GCP stands for "Good Clinical Practice", which defines the standards established by the Japanese Ministry of Health, Labor and Welfare.
GCP provides standards with which all clinical trials must comply. It secures the protection of the subjects' rights, safety and privacy of the clinical trial participants while ensuring the scientific quality of these trials and the reliability of their results.

Protecting the rights, safety and privacy of clinical trial participants

One of the major requirements stated in GCP is so-called "Informed Consent".

Herein, "Informed Consent" signifies that the participants agree to take part in clinical trials based on the individuals' "free will." Institutions performing clinical trials must prepare documents for distribution to prospective subjects. The documents shall describe detailed information on designated clinical trial, including objectives and methods of the trial as well as possible adverse effects.

After an intimate explanation of the clinical trial, and if the prospective subject agrees to participate, he or she must sign an agreement sheet for the clinical trial and declare his or her intention to participate based on free will. Any clinical trial cannot be initiated without the signed agreement. Again, based on free will, subjects can withdraw from the clinical trial participation at anytime.

Ensuring the reliability of results and the scientific quality of clinical trials

GCP describes detailed regulations and standards to assure data validity as well as scientific justification. For example, GCP requires to conduct an "Audit" to ensure regulations and standards are properly followed.
"Audit" is designed to evaluate the medical institutions performing clinical trials from aspects of GCP compliance. Sponsors (Pharmaceutical Companies) are responsible for the Audit.

For more detailed information, please visit the page dedicated to GCP found on the website of the Japanese Ministry of Health, Labor and Welfare.