22 de março de 2019

Natural History Studies for Rare Diseases: FDA Drafts Guidance

From: www.raps.org - By Zachary Brennan 

The US Food and Drug Administration (FDA) on Friday published new draft guidance to help inform the design and implementation of natural history studies that can be used to support the development of treatments for rare diseases.

Specifically, the 19-page draft describes the potential uses of a natural history study in all phases of drug development for rare diseases. It covers the strengths and weaknesses of various types of natural history study designs, common data elements and research plans. The draft also offers a framework for the conduct of such a study, including information on data collection, storage, dissemination and human subject protections. 

“One of the challenges we know innovators encounter developing therapies for rare diseases is the lack of natural history data to guide the design of successful clinical trials. Such data comes from observational studies that track how rare diseases develop and progress over time,” FDA Commissioner Scott Gottlieb said. “Sometimes rigorous natural history models can help inform development programs, and even serve as comparator arms for studies where it may be impractical to randomize patients to placebo.” 

A natural history study is defined in the draft as “a preplanned observational study intended to track the course of the disease. Its purpose is to identify demographic, genetic, environmental, and other variables (e.g., treatment modalities, concomitant medications) that correlate with the disease’s development and outcomes.”

As far as the uses of a natural history study, the draft discusses four possibilities: Identifying the patient population, identifying or developing clinical outcome assessments, identifying or developing biomarkers, and designing externally controlled studies to use natural history study data. This last category features the most in-depth explanations from FDA, which also notes the difficulties in controlling for certain biases that could limit the ability of externally controlled trials to demonstrate substantial evidence of effectiveness.

The types of natural history studies discussed include retrospective and prospective natural history studies, and cross-sectional studies and longitudinal natural history studies.