A simulation study evaluating bio-creep risk in serial non-inferiority clinical trials for preservation of effect

Ensuring Superior Reporting of Radiation Therapy Noninferiority Trials: A Systematic Review

Purpose

Although the frequency of noninferiority trials is increasing, the consistency of the reporting of these trials can vary. The aim of this systematic review was to assess the reporting quality of radiation therapy noninferiority trials.

Methods and Materials

The PubMed, Embase, and Cochrane databases were queried for randomized controlled radiation therapy trials with noninferiority hypotheses published in English between January 2000 and July 2022, and this was performed by an information scientist. Descriptive statistics were used to summarize data.

Results

Of 423 records screened, 59 (14%) were included after full-text review. All were published after 2003 and open label. The most common primary cancer type was breast (n = 15, 25%). Altered radiation fractionation (n = 26, 45%) and radiation de-escalation (n = 11, 19%) were the most common types of interventions. The most common primary endpoints were locoregional control (n = 17, 29%) and progression-free survival (n = 14, 24%). Fifty-three (90%) reported the noninferiority margin, and only 9 (17%) provided statistical justification for the margin. The median absolute noninferiority margin was 9% (interquartile range, 5%-10%), and the median relative margin was 1.51 (interquartile range, 1.33-2.04). Sample size calculations and confidence intervals were reported in 54 studies (92%). Both intention-to-treat and per-protocol analyses were reported in 27 studies (46%). In 31 trials (53%), noninferiority of the primary endpoint was reached.

Conclusions

There was variability in the reporting of key components of noninferiority trials. We encourage consideration of additional statistical reasoning such as guidelines or previous trials in the selection of the noninferiority margin, reporting both absolute and relative margins, and the avoidance of statistically vague or misleading language in the reporting of future noninferiority trials.

Are antifungal non-inferiority trials at risk of eroding effectiveness because of bio-creep? A secondary analysis of a systematic review

Non-inferiority randomized controlled trial (RCT) effectiveness may erode when results favour the active control over time, and when a decreasingly effective control arm is used in serial trials. We analyzed 32 antifungal noninferiority RCTs (NI-RCTs) for these scenarios in this secondary analysis of a systematic review. Our exploratory analysis suggests that the erosion risk in the effectiveness of antifungal non-inferiority trials is uncommon. Findings are limited by small sample size, and overall risk of bias.

Management of hard-to-heal leg ulcers with an acid-oxidising solution versus standard of care: the MACAN study

OBJECTIVE

The efficacy of available wound dressings in the treatment of hard-to-heal wounds is limited. A new therapeutic approach using an acid-oxidising solution (AOS) was developed. Its effect on healing progress, tolerability and safety properties were investigated in a clinical study, and compared with standard of care (SOC) wound dressings. The study aimed to demonstrate the non-inferiority of AOS to SOC in terms of wound healing progress.

METHOD

This open-label, randomised controlled trial was conducted at two study centres in Austria with patients with either infected or non-infected hard-to-heal leg ulcers of different aetiology. Patients were treated for six weeks either with AOS or SOC wound dressings. Outcome assessments included the percentage of granulation and re-epithelialisation tissue, wound size reduction, changes in wound pH, infection control and wound pain, local tolerability and adverse events (AEs). Healing time and rate were also assessed.

RESULTS

A total of 50 patients took part. In the AOS group, wounds exhibited higher amounts of granulation and re-epithelialisation tissue, and a faster and more pronounced wound size reduction compared with wounds in the SOC group. In the AOS-treated versus SOC-treated patients, a greater percentage of complete healing of hard-to-heal ulcers was achieved by the end of the study period (32% versus 8%, respectively). Furthermore, the wound pH decreased significantly faster in these wounds (p<0.0001). In all patients with infected leg ulcers, local infection was overcome more rapidly under AOS treatment. In the AOS group, one AE and no serious adverse events (SAEs) were detected versus 24 AEs and two SAEs in the SOC group.

CONCLUSION

In this study, AOS proved to be a highly effective treatment to support wound healing in infected or non-infected hard-to-heal leg ulcers of different aetiology. Efficacy was found to be not only non-inferior but superior to SOC wound dressings. Furthermore, tolerability and safety profiles were favourable for AOS.

Assessment of Data Supporting the Efficacy of New Antibiotics for Treating Infections Caused by Multidrug-resistant Bacteria

BACKGROUND

Infections caused by multidrug-resistant (MDR) bacteria are a major public health threat. We aimed to assess the data supporting US Food and Drug Administration (FDA) approval of new agents aimed to treat MDR bacterial infections and the data provided by postmarketing studies.

METHODS

We identified all drugs with in vitro activity against MDR bacteria initially approved by the FDA between January 2010 and December 2018. Characteristics of trials supporting approval and regulatory pathways were collected from Drugs@FDA. Characteristics of postmarketing studies were extracted from drug labels and ClinicalTrials.gov entries effective 1 June 2019.

RESULTS

Initial approval of 11 newly approved antibiotics with anti-MDR activity was supported by 20 trials, all with noninferiority design. All initially approved indications were for common infections, mostly acute bacterial skin and skin-structure infections, regardless of causative microorganism. The proportion of MDR bacteria in most trials was low (<10% for gram-negative infections, <1% for gram-positive pneumonia). Most trials (90%) excluded immunocompromised and critically ill patients. Of 16 additional postmarketing randomized controlled trials identified through ClinicalTrials.gov, only 2 exclusively included infections caused by MDR bacteria, comprising 116 patients. No drug was granted accelerated approval, which would mandate postmarketing efficacy studies.

CONCLUSIONS

The approval of new drugs with potential clinical activity against MDR bacteria is supported by trials evaluating infections caused by non-MDR organisms, using noninferiority design and excluding the patients most likely to require these agents. Subsequent postmarketing efficacy data against these organisms are scarce. Healthcare professionals and regulators should demand more robust data to support clinical decision making.

Novel Antibiotics May Be Noninferior but Are They Becoming Less Effective?: a Systematic Review

Novel antibiotics approved by noninferiority trials may become less effective over time in two scenarios: (i) the treatment effect in studies of novel antibiotics may be consistently worse than studies of older antibiotics; (ii) when a decreasingly effective control arm is used in a series of noninferiority trials. Our systematic review of 175 noninferiority antibiotic trials found these scenarios to be rare.

Non-inferiority Trial Design in Drug Development: A Primer for Cardiovascular Healthcare Professionals

Noninferiority trials, in which a new treatment is compared with a standard active treatment, are becoming increasingly popular in cardiovascular medicine. A noninferiority trial seeks to test whether the effect of a new drug is not unacceptably worse than that of an active comparator by more than a predefined noninferiority margin. Noninferiority trials are typically used when a new drug is anticipated to have an efficacy profile similar to its comparator and offers advantages over the existing drug (better toxicity profile, less expensive, less invasive, simpler regimen, shorter treatment duration, different resistance profile). Given the high number of noninferiority trials, it is vital that clinicians fully understand the clinical impacts of the results. Nonetheless, assessing noninferiority in a trial is complex, in both the design and the analysis phases. The crucial issue in the design of a noninferiority trial is the definition of the noninferiority margin, accounting for both statistical (summarizing the historical evidence of the active comparator from randomized controlled trials) and clinical (choosing the fraction of the effect of the old drug that should be "preserved" by the new drug) considerations. We review the role of noninferiority trials in the development of new cardiovascular treatments and discuss a variety of key issues involved in the design and conduction of noninferiority trials, using some examples from real clinical trials in cardiovascular medicine.

Advances in clinical trial design: Weaving tomorrow's TB treatments

Christian Lienhardt and co-authors discuss the conclusions of the PLOS Medicine Collection on advances in clinical trial design for development of new tuberculosis treatments.

Do non-inferiority trials of reduced intensity therapies show reduced effects? A descriptive analysis

OBJECTIVES

To identify non-inferiority trials within a cohort where the experimental therapy is the same as the active control comparator but at a reduced intensity and determine if these non-inferiority trials of reduced intensity therapies have less favourable results than other non-inferiority trials in the cohort. Such a finding would provide suggestive evidence of biocreep in these trials.

DESIGN

This metaresearch study used a cohort of non-inferiority trials published in the five highest impact general medical journals during a 5-year period. Data relating to the characteristics and results of the trials were abstracted.

PRIMARY OUTCOME MEASURES

Proportions of trials with a declaration of superiority, non-inferiority and point estimates favouring the experimental therapy and mean absolute risk differences for trials with outcomes expressed as a proportion.

RESULTS

Our search yielded 163 trials reporting 182 non-inferiority comparisons; 36 comparisons from 31 trials were between the same therapy at reduced and full intensity. Compared with trials not evaluating reduced intensity therapies, fewer comparisons of reduced intensity therapies demonstrated a favourable result (non-inferiority or superiority) (58.3%vs82.2%; P=0.002) and fewer demonstrated superiority (2.8%vs18.5%; P=0.019). Likewise, point estimates for reduced intensity therapies more often favoured active control than those for other trials (77.8%vs39.7%; P<0.001) as did mean absolute risk differences (+2.5% vs -0.7%; P=0.018).

CONCLUSIONS

Non-inferiority trials comparing a therapy at reduced intensity to the same therapy at full intensity showed reduced effects compared with other non-inferiority trials. This suggests these trials may have a high rate of type 1 errors and biocreep, with significant implications for the design and interpretation of future non-inferiority trials.

Comparative Effectiveness Research in Pediatric Respiratory Disease: Promise and Pitfalls

Comparative effectiveness research (CER) has become increasing central to clinical research in medicine. CER seeks to conduct clinical trials that compare different commonly used interventions in real-world settings (pragmatic clinical trials) and use a multitude of sources of evidence (including registries and cohort studies) to inform clinical decision making. CER also ensures that stakeholders (patients, families, care providers, insurers) have a voice in the research process by integrating formal stakeholder engagement as part of the research. This innovative approach to clinical research has distinct benefits and pitfalls. This review first defines what CER is and then describes some of its benefits and then pitfalls. The focus is on the role of CER in pediatrics.

Efficient Delivery of Investigational Antibacterial Agents via Sustainable Clinical Trial Networks

The economics of antibiotics can be improved by infectious diseases–specific clinical trial networks. While developers would still need to implement an independent phase 1 program as well as studies focused on highly resistant pathogens, standardized procedures in a network focused on usual drug resistance phenotype isolates would permit sharing of controls and would predictably generate high-quality pivotal data for product registration while creating cost and time savings in the range of 30%–40%. This would reduce economic barriers to antibiotic development and contribute to public health.

Progress in the Fight Against Multidrug-Resistant Bacteria 2005-2016: Modern Noninferiority Trial Designs Enable Antibiotic Development in Advance of Epidemic Bacterial Resistance

From a public health perspective, new antibacterial agents should be evaluated and approved for use before widespread resistance to existing agents emerges. However, for multidrug-resistant pathogens, demonstration of superior efficacy of a new agent over a current standard-of-care agent is routinely feasible only when epidemic spread of these dangerous organisms has already occurred. One solution to enable proactive drug development is to evaluate new antibiotics with improved in vitro activity against MDR pathogens using recently updated guidelines for active control, noninferiority trials of selected severe infections caused by more susceptible pathogens. Such trials are feasible because they enroll patients with infections due to pathogens with a "usual drug resistance" phenotype that will be responsive to widely registered standard-of-care comparator antibiotics. Such anticipatory drug development has constructively reshaped the antibiotic pipeline and offers the best chance of making safe and efficacious antibiotics available to the public ahead of epidemic resistance.