Why participate in a clinical trial?  

By Sue Bruhn, PhD 

Medical progress doesn’t happen by accident. Every treatment we rely on today exists because people before us chose to take part in research, including clinical trials. For individuals living with Charcot-Marie-Tooth disease, that choice can feel especially meaningful. CMT has no cure, limited treatment options, and a range of symptoms that affect daily life. 

People choose to participate in clinical trials for a variety of reasons. For many, it’s a way to take a more active role in their care and better understand their options. Some are motivated by the opportunity to try new and emerging treatments, while others want to help move research forward to benefit people who share their condition.  

Whatever the reasons, participating in a clinical trial is a deeply personal decision that starts with understanding the basics. Knowing how clinical trials are designed, what the different phases of clinical development mean, and what’s expected can make the decision to participate clearer and more manageable.  

The purpose of clinical development is to test the effects of a potential therapy in people. The primary goal of this research is not to simply answer the question, “Does this therapy work?” but to determine whether the benefits of treatment outweigh the risks for patients who may use it once it is approved and available. Clinical trials are the individual studies within the clinical development process, each designed to answer specific questions about safety, dosing, effectiveness or long-term outcomes.  

In practice, every treatment has both benefits, also called efficacy, and risks, often referred to as safety, or side effects. That balance must be evaluated at every stage of clinical development. This evaluation happens step by step through clinical phases, starting with a small number of participants and expanding to larger groups as more information about benefits and risk is gathered.  

The phases of clinical development 

As clinical development progresses, trials are organized in phases to evaluate the balance between a treatment’s potential benefits and its risks. How that balance is measured depends in part on who is being studied and how many people can realistically participate. In diseases that affect many people, like high blood pressure for example, trials may include thousands of participants. In rare conditions like CMT, trials are smaller by necessity, and may include a just a few participants. 

What are the traditional phases of clinical development?  

• Phase 1: Conducted in a small number of people, with a primary focus on understanding safety and risk rather than benefit. These studies look at how the potential therapy behaves in the body and what side effects may occur. Phase 1 trials are sometimes done in patients, but more commonly in healthy volunteers. 

• Phase 2: Done in a larger, but still intermediate number of patients. These trials begin to examine benefit more closely while continuing to monitor risk. A key goal of phase 2 is identifying the dose that maximizes potential benefits while minimizing risks. 

• Phase 3: The largest and most comprehensive trials, often referred to as “pivotal trials.” These studies evaluate benefit versus risk in patients who most closely represent the population that would use the therapy once its approved and on the market. Phase 3 trials provide critical evidence that regulators, such as the FDA, heavily rely on when assessing whether a treatment’s benefits outweigh its risks. 

Phases can also be combined. In some cases, studies are labeled sometimes we see “phase 1/2” or “phase 2/3” trials, allowing researchers to answer multiple questions within a single trial. This approach is especially common in a rare disease like CMT, where smaller patient populations make it important to gather as much meaningful information as possible from each study. 

After phase 3 studies are complete, companies apply to regulators for approval to market a treatment. Regulators review all of the clinical data alongside preclinical data, including animal safety studies, and manufacturing information to determine whether a therapy should be approved for use a particular patient population. Depending on how the trials were conducted and the treatment works, approval may apply to all patients with CMT or patients with a specific subtype for a more targeted therapy. If approved, the clinical trial development continues into the final phase. 

• Phase 4: Also called post-marketing studies. These trials take place after a therapy has been approved and is available for use. They collect safety information from a broader patient population to identify side effects that may be uncommon or take longer to appear. If a treatment was approved under the Accelerated Approval pathway, phase 4 studies may also be used to confirm effectiveness and further evaluate the balance between benefit and risk. 

The clinical development path can take a long time, but it is purposely designed to ensure that benefits versus risks are well understood before a treatment reaches patients.  

How you can participate in a clinical trial for CMT  

Making an informed decision is an important part of considering a clinical trial. A conversation with your provider can help determine whether participation is appropriate based on your individual health situation. Factors such as symptom severity and other medical conditions are all important to consider as you explore your options.  

Once you’ve had those initial conversations, the next step is to find clinical trials that are currently enrolling. Start with the CMTA Clinical Trials Directory listing active trials in CMT by type and subtype. You can also search for open trials on clincialtrials.gov, a database of clinical studies maintained by the U.S. government.   

Not all clinical trials are right for everyone. Each trial has a list of rules, called inclusion criteria and exclusion criteria, that decides who can and cannot join the study. If you aren’t eligible for a current study, sign up for CMTA’s Patients as Partners in Research and get notified first when a clinical trial for your CMT type or subtype is recruiting.     

Clinical trials are a critical part of how potential treatments for CMT are studied and evaluated. Understanding how these trials are designed, how benefits and risk are assessed, and what participation requires can put the process into perspective, allowing individuals with CMT to evaluate whether a specific trial aligns with their health status and circumstances.