A stepwise approach to justify phase III randomized clinical trials and enhance the likelihood of a positive result

Safety of high-dose amikacin in the first week of all-oral rifampicin-resistant tuberculosis treatment for the prevention of acquired resistance (STAKE): protocol for a single-arm clinical trial

INTRODUCTION

An effective rifampicin-resistant tuberculosis (RR-TB) treatment regimen should include prevention of resistance amplification. While bedaquiline (BDQ) has been recommended in all-oral RR-TB treatment regimen since 2019, resistance is rising at alarming rates. This may be due to BDQ's delayed bactericidal effect, which increases the risk of selecting for resistance to fluoroquinolones and/or BDQ in the first week of treatment when the bacterial load is highest. We aim to strengthen the first week of treatment with the injectable drug amikacin (AMK). To limit the ototoxicity risk while maximising the bactericidal effect, we will evaluate the safety of adding a 30 mg/kg AMK injection on the first and fourth day of treatment.

METHODS AND ANALYSIS

We will conduct a single-arm clinical trial on 20 RR-TB patients nested within an operational study called ShoRRT (All oral Shorter Treatment Regimen for Drug resistant Tuberculosis). In addition to all-oral RR-TB treatment, patients will receive two doses of AMK. The primary safety endpoint is any grade 3-4 adverse event during the first 2 weeks of treatment related to the use of AMK. With a sample size of 20 patients, we will have at least 80% statistical power to support the alternative hypothesis, indicating that less than 14% of patients treated with AMK experience a grade 3-4 adverse event related to its use. Safety data obtained from this study will inform a larger multicountry study on using two high doses of AMK to prevent acquired resistance.

ETHICS AND DISSEMINATION

Approval was obtained from the ethics committee of Rwanda, Rwanda Food and Drug Authority, Universitair Ziekenhuis, the Institute of Tropical Medicine ethics review board. All participants will provide informed consent. Study results will be disseminated through peer-reviewed journals and conferences.

TRIAL REGISTRATION NUMBER

NCT05555303.

Guidelines on the management of acute respiratory distress syndrome

The Faculty of Intensive Care Medicine and Intensive Care Society Guideline Development Group have used GRADE methodology to make the following recommendations for the management of adult patients with acute respiratory distress syndrome (ARDS). The British Thoracic Society supports the recommendations in this guideline. Where mechanical ventilation is required, the use of low tidal volumes (<6 ml/kg ideal body weight) and airway pressures (plateau pressure <30 cmH2O) was recommended. For patients with moderate/severe ARDS (PF ratio<20 kPa), prone positioning was recommended for at least 12 hours per day. By contrast, high frequency oscillation was not recommended and it was suggested that inhaled nitric oxide is not used. The use of a conservative fluid management strategy was suggested for all patients, whereas mechanical ventilation with high positive end-expiratory pressure and the use of the neuromuscular blocking agent cisatracurium for 48 hours was suggested for patients with ARDS with ratio of arterial oxygen partial pressure to fractional inspired oxygen (PF) ratios less than or equal to 27 and 20 kPa, respectively. Extracorporeal membrane oxygenation was suggested as an adjunct to protective mechanical ventilation for patients with very severe ARDS. In the absence of adequate evidence, research recommendations were made for the use of corticosteroids and extracorporeal carbon dioxide removal.

A path to precision in the ICU

Precision medicine is increasingly touted as a groundbreaking new paradigm in biomedicine. In the ICU, the complexity and ambiguity of critical illness syndromes have been identified as fundamental justifications for the adoption of a precision approach to research and practice. Inherently protean diseases states such as sepsis and acute respiratory distress syndrome have manifestations that are physiologically and anatomically diffuse, and that fluctuate over short periods of time. This leads to considerable heterogeneity among patients, and conditions in which a “one size fits all” approach to therapy can lead to widely divergent results. Current ICU therapy can thus be seen as imprecise, with the potential to realize substantial gains from the adoption of precision medicine approaches. A number of challenges still face the development and adoption of precision critical care, a transition that may occur incrementally rather than wholesale. This article describes a few concrete approaches to addressing these challenges.

First, novel clinical trial designs, including registry randomized controlled trials and platform trials, suggest ways in which conventional trials can be adapted to better accommodate the physiologic heterogeneity of critical illness. Second, beyond the “omics” technologies already synonymous with precision medicine, the data-rich environment of the ICU can generate complex physiologic signatures that could fuel precision-minded research and practice. Third, the role of computing infrastructure and modern informatics methods will be central to the pursuit of precision medicine in the ICU, necessitating close collaboration with data scientists. As work toward precision critical care continues, small proof-of-concept studies may prove useful in highlighting the potential of this approach.

Clinical trial design in prevention and treatment of acute respiratory distress syndrome

Our ability to define appropriate molecular targets for preclinical development and develop better methods needs to be improved, to determine the clinical value of novel acute respiratory distress syndrome (ARDS) agents. Clinical trials must have realistic sample sizes and meaningful end points and use the available observation and meta-analytical data to inform design. Biomarker-driven studies or defined ARDS subsets should be considered to categorize specific at-risk populations most likely to benefit from a new treatment. Innovations in clinical trial design should be pursued to improve the outlook for future interventional trials in ARDS.

Outcomes and statistical power in adult critical care randomized trials

RATIONALE

Intensive care unit (ICU)-based randomized clinical trials (RCTs) among adult critically ill patients commonly fail to detect treatment benefits.

OBJECTIVES

Appraise the rates of success, outcomes used, statistical power, and design characteristics of published trials.

METHODS

One hundred forty-six ICU-based RCTs of diagnostic, therapeutic, or process/systems interventions published from January 2007 to May 2013 in 16 high-impact general or critical care journals were studied.

MEASUREMENT AND MAIN RESULTS

Of 146 RCTs, 54 (37%) were positive (i.e., the a priori hypothesis was found to be statistically significant). The most common primary outcomes were mortality (n = 40 trials), infection-related outcomes (n = 33), and ventilation-related outcomes (n = 30), with positive results found in 10, 58, and 43%, respectively. Statistical power was discussed in 135 RCTs (92%); 92 cited a rationale for their power parameters. Twenty trials failed to achieve at least 95% of their reported target sample size, including 11 that were stopped early due to insufficient accrual/logistical issues. Of 34 superiority RCTs comparing mortality between treatment arms, 13 (38%) accrued a sample size large enough to find an absolute mortality reduction of 10% or less. In 22 of these trials the observed control-arm mortality rate differed from the predicted rate by at least 7.5%.

CONCLUSIONS

ICU-based RCTs are commonly negative and powered to identify what appear to be unrealistic treatment effects, particularly when using mortality as the primary outcome. Additional concerns include a lack of standardized methods for assessing common outcomes, unclear justifications for statistical power calculations, insufficient patient accrual, and incorrect predictions of baseline event rates.

Continuous infusion of beta-lactam antibiotics in severe sepsis: a multicenter double-blind, randomized controlled trial

BACKGROUND

Beta-lactam antibiotics are a commonly used treatment for severe sepsis, with intermittent bolus dosing standard therapy, despite a strong theoretical rationale for continuous administration. The aim of this trial was to determine the clinical and pharmacokinetic differences between continuous and intermittent dosing in patients with severe sepsis.

METHODS

This was a prospective, double-blind, randomized controlled trial of continuous infusion versus intermittent bolus dosing of piperacillin-tazobactam, meropenem, and ticarcillin-clavulanate conducted in 5 intensive care units across Australia and Hong Kong. The primary pharmacokinetic outcome on treatment analysis was plasma antibiotic concentration above the minimum inhibitory concentration (MIC) on days 3 and 4. The assessed clinical outcomes were clinical response 7-14 days after study drug cessation, ICU-free days at day 28 and hospital survival.

RESULTS

Sixty patients were enrolled with 30 patients each allocated to the intervention and control groups. Plasma antibiotic concentrations exceeded the MIC in 82% of patients (18 of 22) in the continuous arm versus 29% (6 of 21) in the intermittent arm (P = .001). Clinical cure was higher in the continuous group (70% vs 43%; P = .037), but ICU-free days (19.5 vs 17 days; P = .14) did not significantly differ between groups. Survival to hospital discharge was 90% in the continuous group versus 80% in the intermittent group (P = .47).

CONCLUSIONS

Continuous administration of beta-lactam antibiotics achieved higher plasma antibiotic concentrations than intermittent administration with improvement in clinical cure. This study provides a strong rationale for further multicenter trials with sufficient power to identify differences in patient-centered endpoints.

Strategies to reduce ventilator-associated lung injury (VALI)

Optimal management of the acute respiratory distress syndrome (ARDS) requires prompt recognition, treatment of the underlying cause and the prevention of secondary injury. Ventilator-associated lung injury (VALI) is one of the several iatrogenic factors that can exacerbate lung injury and ARDS. Reduction of VALI by protective low tidal volume ventilation is one of the only interventions with a proven survival benefit in ARDS. There are, however, several factors inhibiting the widespread use of this technique in patients with established lung injury. Prevention of ARDS and VALI by detecting at-risk patients and implementing protective ventilation early is a feasible strategy. Detection of injurious ventilation itself is possible, and potential biological markers of VALI have been investigated. Finally, facilitation of protective ventilation, including techniques such as extracorporeal support, can mitigate VALI.

Biomarkers of acute lung injury: worth their salt?

The validation of biomarkers has become a key goal of translational biomedical research. The purpose of this article is to discuss the role of biomarkers in the management of acute lung injury (ALI) and related research. Biomarkers should be sensitive and specific indicators of clinically important processes and should change in a relevant timeframe to affect recruitment to trials or clinical management. We do not believe that they necessarily need to reflect pathogenic processes. We critically examined current strategies used to identify biomarkers and which, owing to expedience, have been dominated by reanalysis of blood derived markers from large multicenter Phase 3 studies. Combining new and existing validated biomarkers with physiological and other data may add predictive power and facilitate the development of important aids to research and therapy.