Russell Katz

Biomarkers and surrogate markers: An FDA perspective

SummaryInterest is increasing rapidly in the use of surrogate markers as primary measures of the effectiveness of investigational drugs in definitive drug trials. Many such surrogate markers have been proposed as potential candidates for use in definitive effectiveness trials of agents to treat neurologic or psychiatric disease, but as of this date, there are no such markers that have been adequately “validated,” that is, shown to predict the effect of the treatment on the clinical outcome of interest. While the current law and regulations permit the United States Food and Drug Administration to base the approval of a drug product on a determination the effect of the drug on an unvalidated surrogate marker (that is, one for which it is not known that an effect on the surrogate actually predicts the desired clinical benefit), there are a number of difficulties in interpreting trials that use surrogate markers as primary measures of drug effect. In this article, the relevant regulatory context will be discussed, as well as the epistemological problems related to the interpretation of clinical trials in which unvalidated surrogate markers are used as primary outcomes.

Regulatory Innovation and Drug Development for Early-Stage Alzheimer's Disease

The focus of drug development in Alzheimers disease has increasingly been on earlier disease stages, before overt dementia, when it is difficult to assess cognitive impairment. The FDA has now developed guidance for the design and execution of relevant clinical trials.

FDA: evidentiary standards for drug development and approval.

SummaryThe United States Food and Drug Administration is charged with approving drug treatments that have been shown to be safe and effective. Relevant statutes and regulations provide a legal framework for establishing safety and effectiveness that is sufficiently flexible to ensure that appropriate scientific data are collected for specific treatments targeted to particular diseases. Nonetheless, all clinical trials proposed to establish effectiveness must incorporate common elements in order for the appropriate legal and scientific standards of drug approval to be met. This article will discuss the relevant laws and regulations pertaining to the current effectiveness standard and will discuss the most important clinical trial design elements currently considered acceptable for applications for treatments of neurologic and psychiatric illness.

Challenges and opportunities in establishing scientific and regulatory standards for assuring therapeutic equivalence of modified-release products: Workshop summary report

Modified-release products are complex dosage forms designed to release drug in a controlled manner to achieve desired efficacy and safety. Inappropriate control of drug release from such products may result in reduced efficacy or increased toxicity. This workshop provided an opportunity for pharmaceutical scientists from academia, industry and regulatory agencies to discuss current regulatory expectations and industry practices for demonstrating pharmaceutical equivalence and bioequivalence of MR products, further facilitating the establishment of regulatory standards for ensuring therapeutic equivalence of these products.

Building a Roadmap for Developing Combination Therapies for Alzheimer's Disease

Combination therapy has proven to be an effective strategy for treating many of the world’s most intractable diseases. A growing number of investigators in academia, industry, regulatory agencies, foundations and advocacy organizations are interested in pursuing a combination approach to treating Alzheimer’s disease. A meeting co-hosted by the Accelerate Cure/Treatments for Alzheimer’s Disease Coalition, the Critical Path Institute and the Alzheimer’s Association addressed challenges in designing clinical trials to test multiple treatments in combination and outlined a roadmap for making such trials a reality.

Charting a path toward combination therapy for Alzheimer's disease

It is acknowledged that progress in combined therapeutic approaches for Alzheimer’s disease (AD) will require an unprecedented level of collaboration. At a meeting co-hosted by the Accelerate Cure/Treatments for Alzheimer’s Disease Coalition and the Critical Path Institute, investigators from industry, academia and regulatory agencies agreed on the need for combinatorial approaches to treating AD. The need for advancing multiple targets includes recognition for novel adaptive trial designs that incorporate existing and new biomarkers to evaluate drug effects independently and in combination. A combination trial now being planned may test drugs targeting different pathogenic pathways or multiple targets along a common pathway. Collaborations and consortia-based strategies are pivotal for success and a regulatory framework is recommended for success.

Maximizing the Alzheimer's Disease Neuroimaging Initiative II

The Alzheimers Disease Neuroimaging Initiative is the largest public‐private partnership on brain research underway at the National Institutes of Health. This 6‐year study tracks cognitive and brain changes in normal subjects, those with mild cognitive impairment, and individuals with Alzheimers disease. It was designed to provide better tools for performing effective clinical trials, and is slated to run until 2010. While data are being generated and analyzed, researchers involved in the study are developing an extension, i.e., the Alzheimers Disease Neuroimaging Initiative II. The Foundation for the National Institutes of Health and the Alzheimers Association convened a meeting to review the progress, evaluate future directions, and obtain the United States Food and Drug Administrations perspective on how the Alzheimers Disease Neuroimaging Initiative could affect the drug‐approval process.

Challenges, solutions, and recommendations for Alzheimer's disease combination therapy

Given the complex neuropathology Alzheimers disease (AD), combination therapy may be necessary for effective treatment. However, scientific, pragmatic, regulatory, and business challenges need to be addressed before combination therapy for AD can become a reality. Leaders from academia and industry, along with a former member of the Food and Drug Administration and the Alzheimers Association, have explored these challenges and here propose a strategy to facilitate proof‐of‐concept combination therapy trials in the near future. First, a more integrated understanding of the complex pathophysiology and progression of AD is needed to identify the appropriate pathways and the disease stage to target. Once drug candidates are identified, novel clinical trial designs and selection of appropriate outcome assessments will be needed to enable definition and evaluation of the appropriate dose and dosing regimen and determination of efficacy. Success in addressing this urgent problem will only be achieved through collaboration among multiple stakeholders.

Coalition Against Major Diseases Precompetitive Collaborations and Regulatory Paths to Accelerating Drug Development for Neurodegenerative Diseases

Precompetitive collaborations have been successful in several disease areas and industries. Such collaborations are critical to address the gaps and challenges in therapeutic development for chronic neurodegenerative diseases. On November 5, 2012, members of the scientific community, advocates, regulators, industry, and government officials met at the US Food and Drug Administration to develop tools to expedite drug development and maximize the potential for success in future drug trials for Alzheimer disease and Parkinson disease. The meeting established that multiple collaborative approaches are essential for accelerating drug development. Such approaches include precompetitive data sharing, regulatory qualification of biomarkers and clinical outcome assessments, implementation of data standards, and development of quantitative drug disease trial models. While challenges to collaboration among industry partners are formidable, they are not insurmountable. The Coalition Against Major Diseases (CAMD) has several positive examples to highlight. This review represents proceedings from CAMD’s annual conference and discusses the key themes that are being advanced by the Critical Path Institute.

Considerations in the Design of Clinical Trials for Cognitive Aging

What will it take to develop interventions for the treatment of age-related cognitive decline? Session V of the Summit provided perspectives on the design of clinical trials to evaluate promising but unproven interventions, and some of the steps needed to accelerate the discovery and evaluation of promising treatments. It considered strategies to further characterize the biological and cognitive changes associated with normal aging and their translation into the development of new treatments. It provided regulatory, scientific, and clinical perspectives about neurocognitive aging treatments, their potential benefits and risks, and the strategies and endpoints needed to evaluate them in the most rapid, rigorous, and clinically meaningful way. It considered lessons learned from the study of Alzheimers disease, the promising roles of biomarkers in neurocognitive aging research, and ways to help galvanize the scientific study and treatment of neurocognitive aging.