About clinical studies1

People volunteer for clinical studies to help researchers learn about new and existing treatments. Carefully conducted clinical studies—led by medical doctors called principal investigators—are the optimal way to find new treatments.


Each clinical study has a plan, called a protocol, which must be conducted according to strict scientific and ethical principles.

Details include participation criteria, test schedules, procedures, medications, and study length.

Sugar pill

Sometimes, a drug undergoing investigation is compared against a placebo, also called a “sugar” pill.

The placebo looks like the study drug, but contains no active ingredients. Using a placebo helps increase the possibility that any effects seen in the study are due only to the study drug itself.

Inclusion and exclusion criteria

Inclusion criteria are the factors that allow someone to participate in the study. Exclusion criteria are factors that prohibit someone from participating in a study.

These criteria are part of the study protocol, and help to set parameters for study outcomes.

Clinical studies are conducted at approved study sites such as hospitals, universities, doctors’ offices, and community clinics.

Learn About Ultragenyx Clinical Studies for Glut 1 DS

How clinical studies work1,2

The development of potential treatments is divided into steps called “phases.” Generally, the study treatment must pass through each phase successfully before it can continue on to the next.

Phase 1

Phase 2

Phase 3

Usually healthy volunteers (although may include people with the disease)
People with the disease
People with the disease
Safety and how the body breaks down the study treatment
Safety and how the body breaks down the study treatment
Safety and efficacy of the
study treatment

Phase 1

Usually healthy volunteers (although may include people with the disease)
Safety and how the body breaks down the study treatment

Phase 2

People with the disease
Safety and how the body breaks down the study treatment

Phase 3

People with the disease

Once the studies are complete, the results along with other information on the drug is submitted to and reviewed by a government agency, such as, the United States Food and Drug Administration (FDA). If the data shows the study treatment is safe and effective, it may be approved for use by prescription.

Potential benefits

  • Receiving regular, close monitoring and care from an experienced research team
  • Helping others by contributing to medical research
  • Gaining access to investigational treatments
  • Playing an active role in your own health care

Risks and disadvantages

  • Unpleasant, serious, or even life-threatening side effects of the treatments being tested
  • Time commitments for study participation
  • The study treatment may not work

Consider participating1

Taking part in a clinical study is voluntary. That means you don’t have to join if you don’t want to and that your future health options will not be affected if you decide you don’t want to participate.

If you change your mind, you can even withdraw your consent to participate in a study once you’ve joined.

Understanding your rights: informed consent1

If you want to take part in a clinical study, you’ll be asked to review an informed consent form (ICF).

Among other information, an ICF will tell you:

  • What to expect during your time in the study
  • What tests you’ll have
  • The potential risks or benefits of the study drug
  • Your rights as a study participant

You can review the ICF information with a member of the team at the study site—they’ll answer any questions that you might have. You may also ask your doctor or a friend or family member to review the ICF.

Once your questions have been answered, you’ll be asked to sign the ICF. This shows that you understand the study’s requirements and agree to take part.


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References: 1. National Institutes of Health Clinical Center. About Clinical Studies. https://clinicaltrials.gov/ct2/about-studies. Updated December 2015. Accessed March 23, 2016. 2. U.S. Department of Health and Human Services. Development & Approval Process (Drugs). http://www.fda.gov/Drugs/DevelopmentApprovalProcess/. Updated January 2016. Accessed April 27, 2016.