In the United States, following the ICH E6 guideline is:

The ICH E6 guideline, which sets forth Good Clinical Practice (GCP) standards, is primarily regarded as a framework that aims to ensure the safety, integrity, and efficiency of clinical trials involving human subjects. In the United States, adherence to these guidelines is considered voluntary for studies regulated by the FDA, including those focused on drug development. This means that while compliance with ICH E6 is highly encouraged and may be seen as a best practice, it is not legally mandated by regulatory authorities for studies conducted within the country.

This voluntary status allows for flexibility in how clinical trials are designed and simulated, acknowledging the need for innovation and adaptability in research practices while nonetheless stressing the importance of ethical conduct and welfare of participants. In contrast, other choices suggest either mandatory compliance for specific types of studies within the U.S. or an incorrect implication about international studies, which might not reflect the regulatory landscape accurately.

Understanding the status of the ICH E6 guideline is crucial for clinical researchers, as it shapes their responsibilities in conducting trials that protect participant safety while allowing room for scientific discovery.