Leveraging exploratory investigational new drug studies to accelerate drug development

Phase 0 and window of opportunity clinical trial design in neuro-oncology: a RANO review

Glioblastoma is a devastating disease with poor prognosis. Few effective chemotherapeutics are currently available, and much effort has been expended to identify new drugs capable of slowing tumor progression. The phase 0 trial design was developed to facilitate early identification of promising agents for cancer that should undergo accelerated approval. This design features an early in-human study that enrolls a small number of patients who receive subtherapeutic doses of medication with the goals of describing pharmacokinetics through drug blood level measurements and determining intratumoral concentrations of the investigational compound as well as pharmacodynamics by studying the biochemical and physiological effects of drugs. In neuro-oncology, however, the presence of the blood-brain barrier and difficulty in obtaining brain tumor tissue warrant a separate set of considerations. In this paper, we critically reviewed the protocols used in all brain tumor related in-human phase 0 and phase 0-like ("window of opportunity") studies between 1993 and 2018, as well as ongoing clinical trials, and identified major challenges in trial design as applied to central nervous system tumors that include surgical specimen collection and storage, brain tumor drug level analysis, and confirmation of drug action. We therefore propose that phase 0 trials in neuro-oncology should include (i) only patients in whom a resection of the tumor is planned, (ii) use of clinical doses of an investigational agent, (iii) tissue sampling from enhancing and non-enhancing portions of the tumor, and (iv) assessment of drug-specific target effects. Standardization of clinical protocols for phase 0/window of opportunity studies can help accelerate the development of effective treatments for glioblastoma.

[Phase 0 exploratory clinical trials: literature review 2006-2009]

Currently in oncology a novel agent entering development has only 5% chance of making it to commercial use. One of the ways to mitigate this problem would be to conduct exploratory or 'phase 0' clinical trials, conducted before phase 1 dose-escalation safety and tolerance studies. These phase 0 studies are a first administration of the novel agent to humans, at limited doses, on a small number of patients and over a short period. The objectives are to validate preclinical development and to acquire pharmacokinetic and pharmacodynamic data in order to better justify the scientific rational. In this article, we focus on phase 0 trials and their usefulness for the development of new drugs in oncology. We performed a literature review of questions related to phase 0 trials in articles published during 2006 to 2009. Thirty articles on phase 0 clinical trials have been published. The affected fields are oncology and pharmacology. Phase 0 clinical trials are discussed in the literature in terms of theoretical issues and from academic, pharmaceutical industry and patient point of views. If phase 0 clinical trials are a future prospect for drug development against cancer, the clinical applications of these trials need to be specified.

Accelerator mass spectrometry-enabled studies: current status and future prospects

Accelerator mass spectrometry is a detection platform with exceptional sensitivity compared with other bioanalytical platforms. Accelerator mass spectrometry (AMS) is widely used in archeology for radiocarbon dating applications. Early exploration of the biological and pharmaceutical applications of AMS began in the early 1990s. AMS has since demonstrated unique problem-solving ability in nutrition science, toxicology and pharmacology. AMS has also enabled the development of new applications, such as Phase 0 microdosing. Recent development of AMS-enabled applications has transformed this novelty research instrument to a valuable tool within the pharmaceutical industry. Although there is now greater awareness of AMS technology, recognition and appreciation of the range of AMS-enabled applications is still lacking, including study-design strategies. This review aims to provide further insight into the wide range of AMS-enabled applications. Examples of studies conducted over the past two decades will be presented, as well as prospects for the future of AMS.

Phase 0 clinical trials in oncology new drug development

Research focus of pharmaceutical industry has expanded to a larger extent in last few decades putting many more new molecules, particularly targeted agents, for the clinical development. On the other hand, researchers are facing serious challenges due to high failure rates of new molecules in clinical studies. The United States Food and Drug Administration (FDA) in combination with academia and industry experts identified many factors responsible for failures of new molecules, and with a vision of taking traditional drug development model toward an innovative paradigm shift, issued regulatory guidance on conduct of exploratory investigational new drug (exploratory IND) studies, often called as phase 0 clinical trials, requiring reduced preclinical testing, which has special relevance to life-threatening diseases such as cancer. Phase 0 trials, utilizing much lower drug doses, provide an opportunity to explore the clinical behavior of new molecules very early in the drug development pathway, helping to identify the promising candidates and eliminating non-promising molecules, thus improving the efficiency of overall drug development with significant savings of resources. Being non-therapeutic in nature, these studies, however, pose certain ethical challenges requiring careful study designing and informed consent process. This article reviews the insights and perspectives for the feasibility, utility, planning, designing and conduct of phase 0 clinical trials, in addition to ethical issues and industrial perspective focused at oncology new drug development.

PhRMA survey on the conduct of first-in-human clinical trials under exploratory investigational new drug applications

The FDA guidance on exploratory IND studies is intended to enable sponsors to move ahead more efficiently with the development of promising candidates. A survey of PhRMA member companies was conducted in 2007 to obtain a cross-sectional industry perspective on the current and future utility of exploratory IND studies. About 56% of survey responders (9 companies of 16 survey responders) conducted or were planning to conduct clinical studies under exploratory INDs. The majority of microdosing studies are performed to characterize human pharmacokinetics or to examine target organ pharmacokinetics using PET imaging techniques. On the other hand, the majority of pharmacological end point studies conducted under exploratory IND are performed to determine whether the compound modulated its pharmacological target or to evaluate the degree of saturation of a target receptor. The present survey suggests that although the merits of exploratory INDs are still being debated, the diversity in the applications cited, the potential for early clinical guidance in decision making and the increasing pressure on containing drug development costs, suggest that the exploratory IND/CTA will be a valuable option with evolving and possibly more specific applications for the future.

Role of Phase 0 trials in drug development

Phase 0 trials can provide proof of concept that an agent modulates its intended target without exposing patients to the drug-tolerability testing that precedes efficacy evaluation. Drugs that do not modulate their targets can be discarded, focusing development resources on the most clinically promising agents. However, wider uptake of Phase 0 trials may be hindered by ethical concerns over their lack of therapeutic intent, the substantial resources required to develop and validate target assays or skepticism that such trials save development time.

Advancing radiology through informed leadership: summary of the proceedings of the Seventh Biannual Symposium of the International Society for Strategic Studies in Radiology (IS(3)R), 23-25 August 2007

The International Society for Strategic Studies in Radiology (IS³R) brings together thought leaders from academia and industry from around the world to share ideas, points of view and new knowledge. This article summarizes the main concepts presented at the 2007 IS³R symposium, providing a window onto trends shaping the future of radiology. Topics addressed include new opportunities and challenges in the field of interventional radiology; emerging techniques for evaluating and improving quality and safety in radiology; and factors impeding progress in molecular imaging and nanotechnology and possible ways to overcome them. Regulatory hurdles to technical innovation and drug development are also discussed more broadly, along with proposals for addressing regulators’ concerns and streamlining the regulatory process.

The development of phase I cancer trial methodologies: the use of pharmacokinetic and pharmacodynamic end points sets the scene for phase 0 cancer clinical trials

Although the concept of a phase 0 trial is a relatively new one, there has been a slowly increasing trend toward basing early clinical trial designs on pharmacokinetic and pharmacodynamic end points that has been developing over many years. This article will review the early cancer trial methodologies and the various techniques that have been used to refine them. Several illustrative examples will be presented showing their relevance to trial designs using pharmacodynamic end points and targeted agents. Some criteria for characterizing suitable phase 0 end points are suggested. Four trial designs that are essentially developed for cytotoxic agents using the maximal tolerated dose as an end point are described. Although these trials were not designed with the use of more sophisticated pharmacodynamic end points (such as the measurement of the effect of a targeted agent on its target), they have been developed to optimize the speed with which a dose needed to achieve a particular effect can be determined and are, to this extent, relevant to the design of studies with pharmacodynamic end points.

The ethics of phase 0 oncology trials

Recent guidance from the Food and Drug Administration supports the conduct of a new type of exploratory clinical trial, commonly called phase 0 clinical trials. Proponents argue that phase 0 clinical trials have the potential to expedite the development of new oncology drugs while exposing fewer research subjects to the risks of experimental treatments. At the same time, phase 0 oncology trials raise important ethical concerns that have received little attention. In particular, there is a question of whether it is ethical to enroll individuals in research that offers them no potential for clinical benefit. Further concern focuses on the inclusion of terminally ill and consequently vulnerable cancer patients in these trials. To evaluate these concerns, this article considers relevant empirical data from phase 1 oncology trials and develops several recommendations regarding the conduct of phase 0 clinical trials in oncology.

Oncologic phase 0 trials incorporating clinical pharmacodynamics: from concept to patient

The U.S. Food and Drug Administration recently issued an Exploratory Investigational New Drug (IND) guidance that provides a platform for the evaluation of targeted anticancer agents in small, early-phase human clinical trials that can be used to establish the feasibility of proof-of-principle target modulation assays, as well as the preliminary pharmacokinetics and molecular imaging potential of new anticancer molecules. The exploratory IND allows for reduced requirements for manufacturing and toxicologic assessment. Early clinical trials done in this fashion have no therapeutic intent. In this series of articles in CCR Focus, the development of this new IND mechanism, its effect on clinical trial design and clinical pharmacodynamics, the ethical implications of nontherapeutic clinical investigations, and the perspective of the pharmaceutical industry on this approach are examined.

Designing phase 0 cancer clinical trials

Phase 0 trials are designed primarily to evaluate the pharmacodynamic and/or pharmacokinetic properties of selected investigational agents before initiating more traditional phase I testing. One of the major objectives of phase 0 trials is to interrogate and refine a target or biomarker assay for drug effect in human samples implementing procedures developed and validated in preclinical models. Thus, close collaboration between laboratory scientists and clinical investigators is essential to the design and conduct of phase 0 trials. Given the relatively small number of patients and tissue samples, showing a significant drug effect in phase 0 trials requires precise and reproducible assay procedures and innovative statistical methodology. Furthermore, phase 0 trials involving limited exposure of a study agent administered at low doses and/or for a short period allow them to be initiated under the Food and Drug Administration exploratory investigational new drug guidance with less preclinical toxicity data than usually required for traditional first-in-human studies. Because of the very limited drug exposure, phase 0 trials offer no chance of therapeutic benefit, which can impede patient enrollment, particularly if invasive tumor biopsies are required. The challenges to accrual are not insurmountable, however, and well-designed and executed phase 0 trials are feasible and have great potential for improving the efficiency and success of subsequent trials, particularly those evaluating molecularly targeted agents.