Clinical Trials 101

Clinical Trials 101 provides the basics about clinical trials — the different types of trials, how the trial process works, and what you should know about signing up to be a volunteer for Parkinson's disease (PD) research.

What Is a Clinical Trial?

Clinical trials (also referred to as clinical studies or more broadly as clinical research) are research studies involving human volunteers. All trials and studies on Fox Trial Finder relate to Parkinson’s disease. These trials assess the safety and effectiveness of new ways to diagnose, prevent, or treat PD; they also provide insight about the disease process, and how it might be treated. Clinical trials are a vital part of the scientific research process and are essential to developing better treatments for people with Parkinson’s.

Types of Clinical Trials

There are two main types of clinical trials - observational and interventional :

  • Observational clinical trials do not test drugs or treatments. Researchers observe participants by monitoring their health over a period of time. These studies provide researchers with data that advances our understanding of Parkinson’s and how to treat the disease.
  • Interventional clinical trials test the safety and effectiveness of a candidate drug, therapy or experimental treatment.

Within these broad categories, trials also can be classified as follows:

  • Treatment trials test treatments, drug combinations or surgical approaches to alleviate symptoms and/or slow disease progression in people with PD.
  • Prevention trials test approaches, medicines, vitamins, minerals, vaccines or lifestyle changes that may lower the risk of developing PD.
  • Screening trials test ways to detect PD, particularly in its early stages.
  • Quality of Life trials explore ways to improve comfort and quality of life for patients with PD.
  • Genetics trials are designed to improve the ability to look for an inherited risk of PD.

Trial Phases

The U.S. Food and Drug Administration (FDA) and its corollary agencies abroad require that clinical trials be conducted in a series of phases:

  • Phase I trials test a potential therapy, procedure or drug for the first time in human beings. The most important goal at Phase I is to establish that a potential new treatment is safe for humans. For this reason, Phase I trials are typically conducted in very small groups of people (10-80). In addition to safety, Phase I research yields important information on side effects, effectiveness of a chosen delivery method (e.g., by mouth, injection, etc.) and appropriate dosage levels.
  • Phase II trials more comprehensively evaluate a treatment’s safety and effectiveness in a larger group of participants (usually 100 to 300).
  • Phase III trials confirm a therapy’s effectiveness, monitor side effects and compare it against the current standard treatments in a large group of people (around 1,000 to 3,000). Phase III trials last longer, are usually conducted at multiple centers and evaluate whether a treatment will benefit people with Parkinson’s — and if the benefits associated with a therapy outweigh the risks.
  • Phase IV trials are conducted after a treatment has received FDA approval and been brought to market. These trials help further evaluate long-term side effects and potential new uses for other conditions.

Why are clinical trials essential to the drug development process?

The process of developing new drugs is long, expensive and arduous. Unfortunately, a drug is more likely to fail than to succeed at any given stage. The “graduation” of a potential Parkinson’s drug to clinical testing is in itself cause for cautious celebration. This is because clinical testing is initiated only after therapies have already beaten the odds multiple times by moving successfully through years (and millions of dollars of investment) of chemical and biological studies, first in test tubes and Petri dishes, later in pre-clinical models.

The U.S. FDA, and its corollary agencies abroad, requires that a potential therapy’s safety and efficacy be tested extensively in a large group of human volunteers before it can receive approval to be manufactured and made available to patients. Yet clinical testing can — and often does — fail because not enough people volunteer.This lengthens the time it takes for new treatments to come to market. No amount of funding or other resources can compensate for the lack of clinical research volunteers. That’s why volunteers can play a truly unique role at this pivotal stage of drug development, which is crucial for new treatments to reach pharmacy shelves.

How do volunteers get involved in clinical trials for PD?

To get started, interested volunteers can create a profile on Fox Trial Finder. Volunteers can then anonymously reach out to a member of a trial team through the Contact Trial Team messaging feature on the site for a trial they are interested in. Trial teams can answer any questions about the trial and help determine if the trial is the right fit.

Trial team contact information is also provided on Fox Trial Finder, enabling volunteers to call or email to discuss their interest in the trial or specific questions. Trial teams are accustomed to spending time with volunteers to help them make decisions about trial participation, as they know that there are many details to consider before making an informed decision about participating.

Before enrolling in a trial, volunteers may want to discuss trial participation with others, including family, friends, doctors, specialists or even local support group members who have participated in trials.

Why is it so important that more people volunteer for trials?

Clinical trials and studies play a critical role in the development of new and better therapies. Yet under-enrollment in trials is one of the greatest challenges clinical researchers face. Under-enrollment in trials slows research progress and deters potential funders from investing in research — and we all pay the price in terms of higher costs and longer time horizons to get to therapeutic breakthroughs. Across all diseases, 80 percent of clinical trials finish late due to difficulties enrolling participants and nearly one-third of trials fail to recruit a single subject and cannot ever begin.

Fox Trial Finder is one solution to help patients and their loved ones act on the intention to get involved in research by making it easier to find trials that are right for them— and letting volunteers know when new trials start that could be a good match.

What types of volunteers do clinical trials need?

Because clinical trials vary, the needs for volunteers also vary. Researchers design clinical studies with certain eligibility criteria in mind based on the hypothesis they are testing in the trial. These criteria establish a set of guidelines for who can participate in a trial and outline the characteristics qualified volunteers must possess (e.g., age, gender, particular symptoms).

At times, both interventional and observational studies also seek control volunteers who do not have PD. Having a control group in a study allows researchers to compare a drug’s effect or a natural change in people with PD to individuals without PD to determine the difference.

For study results to be statistically significant, researchers must ensure that their volunteer group is large enough and includes those most appropriate for the study.

What is a trial team?

A trial team can consist of a principle investigator, study coordinator, research assistant, research nurses or other members of the research institution’s team conducting the study. The members of this team are responsible for running the trial at a particular trial site. Depending on the size of the trial, trial teams vary in size. Trial teams are the best resource to learn more about what is involved in a study and to ask questions of when you are considering trial participation.

Are there trials that do not require a visit to the trial site?

Yes, some clinical trials may take the form of surveys, typically completed online, that do not require a physical visit to a site. That said, most trials will require at least on in-person visit. Trial teams can provide more information about how many visits are required and the frequency of visits.

Can volunteers leave a clinical trial after joining?

Yes. Although ideally all study participants remain enrolled until the study's completion, circumstances, disease progression and other factors may contribute to a volunteer’s decision to leave a trial. This is permissible at any time. To withdraw from a study, a volunteer should immediately inform the trial coordinator of this decision and will need to follow specific protocols to officially withdraw.

Can volunteers be compensated for participating in a clinical trial?

Due to ethical and practical considerations, every trial has its own policy regarding volunteer compensation. Some trials may reimburse volunteers for expenses related to their participation or even offer some compensation to volunteers for participating. Some trials that require significant travel or an overnight stay may cover the associated expenses. A trial team member can provide more details on whether compensation is available as part of trial participation.

How are volunteer rights and my safety protected in a trial?

Clinical research is subject to federal regulations, many of which focus on the safety of the participants in a trial. Every trial follows an extensive and carefully monitored protocol. The protocol is a detailed plan that describes the study process. In addition to the protocol, each study has a consent form (also sometimes referred to as informed consent or consent to participate) that volunteers must read and sign before joining the study. The consent form will explain rights and responsibilities as a volunteer and what to expect during the study. Study protocols and consent forms must be reviewed and approved by a regulatory body before any volunteers can be approached about or recruited into a study to ensure that the study is safe, ethical and appropriate.

Trial team members will discuss the consent form and any aspects of the protocol in detail during a trial screening visit. Volunteers can also request a copy of the consent form to review it in advance of this in-person visit.

What happens when a trial is over?

Once a clinical trial is over, the trial team assesses the data, distills key findings, publishes or presents any novel findings and determines the appropriate next steps for future testing, as appropriate. They may continue to evaluate the treatment in the next trial or discontinue research because the treatment has not been shown to be safe or effective. In some cases, if the treatment continues to the next phase, trial participants will be given the option of participating in that phase of the study as well.

The FDA requires that trial results be published in a scientific or medical journal and made available to the public within 12 months of the last participant’s visit.* However, because it is hard for the FDA to track and enforce these regulations, it can be difficult to learn about trial results. Volunteers can search the Web or follow up with the trial team to inquire about study outcomes.

* According to the 2007 Federal Drug Administration Amendment Act (FDAA)


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