Aspects Of Clinical Trial Design Research Articles

Possible Strategies to Mitigate Placebo or Vehicle Response in Dry Eye Disease Trials: A Narrative Review.

Many candidate drugs for dry eye disease (DED) have been assessed over the years in pursuit of demonstrating efficacy in both signs and symptoms. However, patients with DED have very limited treatment options for management of both signs and symptoms of DED. There are several potential reasons behind this including the placebo or vehicle response, which is a frequent issue observed in DED trials. A high magnitude of vehicle response interferes with the estimation of a drug's treatment effect and may lead to failure of a clinical trial. To address these concerns, Tear Film and Ocular Surface Society International Dry Eye Workshop II taskforce has recommended a few study design strategies to minimize vehicle response observed in DED trials. This review briefly describes the factors that lead to placebo/vehicle response in DED trials and focuses on the aspects of clinical trial design that can be improved to mitigate vehicle response. In addition, it presents the observations from a recent ECF843 phase2b study, wherein the study design approach consisted of a vehicle run-in phase, withdrawal phase, and masked treatment transition, and led to consistent data for DED signs and symptoms and reduced vehicle response post randomization.

In silico cancer immunotherapy trials uncover the consequences of therapy-specific response patterns for clinical trial design and outcome

Late-stage cancer immunotherapy trials often lead to unusual survival curve shapes, like delayed curve separation or a plateauing curve in the treatment arm. It is critical for trial success to anticipate such effects in advance and adjust the design accordingly. Here, we use in silico cancer immunotherapy trials – simulated trials based on three different mathematical models – to assemble virtual patient cohorts undergoing late-stage immunotherapy, chemotherapy, or combination therapies. We find that all three simulation models predict the distinctive survival curve shapes commonly associated with immunotherapies. Considering four aspects of clinical trial design – sample size, endpoint, randomization rate, and interim analyses – we demonstrate how, by simulating various possible scenarios, the robustness of trial design choices can be scrutinized, and possible pitfalls can be identified in advance. We provide readily usable, web-based implementations of our three trial simulation models to facilitate their use by biomedical researchers, doctors, and trialists.

More and better clinical trials in health care: focusing on people, not just systems and processes.

More and better clinical trials in health care: focusing on people, not just systems and processes.

Randomized Trials Fit for the 21st Century: A Joint Opinion From the European Society of Cardiology, American Heart Association, American College of Cardiology, and the World Heart Federation.

Randomized Trials Fit for the 21st Century: A Joint Opinion From the European Society of Cardiology, American Heart Association, American College of Cardiology, and the World Heart Federation.

Trial by "Firsts": Clinical Trial Design and Regulatory Considerations in the Development and Approval of the First AAV Gene Therapy Product in the United States.

Given the therapeutic potential of supplying a normal copy of a mutant gene to the correct target tissue, gene therapy holds extraordinary promise for the treatment of genetic disease. Like other novel classes of therapeutics however, gene therapies must overcome a range of clinical, regulatory, and manufacturing hurdles to reach regulatory approval. This paper reviews key aspects of clinical trial design, development, and evaluation of a novel primary end point, and regulatory interactions that resulted in the first approval by the U.S. Food and Drug Administration (FDA) of an adeno-associated virus (AAV) gene therapy product.

Choice of Study Populations for Vaccines.

The natural history of cytomegalovirus (CMV) infection is complex. Individuals may experience primary infection, reactivation of latent infection, or reinfection with a new strain despite natural immunity. The ability of this virus to continue to replicate despite substantial immune responses is attributable to the many immune evasion genes encoded within its genome. Given this complex natural history and immunology, the design of clinical trials of CMV vaccines may require components not usually found in trials of vaccines designed to protect against viruses that cause only acute infections. In this article, we focus on specific aspects of clinical trial design that could be adopted to address the complexities of CMV infections. We consider women of childbearing age, toddlers, recipients of solid organ transplantation, and stem cell transplant patients, emphasizing the parallels between women and solid organ transplantation that could allow vaccines to be developed in parallel in both these patient groups. We emphasize the potential for studies of passive immunity to inform the selection of immunogens as candidates for active immunization and vice versa. We also illustrate how application of whole-genomic sequencing could document whether vaccines protect against reactivation or reinfection of CMV or both.

The ACTTION Guide to Clinical Trials of Pain Treatments: standing on the shoulders of giants.

The ACTTION Guide to Clinical Trials of Pain Treatments: standing on the shoulders of giants.

Editorial introductions

Editorial introductions

Designing Trials of Disease Modifying Agents for Early and Preclinical Alzheimer's Disease Intervention: What Evidence is Meaningful to Patients, Providers, and Payers?

Drug development for disease modifying agents in Alzheimer's disease (AD) is focused increasingly on targeting underlying pathology in very early stages of AD or in cognitively normal patients at elevated risk of developing dementia due to Alzheimer's. Very early interventional studies of this type have many uncertainties, including whether they can provide the clinical results that payers, providers, and patients will wish to see for decisions. This paper describes an initiative to create greater transparency for researchers to anticipate these decision needs. To create multi-stakeholder-vetted recommendations for the design of studies in later phases of drug development to evaluate the ability of disease modifying agents to delay or prevent the onset of dementia due to Alzheimer's disease (AD). A multi-stakeholder expert workgroup and overseeing steering group were convened to discuss current advances in early interventional clinical trial design and the evidence needs of patients, providers, and payers. Eight teleconferences and one in-person all-day meeting were held. Meetings were recorded and summary notes prepared between sessions. Final conclusions were consolidated by the project team with the workgroup Chair based on these discussions and were reviewed by group members. The in-person meeting was held in Baltimore, MD. In total, 36 stakeholders representing life sciences industry, payers or health technology assessors, patient advocates and research advocacy organizations, regulators, clinical experts and academic or NIH researchers. N/A. N/A. Certain aspects of clinical trial design were deemed important to address stakeholder decision needs for future Alzheimer's prevention drugs even as the field rapidly progresses. These include the need for more robust behavioral and psychological outcome data in early symptomatic disease and the need to update activities of daily living measures to include "digital independence." Amyloid, tau, and biomarkers of neurodegeneration should be included in trials and studied in relation to other early measures of change meaningful to individuals with AD, their families, and health plans. These measures include early sensitive changes in behavioral and psychological measures and ability to navigate the contemporary digital landscape. Additional work is needed to generate more robust behavioral and psychological outcome data in early symptomatic disease, and to generate multi-stakeholder consensus on early measures of change and magnitudes of change that will be meaningful to patients, providers, and payers.

Which Obstacles Prevent Us from Recruiting into Clinical Trials: A Survey about the Environment for Clinical Studies at a German University Hospital in a Comprehensive Cancer Center.

Prospective clinical studies are the most important tool in modern medicine. The standard in good clinical practice in clinical trials has constantly improved leading to more sophisticated protocols. Moreover, translational questions are increasingly addressed in clinical trials. Such trials must follow elaborate rules and regulations. This is accompanied by a significant increase in documentation issues which require substantial manpower. Furthermore, university-based clinical centers are interested in increasing the amount of patients treated within clinical trials, and this number has evolved to be a key quality criterion. The present study was initiated to elucidate the obstacles that limit clinical scientists in screening and recruiting for clinical trials. A specific questionnaire with 28 questions was developed focusing on all aspects of clinical trial design as well as trial management. This included questions on organizational issues, medical topics as well as potential patients' preferences and physician's goals. The questionnaire was established to collect data anonymously on a web-based platform. The survey was conducted within the Klinikum rechts der Isar, Faculty of Medicine, Technical University of Munich; physicians of all levels (Department Chairs, attending physicians, residents, as well as study nurses, and other study-related staff) were addressed. The answers were analyzed using the Survio analyzing tool (http://www.survio.com/de/). We collected 42 complete sets of answers; in total 28 physicians, 11 study nurses, and 3 persons with positions in administration answered our survey. The study centers reported to participate in a range of 3-160 clinical trials with a recruitment rate of 1-80%. Main obstacles were determined: 31/42 (74%) complained about limited human resources and 22/42 (52%) reported to have a lack on technical resources, too. 30/42 (71%) consented to the answer, that the documentation effort of clinical trials is too large. A possible increase of the patients' study participation rate up to over 20% was deemed to be possible if the described limitations could be overcome. The increasing documentation effort in clinical trials has led to a strong increase in the work load of scientific personnel. Recruiting of patients into clinical trials therefore is not only limited by patient issues, but also by the infrastructure of the centers. Especially the lack of study nurses is likely to be a major limitation. Furthermore, technical resources for time efficient and safe documentation within clinical routine as well as in clinical trials are required. By optimization of these factors, a significant increase in the amount of patients treated in clinical trials seems to be possible.

Population pharmacokinetic modeling of itraconazole and hydroxyitraconazole for oral SUBA-itraconazole and sporanox capsule formulations in healthy subjects in fed and fasted states.

Itraconazole is an orally active antifungal agent that has complex and highly variable absorption kinetics that is highly affected by food. This study aimed to develop a population pharmacokinetic model for itraconazole and the active metabolite hydroxyitraconazole, in particular, quantifying the effects of food and formulation on oral absorption. Plasma pharmacokinetic data were collected from seven phase I crossover trials comparing the SUBA-itraconazole and Sporanox formulations of itraconazole. First, a model of single-dose itraconazole data was developed, which was then extended to the multidose data. Covariate effects on itraconazole were then examined before extending the model to describe hydroxyitraconazole. The final itraconazole model was a 2-compartment model with oral absorption described by 4-transit compartments. Multidose kinetics was described by total effective daily dose- and time-dependent changes in clearance and bioavailability. Hydroxyitraconazole was best described by a 1-compartment model with mixed first-order and Michaelis-Menten elimination for the single-dose data and a time-dependent clearance for the multidose data. The relative bioavailability of SUBA-itraconazole compared to that of Sporanox was 173% and was 21% less variable between subjects. Food resulted in a 27% reduction in bioavailability and 58% reduction in the transit absorption rate constant compared to that with the fasted state, irrespective of the formulation. This analysis presents the most extensive population pharmacokinetic model of itraconazole and hydroxyitraconazole in the literature performed in healthy subjects. The presented model can be used for simulating food effects on itraconazole exposure and for performing prestudy power analysis and sample size estimation, which are important aspects of clinical trial design of bioequivalence studies.

Intricacy of missing data in clinical trials: Deterrence and management.

Missing data is frequently encountered in clinical studies. Unfortunately, they are often neglected or not properly handled during data analysis and this may significantly bias the results of the study, reduce study power and lead to invalid conclusions. Substantial instances of missing data are a serious problem that undermines the scientific trustworthiness of causal conclusions from clinical trials. The assumption that statistical analysis methods can compensate for such missing data is not justified. Hence aspects of clinical trial design that limit the probability of missing data should be an important objective, while planning a clinical trial. In addition to specific aspects of trial design, many components of clinical trial conduct can also limit the extent of missing data. The topic of missing data is often not a major concern until it is time for data collection and data analysis. This article discusses some basic issues about missing data as well as prospective “watch outs” which could reduce the occurrence of missing data. It provides some possible design considerations that should be considered in order to alleviate patients from dropping out of a clinical trial. In addition to these the concept of the missing data mechanism has also been discussed. Three types of missing data mechanisms missing completely at random, missing at random and not missing at random have been discussed in detail.

Challenges to improved therapeutics for metastatic castrate resistant prostate cancer: from recent successes and failures.

Men with metastatic castration-resistant prostate cancer (mCRPC) carry poor prognosis despite the use of docetaxel-based regimens which has modest survival benefit shown by randomized clinical trials. Significant progress in the discovery of novel therapeutic agents has been made in the past few years. While sipuleucel-T, cabazitaxel, and abiraterone gained regulatory approval in 2010 and 2011, several highly promising candidates/regimens have failed in large scale clinical trials. Challenges remain to optimize the design and interpretation of clinical trial results and develop more effective strategies for mCRPC. In this review, we examined the positive and negative clinical trials in mCRPC in the past and discussed the various aspects of clinical trial design including selection of targets and appropriate outcome measures, biomarker development and implementation, and strategies for combination therapy.

Risk-adapted approaches to the management of clinical trials: guidance from the Department of Health (DH)/Medical Research Council(MRC)/Medicines and Healthcare Products Regulatory Agency (MHRA) Clinical Trials Working Group

In 2009, the Department of Health asked the MRC and MHRA to identify major obstacles to non-commercial clinical trials research in the UK and suggest remedial actions. Risk-proportionality in trial management and monitoring was identified as a key area and a sub-group formed to: • Develop a process to facilitate the agreement of key stakeholders on the level of risk associated with a clinical trial of an investigational medicinal product (CTIMP). • Identify how risk-adapted approaches for CTIMPs can be achieved within the current regulatory framework. • Develop guidance on risk assessment and the risk-proportionate management of clinical trials. The resulting guidance focuses on the risks inherent in a trial protocol which impact on participant safety and rights, and the reliability of the results. A two-part assessment is suggested: 1) a simple IMP risk categorisation based on marketing status and standard medical care, and 2) assessment of the trial design, population and procedures to identify specific areas of vulnerability. The first part, IMP risk category, has implications for simplifications of initiation and conduct of a CTIMP that may be possible within the current regulatory framework. Possible risk-adaptations include: the need for competent authority authorisation; content of the Clinical Trials Authorisation (CTA) application; IMP management; safety surveillance; trial documentation; and GCP Inspection. The risks associated with the IMP also determine trial procedures for monitoring participant safety. The second part of the risk assessment addresses other aspects of clinical trial design and methods: safety risks from clinical procedures; risks related to participant rights; and risks to the reliability of trial results. It is designed to help trialists identify potential vulnerabilities and to prepare tailored trial management and monitoring plans to minimise risks which may be reviewed and modified throughout the life of a trial. The IMP risk category and safety monitoring plan may be submitted to the MHRA with the CTA application to ensure that there is shared understanding on this key aspect of a trial. We hope that the entire risk assessment and associated plans will provide the basis for a common understanding of stakeholders of the risks for that trial, and facilitate a risk-proportionate approach to trial activities. The guidance is available on the MHRA and NETSCC websites.

Drug Development in Oncology: A Regulatory Perspective

The ultimate goal of any drug development, including that in oncology, is to register the new medicinal product. A number of challenges remain in this field, primarily in demonstrating the efficacy of the new oncology products to the satisfaction of the regulatory authorities worldwide. Key aspects of clinical trial design, conduct, and analysis that require careful consideration by the sponsors before initiation of drug development programs in oncology include the choice of primary and secondary end points, the choice of comparators, the necessity for independent radiologic review of a disease-related end point such as progression-free survival and tumor response, and the relative value of the independently reviewed and investigator-assessed clinical end points. Many of these aspects, including the choice of comparators and choice of primary/secondary end points, may have a crucial impact on both the eventual registrability of the new medicine and on the feasibility of conducting the clinical trials in the first place. Although both the industry and the regulators share a common goal of developing promising new oncology products that make a tangible contribution to the care of patients with cancer, more harmonized expectations for "proof of efficacy" and more pragmatic, clinically driven decision-making approaches from regulatory authorities would go a long way in making oncology drug development process less fraught with uncertainties and will result in a more efficient path from clinical trials to the clinic for new medicines. An open dialogue and greater collaboration between the industry and the regulators may help in achieving clarity around these goals and in bringing these to fruition.

The role of sampling in clinical trial design

A treatment's recovery rate depends upon the percentage of clients who received the treatment and recovered. This rate is not logically interpretable as the personal probability of recovery of any individual client assigned to this treatment unless the rate is 0% or 100%. So clinical trials need to be designed to help us learn how to distinguish before treatment the sorts of clients who recover in response to each available form of treatment from those who do not. This requires our developing sufficiently comprehensive sampling of clients and client covariates as part of the design of clinical trials, which would be more likely and efficiently achieved were there centralized programmatic planning and coordination of the development of these aspects of clinical trial design.

Critical aspects of clinical trial design for novel cell and gene therapies.

Neural cell transplantation and gene therapy have attracted considerable interest as promising therapeutic alternatives for patients with Parkinson's disease (PD). Preclinical and open-label studies have suggested that grafted fetal neural tissue or viral vector gene transfer can achieve considerable biochemical and clinical improvements, whereas subsequent double-blind, placebo-controlled protocols have produced rather more modest and variable results. Detailed evaluation of these discordant findings has highlighted several crucial issues such as patient selection criteria, details surrounding transplantation or gene therapy methodologies, as well as the study designs themselves that ought to be carefully considered in the planning phases of future clinical trials. Beyond the provision of symptomatic efficacy and safety data, it also remains to be identified whether the possibilities offered by stem cell and gene therapy technological advances might translate to meaningful neuroprotection and/or disease-modifying effects or alleviate the nonmotor aspects of PD and thus offer additional benefits beyond those achieved through conventional pharmacotherapy or deep brain stimulation (DBS).

End-points and clinical trial design in pulmonary arterial hypertension: have we made progress?

There is enormous interest in the treatment of pulmonary arterial hypertension (PAH), so it is appropriate to consider the design of trials of new therapies and the end-points to be measured when trying to decide whether or not a therapy is effective. In May 2003, the first meeting devoted solely to the discussion of end-points and trial design in PAH was held in Gleneagles, UK. At that time, most of the randomised controlled trials in PAH had used 6-min walking distance and/or resting haemodynamics as their primary end-points. The present article considers the progress that has been made since 2003. It deals with aspects of clinical trial design (such as noninferiority, superiority and withdrawal trials), considers end-points used in previous and current studies (such as 6-min walking distance, time to clinical worsening, haemodynamics, imaging and plasma brain natriuretic peptide), and considers what end-points might be used in the future. The second end-points meeting was held in Turnberry, UK, in June 2007. It had a similar format to the first meeting. Much of what is presented here is a summary of the workshops from that meeting. An attempt has been made to both summarise the current state of end-points and trial design and suggest new ways in which they could be improved. The present article forms one of a series being published in the European Respiratory Journal on pulmonary hypertension.

Genomic advances and their impact on clinical trial design

Medical treatment for patients has historically been based on two primary elements: the expected outcome for the patient, and the ability of treatment to improve the expected outcome. The advance in genomic technologies has the potential to change this paradigm and add substantial value to current medical practice by providing an integrated approach to guide patient-specific treatment selection using the genetic make-up of the disease and the genotype of the patient. Specifically, genomic signatures can aid in patient stratification (risk assessment), treatment response identification (surrogate markers), and/or in differential diagnosis (identifying who is likely to respond to which drug(s)). Several critical issues, including scientific rationale, clinical trial design, marker assessment methods, cost and feasibility have to be carefully considered in the validation of biomarkers through clinical research before they can be routinely integrated into clinical practice. Here, we highlight the impact of genomic advances on various aspects of clinical trial design.

Assessing the impact of ICH E9

The ICH harmonized tripartite guideline 'Statistical Principles for Clinical Trials', more commonly referred to as ICH E9, was adopted by the regulatory bodies of the European Union, Japan and the USA in 1998. This document united related guidance documents on statistical methodology from each of the three ICH regions, and meant that for the first time clear consistent guidance on statistical principles was available to those conducting and reviewing clinical trials. At the 10th anniversary of the guideline's adoption, this paper discusses the influence of ICH E9 by presenting a perspective on how approaches to some aspects of clinical trial design, conduct and analysis have changed in that time in the context of regulatory submissions in the European Union.