NCCIH Only Accepts Clinical Trial Applications Proposing Mechanistic Studies for Clinical Trial Parent R01 Announcements

Notice Number: NOT-AT-19-011

Key Dates
Release Date: December 18, 2018

Related Announcements

Issued by
National Center for Complementary and Integrative Health (NCCIH)


The purpose of this Notice is to define the types of clinical trials/studies that may be submitted to NCCIH in response to the NIH Research Project Grant (Parent R01 Clinical Trial Required). For this funding opportunity announcement (FOA) and its subsequent re-issuances, NCCIH will only accept applications that propose human mechanistic trials/studies; no applications will be accepted that include any specific aims that propose to assess efficacy or effectiveness of any intervention.

NIH defines a clinical trial as A research study in which one or more human subjects are prospectively assigned to one or more interventions (which may include placebo or other control) to evaluate the effects of those interventions on health-related biomedical or behavioral outcomes (NOT-OD-15-015). NIH defines a mechanistic study (which can be a type of clinical trial) as: "A mechanistic study is designed to understand a biological or behavioral process, the pathophysiology of a disease, or the mechanism of action of an intervention."

NCCIH recognizes a difference between "clinical trials" that are designed to answer specific questions about the clinical effect of interventions and "mechanistic studies" that have the primary goal of understanding how an intervention works.

  • A clinical outcome study has the objective of determining the clinical safety, tolerability, feasibility, efficacy and/or effectiveness of pharmacologic, non-pharmacologic, behavioral, biologic, surgical, or device (invasive or non-invasive) interventions.
  • A mechanistic study has the objective to understand the mechanism(s) of action of an intervention, a biological or behavioral process, or the pathophysiology of a disease/condition.

NCCIH encourages applications for clinical trials through the FOAs that are listed on the NCCIH website and through FOAs in which NCCIH participates that are issued by other NIH Institutes and Centers (

NCCIH strongly encourages applicants to consult with NCCIH Program Officials prior to submitting an application with human subjects to determine which available FOA would best support the proposed research.

This Notice supersedes the prior NCCIH Policy Notice: NOT-AT-18-001.


Please direct all inquiries to:

Wen G. Chen, MMSc, PhD

National Center for Complementary and Integrative Health (NCCIH)

Telephone: 301-451-3989