Types Of Clinical Trials

Types Of Clinical Trials

Posted on Nov.19, 2019, under Educational

When a person is diagnosed with an illness or a condition, some people like to know what research is being done that may help to improve their symptoms or to treat their disease.  However not all studies are ones that actually provide a medication or therapy.  Some clinical trials are performed to purely to gain more knowledge about the progression of a disease or changes that occur in the body.  The largest international database of clinical trials is the National Institute of Health’s www.ClinicalTrials.gov.  Here you will find that the two main types of studies are either interventional or observational.


Observational Study

An observational study involves the observance of a patient’s physiology, anatomy, or progression or non-progression of a disease or condition.  An example of an observational study is the Study of Dark Adaptation in Age Related Macular Degeneration. It is a study that is looking at a patient’s ability to adapt to a dark environment.  Tests are administered to participants that measure how the eye adjusts to the dark to help identify and monitor early to intermediate dry age-related macular degeneration.  Some studies involve special imaging to observe anatomical or functional changes such as in the study called The Natural Progression of Dry Age-Related Macular Degeneration.


Interventional Study

An interventional study is one in which the study is looking to see if a therapy, drug, or device can positively impact a patient’s condition or symptoms.  It may be a new drug being studied or it may be simply looking to see if a different dose of a conventional drug, a different combination of drugs or different timing is more effective.  One such study is AAVCAGsCD59 for the Treatment of Wet AMD for patients who have been diagnosed with wet AMD but have not yet received treatment.  Along with the standard treatment of an intravitreal anti-VEGF, study patients will receive a new drug called AAVCAGsCD59.  New devices, like the PRIMA bionic retina system, is considered an interventional study as it seeks to determine if the retinal implant can improve a patient’s independence.


An Interventional study will be in one of four phases, with the first phase looking primarily at safety.  It will have the smallest number of participants and will be focused on what are the most frequent and/or serious side effects.  A Phase 2 study will still be looking to find if a new drug or therapy is effective in treating a condition or disease. With each phase there is usually an increase in the number of participants with Phase 4 occurring after there has been FDA approval.


To perform your own search for clinical trials, you can go to www.ClinicalTrials.gov, type in a disease or condition, like macular degeneration, then you can refine your search by using the search tool in the left column and select observational or interventional clinical trials.


Leslie Degner, RN, BSN