Clinical trials are an integral part of a new drug or diagnostic discovery and development process. Before a new medicine can be made available, evidence of its safety and effectiveness must be provided by clinical studies in healthy volunteers and/or patients. Clinical trials also provide important information on the cost-effectiveness of a treatment, the clinical value of a diagnostic test and how a treatment improves quality of life.

Clinical trials are conducted in phases. Each phase is designed to answer certain questions while taking steps necessary to safeguard the people taking part. Every new treatment is usually tested in three phases before regulatory agencies consider it safe and effective. Trials are also conducted according to Good Clinical Practice (GCP) guidelines that regulators require in order to protect patient safety and are reviewed and approved prior to commencement by the NZ Health and Disability (HDEC) Ethics Committees.

Clinical trials are essential to determine whether new drugs, diagnostics or procedures in the laboratory are both safe and effective when used to diagnose or treat people.