Do n-of-1 trials really tailor treatment?

Experimental Designs to Optimize Treatments for Individuals: Personalized N-of-1 Trials

Conventional randomized clinical trials (RCTs) compare treatment effectiveness to provide support for evidence-based treatments that can be generalized to the average patient. However, the information obtained from RCTs may not always be useful for selecting the best treatment for individual patients. This article presents a complementary approach to identifying optimized treatments using experimental designs that focus on individuals. Personalized, or N-of-1, designs provide both a comparative analysis of treatments and a functional analysis demonstrating that changes in patient symptoms are likely because of the treatment implemented. This approach contributes to the zeitgeist of personalized medicine and provides clinicians with a paradigm for investigating optimal treatments for rare diseases for which RCTs are not always feasible, identifying personally effective treatments for patients with comorbidities who have historically been excluded from most RCTs, handling clinical situations in which patients respond idiosyncratically (either positively or negatively) to treatment, and shortening the time lag between identification and implementation of an evidence-based treatment. These designs merge experimental analysis of behavior methods used for decades in psychology with new methodological and statistical advances to assess significance levels of changes in individual patients, and they can be generalized to larger populations for meta-analytic purposes. This article presents a case for why these models are needed, an overview of how to apply personalized designs for different types of clinical scenarios, and a brief discussion of challenges associated with interpretation and implementation of personalized designs. The goal is to empower pediatricians to take personalized trial designs into clinical practice to identify optimal treatments for their patients.

Amantadine Therapy in Traumatic Brain Injury Patients

Objective:

To review literature on amantadine therapy in patients with traumatic brain injury (TBI).

Data Sources:

MEDLINE (1966–March 2006), EMBASE (1974–March 2006), BIOSIS (1969–March 2006), and International Pharmaceutical Abstracts (1970–March 2006) were searched to identify papers on the clinical outcomes of patients with TBI treated with amantadine. A bibliographic search was also performed.

Study Selection and Data Extraction:

Papers were excluded if they were not published in English, if they included patients less than 16 years old, or if they included patients in whom the effects of multiple medications, rather than amantadine alone, were studied. Reports were categorized according to the time of initiation of amantadine following the injury.

Data Synthesis:

Reports examining early initiation of amantadine suggest a possible benefit for treatment of decreased responsiveness and functional recovery. One report examining late initiation of amantadine failed to demonstrate benefit in the treatment of motor impairment, while 2 reports suggested possible improvement of functional recovery. Finally, reports examining late initiation of amantadine in the treatment of cognitive and behavioral therapy demonstrated possible benefit.

Conclusions:

Further investigation is needed before either early or late initiation of amantadine can be recommended for treatment of decreased responsiveness and functional recovery. However, while additional research is conducted, late initiation of amantadine can be considered an option for the treatment of cognitive and behavioral impairments in patients with TBI.

N-of-1 randomized trials for psychological and health behavior outcomes: a systematic review protocol

BACKGROUND

Randomized controlled trials are the sine qua non of causal inference; however, heterogeneity of treatment effects for many chronic conditions and for many symptoms often limits their utility. Single-patient studies in which patients select a treatment after trying a randomized sequence of treatments (i.e., multiple crossover trials) offer an alternative to traditional randomized controlled trials by providing scientifically valid results in a practical manner that can be used by patients and their providers to decide upon their personally optimal treatment. Although N-of-1 trials have been used in the medical literature, their use for interventions that consist of psychological or health behavior outcomes is unknown. This systematic review thus aims to describe the interventions and outcomes and assess the quality of N-of-1 trials for psychological or health behavior outcomes.

METHODS/DESIGN

Electronic databases (Ovid MEDLINE, EMBASE, CINAHL, PsycINFO, and the six databases in the Cochrane Library) will be searched using all relevant subject headings and free-text terms to represent N-of-1 trials and psychological or behavioral interventions. Full text review and bibliography searching will be conducted. Unpublished studies will be sought by searching trial registries and contacting authors of included studies. Eligibility criteria are the following: population, all human participants for whom N-of-1 trials with psychological or health behavior outcomes have been conducted; interventions, all interventions for which N-of-1 trials have been conducted; comparison, placebo or active treatment control; and outcome, psychological and health behavior outcomes including self-perceived disease severity and psychological phenomena such as mood and affect. Studies that do not contain sufficient trial detail, describe only design or statistical analytic issues in N-of-1 trials without presentation of an N-of-1 trial itself, and/or are not written in the English language are ineligible. Screening, data extraction, and quality assessment will be conducted by two independent reviewers with disagreements resolved through discussion.

DISCUSSION

This systematic review will describe the interventions and outcomes and assess the quality of N-of-1 trials for psychological or health behavior outcomes. The results will clarify the use of this research methodology in the health psychology and behavioral medicine literature and may pave the way for additional N-of-1 trials to be conducted.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015017853.

Clinical research and medical care: towards effective and complete integration

Background

Despite their close relationship, clinical research and medical care have become separated by clear boundaries. The purpose of clinical research is to generate generalizable knowledge useful for future patients, whereas medical care aims to promote the well-being of individual patients. The evolution towards patient-centered medicine and patient-oriented research, and the gradual standardization of medicine are contributing to closer ties between clinical research and medical practice. But the integration of both activities requires addressing important ethical and methodological challenges.

Discussion

From an ethical perspective, clinical research should evolve from a position of paternalistic beneficence to a situation in which the principle of non-maleficence and patient autonomy predominate. The progressive adoption of “patient-oriented informed consent”, “patient equipoise”, and “altruism-based research”, and the application of risk-based ethical oversight, in which the level of regulatory scrutiny is adapted to the potential risk for patients, are crucial steps to achieve the integration between research and care.

From a methodological standpoint, careful and systematic observations should have greater relevance in clinical research, and experiments should be embedded into usual clinical practice. Clinical research should focus on individuals through the development of patient-oriented research. In a complementary way, the integration of experiments into medical practice through the systematic application of “point of care research” could help to generate knowledge for the individuals and for the populations.

Summary

The integration of clinical research and medical care will require researchers, clinicians, health care managers, and patients to reevaluate the way they understand both activities. The development of an integrated learning health care system will contribute to generating and applying clinically relevant medical knowledge, producing benefits for present and future patients.

Modulation of oxidative stress and microinflammatory status by colloids in refractory dialytic hypotension

Background

Intradialytic hypotension may adversely affect the outcome of chronic hemodialysis. Therapeutic albumin has powerful anti-oxidant and anti-inflammatory properties. We have recently shown that systematic colloid infusion during hemodialysis sessions improves hemodynamic parameters in most dialysis hypotension-prone patients unresponsive to usual of preventive measures.

We postulated that frequent hypotensive episodes may lead to a noxious inflammatory response mediated by oxidative stress induced by ischemia-reperfusion. The aim of this study was therefore to analyze the effect of 20% albumin and 4% gelatin infusions on oxidative stress and microinflammatory status in hypotension-prone patients unresponsive to usual preventive measures.

Methods

Prospective cross-over study (lasting 20 weeks) of routine infusion of 200 ml of 20% albumin versus 200 ml of 4% gelatin in 10 patients with refractory intradialytic hypotension. We analyzed the effect of 20% albumin and 4% gelatin on microinflammatory status, oxidative stress, serum nitrite and nitrate levels by analysis of variance.

Results

A significant decrease in serum ceruloplasmin and serum C3 was observed during the albumin period (p < 0.05, repeated measure ANOVA). A significant decrease in serum hydrogen peroxide was seen during albumin and gelatin administration (p < 0.01, repeated measure ANOVA) and a very large decrease in serum lipid peroxides was observed during the albumin period only (p < 0.01, Friedman test). Serum lactoferrin, serum proinflammatory cytokines and serum nitrite and nitrate levels remained stable during the different periods of this pilot trial.

Conclusions

We conclude that the improvement in microinflammatory status observed during colloid infusion in hypotension-prone dialysis patients may be related to a decrease in ischemia-reperfusion of noble organs, together with a specific reduction in oxidative stress by albumin.

Trial registration

ISRCTN 20957055

Effectiveness of topical administration of opioids in palliative care: a systematic review

The discovery of peripheral opioid receptors has become the scientific basis for topical use of opioids in malignant and nonmalignant ulcers and oropharyngeal mucositis. This systematic review aimed to assess the quality of published literature and to examine whether topical opioids are effective in controlling pain in palliative care settings. After a systematic literature review, 19 studies (six randomized controlled trials [RCTs] and 13 case reports) met the inclusion criteria for the review. Eighteen studies favored topical opioids in pain relief, as evidenced by reductions in post-treatment pain scores, but time to onset and duration of analgesia varied widely. Because of the heterogeneity of the studies, meta-analysis was not possible. Despite clear clinical benefits described in small RCTs, there is a deficiency of higher-quality evidence on the role of topical opioids, and more robust primary studies are required to inform practice recommendations. N-of-1 trials should be encouraged for specific clinical circumstances.

Use of double-blind placebo-controlled N-of-1 trials among stimulant-treated youths in The Netherlands: a descriptive study

OBJECTIVES

An N-of-1 trial is a double-blind placebo-controlled randomized trial to objectively and systematically evaluate the individual's response. This approach seems extraordinarily suitable for assessing the efficacy of stimulants in the treatment of attention deficit hyperactivity disorder (ADHD). The aim is to examine the use of N-of-1 trials among youths in the Netherlands, the protocols used, and the continuation of stimulant treatment thereafter.

METHODS

Physicians requesting N-of-1 trials with stimulants were interviewed about their rationale and protocol. Prevalence and continuation were investigated by extracting N-of-1 trials among youths <20 years of age from a large pharmacy dispensing database for 2000-2004.

RESULTS

The main purpose of N-of-1 trials mentioned by physicians was the assessing of individuals' response and dose-finding. Trial length, dosing schedule and efficacy assessment differed per physician. Trials consisted of a maximum of two treatment periods per dose. The annual percentage of youths starting stimulant treatment with an N-of-1 trial fluctuated between 0.6% (3/462) and 3.3% (10/301). No statistical significant difference could be detected between the continuation of stimulant treatment with or without an N-of-1 trial (p = 0.71).

CONCLUSIONS

N-of-1 trials with stimulants are infrequently and not optimally used in the Netherlands. The results of N-of-1 protocols described by physicians are of questionable value, due to the small number of treatment periods per dose. More uniformity in the protocols would make it easier to encompass the N-of-1 methodology in physicians' daily practice.

Conducting research in individual patients: lessons learnt from two series of N-of-1 trials

Background

Double-blind randomised N-of-1 trials (N-of-1 trials) may help with decisions concerning treatment when there is doubt regarding the effectiveness and suitability of medication for individual patients. The patient is his or her own control, and receives the experimental and the control treatment during several periods of time in random order. Reports of N-of-1 trials are still relatively scarce, and the research methodology is not as firmly established as that of RCTs. Recently, we have conducted two series of N-of-1 trials in general practice. Before, during, and after data-collection, difficulties regarding outcome assessment, analysis of the results, the withdrawal of patients, and the follow-up had to be dealt with. These difficulties are described and our solutions are discussed.

Discussion

To prevent or anticipate difficulties in N-of-1 trials, we argue that that it is important to individualise the outcome measures, and to carefully consider the objective, type of randomisation and the analysis. It is recommended to use the same dosages and dosage forms that the patient used before the trial, to start the trial with a run-in period, to formulate both general and individualised decision rules regarding the efficacy of treatment, to adjust treatment policies immediately after the trial, and to provide adequate instructions and support if treatment is adjusted.

Summary

Because of the specific characteristics of N-of-1 trials it is difficult to formulate general 'how to do it' guidelines for designing N-of-1 trials. However, when the design of each N-of-1 trial is tailored to the specific characteristics of each individual patient and the underlying medical problem, most difficulties in N-of-1 trials can be prevented or overcome. In this way, N-of-1 trials may be of help when deciding on drug treatment for individual patients.