Personalised randomised controlled trial designs-a new paradigm to define optimal treatments for carbapenem-resistant infections

A comparison of frequentist and Bayesian approaches to the Personalised Randomised Controlled Trial (PRACTical)-design and analysis considerations

BACKGROUND

Multiple treatment options frequently exist for a single medical condition with no single standard of care (SoC), rendering a classic randomised trial comparing a specific treatment to a control treatment infeasible. A novel design, the personalised randomised controlled trial (PRACTical), allows individualised randomisation lists and borrows information across patient subpopulations to rank treatments against each other without comparison to a SoC. We evaluated standard frequentist analysis with Bayesian analyses, and developed a novel performance measure, utilising the precision in treatment coefficient estimates, for treatment ranking.

METHODS

We simulated trial data to compare four targeted antibiotic treatments for multidrug resistant bloodstream infections as an example. Four patient subgroups were simulated based on different combinations of patient and bacteria characteristics, which required four different randomisation lists with some overlapping treatments. The primary outcome was binary, using 60-day mortality. Treatment effects were derived using frequentist and Bayesian analytical approaches, with logistic multivariable regression. The performance measures were: probability of predicting the true best treatment, and novel proxy variables for power (probability of interval separation) and type I error (probability of incorrect interval separation). Several scenarios with varying treatment effects and sample sizes were compared.

RESULTS

The Frequentist model and Bayesian model using a strong informative prior, were both likely to predict the true best treatment (P best ≥ 80 % ) and gave a large probability of interval separation (reaching a maximum ofP IS = 96 % ), at a given sample size. Both methods had a low probability of incorrect interval separation (P IIS < 0.05 ), for all sample sizes ( N = 500 - 5000 ) in the null scenarios considered. The sample size required for probability of interval separation to reach 80% ( N = 1500 - 3000 ), was larger than the sample size required for the probability of predicting the true best treatment to reach 80% ( N ≤ 500 ).

CONCLUSIONS

Utilising uncertainty intervals on the treatment coefficient estimates are highly conservative, limiting applicability to large pragmatic trials. Bayesian analysis performed similarly to the frequentist approach in terms of predicting the true best treatment.

Reserve antibiotics: overcoming limitations of evidence generated from regulatory approval trials

New antibiotics active against multidrug resistant bacteria (MDR-B) are licensed by regulatory agencies based on pivotal trials that serve the primary purpose of obtaining marketing-authorization. There is increasing concern that they do not offer guidance on how to best use new antibiotics, in which population, and to what extent they overcome existing resistance. We reviewed the literature for pre-approval studies (phase 2 and 3 randomized controlled trials) and post-approval studies (randomized and non-randomized controlled trials) evaluating efficacy and safety of new antibiotics, classified by WHO as Reserve, approved in the European Union and the US from January 2010 to May 2023. Substantial failures occur in generating evidence to guide routine clinical use: preapproval studies lack representativeness, select outcomes and comparators to chase statistical significance, and often avoid using prespecified analytical methods. Three recommendations are key to enhance the quality and relevance of clinical data underpinning use of last resort molecules on the WHO AWaRe Reserve list active against carbapenem-resistant MDR-B i). separation of pivotal trials from post-approval studies, which should be funded by public programs and de-linked from commercial purposes, ii). development and maintenance of a global infrastructure to conduct post-approval public health focused studies, and iii). development of trial platforms that use efficient, adaptive designs to inform clinical decision making and country level technology appraisal. These solutions will allow clinicians to determine whether recently approved Reserve antibiotics are not only "newer" but also "better" for vulnerable patient populations at particular risk for infections by MDR-B.

Strengthening the paediatric clinical trial ecosystem to better inform policy and programmes

The first WHO Global Clinical Trials Forum was convened in November, 2023 to develop a shared vision of an effective global clinical trial infrastructure. The Paediatric Clinical Trials Working Group was formed to provide perspectives, identify challenges, and propose solutions to strengthen the paediatric clinical trials ecosystem. Participants represented paediatric disciplines, including infectious diseases, nutrition, neonatology, pharmacology, oncology, neurodevelopment, public health, and policy. Childhood diseases have profound lifelong effects on health, livelihoods, and societies. Investment in early childhood results in highly cost-effective changes to lifelong health, productivity, and human capital returns. Yet, there remain substantial gaps in knowledge on the efficacy and safety of many paediatric interventions, which represents a failure to establish shared priorities and alignment across governments, researchers, communities, and funders. Children are frequently marginalised from clinical trials, which is an issue of equity. Challenges include mismatched priorities and funding, risk adversity, poor design, power imbalances, and inadequate infrastructure. Solutions include aligning on and tracking local and global child health priorities against funding and supporting regional consortia to pool resources for larger, more consequential trials. We propose actions and responsibilities for global, regional, and national institutions for prioritisation, coordination, enabling paediatric trials consortia, funding, and tracking progress.

Assessing the Value of New Antimicrobials: Evaluations of Cefiderocol and Ceftazidime-Avibactam to Inform Delinked Payments by the NHS in England

OBJECTIVES

The UK has recently established subscription-payment agreements for two antimicrobials: cefiderocol and ceftazidime-avibactam. This article summarises the novel value assessments that informed this process and lessons learned for future pricing and funding decisions.

METHODS

The evaluations used decision modelling to predict population incremental net health effects (INHEs), informed by systematic reviews, evidence syntheses, national surveillance data and structured expert elicitation.

RESULTS

Significant challenges faced during the development of the evaluations led to profound uncertainty in the estimates of INHEs. The value assessment required definition of the population expected to receive the new antimicrobials; estimating value within this heterogenous population; assessing comparative efficacy using antimicrobial susceptibility data due to the absence of relevant clinical data; and predicting population-level benefits despite poor data on current numbers of drug-resistant infections and uncertainties around emerging resistance. Though both antimicrobials offer the potential to treat multi-drug resistant infections, the benefits estimated were modest due to the rarity of true pan-resistance, low life expectancy of the patient population and difficulty of identifying and quantifying additional sources of value.

CONCLUSIONS

Assessing the population INHEs of new antimicrobials was complex and resource intensive. Future evaluations should continue to assemble evidence relating to areas of expected usage, patient numbers over time and comparative effectiveness and safety. Projections of patient numbers could be greatly enhanced by the development of national level linked clinical, prescribing and laboratory data. A practical approach to synthesising these data would be to combine expert assessments of key parameters with a simple generic decision model.

Recent updates in treating carbapenem-resistant infections in patients with hematological malignancies

INTRODUCTION

Patients with hematological malignancies (PHMs) are at increased risk for infections caused by carbapenem-resistant organisms (CROs) due to frequent exposure to broad-spectrum antibiotics and prolonged hospital stays. These infections result in high mortality and morbidity rates along with delays in chemotherapy, longer hospitalizations, and increased health care costs.

AREAS COVERED

Treatment alternatives for CRO infections in PHMs.

EXPERT OPINION

The best available treatment option for KPC and OXA-48 producers is ceftazidime/avibactam. Imipenem/cilastatin/relebactam and meropenem/vaborbactam remain as the alternative options. They can also be used as salvage therapy in KPC-positive Enterobacterales infections resistant to ceftazidime/avibactam, if in vitro susceptibility is shown. Treatment of metallo-β-lactamase producers is an unmet need. Ceftazidime/avibactam plus aztreonam or aztreonam/avibactam seems to be the most reliable option for metallo-β-lactamase producers. As a first-line option for carbapenem-resistant Pseudomonas aeruginosa infections, ceftolozane/tazobactam is preferable and ceftazidime/avibactam and imipenem/cilastatin/relebactam constitute alternative regimens. Although sulbactam/durlobactam is the most reliable option against carbapenem-resistant Acinetobacter baumannii infections, its utility as monotherapy and in PHMs is not yet known. Cefiderocol can be selected as a 'last-resort' option for CRO infections. New risk score models supported by artificial intelligence algorithms can be used to predict the exact risk of infections in previously colonized patients.

Randomised Trial of No, Short-term, or Long-term Androgen Deprivation Therapy with Postoperative Radiotherapy After Radical Prostatectomy: Results from the Three-way Comparison of RADICALS-HD (NCT00541047)

BACKGROUND AND OBJECTIVE

The use and duration of androgen deprivation therapy (ADT) with postoperative radiotherapy (RT) have been uncertain. RADICALS-HD compared adding no ("None"), 6-months ("Short"), or 24-mo ("Long") ADT to study efficacy in the long term.

METHODS

Participants with prostate cancer were indicated for postoperative RT and agreed randomisation between all durations. ADT was allocated for 0, 6, or 24 mo. The primary outcome measure (OM) was metastasis-free survival (MFS). The secondary OMs included freedom from distant metastasis, overall survival, and initiation of nonprotocol ADT. Sample size was determined by two-way comparisons. Analyses followed standard time-to-event approaches and intention-to-treat principles.

KEY FINDINGS AND LIMITATIONS

Between 2007 and 2015, 492 participants were randomised one of three groups: 166 None, 164 Short, and 162 Long. The median age at randomisation was 66 yr; Gleason scores at surgery were as follows: <7 = 64 (13%), 3+4 = 229 (47%), 4+3 = 127 (26%), and 8+ = 72 (15%); T3b was 112 (23%); and T4 was 5 (1%). The median follow-up was 9.0 yr and, with MFS events reported for 89 participants (32 None, 31 Short, and 26 Long), there was no evidence of difference in MFS overall (logrank p = 0.98), and, for Long versus None, hazard ratio = 0.948 (95% confidence interval 0.54-1.68). After 10 yr, 80% None, 77% Short, and 81% Long patients were alive without metastatic disease. The three-way randomisation was not powered to conventional levels for assessment, yet provides a fair comparison.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Long-term outcomes after radical prostatectomy are usually favourable. In those indicated for postoperative RT and considered suitable for no, short-term, or long-term ADT, there was no evidence of improvement with addition of ADT. Future research should focus on patients at a higher risk of metastases in whom improvements are required more urgently.

Combination Versus Monotherapy for Carbapenem-Resistant Acinetobacter Species Serious Infections: A Prospective IPTW Adjusted Cohort Study

INTRODUCTION

International guidelines recommend definitive combination antibiotic therapy for the management of serious infections involving carbapenem-resistant Acinetobacter (CRAB) species. The commonly available combination options include high-dose sulbactam, polymyxins, tetracyclines, and cefiderocol. Scanty prospective data exist to support this approach.

METHODS

Patients with CRAB bacteraemia, ventilator-associated pneumonia (VAP), or both were categorized based on whether they received combination therapy or monotherapy. The 30-day mortality was compared between the two groups. Inverse probability treatment weighting (IPTW) was done using propensity score (PS) for a balanced comparison between groups.

RESULTS

Between January 2021 and May 2023, of the 161 patients with CRAB bacteraemia (n = 55, 34.2%), VAP (n = 46, 28.6%), or both (n = 60, 37.3%) who received appropriate intravenous antibiotic therapy, 70% (112/161) received monotherapy, and the rest received combination therapy. The overall 30-day mortality was 62% (99/161) and not different (p = 0.76) between the combination therapy (31/49, 63.3%) and monotherapy (68/112, 60.7%) groups. The propensity score matching using IPTW did not show a statistical difference (p = 0.47) in 30-day mortality for receiving combination therapy with an adjusted odds ratio (OR) P of 1.29 (0.64, 2.58).

CONCLUSION

Combination therapy for CRAB infections needs further study in a randomised controlled trial, as this observational study showed no difference in 30-day mortality between monotherapy and combination therapy.

Ceftazidime with avibactam for treating severe aerobic Gram-negative bacterial infections: technology evaluation to inform a novel subscription-style payment model

Background

To limit the use of antimicrobials without disincentivising the development of novel antimicrobials, there is interest in establishing innovative models that fund antimicrobials based on an evaluation of their value as opposed to the volumes used. The aim of this project was to evaluate the population-level health benefit of ceftazidime-avibactam in the NHS in England, for the treatment of severe aerobic Gram-negative bacterial infections when used within its licensed indications. The results were used to inform National Institute for Health and Care Excellence guidance in support of commercial discussions regarding contract value between the manufacturer and NHS England.

Methods

The health benefit of ceftazidime-avibactam was first derived for a series of high-value clinical scenarios. These represented uses that were expected to have a significant impact on patients' mortality risks and health-related quality of life. Patient-level costs and health-related quality of life of ceftazidime-avibactam under various usage scenarios compared with alternative management strategies in the high-value clinical scenarios were quantified using decision modelling. Results were reported as incremental net health effects expressed in quality-adjusted life-years, which were scaled to 20-year population in quality-adjusted life-years using infection number forecasts based on data from Public Health England. The outcomes estimated for the high-value clinical scenarios were extrapolated to other expected uses for ceftazidime-avibactam.

Results

The clinical effectiveness of ceftazidime-avibactam relative to its comparators was estimated by synthesising evidence on susceptibility of the pathogens of interest to the antimicrobials in a network meta-analysis. In the base case, ceftazidime-avibactam was associated with a statistically significantly higher susceptibility relative to colistin (odds ratio 7.24, 95% credible interval 2.58 to 20.94). The remainder of the treatments were associated with lower susceptibility than colistin (odds ratio < 1). The results were sensitive to the definition of resistance and the studies included in the analysis. In the base case, patient-level benefit of ceftazidime-avibactam was between 0.08 and 0.16 quality-adjusted life-years, depending on the site of infection and the usage scenario. There was a high degree of uncertainty surrounding the benefits of ceftazidime-avibactam across all subgroups, and the results were sensitive to assumptions in the meta-analysis used to estimate susceptibility. There was substantial uncertainty in the number of infections that are suitable for treatment with ceftazidime-avibactam, so population-level results are presented for a range of scenarios for the current infection numbers, the expected increases in infections over time, and rates of emergence of resistance. The population-level benefit varied substantially across the scenarios, from 531 to 2342 quality-adjusted life-years over 20 years.

Conclusion

This work has provided quantitative estimates of the value of ceftazidime-avibactam within its areas of expected usage within the NHS.

Limitations

Given existing evidence, the estimates of the value of ceftazidime-avibactam are highly uncertain.

Future work

Future evaluations of antimicrobials would benefit from improvements to NHS data linkages, research to support appropriate synthesis of susceptibility studies, and application of routine data and decision modelling to assess enablement value.

Study registration

No registration of this study was undertaken.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Policy Research Programme (NIHR award ref: NIHR135592), conducted through the Policy Research Unit in Economic Methods of Evaluation in Health and Social Care Interventions, PR-PRU-1217-20401, and is published in full in Health Technology Assessment; Vol. 28, No. 73. See the NIHR Funding and Awards website for further award information.

Drug-resistant tuberculosis treatments, the case for a phase III platform trial

Most phase III trials in drug-resistant tuberculosis have either been underpowered to quantify differences in microbiological endpoints or have taken up to a decade to complete. Composite primary endpoints, dominated by differences in treatment discontinuation and regimen changes, may mask important differences in treatment failure and relapse. Although new regimens for drug-resistant tuberculosis appear very effective, resistance to new drugs is emerging rapidly. There is a need for shorter, safer and more tolerable regimens, including those active against bedaquiline-resistant tuberculosis. Transitioning from multiple regimen A versus regimen B trials to a single large phase III platform trial would accelerate the acquisition of robust estimates of relative efficacy and safety. Further efficiencies could be achieved by adopting modern adaptive platform designs. Collaboration among trialists, affected community representatives, funders and regulators is essential for developing such a phase III platform trial for drug-resistant tuberculosis treatment regimens.

Analysis of Nonconcurrent Controls in Adaptive Platform Trials: Separating Randomized and Nonrandomized Information

Adaptive platform trials allow treatments to be added or dropped during the study, meaning that the control arm may be active for longer than the experimental arms. This leads to nonconcurrent controls, which provide nonrandomized information that may increase efficiency but may introduce bias from temporal confounding and other factors. Various methods have been proposed to control confounding from nonconcurrent controls, based on adjusting for time period. We demonstrate that time adjustment is insufficient to prevent bias in some circumstances where nonconcurrent controls are present in adaptive platform trials, and we propose a more general analytical framework that accounts for nonconcurrent controls in such circumstances. We begin by defining nonconcurrent controls using the concept of a concurrently randomized cohort, which is a subgroup of participants all subject to the same randomized design. We then use cohort adjustment rather than time adjustment. Due to flexibilities in platform trials, more than one randomized design may be in force at any time, meaning that cohort-adjusted and time-adjusted analyses may be quite different. Using simulation studies, we demonstrate that time-adjusted analyses may be biased while cohort-adjusted analyses remove this bias. We also demonstrate that the cohort-adjusted analysis may be interpreted as a synthesis of randomized and indirect comparisons analogous to mixed treatment comparisons in network meta-analysis. This allows the use of network meta-analysis methodology to separate the randomized and nonrandomized components and to assess their consistency. Whenever nonconcurrent controls are used in platform trials, the separate randomized and indirect contributions to the treatment effect should be presented.

Cefiderocol for treating severe aerobic Gram-negative bacterial infections: technology evaluation to inform a novel subscription-style payment model

Background

To limit the use of antimicrobials without disincentivising the development of novel antimicrobials, there is interest in establishing innovative models that fund antimicrobials based on an evaluation of their value as opposed to the volumes used. The aim of this project was to evaluate the population-level health benefit of cefiderocol in the NHS in England, for the treatment of severe aerobic Gram-negative bacterial infections when used within its licensed indications. The results were used to inform the National Institute for Health and Care Excellence guidance in support of commercial discussions regarding contract value between the manufacturer and NHS England.

Methods

The health benefit of cefiderocol was first derived for a series of high-value clinical scenarios. These represented uses that were expected to have a significant impact on patients' mortality risks and health-related quality of life. The clinical effectiveness of cefiderocol relative to its comparators was estimated by synthesising evidence on susceptibility of the pathogens of interest to the antimicrobials in a network meta-analysis. Patient-level costs and health outcomes of cefiderocol under various usage scenarios compared with alternative management strategies were quantified using decision modelling. Results were reported as incremental net health effects expressed in quality-adjusted life-years, which were scaled to 20-year population values using infection number forecasts based on data from Public Health England. The outcomes estimated for the high-value clinical scenarios were extrapolated to other expected uses for cefiderocol.

Results

Among Enterobacterales isolates with the metallo-beta-lactamase resistance mechanism, the base-case network meta-analysis found that cefiderocol was associated with a lower susceptibility relative to colistin (odds ratio 0.32, 95% credible intervals 0.04 to 2.47), but the result was not statistically significant. The other treatments were also associated with lower susceptibility than colistin, but the results were not statistically significant. In the metallo-beta-lactamase Pseudomonas aeruginosa base-case network meta-analysis, cefiderocol was associated with a lower susceptibility relative to colistin (odds ratio 0.44, 95% credible intervals 0.03 to 3.94), but the result was not statistically significant. The other treatments were associated with no susceptibility. In the base case, patient-level benefit of cefiderocol was between 0.02 and 0.15 quality-adjusted life-years, depending on the site of infection, the pathogen and the usage scenario. There was a high degree of uncertainty surrounding the benefits of cefiderocol across all subgroups. There was substantial uncertainty in the number of infections that are suitable for treatment with cefiderocol, so population-level results are presented for a range of scenarios for the current infection numbers, the expected increases in infections over time and rates of emergence of resistance. The population-level benefits varied substantially across the base-case scenarios, from 896 to 3559 quality-adjusted life-years over 20 years.

Conclusion

This work has provided quantitative estimates of the value of cefiderocol within its areas of expected usage within the NHS.

Limitations

Given existing evidence, the estimates of the value of cefiderocol are highly uncertain.

Future work

Future evaluations of antimicrobials would benefit from improvements to NHS data linkages; research to support appropriate synthesis of susceptibility studies; and application of routine data and decision modelling to assess enablement value.

Study registration

No registration of this study was undertaken.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment Policy Research Programme (NIHR award ref: NIHR135591), conducted through the Policy Research Unit in Economic Methods of Evaluation in Health and Social Care Interventions, PR-PRU-1217-20401, and is published in full in Health Technology Assessment; Vol. 28, No. 28. See the NIHR Funding and Awards website for further award information.

System-wide approaches to antimicrobial therapy and antimicrobial resistance in the UK: the AMR-X framework

Antimicrobial resistance (AMR) threatens human, animal, and environmental health. Acknowledging the urgency of addressing AMR, an opportunity exists to extend AMR action-focused research beyond the confines of an isolated biomedical paradigm. An AMR learning system, AMR-X, envisions a national network of health systems creating and applying optimal use of antimicrobials on the basis of their data collected from the delivery of routine clinical care. AMR-X integrates traditional AMR discovery, experimental research, and applied research with continuous analysis of pathogens, antimicrobial uses, and clinical outcomes that are routinely disseminated to practitioners, policy makers, patients, and the public to drive changes in practice and outcomes. AMR-X uses connected data-to-action systems to underpin an evaluation framework embedded in routine care, continuously driving implementation of improvements in patient and population health, targeting investment, and incentivising innovation. All stakeholders co-create AMR-X, protecting the public from AMR by adapting to continuously evolving AMR threats and generating the information needed for precision patient and population care.

Cost-effectiveness analysis of serplulimab in combination with cisplatin plus 5-fluorouracil chemotherapy compared to cisplatin plus 5-fluorouracil chemotherapy as first-line treatment for advanced or metastatic esophageal squamous cell carcinoma in China

Background

This study evaluated the cost-effectiveness of serplulimab plus chemotherapy versus chemotherapy alone in treating advanced/metastatic esophageal squamous cell carcinoma (ESCC) within the Chinese health care system.

Methods

A partitioned survival model based on ASTRUM-007 trial patient characteristics was developed. Efficacy, safety, and medical/economic data were obtained from the trial and real-world clinical practice. Costs, quality-adjusted life years (QALY), and incremental cost-effectiveness ratios (ICERs) were calculated for both treatment strategies. Sensitivity, subgroup, and scenario analyses were performed to assess the uncertainty impact.

Results

Serplulimab combined with chemotherapy yielded an ICER of US$ 53,538.27/QALY. Deterministic sensitivity analysis identified patient survival and serplulimab price as influential parameters. Probabilistic sensitivity analysis showed a 47.33% probability of cost-effectiveness at a willingness-to-pay (WTP) threshold of US$ 53,541/QALY and 0.05% at three times China's GDP per capita. Subgroup analysis revealed that patients with a programmed death-ligand 1 (PD-L1) expression combined positive score (CPS) ⩾10 had a lower hazard ratio (0.59) and ICER (US$ 29,935.23/QALY), with a 95.36% probability of cost-effectiveness. Scenario analysis demonstrated that the drug donation discount policy significantly increased the likelihood of cost-effective serplulimab-chemotherapy combinations in Jiangsu, Fujian, and Guangdong at 99.99%, 99.90%, and 94.16%, respectively.

Conclusion

Compared to chemotherapy alone, serplulimab combined with chemotherapy is currently not a cost-effective first-line treatment for advanced/metastatic ESCC in China. However, as serplulimab plus chemotherapy regimens evolve and price competition among programmed death 1 (PD-1) inhibitors intensifies, this combination may become a cost-effective treatment option.

Perspectives on research needs in healthcare epidemiology, infection prevention, and antimicrobial stewardship: what's on the horizon-Part II

In this overview, we articulate research needs and opportunities in the field of infection prevention that have been identified from insights gained during operative infection prevention work, our own research in healthcare epidemiology, and from reviewing the literature. The 10 areas of research need are: 1) Transmissions and interruptions, 2) personal protective equipment and other safety issues in occupational health, 3) climate change and other crises, 4) device, diagnostic, and antimicrobial stewardship, 5) implementation and deimplementation, 6) healthcare outside the acute care hospital, 7) low- and middle-income countries, 8) networking with the "neighbors," 9) novel research methodologies, and 10) the future state of surveillance. An introduction and chapters 1-5 are presented in part I of the article and chapters 6-10 and the discussion in part II. There are many barriers to advancing the field, such as finding and motivating the future IP workforce including professionals interested in conducting research, a constant confrontation with challenges and crises, the difficulty of performing studies in a complex environment, the relative lack of adequate incentives and funding streams, and how to disseminate and validate the often very local quality improvement projects. Addressing research gaps now (i.e., in the post-pandemic phase) will make healthcare systems more resilient when facing future crises.

Patterns of antibiotic use, pathogens, and prediction of mortality in hospitalized neonates and young infants with sepsis: A global neonatal sepsis observational cohort study (NeoOBS)

BACKGROUND

There is limited data on antibiotic treatment in hospitalized neonates in low- and middle-income countries (LMICs). We aimed to describe patterns of antibiotic use, pathogens, and clinical outcomes, and to develop a severity score predicting mortality in neonatal sepsis to inform future clinical trial design.

METHODS AND FINDINGS

Hospitalized infants <60 days with clinical sepsis were enrolled during 2018 to 2020 by 19 sites in 11 countries (mainly Asia and Africa). Prospective daily observational data was collected on clinical signs, supportive care, antibiotic treatment, microbiology, and 28-day mortality. Two prediction models were developed for (1) 28-day mortality from baseline variables (baseline NeoSep Severity Score); and (2) daily risk of death on IV antibiotics from daily updated assessments (NeoSep Recovery Score). Multivariable Cox regression models included a randomly selected 85% of infants, with 15% for validation. A total of 3,204 infants were enrolled, with median birth weight of 2,500 g (IQR 1,400 to 3,000) and postnatal age of 5 days (IQR 1 to 15). 206 different empiric antibiotic combinations were started in 3,141 infants, which were structured into 5 groups based on the World Health Organization (WHO) AWaRe classification. Approximately 25.9% (n = 814) of infants started WHO first line regimens (Group 1-Access) and 13.8% (n = 432) started WHO second-line cephalosporins (cefotaxime/ceftriaxone) (Group 2-"Low" Watch). The largest group (34.0%, n = 1,068) started a regimen providing partial extended-spectrum beta-lactamase (ESBL)/pseudomonal coverage (piperacillin-tazobactam, ceftazidime, or fluoroquinolone-based) (Group 3-"Medium" Watch), 18.0% (n = 566) started a carbapenem (Group 4-"High" Watch), and 1.8% (n = 57) a Reserve antibiotic (Group 5, largely colistin-based), and 728/2,880 (25.3%) of initial regimens in Groups 1 to 4 were escalated, mainly to carbapenems, usually for clinical deterioration (n = 480; 65.9%). A total of 564/3,195 infants (17.7%) were blood culture pathogen positive, of whom 62.9% (n = 355) had a gram-negative organism, predominantly Klebsiella pneumoniae (n = 132) or Acinetobacter spp. (n = 72). Both were commonly resistant to WHO-recommended regimens and to carbapenems in 43 (32.6%) and 50 (71.4%) of cases, respectively. MRSA accounted for 33 (61.1%) of 54 Staphylococcus aureus isolates. Overall, 350/3,204 infants died (11.3%; 95% CI 10.2% to 12.5%), 17.7% if blood cultures were positive for pathogens (95% CI 14.7% to 21.1%, n = 99/564). A baseline NeoSep Severity Score had a C-index of 0.76 (0.69 to 0.82) in the validation sample, with mortality of 1.6% (3/189; 95% CI: 0.5% to 4.6%), 11.0% (27/245; 7.7% to 15.6%), and 27.3% (12/44; 16.3% to 41.8%) in low (score 0 to 4), medium (5 to 8), and high (9 to 16) risk groups, respectively, with similar performance across subgroups. A related NeoSep Recovery Score had an area under the receiver operating curve for predicting death the next day between 0.8 and 0.9 over the first week. There was significant variation in outcomes between sites and external validation would strengthen score applicability.

CONCLUSION

Antibiotic regimens used in neonatal sepsis commonly diverge from WHO guidelines, and trials of novel empiric regimens are urgently needed in the context of increasing antimicrobial resistance (AMR). The baseline NeoSep Severity Score identifies high mortality risk criteria for trial entry, while the NeoSep Recovery Score can help guide decisions on regimen change. NeoOBS data informed the NeoSep1 antibiotic trial (ISRCTN48721236), which aims to identify novel first- and second-line empiric antibiotic regimens for neonatal sepsis.

TRIAL REGISTRATION

ClinicalTrials.gov, (NCT03721302).

The Personalised Randomized Controlled Trial: Evaluation of a new trial design

In some clinical scenarios, for example, severe sepsis caused by extensively drug resistant bacteria, there is uncertainty between many common treatments, but a conventional multiarm randomized trial is not possible because individual participants may not be eligible to receive certain treatments. The Personalised Randomized Controlled Trial design allows each participant to be randomized between a "personalised randomization list" of treatments that are suitable for them. The primary aim is to produce treatment rankings that can guide choice of treatment, rather than focusing on the estimates of relative treatment effects. Here we use simulation to assess several novel analysis approaches for this innovative trial design. One of the approaches is like a network meta-analysis, where participants with the same personalised randomization list are like a trial, and both direct and indirect evidence are used. We evaluate this proposed analysis and compare it with analyses making less use of indirect evidence. We also propose new performance measures including the expected improvement in outcome if the trial's rankings are used to inform future treatment rather than random choice. We conclude that analysis of a personalized randomized controlled trial can be performed by pooling data from different types of participants and is robust to moderate subgroup-by-intervention interactions based on the parameters of our simulation. The proposed approach performs well with respect to estimation bias and coverage. It provides an overall treatment ranking list with reasonable precision, and is likely to improve outcome on average if used to determine intervention policies and guide individual clinical decisions.

Clinical trials of tuberculosis vaccines in the era of increased access to preventive antibiotic treatment

Approximately 10·6 million people worldwide develop tuberculosis each year, representing a failure in epidemic control that is accentuated by the absence of effective vaccines to prevent infection or disease in adolescents and adults. Without effective vaccines, tuberculosis prevention has relied on testing for Mycobacterium tuberculosis infection and treating with antibiotics to prevent progression to tuberculosis disease, known as tuberculosis preventive treatment (TPT). Novel tuberculosis vaccines are in development and phase 3 efficacy trials are imminent. The development of effective, shorter, and safer TPT regimens has broadened the groups eligible for TPT beyond people with HIV and child contacts of people with tuberculosis; future vaccine trials will be undertaken in an era of increased TPT access. Changes in the prevention standard will have implications for tuberculosis vaccine trials of disease prevention, for which safety and sufficient accrual of cases are crucial. In this paper, we examine the urgent need for trials that allow the evaluation of new vaccines and fulfil the ethical duty of researchers to provide TPT. We observe how HIV vaccine trials have incorporated preventive treatment in the form of pre-exposure prophylaxis, propose trial designs that integrate TPT, and summarise considerations for each design in terms of trial validity, efficiency, participant safety, and ethics.

A Clinically Oriented antimicrobial Resistance surveillance Network (ACORN): pilot implementation in three countries in Southeast Asia, 2019-2020

Background: Case-based surveillance of antimicrobial resistance (AMR) provides more actionable data than isolate- or sample-based surveillance. We developed A Clinically Oriented antimicrobial Resistance surveillance Network (ACORN) as a lightweight but comprehensive platform, in which we combine clinical data collection with diagnostic stewardship, microbiological data collection and visualisation of the linked clinical-microbiology dataset. Data are compatible with WHO GLASS surveillance and can be stratified by syndrome and other metadata. Summary metrics can be visualised and fed back directly for clinical decision-making and to inform local treatment guidelines and national policy. Methods: An ACORN pilot was implemented in three hospitals in Southeast Asia (1 paediatric, 2 general) to collect clinical and microbiological data from patients with community- or hospital-acquired pneumonia, sepsis, or meningitis. The implementation package included tools to capture site and laboratory capacity information, guidelines on diagnostic stewardship, and a web-based data visualisation and analysis platform. Results: Between December 2019 and October 2020, 2294 patients were enrolled with 2464 discrete infection episodes (1786 community-acquired, 518 healthcare-associated and 160 hospital-acquired). Overall, 28-day mortality was 8.7%. Third generation cephalosporin resistance was identified in 54.2% (39/72) of E. coli and 38.7% (12/31) of K. pneumoniae isolates . Almost a quarter of S. aureus isolates were methicillin resistant (23.0%, 14/61). 290/2464 episodes could be linked to a pathogen, highlighting the level of enrolment required to achieve an acceptable volume of isolate data. However, the combination with clinical metadata allowed for more nuanced interpretation and immediate feedback of results. Conclusions: ACORN was technically feasible to implement and acceptable at site level. With minor changes from lessons learned during the pilot ACORN is now being scaled up and implemented in 15 hospitals in 9 low- and middle-income countries to generate sufficient case-based data to determine incidence, outcomes, and susceptibility of target pathogens among patients with infectious syndromes.

Combining factorial and multi-arm multi-stage platform designs to evaluate multiple interventions efficiently

BACKGROUND

Factorial designs and multi-arm multi-stage (MAMS) platform designs have many advantages, but the practical advantages and disadvantages of combining the two designs have not been explored.

METHODS

We propose practical methods for a combined design within the platform trial paradigm where some interventions are not expected to interact and could be given together.

RESULTS

We describe the combined design and suggest diagrams that can be used to represent it. Many properties are common both to standard factorial designs, including the need to consider interactions between interventions and the impact of intervention efficacy on power of other comparisons, and to standard multi-arm multi-stage designs, including the need to pre-specify procedures for starting and stopping intervention comparisons. We also identify some specific features of the factorial-MAMS design: timing of interim and final analyses should be determined by calendar time or total observed events; some non-factorial modifications may be useful; eligibility criteria should be broad enough to include any patient eligible for any part of the randomisation; stratified randomisation may conveniently be performed sequentially; and analysis requires special care to use only concurrent controls.

CONCLUSION

A combined factorial-MAMS design can combine the efficiencies of factorial trials and multi-arm multi-stage platform trials. It allows us to address multiple research questions under one protocol and to test multiple new treatment options, which is particularly important when facing a new emergent infection such as COVID-19.

Risk Factors for Mortality Among Critical Acute Pancreatitis Patients with Carbapenem-Resistant Organism Infections and Drug Resistance of Causative Pathogens

Introduction

Carbapenem-resistant organisms (CRO) have emerged as a major global public health threat, but their role in critical acute pancreatitis (CAP) is still not defined. Our study aims to investigate risk factors associated with mortality and drug resistance among CAP patients with CRO infection.

Methods

The clinical characteristics of CAP patients with CRO infection and drug resistance of causative pathogens from January 1, 2016, to October 1, 2021, were reviewed retrospectively. Independent risk factors for mortality were determined via univariate and multivariate analyses.

Result

Eighty-two CAP patients suffered from CRO infection, with mortality of 60.0%. The independent risk factors for mortality were procalcitonin > 5 ng/L (hazard ratio = 2.300, 95% confidence interval = 1.180–4.484, P = 0.014) and lactic acid > 2 mmol/L (hazard ratio = 2.101, 95% confidence interval = 1.151–3.836, P = 0.016). The pancreas was the main site of infection, followed by lung, bloodstream and urinary tract. Klebsiella pneumoniae and Acinetobacter baumannii were the main pathogenic bacteria of CRO strains with extensive antibiotic resistance (> 60%) to 6 of 8 common antibiotics, except sulfamethoxazole (56.3%) and tigecycline (33.2%).

Conclusion

CRO infection has become a serious threat for CAP patients, with high rates of mortality. Procalcitonin and lactic acid represent two independent risk factors for mortality in CAP patients with CRO infection. Klebsiella pneumoniae and Acinetobacter baumannii are the primary categories of CRO pathogens. Greater efforts are needed for early prevention and prompt treatment of CRO infections in CAP patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-022-00624-w.