Pedley CF, Case LD, Blackwell CS, Katula JA, Vitolins MZ The 24-month metabolic benefits of the healthy living partnerships to prevent diabetes: A community-based translational study. Diabetes Metab Syndr. 2018 May;12(3):215-220. doi: 10.1016/j.dsx.2017.
Vitolins MZ, Blackwell CS, Katula JA, Isom SP, Case LD Long-term Weight Loss Maintenance in the Continuation of a Randomized Diabetes Prevention Translational Study: The Healthy Living Partnerships to Prevent Diabetes (HELP PD) Continuation Trial. Diabet
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.