Response Adjusted for Days of Antibiotic Risk (RADAR): evaluation of a novel method to compare strategies to optimize antibiotic use

Randomised, open-label, non-inferiority clinical trial on the efficacy and safety of a 7-day vs 14-day course of antibiotic treatment for uncomplicated enterococcal bacteraemia: the INTENSE trial protocol

INTRODUCTION

Enterococcus spp is responsible for 8%-15% of total bacteraemias with an associated global mortality around 23%-30%. Regarding the clinical management of enterococcal bacteraemia, the evidence on the duration of antibiotic treatment is scarce and the studies do not discriminate between complicated and uncomplicated bacteraemia.

METHODS

The INTENSE study is a multicentre, open-label, randomised, pragmatic, phase-IV clinical trial to demonstrate the non-inferiority of a 7-day vs 14-day course for the treatment of uncomplicated enterococcal bacteraemia and incorporating the early switching to oral antibiotics when feasible. The primary efficacy endpoint is the clinical cure at day 30±2 after the end of the treatment. Secondary endpoints will include the rate of relapse or infective endocarditis, length of stay, duration of intravenous therapy, Clostridioides difficile infection and the evaluation of the safety of both treatment arms through the recording and analysis of adverse events. For a 6% non-inferiority margin and considering a 5% withdrawal rate, 284 patients will be included.

ANALYSIS

The difference in proportions with one-sided 95% CIs will be calculated for the clinical cure rate using the control group as reference. For secondary categorical endpoints, a similar analysis will be performed and Mann-Whitney U-test will be used to compare median values of quantitative variables. A superiority analysis applying the response adjusted for days of antibiotic risk will be performed if there were incidents in recruitment; will allow obtaining results with 194 patients recruited.

ETHICS AND DISSEMINATION

The study has obtained the authorisation from the Spanish Regulatory Authority, the approval of the ethics committee and the agreement of the directors of each centre. Data will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05394298.

Unlocking the DOOR - how to design, apply, analyse, and interpret desirability of outcome ranking (DOOR) endpoints in infectious diseases clinical trials

BACKGROUND

Desirability of outcome ranking (DOOR) outcomes, with or without response adjusted for antibiotic risk (RADAR), are increasingly used in infectious diseases randomized clinical trials (RCTs), with the advantage of being able to combine multiple clinical outcomes and antibiotic duration in a single metric. However, it remains poorly understood, and there is considerable heterogeneity in its use.

OBJECTIVES

In this scoping review, we explain how to design, use, and analyse a DOOR endpoint, and highlight several pitfalls and potential improvements that can be made to DOOR/RADAR.

SOURCES

The Ovid MEDLINE database was searched for terms related to DOOR in English-language papers published up to 31 December 2022. Papers discussing DOOR methodology and/or reporting clinical trial analyses (as either primary, secondary, or post-hoc analysis) using a DOOR outcome were included.

CONTENT

17 papers were included in the final review, of which 9 reported DOOR analyses of 12 RCTs. 8 papers discussed DOOR methodology. We synthesised information from these papers and discuss (a) How to develop a DOOR scale, (b) How to conduct a DOOR/RADAR analysis, (c) Use in clinical trials, (d) Use of alternative tiebreakers apart from RADAR, (e) Partial credit analyses, and (f) Criticisms and pitfalls of DOOR/RADAR.

IMPLICATIONS

DOOR is an important innovation for RCTs in infectious diseases. We highlight potential areas of methodological improvement for future research. There remains considerable heterogeneity in its implementation, and further collaborative efforts, with a more diverse range of perspectives, should be made to develop consensus scales for use in prospective studies.

Outcomes of Restricted versus Liberal Post-Operative Antibiotic Use in Patients Undergoing Appendectomy: A DOOR/RADAR Post Hoc Analysis of the EAST Appendicitis MUSTANG Study

Background: There is no consensus on the duration of antibiotic use after appendectomy. We hypothesized that restricted antibiotic use is associated with better clinical outcomes. Patients and Methods: We performed a post hoc analysis of the Eastern Association for the Surgery of Trauma (EAST) Multicenter Study of the Treatment of Appendicitis in America-Acute, Perforated, and Gangrenous (MUSTANG) study using the desirability of outcome ranking/response adjusted for duration of antibiotic risk (DOOR/RADAR) framework. Three separate datasets were analyzed based on restricted versus liberal post-operative antibiotic groups: simple appendicitis (no vs. yes); complicated appendicitis, only four days (≤24 hours vs. 4 days); and complicated appendicitis, four or more days (≤24 hours vs. ≥4 days). Patients were assigned to one of seven mutually exclusive DOOR categories RADAR ranked within each category. DOOR/RADAR score pairwise comparisons were performed between all patients. Each patient was assigned either 1, 0, or -1 if they had better, same, or worse outcomes than the other patient in the pair, respectively. The sum of these numbers (cumulative comparison score) was calculated for each patient and the group medians of individual sums were compared by Wilcoxon rank sum. Results: For simple appendicitis, the restricted group had higher median sums than the liberal group (552 [552,552] vs. -1,353 [-1,353, -1,353], p < 0.001). For both complicated appendicitis analyses, the restricted group had higher median sums than the liberal: only 4 (196 [23,196] vs. -121 [-121, -121], p < 0.02) and 4 or more (660 [484,660] vs -169 [-444,181], p < 0.001). Conclusions: Restricted post-operative antibiotic use in patients after appendectomy is a dominant strategy when considering treatment effectiveness and antibiotic exposure.

Elaboration of Consensus Clinical Endpoints to Evaluate Antimicrobial Treatment Efficacy in Future Hospital-acquired/Ventilator-associated Bacterial Pneumonia Clinical Trials

BACKGROUND

Randomized clinical trials (RCTs) in hospital-acquired and ventilator-associated bacterial pneumonia (HABP and VABP, respectively) are important for the evaluation of new antimicrobials. However, the heterogeneity in endpoints used in RCTs evaluating treatment of HABP/VABP may puzzle clinicians. The aim of this work was to reach a consensus on clinical endpoints to consider in future clinical trials evaluating antimicrobial treatment efficacy for HABP/VABP.

METHODS

Twenty-six international experts from intensive care, infectious diseases, and the pharmaceutical industry were polled using the Delphi method.

RESULTS

The panel recommended a hierarchical composite endpoint including, by priority order, (1) survival at day 28, (2) mechanical ventilation-free days through day 28, and (3) clinical cure between study days 7 and 10 for VABP; and (1) survival (day 28) and (2) clinical cure (days 7-10) for HABP. Clinical cure was defined as the combination of resolution of signs and symptoms present at enrollment and improvement or lack of progression of radiological signs. More than 70% of the experts agreed to assess survival and mechanical ventilation-free days though day 28, and clinical cure between day 7 and day 10 after treatment initiation. Finally, the hierarchical order of endpoint components was reached after 3 Delphi rounds (72% agreement).

CONCLUSIONS

We provide a multinational expert consensus on separate hierarchical composite endpoints for VABP and HABP, and on a definition of clinical cure that could be considered for use in future HABP/VABP clinical trials.

Measuring outcomes in complicated intra-abdominal infections

PURPOSE OF REVIEW

Complicated intra-abdominal infections (cIAIs) are associated with significant morbidity and mortality. Clinical trials should help guide and improve the management of cIAIs. However, inappropriate selection or measurement of outcomes in cIAIs clinical trials can lead to misleading results on the effectiveness of interventions. This review aims to describe how outcomes are reported in randomized controlled trials evaluating antibiotic treatment for cIAIs and discuss how outcome reporting may be improved.

RECENT FINDINGS

Commonly used primary outcomes are treatment success or failure, and these outcomes are endorsed by regulatory bodies. However, a consensus objective definition of either is not available and current measures are prone to bias. Variation exists in timing of outcome evaluation and analysis populations, which can lead to further bias. Use of core outcome sets can help standardize outcome reporting.

SUMMARY

Inconsistency in outcome selection and reporting can lead to misleading results and impedes meta-analysis of data. Further progress, engaging clinical trialists, regulatory authorities, clinicians and patients is required to achieve consensus on which outcomes should be reported and how and when to measure them.

Optimizing the Design and Analysis of Clinical Trials for Antibacterials Against Multidrug-resistant Organisms: A White Paper From COMBACTE's STAT-Net

Innovations are urgently required for clinical development of antibacterials against multidrug-resistant organisms. Therefore, a European, public-private working group (STAT-Net; part of Combatting Bacterial Resistance in Europe [COMBACTE]), has reviewed and tested several innovative trials designs and analytical methods for randomized clinical trials, which has resulted in 8 recommendations. The first 3 focus on pharmacokinetic and pharmacodynamic modeling, emphasizing the pertinence of population-based pharmacokinetic models, regulatory procedures for the reassessment of old antibiotics, and rigorous quality improvement. Recommendations 4 and 5 address the need for more sensitive primary end points through the use of rank-based or time-dependent composite end points. Recommendation 6 relates to the applicability of hierarchical nested-trial designs, and the last 2 recommendations propose the incorporation of historical or concomitant trial data through Bayesian methods and/or platform trials. Although not all of these recommendations are directly applicable, they provide a solid, evidence-based approach to develop new, and established, antibacterials and address this public health challenge.

Optimizing design of research to evaluate antibiotic stewardship interventions: consensus recommendations of a multinational working group

BACKGROUND

Antimicrobial stewardship interventions and programmes aim to ensure effective treatment while minimizing antimicrobial-associated harms including resistance. Practice in this vital area is undermined by the poor quality of research addressing both what specific antimicrobial use interventions are effective and how antimicrobial use improvement strategies can be implemented into practice. In 2016 we established a working party to identify the key design features that limit translation of existing research into practice and then to make recommendations for how future studies in this field should be optimally designed. The first part of this work has been published as a systematic review. Here we present the working group's final recommendations.

METHODS

An international working group for design of antimicrobial stewardship intervention evaluations was convened in response to the fourth call for leading expert network proposals by the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR). The group comprised clinical and academic specialists in antimicrobial stewardship and clinical trial design from six European countries. Group members completed a structured questionnaire to establish the scope of work and key issues to develop ahead of a first face-to-face meeting that (a) identified the need for a comprehensive systematic review of study designs in the literature and (b) prioritized key areas where research design considerations restrict translation of findings into practice. The working group's initial outputs were reviewed by independent advisors and additional expertise was sought in specific clinical areas. At a second face-to-face meeting the working group developed a theoretical framework and specific recommendations to support optimal study design. These were finalized by the working group co-ordinators and agreed by all working group members.

RESULTS

We propose a theoretical framework in which consideration of the intervention rationale the intervention setting, intervention features and the intervention aims inform selection and prioritization of outcome measures, whether the research sets out to determine superiority or non-inferiority of the intervention measured by its primary outcome(s), the most appropriate study design (e.g. experimental or quasi- experimental) and the detailed design features. We make 18 specific recommendation in three domains: outcomes, objectives and study design.

CONCLUSIONS

Researchers, funders and practitioners will be able to draw on our recommendations to most efficiently evaluate antimicrobial stewardship interventions.