Parkinson's Clinical Trial Companion Navigating Clinical Trials - Page 10

Types of Clinical Trials The many different types of clinical trials can be broadly divided into two main categories: + + Observational studies do not test drugs or treatments. Instead, researchers examine participants’ health and may monitor volunteers over a certain period. With observational studies, researchers collect data to advance their understanding of how to track and treat Parkinson’s, and how the disease naturally changes with time. Participating in some observational studies could include visiting a clinic for examinations, having blood drawn or undergoing brain scans. Other studies, such as The Michael J. Fox Foundation’s Fox Insight (, only require that you log on to your computer or smartphone to complete a questionnaire every few months. (See: “A Technological Revolution in Research,” pg. 13.) + + Interventional trials test whether a drug or other type of therapy works and is safe. Experimental therapies could include not only medications, but also exercise, surgical procedures, vitamins, supplements and even complementary therapies such as acupuncture or meditation. Each trial has a different objective and a unique plan called a protocol so the level of volunteer commitment for each varies. Phases of Interventional Clinical Trials Clinical trial testing of a new therapy follows a sequence of phases. Each phase answers different questions and requires a thoughtfully designed trial and new group of willing volunteers: + + Phase I trials test a potential therapy, procedure or drug for the first time in a small number of people (usually about 10 to 100). Often these are “control,”* volunteers — people without Parkinson’s. These trials typically evaluate the safety of a new therapy. They also often yield information on side effects, effectiveness of delivery method (e.g., by mouth, injection, etc.) and appropriate dosage levels. For most interventions, they last on average several months, but they may be much longer for certain surgical therapies. + + Phase II trials more comprehensively assess a treatment’s safety, and determine preliminary efficacy and side effects in a larger group of people (usually a few hundred) with Parkinson’s. They can last months to a few years. These trials typically are randomized, controlled studies. This means that one group of participants receives the experimental treatment, while the other (a “control” group) receives either the standard of care or a placebo (an inactive substance that looks exactly like the treatment). The standard of care is one that medical experts accept as the proper one and widely use. When this doesn’t exist, researchers use a placebo. For example, we don’t currently have Parkinson’s disease-modifying therapies (medications that slow or stop disease progression). So, in trials testing new potential disease-modifying therapies, researchers use placebos for comparison to evaluate the therapy’s effects. Participants are assigned to groups by a strategy that mimics chance, or flip of a coin. Often these studies are “double-blind” as well, meaning that neither patients nor the research team know who is getting the experimental treatment. + + Phase III trials confirm or disprove a therapy’s efficacy, safety and side effects in an even larger group of people with Parkinson’s (anywhere from 200 to 2,000, although trials testing surgical therapies may be smaller). Phase III trials, which also are randomized and controlled, last several years. Rather than being carried out at one location, Phase III are often multicenter trials, meaning they combine the results from volunteers who participate at many different medical centers. In order for a therapy to move forward through Phase I and II, it must meet safety and efficacy standards. When Phase III studies confirm these results, a drug maker can submit a new drug application to the U.S. Food and Drug Administration or an equivalent application to the European Medicines Agency or another governmental body. From there, the review process can take six to 12 or more months, depending on the agency’s protocol. If approved, a drug then can be manufactured and sent to pharmacy shelves. Once therapies reach the market and doctors and patients are using them in the “real world,” companies conduct Phase IV clinical trials. These studies primarily evaluate long-term side effects in *Underlined words indicate a commonly used term. Find the definitions in the glossary, starting on page 44. 8 Navigating Clinical Trials: A Guide for Parkinson’s Patients and Families