted analyses, highlighting the estimate with the higher certainty.

RESULTS

We included 26 cohort studies, involving 20,458 patients with blunt trauma. The overall incidence of stroke following BCVI was 7.7 %. Studies were predominantly retrospective cohorts from North America and included both carotid and vertebral artery injuries. Diagnosis of BCVI was most commonly confirmed with CT angiography. We demonstrated with moderate to high certainty that factors associated with increased risk of stroke included carotid artery injury (as compared to vertebral artery injury, unadjusted odds ratio [uOR] 1.94, 95 % CI 1.62 to 2.32), Grade III Injury (as compared to grade I or II) (uOR 2.45, 95 % CI 1.88 to 3.20), Grade IV injury (uOR 3.09, 95 % CI 2.20 to 4.35), polyarterial injury (uOR 3.11 (95 % CI 2.05 to 4.72), occurrence of hypotension at the time of hospital admission (adjusted odds ratio [aOR] 1.32, 95 % CI 0.87 to 2.03) and higher total body injury severity (aOR 5.91, 95 % CI 1.90 to 18.39).

CONCLUSION

Local anatomical injury pattern, overall burden of injury and flow dynamics contribute to BCVI-related stroke risk. These findings provide the foundational evidence base for risk stratification to support clinical decision making and further research.

Do Patients With Low-Risk Pulmonary Arterial Hypertension Really Benefit From Upfront Combination Therapy?: Insight From the AMBITION Trial

BACKGROUND

Based on results of the Ambrisentan and Tadalafil in Patients with Pulmonary Arterial Hypertension (AMBITION) trial, upfront combination therapy is recommended for treatment-naive patients with low-risk pulmonary arterial hypertension (PAH). However, conflicting data exist whether adopting this treatment strategy in this risk group is beneficial or well tolerated.

RESEARCH QUESTION

Do patients with low-risk PAH really benefit from upfront combination therapy?

STUDY DESIGN AND METHODS

Using the data from the original AMBITION trial, patients with PAH were classified as low, intermediate, or high risk using the Registry to Evaluate Early and Long-term PAH Disease Management 2.0 (REVEAL 2.0) score and the Pulmonary Hypertension Outcomes and Risk Assessment (PHORA) tool. The primary end point was time to clinical worsening (including death, hospitalization for PAH worsening, and disease progression) censored at 1- and 3-year post-enrollment. Side effects that led to withdrawal of treatment were also considered.

RESULTS

Patients with low-risk PAH categorized by REVEAL 2.0 and PHORA did not see a statistically significant benefit of upfront combination therapy vs monotherapy for time to clinical worsening at 1 and 3 years' post-enrollment using Cox proportional analysis (3-year hazard ratio of 0.40 [95% CI, 0.15-1.06; P = .07] and 0.55 [95% CI, 0.26-1.18; P = .12] for REVEAL 2.0 and PHORA, respectively) or considering time to clinical worsening or side effects (3-year hazard ratio of 0.75 [95% CI, 0.39-1.47; P = .4] and 0.87 [95% CI, 0.49-1.54; P = .63] for REVEAL 2.0 and PHORA). Patients with low-risk PAH on upfront combination therapy experienced a higher but not significant incidence of side effects using REVEAL 2.0 and PHORA. In contrast, patients at intermediate or high risk saw a statistically significant benefit of upfront combination therapy considering each of the end points regardless of side effects.

INTERPRETATION

This analysis suggests that perhaps some patients with low-risk PAH should be further stratified using other modalities prior to committing to upfront combination therapy, especially when the occurrence of side effects is considered. Further prospective data are needed to validate this hypothesis prior to changes in current guideline directed therapy are contemplated.

An explainable machine learning-based phenomapping strategy for adaptive predictive enrichment in randomized clinical trials

Randomized clinical trials (RCT) represent the cornerstone of evidence-based medicine but are resource-intensive. We propose and evaluate a machine learning (ML) strategy of adaptive predictive enrichment through computational trial phenomaps to optimize RCT enrollment. In simulated group sequential analyses of two large cardiovascular outcomes RCTs of (1) a therapeutic drug (pioglitazone versus placebo; Insulin Resistance Intervention after Stroke (IRIS) trial), and (2) a disease management strategy (intensive versus standard systolic blood pressure reduction in the Systolic Blood Pressure Intervention Trial (SPRINT)), we constructed dynamic phenotypic representations to infer response profiles during interim analyses and examined their association with study outcomes. Across three interim timepoints, our strategy learned dynamic phenotypic signatures predictive of individualized cardiovascular benefit. By conditioning a prospective candidate's probability of enrollment on their predicted benefit, we estimate that our approach would have enabled a reduction in the final trial size across ten simulations (IRIS: -14.8% ± 3.1%, pone-sample t-test = 0.001; SPRINT: -17.6% ± 3.6%, pone-sample t-test < 0.001), while preserving the original average treatment effect (IRIS: hazard ratio of 0.73 ± 0.01 for pioglitazone vs placebo, vs 0.76 in the original trial; SPRINT: hazard ratio of 0.72 ± 0.01 for intensive vs standard systolic blood pressure, vs 0.75 in the original trial; all simulations with Cox regression-derived p value of  < 0.01 for the effect of the intervention on the respective primary outcome). This adaptive framework has the potential to maximize RCT enrollment efficiency.

An explainable machine learning-based phenomapping strategy for adaptive predictive enrichment in randomized controlled trials

Randomized controlled trials (RCT) represent the cornerstone of evidence-based medicine but are resource-intensive. We propose and evaluate a machine learning (ML) strategy of adaptive predictive enrichment through computational trial phenomaps to optimize RCT enrollment. In simulated group sequential analyses of two large cardiovascular outcomes RCTs of (1) a therapeutic drug (pioglitazone versus placebo; Insulin Resistance Intervention after Stroke (IRIS) trial), and (2) a disease management strategy (intensive versus standard systolic blood pressure reduction in the Systolic Blood Pressure Intervention Trial (SPRINT)), we constructed dynamic phenotypic representations to infer response profiles during interim analyses and examined their association with study outcomes. Across three interim timepoints, our strategy learned dynamic phenotypic signatures predictive of individualized cardiovascular benefit. By conditioning a prospective candidate's probability of enrollment on their predicted benefit, we estimate that our approach would have enabled a reduction in the final trial size across ten simulations (IRIS: -14.8% ± 3.1%, pone-sample t-test=0.001; SPRINT: -17.6% ± 3.6%, pone-sample t-test<0.001), while preserving the original average treatment effect (IRIS: hazard ratio of 0.73 ± 0.01 for pioglitazone vs placebo, vs 0.76 in the original trial; SPRINT: hazard ratio of 0.72 ± 0.01 for intensive vs standard systolic blood pressure, vs 0.75 in the original trial; all with pone-sample t-test<0.01). This adaptive framework has the potential to maximize RCT enrollment efficiency.

Real-world evidence to advance knowledge in pulmonary hypertension: Status, challenges, and opportunities. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative's Real-world Evidence Working Group

This manuscript on real-world evidence (RWE) in pulmonary hypertension (PH) incorporates the broad experience of members of the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative Real-World Evidence Working Group. We aim to strengthen the research community's understanding of RWE in PH to facilitate clinical research advances and ultimately improve patient care. Herein, we review real-world data (RWD) sources, discuss challenges and opportunities when using RWD sources to study PH populations, and identify resources needed to support the generation of meaningful RWE for the global PH community.

Treatment of pulmonary arterial hypertension: recent progress and a look to the future

Pulmonary arterial hypertension (PAH) is a severe but treatable form of pre-capillary pulmonary hypertension caused by pulmonary vascular remodelling. As a result of basic science discoveries, randomised controlled trials, studies of real-world data, and the development of clinical practice guidelines, considerable progress has been made in the treatment options and outcomes for patients with PAH, underscoring the importance of seamless translation of information from bench to bedside and, ultimately, to patients. However, PAH still carries a high mortality rate, which emphasises the urgent need for transformative innovations in the field. In this Series paper, written by a group of clinicians, researchers, and a patient with PAH, we review therapeutic approaches and treatment options for PAH. We summarise current knowledge of the cellular and molecular mechanisms of PAH, with an emphasis on emerging treatable pathways and optimisation of current management strategies. In considering future directions for the field, our ambition is to identify therapies with the potential to stall or reverse pulmonary vascular remodelling. We highlight novel therapeutic approaches, the important role of patients as partners in research, and innovative approaches to PAH clinical trials.

Heterogeneity of treatment effects by risk in pulmonary arterial hypertension

BACKGROUND

It is currently unknown if disease severity modifies response to therapy in pulmonary arterial hypertension (PAH). We aimed to explore if disease severity, as defined by established risk-prediction algorithms, modified response to therapy in randomised clinical trials in PAH.

METHODS

We performed a meta-analysis using individual participant data from 18 randomised clinical trials of therapy for PAH submitted to the United States Food and Drug Administration to determine if predicted risk of 1-year mortality at randomisation modified the treatment effect on three outcomes: change in 6-min walk distance (6MWD), clinical worsening at 12 weeks and time to clinical worsening.

RESULTS

Of 6561 patients with a baseline US Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL 2.0) score, we found that individuals with higher baseline risk had higher probabilities of clinical worsening but no difference in change in 6MWD. We detected a significant interaction of REVEAL 2.0 risk and treatment assignment on change in 6MWD. For every 3-point increase in REVEAL 2.0 score, there was a 12.49 m (95% CI 5.86-19.12 m; p=0.001) greater treatment effect in change in 6MWD. We did not detect a significant risk by treatment interaction on clinical worsening with most of the risk-prediction algorithms.

CONCLUSIONS

We found that predicted risk of 1-year mortality in PAH modified treatment effect as measured by 6MWD, but not clinical worsening. Our findings highlight the importance of identifying sources of treatment heterogeneity by predicted risk to tailor studies to patients most likely to have the greatest treatment response.

Evolution and optimization of clinical trial endpoints and design in pulmonary arterial hypertension

Selection of endpoints for clinical trials in pulmonary arterial hypertension (PAH) is challenging because of the small numbers of patients and the changing expectations of patients, clinicians, and regulators in this evolving therapy area. The most commonly used primary endpoint in PAH trials has been 6-min walk distance (6MWD), leading to the approval of several targeted therapies. However, single surrogate endpoints such as 6MWD or hemodynamic parameters may not correlate with clinical outcomes. Composite endpoints of clinical worsening have been developed to reflect patients' overall condition more accurately, although there is no standard definition of worsening. Recently there has been a shift to composite endpoints assessing clinical improvement, and risk scores developed from registry data are increasingly being used. Biomarkers are another area of interest, although brain natriuretic peptide and its N-terminal prohormone are the only markers used for risk assessment or as endpoints in PAH. A range of other genetic, metabolic, and immunologic markers is currently under investigation, along with conventional and novel imaging modalities. Patient-reported outcomes are an increasingly important part of evaluating new therapies, and several PAH-specific tools are now available. In the future, alternative statistical techniques and trial designs, such as patient enrichment strategies, will play a role in evaluating PAH-targeted therapies. In addition, modern sequencing techniques, imaging analyses, and high-dimensional statistical modeling/machine learning may reveal novel markers that can play a role in the diagnosis and monitoring of PAH.

The sine transform is the sine qua non of the pulmonary and systemic pressure relationship

Assessment of therapeutic interventions in patients with pulmonary arterial hypertension (PAH) suffers from several commonly encountered limitations: (1) patient studies are often too small and short-term to provide definitive conclusions, (2) there is a lack of a universal set of metrics to adequately assess therapy and (3) while clinical treatments focus on management of symptoms, there remain many cases of early loss of life in a seemingly arbitrary distribution. Here we provide a unified approach to assess right and left pressure relationships in PAH and pulmonary hypertension (PH) patients by developing linear models informed by the observation of Suga and Sugawa that pressure generation in the ventricle (right or left) approximately follows a single lobe of a sinusoid. We sought to identify a set of cardiovascular variables that either linearly or via a sine transformation related to systolic pulmonary arterial pressure (PAPs) and systemic systolic blood pressure (SBP). Importantly, both right and left cardiovascular variables are included in each linear model. Using non-invasively obtained cardiovascular magnetic resonance (CMR) image metrics the approach was successfully applied to model PAPs in PAH patients with an r2 of 0.89 (p < 0.05) and SBP with an r2 of 0.74 (p < 0.05). Further, the approach clarified the relationships that exist between PAPs and SBP separately for PAH and PH patients, and these relationships were used to distinguish PAH vs. PH patients with good accuracy (68%, p < 0.05). An important feature of the linear models is that they demonstrate that right and left ventricular conditions interact to generate PAPs and SBP in PAH patients, even in the absence of left-sided disease. The models predicted a theoretical right ventricular pulsatile reserve that in PAH patients was shown to be predictive of the 6 min walk distance (r2 = 0.45, p < 0.05). The linear models indicate a physically plausible mode of interaction between right and left ventricles and provides a means of assessing right and left cardiac status as they relate to PAPs and SBP. The linear models have potential to allow assessment of the detailed physiologic effects of therapy in PAH and PH patients and may thus permit cross-over of knowledge between PH and PAH clinical trials.

The evolving landscape of pulmonary arterial hypertension clinical trials

Although it is a rare disease, the number of available therapeutic options for treating pulmonary arterial hypertension has increased since the late 1990s, with multiple drugs developed that are shown to be effective in phase 3 randomised controlled trials. Despite considerable advancements in pulmonary arterial hypertension treatment, prognosis remains poor. Existing therapies target pulmonary endothelial dysfunction with vasodilation and anti-proliferative effects. Novel therapies that target proliferative vascular remodelling and affect important outcomes are urgently needed. There is need for additional innovations in clinical trial design so that all emerging candidate therapies can be rigorously studied. Pulmonary arterial hypertension trial design has shifted from short-term submaximal exercise capacity as a primary endpoint, to larger clinical event-driven trial outcomes. Event-driven pulmonary arterial hypertension trials could face feasibility and efficiency issues in the future because increasing sample sizes and longer follow-up durations are needed, which would be problematic in such a rare disease. Enrichment strategies, innovative and alternative trial designs, and novel trial endpoints are potential solutions that could improve the efficiency of future pulmonary arterial hypertension trials while maintaining robustness and clinically meaningful evidence.

Improving Clinical Trial Efficiency Using a Machine Learning Based Risk Score to Enrich Study Populations

AIMS

Prognostic enrichment strategies can make trials more efficient, although potentially at the cost of diminishing external validity. Whether using a risk score to identify a population at increased mortality risk could improve trial efficiency is uncertain. We aimed to assess whether Machine learning Assessment of RisK and EaRly mortality in Heart Failure (MARKER-HF), a previously validated risk score, could improve clinical trial efficiency.

METHODS AND RESULTS

Mortality rates and association of MARKER-HF with all-cause death by one year was evaluated in four community-based heart failure (HF) and five HF clinical trial cohorts. Sample size required to assess effects of an investigational therapy on mortality was calculated assuming varying underlying MARKER-HF risk and proposed treatment effect profiles. Patients from community-based HF cohorts (n=11,297) had higher observed mortality and MARKER-HF scores than did clinical trial patients (n=13,165) with HF with either reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). MARKER-HF score was strongly associated with risk of one-year mortality both in the community (HR 1.48 [95% CI: 1.44-1.52]) and clinical trial cohorts with HFrEF (HR 1.41 [95% CI: 1.30-1.54]), and HFpEF (HR 1.74 [95% CI: 1.53-1.98]), per 0.1 increase in MARKER-HF. Using MARKER-HF to identify patients for a hypothetical clinical trial assessing mortality reduction with an intervention, enabled a reduction in sample size required to show benefit.

CONCLUSION

Using a reliable predictor of mortality such as MARKER-HF to enrich clinical trial populations provides a potential strategy to improve efficiency by requiring a smaller sample size to demonstrate a clinical benefit.

Prognostic factors associated with development of infected necrosis in patients with acute necrotizing or severe pancreatitis-A systematic review and meta-analysis

PURPOSE

Acute pancreatitis is a potentially life-threatening condition with a wide spectrum of clinical presentation and illness severity. An infection of pancreatic necrosis (IPN) results in a more than twofold increase in mortality risk as compared with patients with sterile necrosis. We sought to identify prognostic factors for the development of IPN among adult patients with severe or necrotizing pancreatitis.

METHODS

We conducted this prognostic review in accordance with systematic review methodology guidelines. We searched six databases from inception through March 21, 2021. We included English language studies describing prognostic factors associated with the development of IPN. We pooled unadjusted odds ratio (uOR) and adjusted odds ratios (aOR) for prognostic factors using a random-effects model. We assessed risk of bias using the Quality in Prognosis Studies tool and certainty of evidence using the GRADE approach.

RESULTS

We included 31 observational studies involving 5,210 patients. Factors with moderate or higher certainty of association with increased IPN risk include older age (uOR, 2.19; 95% confidence interval [CI], 1.39-3.45, moderate certainty), gallstone etiology (aOR, 2.35; 95% CI, 1.36-4.04, high certainty), greater than 50% necrosis of the pancreas (aOR, 3.61; 95% CI, 2.15-6.04, high certainty), delayed enteral nutrition (aOR, 2.09; 95% CI, 1.26-3.47, moderate certainty), multiple or persistent organ failure (aOR, 11.71; 95% CI, 4.97-27.56, high certainty), and invasive mechanical ventilation (uOR, 12.24; 95% CI, 2.28-65.67, high certainty).

CONCLUSION

This meta-analysis confirms the association between several clinical early prognostic factors and the risk of IPN development among patients with severe or necrotizing pancreatitis. These findings provide the foundation for the development of an IPN risk stratification tool to guide more targeted clinical trials for prevention or early intervention strategies.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, Level IV.

[Risk Stratification in Patients with Pulmonary Arterial Hypertension under Treatment - Results of Four German Centers]

Risk stratification plays an essential role in the management of patients with pulmonary arterial hypertension (PAH). According to the current European guidelines the expected 1-year risk of mortality for PAH patients can be categorized as low, intermediate, or high, based on clinical, non-invasive and hemodynamic data.Data from 131 patients with incident PAH (age 64 ± 14) and frequent comorbidities (in 66.4 %) treated between 2016 and 2018 at 4 German PH centers were analyzed. At baseline, most patients were classified as intermediate risk (76 %), 13.8 % as high risk and only 9.9 % as low risk.During follow-up while on treatment after 12 ± 3 months (range 9-16 months) 64.9 % were still classified as intermediate risk (76 %), 14.4 % as high risk and 20.7 % as low risk.Survival at 12 and 24 months was 96 % and 82 % in the intermediate risk group, while only 89 % and 51 % of the high risk patients were alive at these time points. In contrast, all patients in the low risk category were alive at 24 months.Despite the availability of various treatment options for patients with PAH even in specialized centers only a minority of patients can be stabilized in the low risk group associated with a good outcome.

Strategies for optimizing intravenous prostacyclin-analog therapy in patients with pulmonary arterial hypertension

INTRODUCTION

Intravenous prostacyclin-analogs (PCA, e.g. epoprostenol, treprostinil, iloprost) have become an essential part in the therapy of patients with pulmonary hypertension (PH), mainly pulmonary arterial hypertension (PAH). They show considerable differences in pharmacology. A combination therapy including intravenous drugs is regarded as the 'gold standard' in most of PAH patients.

AREAS COVERED

This review discusses and summarizes the studies and concepts on which this therapy is based. To date, intravenous prostacyclin-analogs are mainly administered when standard therapy fails to improve patients to low-risk status. However, preliminary data from uncontrolled studies suggest that an 'upfront triple' therapy including intravenous or subcutaneous prostacyclin-analogs could be preferable in selected patients.

EXPERT OPINION

Various IV PCA have been evaluated in the treatment of patients with PAH. Today, combination therapy is the 'gold standard' for the majority of patients. Intravenous PCA is recommended from functional class III onwards. Timing of its initiation is still a point of discussion. An escalation of therapy to IV or SC PCA is always necessary if a low-risk status cannot be achieved with other targeted therapies. Preliminary data suggest that selected patients could benefit from an 'upfront triple' therapy. Controlled studies on which such recommendation could be based are lacking.

What's new in pulmonary hypertension clinical research: lessons from the best abstracts at the 2020 American Thoracic Society International Conference

In this conference paper, we review the 2020 American Thoracic Society International Conference session titled, "What's New in Pulmonary Hypertension Clinical Research: Lessons from the Best Abstracts". This virtual mini-symposium took place on 21 October 2020, in lieu of the annual in-person ATS International Conference which was cancelled due to the COVID-19 pandemic. Seven clinical research abstracts were selected for presentation in the session, which encompassed five major themes: (1) standardizing diagnosis and management of pulmonary hypertension, (2) improving risk assessment in pulmonary arterial hypertension, (3) evaluating biomarkers of disease activity, (4) understanding metabolic dysregulation across the spectrum of pulmonary hypertension, and (5) advancing knowledge in chronic thromboembolic pulmonary hypertension. Focusing on these five thematic contexts, we review the current state of knowledge, summarize presented research abstracts, appraise their significance and limitations, and then discuss relevant future directions in pulmonary hypertension clinical research.

Novel composite clinical endpoints and risk scores used in clinical trials in pulmonary arterial hypertension

This manuscript on endpoints incorporates the broad experience of members of Pulmonary Vascular Research Institute’s Innovative Drug Development Initiative as an open debate platform for academia, the pharmaceutical industry and regulatory experts surrounding the future design of clinical trials in pulmonary hypertension. It reviews our current understanding of endpoints used in phase 2 and 3 trials for pulmonary hypertension and discusses in detail the value of newer approaches. These include the roles of composite endpoints and how these can be developed and validated. The newer concept of risk analysis is also discussed, including how such risk scores might be utilised as endpoints in clinical trials.