Clinical trials 101

Learn about the methods of medical research
Clinical Trials for MS


This has been added to your Favorites

Because a big part of managing your multiple sclerosis (MS) is properly treating it, you may find it helpful to understand what clinical trials are and how they work. A clinical trial is a research study used to determine if a certain treatment is safe and effective. It’s a way for the Food and Drug Administration (FDA) to determine if a treatment should be approved for doctors to legally prescribe to patients.

The process

Clinical trials are part of a lengthy research process. This process usually begins in a lab on a cellular level and then moves to testing on animals. If the research appears to have potential, clinical trials may be set up to see how the treatment being researched would work on a person. If the treatment is approved, the outcome of the clinical trial is one piece of information your doctor may use when recommending treatment options. 

It typically takes 10 to 15 years for an experimental drug to get approved for use in patients.

Designing clinical trials

Clinical trials are meant to determine how safe and effective a treatment may be for patients. To help determine this, researchers and manufacturers will work together to develop the study's objectives, design, and methods—also known as a protocol. Some of the ways a research group may choose to design a study are:

  • Randomized: Participants are assigned by chance to separate groups. These groups could get a different treatment or placebo, such as a simple sugar pill. Neither the researchers nor the participants can choose which group they are placed in
  • Nonrandomized: Participants may choose which group they want to be in, or they may be put in groups selected by the researchers
  • Blinded: Participants are grouped together but do not know what treatment they are taking or if they are receiving placebo
  • Double blinded: Similar to blinded, except that neither the researchers nor the participants know who’s receiving what treatment

By breaking the participants into groups, researchers can compare treatments with one another or compare a treatment with a placebo. The two main groups participants are usually placed in are:

  • The control group 
    This group tries something different, such as a placebo or another medicine, to see how it compares with the treatment being studied.
  • The active group 
    This group takes the treatment being studied.

Who can participate?

Enrolling individuals with certain conditions or symptoms is an important part of the clinical trial process. This allows researchers to determine if the treatment may work in a specific population. Every trial develops unique guidelines that determine which patients are able to participate based on a number of different criteria specific to that trial. Criteria may include a certain age range, gender, symptom, or illness. And the number of participants can change based on the disease state or condition.

Phases of a clinical trial

New treatments go through three phases of research before they can be approved by the FDA and become available to the public. Each phase is designed to answer a separate research question. This is usually determined in the protocol. Knowing the phase of the clinical trial is important because it can give an idea about how much is known about the treatment being studied.

Phase 1 

In phase 1, the goal is to find out how a treatment will interact with the body. Researchers test a new treatment in a small group of healthy people to evaluate how safe it is, determine how much should be given, and identify possible side effects.

Average length of study: Several months 

Phase 2 

In phase 2, the goal is to gather data on whether the treatment works in people with a certain disease or condition. The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety. During this phase, different doses of a drug may be studied to determine the safest and most effective dose.

Average length of study: Several months to two years 

Phase 3 

The goal is to gather more information about safety and demonstrate whether or not a treatment can be beneficial to a specific population. The treatment is given to larger groups of people to determine its benefits, identify side effects, compare it with other treatments, and see how the treatment can be used appropriately. 

Average length of study: One to four years

Getting results

The main objective of a clinical trial is to produce results for something called a primary endpoint. This is the key piece of information the trial was designed to measure. In MS, two commonly measured endpoints are:

  • Relapse rate:  compares how often flare-ups occurred in people in the active group vs. people in the control group
  • Sustained increase in disability:  compares how many people in the active and control groups experienced disability progression

Clinical trials can be a way to research new treatments. They not only provide the basis for the development and marketing of new treatments, but also help develop other products and devices.

Because Biogen is committed to helping to advance science, we are continuously doing research on new treatments for MS.


Road Trip
Home & Travel

10 tips for traveling with MS

From Paul P.

Avoiding holiday stress for people living with MS
Daily life with MS

4 ways to help avoid holiday stress

From Gina F.

Maintaining Mindfulness at Work
Mental & emotional health

Maintaining mindfulness at work

From Biogen


Learn about MS and connect with others. Check out in-person and online events

From Biogen

Alt –Ways to Stay Active for People Living With MS
Exercise & fitness

6 ways to help stay active

From Herb L.

Daily life with MS

A care partner’s perspective

From James T.

Daily life with MS

A day in the life of MS

From Julie D.

Female Nurse on Phone

Access to Nurse Educators

From Biogen

Daily life with MS

Accessorizing while living with MS

From Gina F.