Evaluating the balance of benefits and harms in chronic pain clinical trials: prioritizing individual participants over individual outcomes

BACKGROUND

Randomized clinical trials (RCTs) generally assess efficacy and safety separately, with the conclusion of whether a treatment is beneficial based solely on the efficacy endpoint. However, assessing and combining efficacy and safety domains, using a single composite outcome measure, can provide a more comprehensive assessment of the overall effect of a treatment. Furthermore, composite outcomes can incorporate information regarding the relationship between the individual outcomes. In fact, such outcomes have been suggested in the clinical trials literature for at least 15 years.

OBJECTIVES

To (1) identify whether recent primary publications of chronic pain RCTs from major pain journals included a composite outcome measure of benefits and harms and (2) discuss the potential benefits of such outcomes in various stages of treatment development, including as outcome measures in RCTs, and to support decisions of Data and Safety Monitoring Boards and ordering of treatments in the context of treatment guidelines.

EVIDENCE REVIEW

RCTs published in 6 major pain journals published between 2016 and 2021 that investigated interventions for chronic pain were reviewed.

FINDINGS

Of 73 RCTs identified, only 2 included a composite outcome measure of benefits and harms. Both of these articles compared 2 active treatments.

CONCLUSIONS

Composite outcomes of benefits and harms are underutilized in chronic pain RCTs. The advantages and challenges of using such outcomes are discussed.

Exploration of a Potential DOOR Endpoint for Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia Using Six Registrational Trials for Antibacterial Drugs

BACKGROUND

Desirability of outcome ranking (DOOR) is an innovative approach to clinical trial design and analysis that uses an ordinal ranking system to incorporate the overall risks and benefits of a therapeutic intervention into a single measurement. Here, we derived and evaluated a disease-specific DOOR endpoint for registrational trials for hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP).

METHODS

Through comprehensive examination of data from nearly 4,000 participants enrolled in six registrational trials for HABP/VABP submitted to the FDA between 2005-2022, we derived and applied a HABP/VABP specific endpoint. We estimated the probability that a participant assigned to the study treatment arm would have a more favorable overall DOOR or component outcome than a participant assigned to comparator.

RESULTS

DOOR distributions between treatment arms were similar in all trials. DOOR probability estimates ranged from 48.3% to 52.9% and were not statistically different. There were no significant differences between treatment arms in the component analyses. Though infectious complications and serious adverse events occurred more frequently in ventilated participants compared to non-ventilated participants, the types of events were similar.

CONCLUSIONS

Through a data-driven approach, we constructed and applied a potential DOOR endpoint for HABP/VABP trials. The inclusion of syndrome-specific events may help to better delineate and evaluate participant experiences and outcomes in future HABP/VABP trials and could help inform data collection and trial design.

Desirability of outcome ranking for obstetrical trials: illustration and application to the ARRIVE trial

BACKGROUND

In randomized trials, 1 primary outcome is typically chosen to evaluate the consequences of an intervention, whereas other important outcomes are relegated to secondary outcomes. This issue is amplified for many obstetrical trials in which an intervention may have consequences for both the pregnant person and the child. In contrast, desirability of outcome ranking, a paradigm shift for the design and analysis of clinical trials based on patient-centric evaluation, allows multiple outcomes-including from >1 individual-to be considered concurrently.

OBJECTIVE

This study aimed to describe desirability of outcome ranking methodology tailored to obstetrical trials and to apply the methodology to maternal-perinatal paired (dyadic) outcomes in which both individuals may be affected by an intervention but may experience discordant outcomes (eg, an obstetrical intervention may improve perinatal but worsen maternal outcomes).

STUDY DESIGN

This secondary analysis applies the desirability of outcome ranking methodology to data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network ARRIVE trial. The original analysis found no substantial difference in the primary (perinatal composite) outcome, but a decreased risk of the secondary outcome of cesarean delivery with elective induction at 39 weeks. In the present desirability-of-outcome-ranking analysis, dyadic outcomes ranging from spontaneous vaginal delivery without severe neonatal complication (most desirable) to cesarean delivery with perinatal death (least desirable) were classified into 8 categories ranked by overall desirability by experienced investigators. Distributions of the desirability of outcome ranking were compared by estimating the probability of having a more desirable dyadic outcome with elective induction at 39 weeks of gestation than with expectant management. To account for various perspectives on these outcomes, a complementary analysis, called the partial credit strategy, was used to grade outcomes on a 100-point scale and estimate the difference in overall treatment scores between groups using a t test.

RESULTS

All 6096 participants from the trial were included. The probability of a better dyadic outcome for a randomly selected patient who was randomized to elective induction was 53% (95% confidence interval, 51-54), implying that elective induction led to a better overall outcome for the dyad when taking multiple outcomes into account concurrently. Furthermore, the desirability-of-outcome-ranking probability of averting cesarean delivery with elective induction was 52% (95% confidence interval, 51-53), which was not at the expense of an operative vaginal delivery or a poorer outcome for the perinate (ie, survival with a severe neonatal complication or perinatal death). Randomization to elective induction was also advantageous in most of the partial credit score scenarios.

CONCLUSION

Desirability-of-outcome-ranking methodology is a useful tool for obstetrical trials because it provides a concurrent view of the effect of an intervention on multiple dyadic outcomes, potentially allowing for better translation of data for decision-making and person-centered care.

Clinical Outcomes and Bacterial Characteristics of Carbapenem-resistant Acinetobacter baumannii Among Patients From Different Global Regions

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii (CRAb) is 1 of the most problematic antimicrobial-resistant bacteria. We sought to elucidate the international epidemiology and clinical impact of CRAb.

METHODS

In a prospective observational cohort study, 842 hospitalized patients with a clinical CRAb culture were enrolled at 46 hospitals in five global regions between 2017 and 2019. The primary outcome was all-cause mortality at 30 days from the index culture. The strains underwent whole-genome analysis.

RESULTS

Of 842 cases, 536 (64%) represented infection. By 30 days, 128 (24%) of the infected patients died, ranging from 1 (6%) of 18 in Australia-Singapore to 54 (25%) of 216 in the United States and 24 (49%) of 49 in South-Central America, whereas 42 (14%) of non-infected patients died. Bacteremia was associated with a higher risk of death compared with other types of infection (40 [42%] of 96 vs 88 [20%] of 440). In a multivariable logistic regression analysis, bloodstream infection and higher age-adjusted Charlson comorbidity index were independently associated with 30-day mortality. Clonal group 2 (CG2) strains predominated except in South-Central America, ranging from 216 (59%) of 369 in the United States to 282 (97%) of 291 in China. Acquired carbapenemase genes were carried by 769 (91%) of the 842 isolates. CG2 strains were significantly associated with higher levels of meropenem resistance, yet non-CG2 cases were over-represented among the deaths compared with CG2 cases.

CONCLUSIONS

CRAb infection types and clinical outcomes differed significantly across regions. Although CG2 strains remained predominant, non-CG2 strains were associated with higher mortality. Clinical Trials Registration. NCT03646227.

Moving Beyond Mortality: Development and Application of a Desirability of Outcome Ranking (DOOR) Endpoint for Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia

BACKGROUND

Hospital-acquired and ventilator-associated bacterial pneumonia (HABP/VABP) are frequently caused by multidrug-resistant organisms. Patient-centered endpoints in clinical trials are needed to develop new antibiotics for HABP/VABP. Desirability of outcome ranking (DOOR) is a paradigm for the design, analysis, and interpretation of clinical trials based on a patient-centered, benefit-risk evaluation.

METHODS

A multidisciplinary committee created an infectious diseases DOOR endpoint customized for HABP/VABP, incorporating infectious complications, serious adverse events, and mortality. We applied this to 2 previously completed, large randomized controlled trials for HABP/VABP. ZEPHyR compared vancomycin to linezolid and VITAL compared linezolid to tedizolid. For each trial, we evaluated the DOOR distribution and probability, including DOOR component and partial credit analyses. We also applied DOOR in subgroup analyses.

RESULTS

In both trials, the HABP/VABP DOOR demonstrated similar overall clinical outcomes between treatment groups. In ZEPHyR, the probability that a participant treated with linezolid would have a more desirable outcome than a participant treated with vancomycin was 50.2% (95% confidence interval [CI], 45.1%--55.3%). In VITAL, the probability that a participant treated with tedizolid would have a more desirable outcome than a participant treated with linezolid was 48.7% (95% CI, 44.8%-52.6%). The DOOR component analysis revealed that participants treated with tedizolid had a less desirable outcome than those treated with linezolid when considering clinical response alone. However, participants with decreased renal function had improved overall outcomes with tedizolid.

CONCLUSIONS

The HABP/VABP DOOR provided more granular information about clinical outcomes than is typically presented in clinical trials. HABP/VABP trials would benefit from prospectively using DOOR.

Application of desirability of outcome ranking to the milking in non-vigorous infants trial

OBJECTIVES

Neonatal trials have traditionally used binary composite short-term (such as death or bronchopulmonary dysplasia) or longer-term (such as death or severe neurodevelopmental impairment) outcomes. We applied the Desirability Of Outcome Ranking (DOOR) method to rank the overall patient outcome by best (no morbidities) to worst (death).

STUDY DESIGN

Using a completed large multicenter trial (Milking In Non-Vigorous Infants [MINVI]) of umbilical cord milking (UCM) vs. early cord clamping (ECC), we applied the DOOR methodology to neonatal outcomes. Six outcomes were chosen and ranked: no interventions or NICU admission (most desirable); received initial cardiorespiratory support at birth; neonatal intensive care unit (NICU) admission for predefined criteria; mild hypoxic-ischemic encephalopathy (HIE); moderate to severe HIE; and death (least desirable).

RESULTS

1524 non-vigorous newborns born between 35 and 42 weeks' gestation had data for analysis. The DOOR distribution was different between the UCM and ECC arms, with a significantly greater probability (55.8 % [95 % CI 53.1-58.5 %; p < 0.0001]) of a randomly selected neonate having a more desirable outcome if they were in the UCM arm. DOOR probabilities of averting individual adverse outcomes such as NICU admission for predefined criteria (52.8 %; 95%CI 50.5-55.1 %) and cardiorespiratory support (54.0 %; 95%CI 51.6-56.4 %) were significantly higher among those in the UCM group.

CONCLUSION

DOOR provides an overall assessment of the benefits and harms with greater insight than typical binary composite measures to clinicians and parents when evaluating an intervention. Future neonatal trials should consider the a priori use of the DOOR methodology to evaluate trial outcomes.

Interlaboratory comparison of Pseudomonas aeruginosa phage susceptibility testing

Standardized approaches to phage susceptibility testing (PST) are essential to inform selection of phages for study in patients with bacterial infections. There is no reference standard for assessing bacterial susceptibility to phage. We compared agreement between PST performed at three centers: two centers using a liquid assay standardized between the sites with the third, a plaque assay. Four Pseudomonas aeruginosa phages: PaWRA01ø11 (EPa11), PaWRA01ø39 (EPa39), PaWRA02ø83 (EPa83), PaWRA02ø87 (EPa87), and a cocktail of all four phages were tested against 145 P. aeruginosa isolates. Comparisons were made within measurements at the two sites performing the liquid assay and between these two sites. Agreement was assessed based on coverage probability (CP8), total deviation index, concordance correlation coefficient (CCC), measurement accuracy, and precision. For the liquid assay, there was satisfactory agreement among triplicate measurements made on different days at site 1, and high agreement based on accuracy and precision between duplicate measurements made on the same run at site 2. There was fair accuracy between measurements of the two sites performing the liquid assay, with CCCs below 0.6 for all phages tested. When compared to the plaque assay (performed once at site 3), there was less agreement between results of the liquid and plaque assays than between the two sites performing the liquid assay. Similar findings to the larger group were noted in the subset of 46 P. aeruginosa isolates from cystic fibrosis. Results of this study suggest that reproducibility of PST methods needs further development.

Desirability of Outcome Ranking for Status Epilepticus: A Benefit-Risk Approach to Design and Analyses of Clinical SE Trials

Most clinical trials of treatment efficacy evaluate benefits and harms separately. Investigators generally rate the primary outcome of a trial with a binary outcome measure and consider harms separately as adverse events. This approach fails to recognize finer gradations of patient response, correlations between benefits and harms, and the overall effects on individual patients. For example, in status epilepticus trials, efficacy is often defined as the absence of clinically apparent seizures with recovery of consciousness. Such an efficacy outcome fails to recognize that some causes of status epilepticus, such as subarachnoid hemorrhage or stroke, may not be accompanied by return of consciousness, and the need to intubate a patient may be classified as treatment failure even if status was successfully terminated. The Desirability of Outcome Ranking (DOOR) method uses a different approach. The DOOR method involves comparing the experiences of trial participants in different treatment arms by the desirability of the overall patient outcome. Using status epilepticus treatment as an example, a patient who experiences successful termination of status epilepticus but with major side effects would have a less desirable outcome than a patient with treatment success and minor side effects, who in turn would have a less desirable outcome than a patient with treatment success but no side effects. This is a patient-centered approach because it considers treatment efficacy in the context of the costs borne by the patient, for example, toxicity in achieving efficacy. Thus, DOOR considers both the benefits and harms to individual patients in assessing the outcome of a clinical trial. In this article, we present the rationale for the use of DOOR, the issues involved in the development of and statistical analyses of an ordinal outcome, and an example of the potential application of the DOOR method to a clinical trial of convulsive status epilepticus.

The Future Ain't What It Used to Be…Out With the Old…In With the Better: Antibacterial Resistance Leadership Group Innovations

Clinical research networks conduct important studies that would not otherwise be performed by other entities. In the case of the Antibacterial Resistance Leadership Group (ARLG), such studies include diagnostic studies using master protocols, controlled phage intervention trials, and studies that evaluate treatment strategies or dynamic interventions, such as sequences of empiric and definitive therapies. However, the value of a clinical research network lies not only in the results from these important studies but in the creation of new approaches derived from collaborative thinking, carefully examining and defining the most important research questions for clinical practice, recognizing and addressing common but suboptimal approaches, and anticipating that the standard approaches of today may be insufficient for tomorrow. This results in the development and implementation of new methodologies and tools for the design, conduct, analyses, and reporting of research studies. These new methodologies directly impact the studies conducted within the network and have a broad and long-lasting impact on the field, enhancing the scientific value and efficiency of generations of research studies. This article describes innovations from the ARLG in diagnostic studies, observational studies, and clinical trials evaluating interventions for the prevention and treatment of antibiotic-resistant bacterial infections.

Priorities and Progress in Diagnostic Research by the Antibacterial Resistance Leadership Group

The advancement of infectious disease diagnostics, along with studies devoted to infections caused by gram-negative and gram-positive bacteria, is a top scientific priority of the Antibacterial Resistance Leadership Group (ARLG). Diagnostic tests for infectious diseases are rapidly evolving and improving. However, the availability of rapid tests designed to determine antibacterial resistance or susceptibility directly in clinical specimens remains limited, especially for gram-negative organisms. Additionally, the clinical impact of many new tests, including an understanding of how best to use them to inform optimal antibiotic prescribing, remains to be defined. This review summarizes the recent work of the ARLG toward addressing these unmet needs in the diagnostics field and describes future directions for clinical research aimed at curbing the threat of antibiotic-resistant bacterial infections.

Priorities and Progress in Gram-negative Bacterial Infection Research by the Antibacterial Resistance Leadership Group

Addressing the treatment and prevention of antibacterial-resistant gram-negative bacterial infections is a priority area of the Antibacterial Resistance Leadership Group (ARLG). The ARLG has conducted a series of observational studies to define the clinical and molecular global epidemiology of carbapenem-resistant and ceftriaxone-resistant Enterobacterales, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii, with the goal of optimizing the design and execution of interventional studies. One ongoing ARLG study aims to better understand the impact of fluoroquinolone-resistant gram-negative gut bacteria in neutropenic patients, which threatens to undermine the effectiveness of fluoroquinolone prophylaxis in these vulnerable patients. The ARLG has conducted pharmacokinetic studies to inform the optimal dosing of antibiotics that are important in the treatment of drug-resistant gram-negative bacteria, including oral fosfomycin, intravenous minocycline, and a combination of intravenous ceftazidime-avibactam and aztreonam. In addition, randomized clinical trials have assessed the safety and efficacy of step-down oral fosfomycin for complicated urinary tract infections and single-dose intravenous phage therapy for adult patients with cystic fibrosis who are chronically colonized with P. aeruginosa in their respiratory tract. Thus, the focus of investigation in the ARLG has evolved from improving understanding of drug-resistant gram-negative bacterial infections to positively affecting clinical care for affected patients through a combination of interventional pharmacokinetic and clinical studies, a focus that will be maintained moving forward.

The Antibacterial Resistance Leadership Group: Scientific Advancements and Future Directions

In this overview, we describe important contributions from the Antibacterial Resistance Leadership Group (ARLG) to patient care, clinical trials design, and mentorship while outlining future priorities. The ARLG research agenda is focused on 3 key areas: gram-positive infections, gram-negative infections, and diagnostics. The ARLG has developed an innovative approach to clinical trials design, the desirability of outcome ranking (DOOR), which uses an ordinal measure of global outcome to assess both benefits and harms. DOOR was initially applied to observational studies to determine optimal dosing of vancomycin for methicillin-resistant Staphylcococcus aureus bacteremia and the efficacy of ceftazidime-avibactam versus colistin for the treatment of carbapenem-resistant Enterobacterales infection. DOOR is being successfully applied to the analysis of interventional trials and, in collaboration with the US Food and Drug Administration (FDA), for use in registrational trials. In the area of diagnostics, the ARLG developed Master Protocol for Evaluating Multiple Infection Diagnostics (MASTERMIND), an innovative design that allows simultaneous testing of multiple diagnostic platforms in a single study. This approach will be used to compare molecular assays for the identification of fluoroquinolone-resistant Neisseria gonorrhoeae (MASTER GC) and to compare rapid diagnostic tests for bloodstream infections. The ARLG has initiated a first-in-kind randomized, double-blind, placebo-controlled trial in participants with cystic fibrosis who are chronically colonized with Pseudomonas aeruginosa to assess the pharmacokinetics and antimicrobial activity of bacteriophage therapy. Finally, an engaged and highly trained workforce is critical for continued and future success against antimicrobial drug resistance. Thus, the ARLG has developed a robust mentoring program targeted to each stage of research training to attract and retain investigators in the field of antimicrobial resistance research.

Priorities and Progress in Gram-positive Bacterial Infection Research by the Antibacterial Resistance Leadership Group: A Narrative Review

The Antibacterial Resistance Leadership Group (ARLG) has prioritized infections caused by gram-positive bacteria as one of its core areas of emphasis. The ARLG Gram-positive Committee has focused on studies responding to 3 main identified research priorities: (1) investigation of strategies or therapies for infections predominantly caused by gram-positive bacteria, (2) evaluation of the efficacy of novel agents for infections caused by methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci, and (3) optimization of dosing and duration of antimicrobial agents for gram-positive infections. Herein, we summarize ARLG accomplishments in gram-positive bacterial infection research, including studies aiming to (1) inform optimal vancomycin dosing, (2) determine the role of dalbavancin in MRSA bloodstream infection, (3) characterize enterococcal bloodstream infections, (4) demonstrate the benefits of short-course therapy for pediatric community-acquired pneumonia, (5) develop quality of life measures for use in clinical trials, and (6) advance understanding of the microbiome. Future studies will incorporate innovative methodologies with a focus on interventional clinical trials that have the potential to change clinical practice for difficult-to-treat infections, such as MRSA bloodstream infections.

Under the Hood: The Scientific Leadership, Clinical Operations, Statistical and Data Management, and Laboratory Centers of the Antibacterial Resistance Leadership Group

Developing and implementing the scientific agenda of the Antibacterial Resistance Leadership Group (ARLG) by soliciting input and proposals, transforming concepts into clinical trials, conducting those trials, and translating trial data analyses into actionable information for infectious disease clinical practice is the collective role of the Scientific Leadership Center, Clinical Operations Center, Statistical and Data Management Center, and Laboratory Center of the ARLG. These activities include shepherding concept proposal applications through peer review; identifying, qualifying, training, and overseeing clinical trials sites; recommending, developing, performing, and evaluating laboratory assays in support of clinical trials; and designing and performing data collection and statistical analyses. This article describes key components involved in realizing the ARLG scientific agenda through the activities of the ARLG centers.

Cost-effectiveness of ticagrelor plus aspirin versus aspirin in acute ischaemic stroke or transient ischaemic attack: an economic evaluation of the THALES trial

Objective

THALES demonstrated that ticagrelor plus aspirin reduced the risk of stroke or death but increased bleeding versus aspirin during the 30 days following a mild-to-moderate acute non-cardioembolic ischaemic stroke (AIS) or high-risk transient ischaemic attack (TIA). There are no cost-effectiveness analyses supporting this combination in Europe. To address this, a cost-effectiveness analysis was performed.

Methods

Cost-effectiveness was evaluated using a decision tree and Markov model with a short-term and long-term (30-year) horizon. Stroke, mortality, bleeding and EuroQol-5 Dimension (EQ-5D) data from THALES were used to estimate short-term outcomes. Model transitions were based on stroke severity (disabling stroke was defined as modified Rankin Scale >2). Healthcare resource utilisation and EQ-5D data beyond 30 days were based on SOCRATES, another trial in AIS/TIA that compared ticagrelor with aspirin. Long-term costs, survival and disutilities were based on published literature. Unit costs were derived from national databases and discounted at 3% annually from a Swedish healthcare perspective.

Results

One-month treatment with ticagrelor plus aspirin resulted in 12 fewer strokes, 4 additional major bleeds and cost savings of €95 000 per 1000 patients versus aspirin from a Swedish healthcare perspective. This translated into increased quality-adjusted life-years (0.04) and reduced societal costs (-€1358) per patient over a lifetime horizon. Key drivers of cost-effectiveness were number of patients experiencing subsequent disabling stroke and degree of disability. Findings were robust over a range of input assumptions.

Conclusion

One month of treatment with ticagrelor plus aspirin is likely to improve outcomes and reduce costs versus aspirin in mild-to-moderate AIS or high-risk TIA.

Trial registration number

NCT03354429.

Efficacy and safety of azithromycin versus placebo to treat lower respiratory tract infections associated with low procalcitonin: a randomised, placebo-controlled, double-blind, non-inferiority trial

BACKGROUND

Lower respiratory tract infections are frequently treated with antibiotics, despite a viral cause in many cases. It remains unknown whether low procalcitonin concentrations can identify patients with lower respiratory tract infection who are unlikely to benefit from antibiotics. We aimed to compare the efficacy and safety of azithromycin versus placebo to treat lower respiratory tract infections in patients with low procalcitonin.

METHODS

We conducted a randomised, placebo-controlled, double-blind, non-inferiority trial at five health centres in the USA. Adults aged 18 years or older with clinically suspected non-pneumonia lower respiratory tract infection and symptom duration from 24 h to 28 days were eligible for enrolment. Participants with a procalcitonin concentration of 0·25 ng/mL or less were randomly assigned (1:1), in blocks of four with stratification by site, to receive over-encapsulated oral azithromycin 250 mg or matching placebo (two capsules on day 1 followed by one capsule daily for 4 days). Participants, non-study clinical providers, investigators, and study coordinators were masked to treatment allocation. The primary outcome was efficacy of azithromycin versus placebo in terms of clinical improvement at day 5 in the intention-to-treat population. The non-inferiority margin was -12·5%. Solicited adverse events (abdominal pain, vomiting, diarrhoea, allergic reaction, or yeast infections) were recorded as a secondary outcome. This trial is registered with ClinicalTrials.gov, NCT03341273.

FINDINGS

Between Dec 8, 2017, and March 9, 2020, 691 patients were assessed for eligibility and 499 were enrolled and randomly assigned to receive azithromycin (n=249) or placebo (n=250). Clinical improvement at day 5 was observed in 148 (63%, 95% CI 54 to 71) of 238 participants with full data in the placebo group and 155 (69%, 61 to 77) of 227 participants with full data in the azithromycin group in the intention-to-treat analysis (between-group difference -6%, 95% CI -15 to 2). The 95% CI for the difference did not meet the non-inferiority margin. Solicited adverse events and the severity of solicited adverse events were not significantly different between groups at day 5, except for increased abdominal pain associated with azithromycin (47 [23%, 95% CI 18 to 29] of 204 participants) compared with placebo (35 [16%, 12 to 21] of 221; between-group difference -7% [95% CI -15 to 0]; p=0·066).

INTERPRETATION

Placebo was not non-inferior to azithromycin in terms of clinical improvement at day 5 in adults with lower respiratory tract infection and a low procalcitonin concentration. After accounting for both the rates of clinical improvement and solicited adverse events at day 5, it is unclear whether antibiotics are indicated for patients with lower respiratory tract infection and a low procalcitonin concentration.

FUNDING

National Institute of Allergy and Infectious Diseases, bioMérieux.

Improving Traditional Registrational Trial End Points: Development and Application of a Desirability of Outcome Ranking End Point for Complicated Urinary Tract Infection Clinical Trials

BACKGROUND

Traditional end points used in registrational randomized, controlled trials (RCTs) often do not allow for complete interpretation of the full range of potential clinical outcomes. Desirability of outcome ranking (DOOR) is an approach to the design and analysis of clinical trials that incorporates benefits and risks of novel treatment strategies and provides a global assessment of patient experience.

METHODS

Through a multidisciplinary committee of experts in infectious diseases, clinical trial design, drug regulation, and patient experience, we developed a DOOR end point for infectious disease syndromes and demonstrated how this could be applied to 3 registrational drug trials (ZEUS, APEKS-cUTI, and DORI-05) for complicated urinary tract infections (cUTIs). ZEUS compared fosfomycin to piperacillin/tazobactam, APEKS-cUTI compared cefiderocol to imipenem, and DORI-05 compared doripenem to levofloxacin. Using DOOR, we estimated the probability of a more desirable outcome with each investigational antibacterial drug.

RESULTS

In each RCT, the DOOR distribution was similar and the probability that a patient in the investigational arm would have a more desirable outcome than a patient in the control arm had a 95% confidence interval containing 50%, indicating no significant difference between treatment arms. DOOR facilitated improved understanding of potential trade-offs between clinical efficacy and safety. Partial credit and subgroup analyses also highlight unique attributes of DOOR.

CONCLUSIONS

DOOR can effectively be used in registrational cUTI trials. The DOOR end point presented here can be adapted for other infectious disease syndromes and prospectively incorporated into future clinical trials.

The Data and Safety Monitoring Board: The Toughest Job in Clinical Trials

The DSMB: The Toughest Job in Clinical TrialsIn this review article, the authors discuss methods that DSMBs can use to compare the absolute and relative risks of benefits and adverse effects between trial interventions and illustrate how the DSMB can use this approach to evaluate the balance of these competing risks. Two approaches are discussed - the win ratio and the DOOR probability on one treatment relative to another.

Safety and microbiological activity of phage therapy in persons with cystic fibrosis colonized with Pseudomonas aeruginosa: study protocol for a phase 1b/2, multicenter, randomized, double-blind, placebo-controlled trial

BACKGROUND

Bacteriophages (phages) are a promising anti-infective option for human disease. Major gaps remain in understanding their potential utility.

METHODS

This is a randomized, placebo-controlled, double-blind study of a single dose of intravenous phage in approximately 72 clinically stable adult cystic fibrosis volunteers recruited from up to 20 US sites with Pseudomonas aeruginosa airway colonization. The single dose of phage consists of a mixture of four anti-pseudomonal phages. Six sentinel participants will be sequentially enrolled with dose escalation of the phage mixture by one log₁₀ beginning with 4 × 10⁷ plaque-forming units in an unblinded stage 1. If no serious adverse events related to the study product are identified, the trial will proceed to a double-blinded stage 2. In stage 2a, 32 participants will be randomly assigned to one of three phage dosages or placebo in a 1:1:1:1 allocation. An interim analysis will be performed to determine the phage dosage with the most favorable safety and microbiological activity profile to inform phage dosing in stage 2b. During stage 2b, up to 32 additional volunteers will be randomized 1:1 to the phage or placebo arm. Primary outcomes include (1) the number of grade 2 or higher treatment-emergent adverse events, (2) change in log₁₀ P. aeruginosa total colony counts in sputum, and (3) the probability of a randomly selected subject having a more favorable outcome ranking if assigned to receive phage therapy versus placebo. Exploratory outcomes include (1) sputum and serum phage pharmacokinetics, (2) the impact of phage on lung function, (3) the proportion of P. aeruginosa isolates susceptible to the phage mixture before and after study product administration, and (4) changes in quality of life.

DISCUSSION

This trial will investigate the activity of phages in reducing P. aeruginosa colony counts and provide insights into the safety profile of phage therapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05453578. Registered on 12 July 2022.

223. Development and Analysis of a Novel DOOR Endpoint for Complicated Intra-abdominal Infections (cIAI) Using 10 Registrational Trials for Antibacterial Drugs

Background

Desirability of outcome ranking (DOOR) uses an ordinal ranking system to evaluate global outcomes in clinical trial participants by incorporating safety and efficacy assessments into a single endpoint. In this study, we developed and applied a DOOR endpoint for cIAI clinical trials.

Methods

We reviewed 10 Phase 3 noninferiority trials for cIAI with electronic patient-level data (n=5473 participants) submitted to the FDA between 2005-2021. Extending previous work [CID. 2019:68(10):1691-8)], we developed an expanded cIAI-specific DOOR endpoint based on clinically meaningful events captured in trial datasets and those that were unique to patients with cIAI. Using this DOOR endpoint, we assigned each participant a DOOR rank, estimated the probability that a participant in the study treatment arm in each trial would have a more desirable DOOR rank than if assigned to the comparator arm, and analyzed individual components of clinical experience in each trial.

Results

Based on analysis of available data, we noted heterogeneity in definitions of “indeterminate” clinical outcomes, and significant diversity and increased incidence of infectious complications (ICs), serious adverse events (SAEs), and surgical/percutaneous procedures in participants without clinical cure. These informed the expansion of the DOOR endpoint for cIAI to include clinical efficacy outcomes, ICs, SAEs, and additional procedures (Table 1). The DOOR distributions between treatment and comparator arms in all 10 trials were similar. DOOR probability estimates for the 10 trials ranged from 44.5% to 50.3% but were not nominally statistically significant. Component analyses in two trials showed that the study treatment was nominally statistically inferior to the comparator with regard to SAEs and clinical failure, respectively (Fig. 1b, 1c). Table 1.

Clinical Impact of Ceftriaxone Resistance in Escherichia coli Bloodstream Infections: A Multicenter Prospective Cohort Study

Background

Ceftriaxone-resistant (CRO-R) Escherichia coli bloodstream infections (BSIs) are common.

Methods

This is a prospective cohort of patients with E coli BSI at 14 United States hospitals between November 2020 and April 2021. For each patient with a CRO-R E coli BSI enrolled, the next consecutive patient with a ceftriaxone-susceptible (CRO-S) E coli BSI was included. Primary outcome was desirability of outcome ranking (DOOR) at day 30, with 50% probability of worse outcomes in the CRO-R group as the null hypothesis. Inverse probability weighting (IPW) was used to reduce confounding.

Results

Notable differences between patients infected with CRO-R and CRO-S E coli BSI included the proportion with Pitt bacteremia score ≥4 (23% vs 15%, P = .079) and the median time to active antibiotic therapy (12 hours [interquartile range {IQR}, 1-35 hours] vs 1 hour [IQR, 0-6 hours]; P < .001). Unadjusted DOOR analyses indicated a 58% probability (95% confidence interval [CI], 52%-63%) for a worse clinical outcome in CRO-R versus CRO-S BSI. In the IPW-adjusted cohort, no difference was observed (54% [95% CI, 47%-61%]). Secondary outcomes included unadjusted and adjusted differences in the proportion of 30-day mortality between CRO-R and CRO-S BSIs (-5.3% [95% CI, -10.3% to -.4%] and -1.8 [95% CI, -6.7% to 3.2%], respectively), postculture median length of stay (8 days [IQR, 5-13 days] vs 6 days [IQR, 4-9 days]; P < .001), and incident admission to a long-term care facility (22% vs 12%, P = .045).

Conclusions

Patients with CRO-R E coli BSI generally have poorer outcomes compared to patients infected with CRO-S E coli BSI, even after adjusting for important confounders.

Benefit-risk assessment and reporting in clinical trials of chronic pain treatments: IMMPACT recommendations

ABSTRACT

Chronic pain clinical trials have historically assessed benefit and risk outcomes separately. However, a growing body of research suggests that a composite metric that accounts for benefit and risk in relation to each other can provide valuable insights into the effects of different treatments. Researchers and regulators have developed a variety of benefit-risk composite metrics, although the extent to which these methods apply to randomized clinical trials (RCTs) of chronic pain has not been evaluated in the published literature. This article was motivated by an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials consensus meeting and is based on the expert opinion of those who attended. In addition, a review of the benefit-risk assessment tools used in published chronic pain RCTs or highlighted by key professional organizations (ie, Cochrane, European Medicines Agency, Outcome Measures in Rheumatology, and U.S. Food and Drug Administration) was completed. Overall, the review found that benefit-risk metrics are not commonly used in RCTs of chronic pain despite the availability of published methods. A primary recommendation is that composite metrics of benefit-risk should be combined at the level of the individual patient, when possible, in addition to the benefit-risk assessment at the treatment group level. Both levels of analysis (individual and group) can provide valuable insights into the relationship between benefits and risks associated with specific treatments across different patient subpopulations. The systematic assessment of benefit-risk in clinical trials has the potential to enhance the clinical meaningfulness of RCT results.

A Desirability of Outcome Ranking Analysis of a Randomized Clinical Trial Comparing Seven Versus Fourteen Days of Antibiotics for Uncomplicated Gram-Negative Bloodstream Infection

Background

Although a short course (7 days) of antibiotics has been demonstrated to be noninferior to a conventional course (14 days) in terms of mortality and infectious complications for patients with a Gram-negative bacterial bloodstream infection (GNB), it is unknown whether a shorter treatment duration can provide a better overall clinical outcome.

Methods

We applied a bloodstream infection-specific desirability of outcome ranking (DOOR) analysis to the results of a previously completed, randomized controlled trial comparing short versus conventional course antibiotic therapy for hospitalized patients with uncomplicated GNB. We determined the probability that a randomly selected participant in the short course group would have a more desirable overall outcome than a participant in the conventional duration group. We performed (1) partial credit analyses allowing for calculated and variable weighting of DOOR ranks and (2) subgroup analyses to elucidate which patients may benefit the most from short durations of therapy.

Results

For the 604 patients included in the original study (306 short course, 298 conventional course), the probability of having a more desirable outcome with a short course of antibiotics compared with a conventional course was 51.1% (95% confidence interval, 46.7% to 55.4%), indicating no significant difference. Partial credit analyses indicated that the DOOR results were similar across different patient preferences. Prespecified subgroup analyses using DOOR did not reveal significant differences between short and conventional courses of therapy.

Conclusions

Both short and conventional durations of antibiotic therapy provide comparable clinical outcomes when using DOOR to consider benefits and risks of treatment options for GNB.

Time Course for Benefit and Risk of Ticagrelor and Aspirin in Acute Ischemic Stroke or Transient Ischemic Attack

OBJECTIVES

To investigate the short-term time course benefit and risk of ticagrelor with aspirin in acute mild-moderate ischemic stroke or high-risk transient ischemic attack (TIA) in the THALES (The Acute Stroke or Transient Ischemic Attack Treated with Ticagrelor and ASA for Prevention of Stroke and Death) trial.

METHODS

In an exploratory analysis of the THALES trial, we evaluated the cumulative incidence of irreversible efficacy and safety outcomes at different timepoints during the 30-day treatment period. The efficacy outcome was major ischemic events defined as a composite of ischemic stroke or non-hemorrhagic death. The safety outcome was major hemorrhage defined as a composite of intracranial hemorrhage and fatal bleedings. Net clinical impact was defined as the combination of these two endpoints.

RESULTS

This analysis included a total of 11,016 patients (5523 in the ticagrelor-aspirin group and 5493 in the aspirin group) with mean age of 65 years, and 39% were women. The reduction of major ischemic events by ticagrelor occurred in the first week (4.1% vs 5.3%; absolute risk reduction 1.15%, 95% CI 0.36% to 1.94%), and remained throughout the 30-day treatment period. An increase in major hemorrhage was seen during the first week and remained relatively constant in the following weeks (absolute risk increase, approximately 0.3%). Cumulative analysis showed that the net clinical impact favored ticagrelor-aspirin in the first week (absolute risk reduction 0.97%, 95% CI, 0.17% to 1.77%) and remained constant throughout the 30 days.

DISCUSSION

In patients with mild-moderate ischemic stroke or high-risk TIA, the treatment effect of ticagrelor-aspirin was present from the first week. The ischemic benefit of ticagrelor-aspirin outweighs the risk of major hemorrhage throughout the treatment period, which may support the use of 30 days treatment with ticagrelor and aspirin in these patients.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that for patients with mild-moderate ischemic stroke or high-risk TIA, the ischemic benefit of ticagrelor-aspirin outweighs the risk of major hemorrhage throughout the 30-day treatment period.

Prospective Validation of a Rapid Host Gene Expression Test to Discriminate Bacterial From Viral Respiratory Infection

Importance

Bacterial and viral causes of acute respiratory illness (ARI) are difficult to clinically distinguish, resulting in the inappropriate use of antibacterial therapy. The use of a host gene expression-based test that is able to discriminate bacterial from viral infection in less than 1 hour may improve care and antimicrobial stewardship.

Objective

To validate the host response bacterial/viral (HR-B/V) test and assess its ability to accurately differentiate bacterial from viral infection among patients with ARI.

Design, Setting, and Participants

This prospective multicenter diagnostic study enrolled 755 children and adults with febrile ARI of 7 or fewer days' duration from 10 US emergency departments. Participants were enrolled from October 3, 2014, to September 1, 2019, followed by additional enrollment of patients with COVID-19 from March 20 to December 3, 2020. Clinical adjudication of enrolled participants identified 616 individuals as having bacterial or viral infection. The primary analysis cohort included 334 participants with high-confidence reference adjudications (based on adjudicator concordance and the presence of an identified pathogen confirmed by microbiological testing). A secondary analysis of the entire cohort of 616 participants included cases with low-confidence reference adjudications (based on adjudicator discordance or the absence of an identified pathogen in microbiological testing). Thirty-three participants with COVID-19 were included post hoc.

Interventions

The HR-B/V test quantified the expression of 45 host messenger RNAs in approximately 45 minutes to derive a probability of bacterial infection.

Main Outcomes and Measures

Performance characteristics for the HR-B/V test compared with clinical adjudication were reported as either bacterial or viral infection or categorized into 4 likelihood groups (viral very likely [probability score <0.19], viral likely [probability score of 0.19-0.40], bacterial likely [probability score of 0.41-0.73], and bacterial very likely [probability score >0.73]) and compared with procalcitonin measurement.

Results

Among 755 enrolled participants, the median age was 26 years (IQR, 16-52 years); 360 participants (47.7%) were female, and 395 (52.3%) were male. A total of 13 participants (1.7%) were American Indian, 13 (1.7%) were Asian, 368 (48.7%) were Black, 131 (17.4%) were Hispanic, 3 (0.4%) were Native Hawaiian or Pacific Islander, 297 (39.3%) were White, and 60 (7.9%) were of unspecified race and/or ethnicity. In the primary analysis involving 334 participants, the HR-B/V test had sensitivity of 89.8% (95% CI, 77.8%-96.2%), specificity of 82.1% (95% CI, 77.4%-86.6%), and a negative predictive value (NPV) of 97.9% (95% CI, 95.3%-99.1%) for bacterial infection. In comparison, the sensitivity of procalcitonin measurement was 28.6% (95% CI, 16.2%-40.9%; P < .001), the specificity was 87.0% (95% CI, 82.7%-90.7%; P = .006), and the NPV was 87.6% (95% CI, 85.5%-89.5%; P < .001). When stratified into likelihood groups, the HR-B/V test had an NPV of 98.9% (95% CI, 96.1%-100%) for bacterial infection in the viral very likely group and a positive predictive value of 63.4% (95% CI, 47.2%-77.9%) for bacterial infection in the bacterial very likely group. The HR-B/V test correctly identified 30 of 33 participants (90.9%) with acute COVID-19 as having a viral infection.

Conclusions and Relevance

In this study, the HR-B/V test accurately discriminated bacterial from viral infection among patients with febrile ARI and was superior to procalcitonin measurement. The findings suggest that an accurate point-of-need host response test with high NPV may offer an opportunity to improve antibiotic stewardship and patient outcomes.

Pragmatic trials of pain therapies: a systematic review of methods

ABSTRACT

Pragmatic randomised clinical trials aim to directly inform clinical or health policy decision making. Here, we systematically review methods and design of pragmatic trials of pain therapies to examine methods, identify common challenges, and areas for improvement. Seven databases were searched for pragmatic randomised controlled clinical trials that assessed pain treatment in a clinical population of adults reporting pain. All screening steps and data extractions were performed twice. Data were synthesised descriptively, and correlation analyses between prespecified trial features and PRECIS-2 (PRagmatic-Explanatory Continuum Indicator Summary 2) ratings and attrition were performed. Protocol registration: PROSPERO-ID CRD42020178954. Of 57 included trials, only 21% assessed pharmacological interventions, the remainder physical, surgical, psychological, or self-management pain therapies. Three-quarters of the trials were comparative effectiveness designs, often conducted in multiple centres (median: 5; Q1/3: 1, 9.25) and with a median sample size of 234 patients at randomization (Q1/3: 135.5; 363.5). Although most trials recruited patients with chronic pain, reporting of pain duration was poor and not well described. Reporting was comprehensive for most general items, while often deficient for specific pragmatic aspects. Average ratings for pragmatism were highest for treatment adherence flexibility and clinical relevance of outcome measures. They were lowest for patient recruitment methods and extent of follow-up measurements and appointments. Current practice in pragmatic trials of pain treatments can be improved in areas such as patient recruitment and reporting of methods, analysis, and interpretation of data. These improvements will facilitate translatability to other real-world settings-the purpose of pragmatic trials.

Independent Oversight of Clinical Trials through Data and Safety Monitoring Boards

DSMBs: Protecting Patients and Scientific IntegrityDSMBs look after the welfare of patients enrolled in interventional clinical trials. DSMBs monitor for early establishment of efficacy, findings of harm, futility in obtaining a meaningful outcome, or changes in the ecology of care that render moot the question a trial aims to answer. This article opens a series of NEJM Evidence reviews about DSMBs.

1219. Unfavorable Clinical Outcomes with Polymyxins Compared to Ceftolozane/Tazobactam for the Treatment of Carbapenem-Resistant Pseudomonas aeruginosa

Background

Patients with carbapenem-resistant Pseudomonas aeruginosa (CRPA) have high in-hospital mortality rates. It is unknown if patients with CRPA treated with ceftolozane/tazobactam (C/T) have improved clinical outcomes compared to those treated with polymyxins.

Methods

The CDC-funded, Georgia Emerging Infections Program performed active population- and laboratory-based surveillance for CRPA isolated from sterile sites, urine, lower respiratory tract and wounds in metropolitan Atlanta, GA from 8/1/2016–7/31/2018. We reviewed charts of adults without cystic fibrosis who were hospitalized within 1 week of CRPA culture. Using a desirability of outcome ranking (DOOR) analysis which incorporates both benefits and risks into a single outcome, we estimated the probability that a patient treated first with C/T would have a more desirable clinical outcome at 30-days than a patient treated with polymyxins (polymyxin B or colistin). We adjusted for confounding using inverse probability of treatment weighting (IPTW) based on culture source and need for dialysis at baseline. A partial credit analysis allowed for variable weighting of DOOR ranks and calculation of differences in mean partial credit scores.

Results

Among 710 cases from 18 different hospitals, we identified 73 patients treated for CRPA infections with polymyxins (n=31) or C/T (n=42). Most patients were male (64%) and Black (80%), and those receiving polymyxins were more likely to have required dialysis at baseline (35% vs. 14%, p=0.03) (Table 1). At 30 days after culture, 34 (47%) were alive with no adverse events, 21 (29%) were alive with ≥ 1 adverse event, and 18 (25%) had died. Patients first treated with C/T had a lower 30-day mortality rate than those treated with polymyxins (14% vs 39%, p=0.03). Additionally, those receiving C/T had better overall clinical outcomes, with an adjusted DOOR probability of having an improved outcome of 67% (95% CI 53%–80%) compared to those receiving polymyxins (Figure 1). Partial credit analyses indicated consistent results across different patient values of survival with adverse events (Figure 2).

Figure 1: Inverse probability of treatment weighting-adjusted desirability of outcome ranking (DOOR) distributions by treatment group, accounting for adverse events and survival status that occurred up to 30 days after CRPA culture.

1. Percentages are adjusted using inverse probability of treatment weighting, controlling for culture source and need for dialysis at baseline 2. Adverse events measured included: acute kidney injury, discharge to higher acuity location than previous residence, or being hospitalized 30 days after culture

Figure 2: Inverse probability of treatment weighting-adjusted partial credit analysis.

This displays the difference (ceftolozane/tazobactam minus polymyxin) in mean partial credit scores (black line) and associated 95% confidence bands (gray lines) as a function of the partial credit score assigned to an individual having at least one adverse event (range 0 – 100%). A score of 100% is assigned to patients alive with no adverse events and a score of 0% is assigned to patients who die. A difference in mean partial credit scores of approximately zero suggests there was no difference observed between treatment groups.

Conclusion

These findings support the recent Infectious Diseases Society of America guidance favoring C/T over polymyxins for treatment of CRPA infections.

Disclosures

David van Duin, MD, PhD, Entasis (Advisor or Review Panel member)genentech (Advisor or Review Panel member)Karius (Advisor or Review Panel member)Merck (Grant/Research Support, Advisor or Review Panel member)Pfizer (Consultant, Advisor or Review Panel member)Qpex (Advisor or Review Panel member)Shionogi (Grant/Research Support, Scientific Research Study Investigator, Advisor or Review Panel member)Utility (Advisor or Review Panel member) Scott R. Evans, PhD, Abbvie (Consultant)Advantagene (Consultant)Alexion (Consultant)Amgen (Consultant)AstraZeneca (Consultant)Atricure (Consultant)Breast International Group (Consultant)Cardinal Health (Consultant)Clover (Consultant)FHI Clinical (Consultant)Genentech (Consultant)Gilead (Consultant)Horizon (Consultant)International Drug Development Institute (Consultant)Lung Biotech (Consultant)Microbiotix (Consultant)Neovasc (Consultant)Nobel Pharma (Consultant)Novartis (Consultant)Nuvelution (Consultant)Pfizer (Consultant)Rakuten (Consultant)Roche (Consultant)Roivant (Consultant)SAB Biopharm (Consultant)Shire (Consultant)Stryker (Consultant)SVB Leerink (Consultant)Takeda (Consultant)Teva (Consultant)Tracon (Consultant)Vir (Consultant)

Ischemic Benefit and Hemorrhage Risk of Ticagrelor-Aspirin Versus Aspirin in Patients With Acute Ischemic Stroke or Transient Ischemic Attack

Supplemental Digital Content is available in the text.

Background and Purpose:

In patients with acute mild-moderate ischemic stroke or high-risk transient ischemic attack, the THALES trial (Acute Stroke or Transient Ischemic Attack Treated With Ticagrelor and Aspirin for Prevention of Stroke and Death) demonstrated that when added to aspirin, ticagrelor reduced stroke or death but increased risk of severe hemorrhage compared with placebo. The primary efficacy outcome of THALES included hemorrhagic stroke and death, events also counted in the primary safety outcome. We sought to disentangle risk and benefit, assess their relative impact, and attempt to identify subgroups with disproportionate risk or benefit.

Methods:

In a randomized, placebo-controlled, double-blind trial of patients with mild-to-moderate acute noncardioembolic ischemic stroke or high-risk transient ischemic attack, patients were randomized within 24 hours after symptom onset to a 30-day regimen of either ticagrelor plus aspirin or matching placebo plus aspirin. For the present analyses, we defined the efficacy outcome, major ischemic events, as the composite of ischemic stroke or nonhemorrhagic death, and defined the safety outcome, major hemorrhage, as intracranial hemorrhage or hemorrhagic death. Net clinical impact was defined as the combination of these 2 end points.

Results:

In 11 016 patients (5523 ticagrelor-aspirin and 5493 aspirin), a major ischemic event occurred in 294 patients (5.3%) in the ticagrelor-aspirin group and in 359 patients (6.5%) in the aspirin group (absolute risk reduction 1.19% [95% CI, 0.31%–2.07%]). Major hemorrhage occurred in 22 patients (0.4%) in the ticagrelor-aspirin group and 6 patients (0.1%) in the aspirin group (absolute risk increase 0.29% [95% CI, 0.10%–0.48%]). Net clinical impact favored ticagrelor-aspirin (absolute risk reduction 0.97% [95% CI, 0.08%–1.87%]). Findings were similar when different thresholds for disability were applied and over a range of predefined subgroups.

Conclusions:

In patients with mild-moderate ischemic stroke or high-risk transient ischemic attack, ischemic benefits of 30-day treatment with ticagrelor-aspirin outweigh risks of hemorrhage.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03354429.

Desirability of Outcome Ranking for the Management of Antimicrobial Therapy (DOOR MAT): A Framework for Assessing Antibiotic Selection Strategies in the Presence of Drug Resistance

The complexities of antibiotic resistance mean that successful stewardship must consider both the effectiveness of a given antibiotic and the spectrum of that therapy to minimize imposing further selective pressure. To meet this challenge, we propose the Desirability of Outcome Ranking approach for the Management of Antimicrobial Therapy (DOOR MAT), a flexible quantitative framework that evaluates the desirability of antibiotic selection. Herein, we describe the steps required to implement DOOR MAT and present examples to illustrate how the desirability of treatment selection can be evaluated using resistance information. While treatments and the scoring of treatment selections must be adapted to specific clinical settings, the principle of DOOR MAT remains constant: The most desirable antibiotic choice effectively treats the patient while exerting minimal pressure on future resistance.

Efficacy and Safety of Ticagrelor and Aspirin in Patients With Moderate Ischemic Stroke: An Exploratory Analysis of the THALES Randomized Clinical Trial

Question

Is dual antiplatelet therapy with ticagrelor plus aspirin of benefit for patients with moderate acute ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score of 4 to 5)?

Findings

In this exploratory post-hoc analysis of the THALES trial including 9983 patients with moderate or less severe stroke (NIHSS score of 0 to 3), treatment with ticagrelor plus aspirin showed similar efficacy and safety vs aspirin alone among patients presenting with moderate acute ischemic stroke and those presenting with less severe ischemic cerebrovascular events.

Meaning

Patients with moderate ischemic stroke may benefit from dual antiplatelet therapy with ticagrelor and aspirin.

Importance

Prior trials of dual antiplatelet therapy excluded patients with moderate ischemic stroke. These patients were included in the Acute Stroke or Transient Ischaemic Attack Treated With Ticagrelor and ASA for Prevention of Stroke and Death (THALES) trial, but results have not been reported separately, raising concerns about safety and efficacy in this subgroup.

Objective

To evaluate the efficacy and safety of ticagrelor plus aspirin in patients with moderate ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score of 4 to 5).

Design, Setting, and Participants

The THALES trial was a randomized trial conducted at 414 hospitals in 28 countries in January 2018 and December 2019. This exploratory analysis compared patients with moderate stroke (baseline NIHSS score of 4 to 5) with patients with less severe stroke (NIHSS score of 0 to 3). A total of 9983 patients with stroke were included in the present analysis, after excluding 2 patients with NIHSS scores greater than 5 and 1031 patients with transient ischemic attack. Data were analyzed from March to April 2021.

Interventions

Ticagrelor (180-mg loading dose on day 1 followed by 90 mg twice daily on days 2 to 30) or placebo within 24 hours after symptom onset. All patients received aspirin, 300 to 325 mg, on day 1 followed by aspirin, 75 to 100 mg, daily on days 2 to 30. Patients were observed for 30 additional days.

Main Outcomes and Measures

The primary outcome was time to stroke or death within 30 days. The primary safety outcome was time to severe bleeding.

Results

In total, 3312 patients presented with moderate stroke and 6671 presented with less severe stroke. Of those in the moderate stroke group, 1293 (39.0%) were female, and the mean (SD) age was 64.5 (10.8) years; of those in the less severe stroke group, 2518 (37.7%) were female, and the mean (SD) age was 64.8 (11.2) years. The observed primary outcome event rate in patients with moderate stroke was 7.6% (129 of 1671) for those in the ticagrelor group and 9.1% (150 of 1641) for those in the placebo group (hazard ratio, 0.84; 95% CI, 0.66-1.06); the primary outcome event rate in patients with less severe stroke was 4.7% (158 of 3359) for those in the ticagrelor group and 5.7% (190 of 3312) for those in the placebo group (hazard ratio, 0.82; 95% CI, 0.66-1.01) (P for interaction = .88). Severe bleeding occurred in 8 patients (0.5%) in the ticagrelor group and in 4 patients (0.2%) in the placebo group in those with moderate stroke compared with 16 patients (0.5%) and 3 patients (0.1%), respectively, with less severe stroke (P for interaction = .26).

Conclusions and Relevance

In this study, patients with a moderate ischemic stroke had consistent benefit from ticagrelor plus aspirin vs aspirin alone compared with patients with less severe ischemic stroke, with no further increase in the risk of intracranial bleeding or other severe bleeding events.

Trial Registration

ClinicalTrials.gov Identifier: NCT03354429

The Desirability of Outcome Ranking for the Management of Antimicrobial Therapy (DOOR MAT) Reveals Improvements in the Treatment of Bloodstream Infection Caused by Escherichia coli and Klebsiella pneumoniae in Patients from the Veterans Health Administration

BACKGROUND

Reductions in the use of broad-spectrum antibiotics is a cornerstone of antimicrobial stewardship. We aim to demonstrate the use of Desirability of Outcome Ranking Approach for the Management of Antimicrobial Therapy (DOOR MAT) to evaluate the treatment of Escherichia coli and Klebsiella pneumoniae bloodstream infection in patients from the Veterans Health Administration (VHA) across a decade.

METHODS

Using electronic records, we determined empiric and definitive antibiotic treatments, clinical characteristics and 30-day mortality of subjects with monomicrobial E. coli and K. pneumoniae bloodstream infection hospitalized in VHA medical centers from 2009 to 2018. Focusing on patients treated with parenteral β-lactams and with available antibiotic susceptibility testing results, we applied a range of DOOR MAT scores that reflect the desirability of antibiotic choices according to spectrum and activity against individual isolates. We report trends in resistance and desirability of empiric and definitive antibiotic treatments.

RESULTS

During the 10-year period analyzed, resistance to expanded-spectrum cephalosporins and fluoroquinolones increased in E. coli but not in K. pneumoniae, while resistance remained unchanged to carbapenems and piperacillin-tazobactam. In 6,451 cases analyzed, we observed improvements in DOOR MAT scores consistent with de-escalation. Improvement in desirability of definitive treatment compared to empiric treatment occurred in 26% of cases, increasing from 16% in 2009 to 34% in 2018. Reductions in overtreatment were sustained and without negative impact on survival.

CONCLUSION

DOOR MAT provides a framework to assess antibiotic treatment of E. coli and K. pneumoniae bloodstream infection and can be a useful metric in antimicrobial stewardship.

Simultaneous Evaluation of Diagnostic Assays for Pharyngeal and Rectal Neisseria gonorrhoeae and Chlamydia trachomatis Using a Master Protocol

Background

Pharyngeal and rectal Neisseria gonorrhoeae and Chlamydia trachomatis play important roles in infection and antibacterial resistance transmission, but no US Food and Drug Administration (FDA)–cleared assays for detection at these sites existed prior to this study. The objective was to estimate performance of assays to detect those infections in pharyngeal and rectal specimens to support regulatory submission.

Methods

We performed a cross-sectional, single-visit study of adults seeking sexually transmitted infection testing at 9 clinics in 7 states. We collected pharyngeal and rectal swabs from participants. The primary outcome was positive and negative percent agreement for detection of N. gonorrhoeae and C. trachomatis for 3 investigational assays compared to a composite reference. Secondary outcomes included positivity as well as positive and negative predictive values and likelihood ratios. Subgroup analyses included outcomes by symptom status and sex.

Results

A total of 2598 participants (79% male) underwent testing. We observed N. gonorrhoeae positivity of 8.1% in the pharynx and 7.9% in the rectum and C. trachomatis positivity of 2.0% in the pharynx and 8.7% in the rectum. Positive percent agreement ranged from 84.8% to 96.5% for different anatomic site infection combinations, whereas negative percent agreement was 98.8% to 99.6%.

Conclusions

This study utilized a Master Protocol to generate diagnostic performance data for multiple assays from different manufacturers in a single study population, which ultimately supported first-in-class FDA clearance for extragenital assays. We observed very good positive percent agreement when compared to a composite reference method for the detection of both pharyngeal and rectal N. gonorrhoeae and C. trachomatis.

Clinical Trials Registration

NCT02870101.

Modern Clinician-initiated Clinical Trials to Determine Optimal Therapy for Multidrug-resistant Gram-negative Infections

Treatment options for multidrug-resistant (MDR) gram-negative infection are growing. However, postregistration, pragmatic, and clinician-led clinical trials in this field are few, recruit small sample sizes, and experience deficiencies in design and operations. MDR gram-negative therapeutic trials are often inefficient, only evaluating a single antibiotic or strategy at a time. Novel clinical trial designs offer potential solutions by attempting to obtain clinically meaningful conclusions at the end or during a trial, for many treatment strategies, simultaneously. An integrated, consensus approach to MDR gram-negative infection trial design is crucial.

Antibacterial Resistance Leadership Group 2.0 - Back to Business

In December 2019, the Antibacterial Resistance Leadership Group (ARLG) was awarded funding for another seven-year cycle to support a clinical research network on antibacterial resistance. ARLG 2.0 has three overarching research priorities: (1) infections caused by antibiotic resistant (AR) Gram-negative bacteria; (2) infections caused by AR Gram-positive bacteria, and (3) diagnostic tests to optimize use of antibiotics. To support the next generation of AR researchers, the ARLG offers three mentoring opportunities: the ARLG Fellowship, Early Stage Investigator Seed Grants, and the Trialists in Training Program. The purpose of this article is to update the scientific community on the progress made in the original funding period and to encourage submission of clinical research that addresses one or more of the research priority areas of ARLG 2.0.

On selecting the critical boundary functions in group-sequential trials with two time-to-event outcomes

We investigate selection of critical boundary functions for testing the hypotheses of two time-to-event outcomes as both primary endpoints or a primary and a secondary endpoint in group-sequential clinical trials, where (1) the effect sizes of endpoints are unequal, or (2) one endpoint is for short-term evaluation and the other for long-term evaluation. Bonferroni-Holm and fixed-sequence procedures are considered. We assess the effects of the magnitudes of the hazard ratios and the correlation between the endpoints on statistical powers and provide guidance for consideration.

Applying a Risk-benefit Analysis to Outcomes in Tuberculosis Clinical Trials

Although it is common to analyze efficacy and safety separately in clinical trials, this could yield a misleading study conclusion if an increase in efficacy is accompanied by a decrease in safety. A risk-benefit analysis is a systematic approach to examine safety and efficacy jointly. Both the "rank-based" and "partial-credit" methods described in this paper allow researchers to create a single, composite outcome incorporating efficacy, safety, and other factors. The first approach compares the distribution of rankings between arms. In the second approach, a score can be assigned to each outcome category, considering its severity and comparing the mean or median scores of arms. The methods were applied to the A5279/Brief Rifapentine-Isoniazid Efficacy for TB Prevention study, and design considerations for future clinical trials are discussed, including the challenge of arriving at a consensus on rankings/scorings. If well designed, a risk-benefit analysis may allow for a superiority comparison and, therefore, avoid setting a noninferiority margin. Clinical Trials Registration. NCT01404312 (A5279).

Real-World Data for Planning Eligibility Criteria and Enhancing Recruitment: Recommendations from the Clinical Trials Transformation Initiative

The growing availability of real-world data (RWD) creates opportunities for new evidence generation and improved efficiency across the research enterprise. To varying degrees, sponsors now regularly use RWD to make data-driven decisions about trial feasibility, based on assessment of eligibility criteria for planned clinical trials. Increasingly, RWD are being used to support targeted, timely, and personalized outreach to potential trial participants that may improve the efficiency and effectiveness of the recruitment process. This paper highlights recommendations and resources, including specific case studies, developed by the Clinical Trials Transformation Initiative (CTTI) for applying RWD to planning eligibility criteria and recruiting for clinical trials. Developed through a multi-stakeholder, consensus- and evidence-driven process, these actionable tools support researchers in (1) determining whether RWD are fit for purpose with respect to study planning and recruitment, (2) engaging cross-functional teams in the use of RWD for study planning and recruitment, and (3) understanding patient and site needs to develop successful and patient-centric approaches to RWD-supported recruitment. Future considerations for the use of RWD are explored, including ensuring full patient understanding of data use and developing global datasets.

175. Randomized Double-blind Controlled Trial of Short vs. Standard Course Outpatient Therapy of Community Acquired Pneumonia in Children (SCOUT-CAP)

Background

Community-acquired pneumonia (CAP) in children is usually treated with 10 days of antibiotics. Shorter antibiotic courses may be beneficial if proven effective, with potentially fewer antibiotic adverse effects and decreased antibiotic exposure.

Methods

This randomized, double-blind, placebo-controlled superiority trial (NCT02891915) compared a strategy of short vs standard course ß-lactam therapy for outpatient CAP in children ages 6–71 months. Children demonstrating clinical improvement by day 3–5 of initial therapy were considered for enrollment. Enrolled children were randomized 1:1 to receive either 5 additional days of the originally prescribed antibiotic (standard) or matching placebo (short). The Desirability of Outcome Ranking (DOOR; PMID: 26113652) was the primary outcome, and was defined by classifying the global experience of children into an ordinal clinical response (OCR) that combined the response to CAP treatment and antibiotic adverse effects 11–15 days after the start of therapy. For those subjects with equivalent OCR, documented days of antibiotic administration was used to further rank the desirability of the outcome with the a priori assumption that shorter antibiotic exposure was more desirable. The OCR was a secondary outcome. The intention to treat population was used to estimate the probability of a more desirable outcome for the strategy of short vs. standard course therapy for both outcomes.

Results

385 children were enrolled; 380 had complete data for analysis. Baseline characteristics were similar between the two strategies. In both strategies, > 90% of children had an adequate response to CAP treatment and most antibiotic adverse effects were minor (Table). In the OCR analysis, short course therapy had a 48% probability (95% CI: 42%-53%) of a more desirable outcome. In the DOOR analysis, short course therapy was superior to standard therapy with a 69% probability (95% CI: 63%-72%; p< 0.001) of a more desirable outcome.

Conclusion

Among children with CAP demonstrating initial clinical improvement with outpatient therapy, both strategies had a similar response to CAP treatment and antibiotic adverse effects, but short course therapy was superior in our a priori defined outcome that incorporated decreased antibiotic exposure.

Disclosures

Emmanuel B. Walter, MD, MPH, Moderna (Grant/Research Support)Pfizer (Grant/Research Support) Jason Newland, MD, MEd, FPIDS, Merck (Grant/Research Support)Pfizer (Other Financial or Material Support, Industry funded clinical trial) Vance G. Fowler, Jr., MD, MHS, Achaogen (Consultant)Actavis (Grant/Research Support)Advanced Liquid Logics (Grant/Research Support)Affinergy (Consultant, Research Grant or Support)Affinium (Consultant)Allergan (Grant/Research Support)Ampliphi Biosciences (Consultant)Basilea (Consultant, Research Grant or Support)Bayer (Consultant)C3J (Consultant)Cerexa (Consultant, Research Grant or Support)Contrafect (Consultant, Research Grant or Support)Cubist (Grant/Research Support)Debiopharm (Consultant)Destiny (Consultant)Durata (Consultant)Forest (Grant/Research Support)Genentech (Consultant, Research Grant or Support)Integrated Biotherapeutics (Consultant)Janssen (Consultant, Research Grant or Support)Karius (Grant/Research Support)Locus (Grant/Research Support)Medical Biosurfaces (Grant/Research Support)Medicines Co. (Consultant)Medimmune (Consultant, Research Grant or Support)Merck (Consultant, Research Grant or Support)NIH (Grant/Research Support)Novadigm (Consultant)Novartis (Consultant, Research Grant or Support)Pfizer (Grant/Research Support)Regeneron (Consultant, Research Grant or Support)Tetraphase (Consultant)Theravance (Consultant, Research Grant or Support)Trius (Consultant)xBiotech (Consultant) W. Charles Huskins, MD, MSc, ADMA Biologics (Consultant)Pfizer, Inc (Consultant)

Ticagrelor Added to Aspirin in Acute Nonsevere Ischemic Stroke or Transient Ischemic Attack of Atherosclerotic Origin

BACKGROUND AND PURPOSE

Among patients with a transient ischemic attack or minor ischemic strokes, those with ipsilateral atherosclerotic stenosis of cervicocranial vasculature have the highest risk of recurrent vascular events.

METHODS

In the double-blind THALES (The Acute Stroke or Transient Ischemic Attack Treated With Ticagrelor and ASA for Prevention of Stroke and Death) trial, we randomized patients with a noncardioembolic, nonsevere ischemic stroke, or high-risk transient ischemic attack to ticagrelor (180 mg loading dose on day 1 followed by 90 mg twice daily for days 2-30) or placebo added to aspirin (300-325 mg on day 1 followed by 75-100 mg daily for days 2-30) within 24 hours of symptom onset. The present paper reports a prespecified analysis in patients with and without ipsilateral, potentially causal atherosclerotic stenosis ≥30% of cervicocranial vasculature. The primary end point was time to the occurrence of stroke or death within 30 days.

RESULTS

Of 11 016 randomized patients, 2351 (21.3%) patients had an ipsilateral atherosclerotic stenosis. After 30 days, a primary end point occurred in 92/1136 (8.1%) patients with ipsilateral stenosis randomized to ticagrelor and in 132/1215 (10.9%) randomized to placebo (hazard ratio 0.73 [95% CI, 0.56-0.96], P=0.023) resulting in a number needed to treat of 34 (95% CI, 19-171). In patients without ipsilateral stenosis, the corresponding event rate was 211/4387 (4.8%) and 230/4278 (5.4%), respectively (hazard ratio, 0.89 [95% CI, 0.74-1.08]; P=0.23, Pinteraction=0.245). Severe bleeding occurred in 4 (0.4%) and 3 (0.2%) patients with ipsilateral atherosclerotic stenosis on ticagrelor and on placebo, respectively (P=NS), and in 24 (0.5%) and 4 (0.1%), respectively, in 8665 patients without ipsilateral stenosis (hazard ratio=5.87 [95% CI, 2.04-16.9], P=0.001).

CONCLUSIONS

In this exploratory analysis comparing ticagrelor added to aspirin to aspirin alone, we found no treatment by ipsilateral atherosclerosis stenosis subgroup interaction but did identify a higher absolute risk and a greater absolute risk reduction of stroke or death at 30 days in patients with ipsilateral atherosclerosis stenosis than in those without. In this easily identified population, ticagrelor added to aspirin provided a clinically meaningful benefit with a number needed to treat of 34 (95% CI, 19-171). Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03354429.

Ticagrelor Added to Aspirin in Acute Ischemic Stroke or Transient Ischemic Attack in Prevention of Disabling Stroke: A Randomized Clinical Trial

IMPORTANCE

Reduction of subsequent disabling stroke is the main goal of preventive treatment in the acute setting after transient ischemic attack (TIA) or minor ischemic stroke.

OBJECTIVE

To evaluate the superiority of ticagrelor added to aspirin in preventing disabling stroke and to understand the factors associated with recurrent disabling stroke.

DESIGN, SETTING, AND PARTICIPANTS

The Acute Stroke or Transient Ischemic Attack Treated With Ticagrelor and Aspirin for Prevention of Stroke and Death (THALES) was a randomized clinical trial conducted between January 22, 2018, and December 13, 2019, with a 30-day follow-up, at 414 hospitals in 28 countries. The trial included 11 016 patients with a noncardioembolic, nonsevere ischemic stroke or high-risk TIA, including 10 803 with modified Rankin Scale score (mRS) recorded at 30 days.

INTERVENTIONS

Ticagrelor (180-mg loading dose on day 1 followed by 90 mg twice daily for days 2-30) or placebo within 24 hours of symptom onset. All patients received aspirin, 300 to 325 mg on day 1 followed by 75 to 100 mg daily for days 2 to 30.

MAIN OUTCOMES AND MEASURES

Time to the occurrence of disabling stroke (progression of index event or new stroke) or death within 30 days, as measured by mRS at day 30. Disabling stroke was defined by mRS greater than 1.

RESULTS

Among participants with 30-day mRS greater than 1, mean age was 68.1 years, 1098 were female (42.6%), and 2670 had an ischemic stroke (95.8%) as a qualifying event. Among 11 016 patients, a primary end point with mRS greater than 1 at 30 days occurred in 221 of 5511 patients (4.0%) randomized to ticagrelor and in 260 of 5478 patients (4.7%) randomized to placebo (hazard ratio [HR], 0.83; 95% CI, 0.69-0.99, P = .04). A primary end point with mRS 0 or 1 at 30 days occurred in 70 of 5511 patients (1.3%) and 87 of 5478 patients (1.6%) (HR, 0.79; 95% CI, 0.57-1.08; P = .14). The ordinal analysis of mRS in patients with recurrent stroke showed a shift of the disability burden following a recurrent ischemic stroke in favor of ticagrelor (odds ratio, 0.77; 95% CI, 0.65-0.91; P = .002). Factors associated with disability were baseline National Institutes of Health Stroke Scale score 4 to 5, ipsilateral stenosis of at least 30%, Asian race/ethnicity, older age, and higher systolic blood pressure, while treatment with ticagrelor was associated with less disability.

CONCLUSIONS AND RELEVANCE

In patients with TIA and minor ischemic stroke, ticagrelor added to aspirin was superior to aspirin alone in preventing disabling stroke or death at 30 days and reduced the total burden of disability owing to ischemic stroke recurrence.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03354429.

Interpretation of chronic pain clinical trial outcomes: IMMPACT recommended considerations

Interpreting randomized clinical trials (RCTs) is crucial to making decisions regarding the use of analgesic treatments in clinical practice. In this article, we report on an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) consensus meeting organized by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks, the purpose of which was to recommend approaches that facilitate interpretation of analgesic RCTs. We review issues to consider when drawing conclusions from RCTs, as well as common methods for reporting RCT results and the limitations of each method. These issues include the type of trial, study design, statistical analysis methods, magnitude of the estimated beneficial and harmful effects and associated precision, availability of alternative treatments and their benefit-risk profile, clinical importance of the change from baseline both within and between groups, presentation of the outcome data, and the limitations of the approaches used.

Sequential, Multiple-Assignment, Randomized Trials for COMparing Personalized Antibiotic StrategieS (SMART-COMPASS)

Patient management is not based on a single decision. Rather, it is dynamic: based on a sequence of decisions, with therapeutic adjustments made over time. Adjustments are personalized: tailored to individual patients as new information becomes available. However, strategies allowing for such adjustments are infrequently studied. Traditional antibiotic trials are often nonpragmatic, comparing drugs for definitive therapy when drug susceptibilities are known. COMparing Personalized Antibiotic StrategieS (COMPASS) is a trial design that compares strategies consistent with clinical practice. Strategies are decision rules that guide empiric and definitive therapy decisions. Sequential, multiple-assignment, randomized (SMART) COMPASS allows evaluation when there are multiple, definitive therapy options. SMART COMPASS is pragmatic, mirroring clinical, antibiotic-treatment decision-making and addressing the most relevant issue for treating patients: identification of the patient-management strategy that optimizes the ultimate patient outcomes. SMART COMPASS is valuable in the setting of antibiotic resistance, when therapeutic adjustments may be necessary due to resistance.