Clinical Trials 101

Drugs and treatments are all tested for safety and efficacy before being approved and made available for prescription. In the U.S., drug safety and efficacy is regulated by the U.S. Food and Drug Administration (FDA).

Clinical trials play an important role in the development of new treatments for psoriasis and psoriatic arthritis. The findings from clinical trials are submitted to the FDA to review and determine if a new treatment will be approved to go to market. Knowing the different types of research can help you understand what clinical trials are and where their results might lead.

There are three types of research:

Basic research answers questions about how a disease works or affects the body.

Translational research uses discoveries from basic research and turns them into treatments that can then be tested.

Clinical research involves different steps of testing for safety and efficacy. Preclinical testing is when researchers perform lab tests and animal testing. After a treatment is found to be safe and effective in preclinical testing, researchers start the clinical studies, which consist of four phases. Phases I, II and III are clinical trials or interventional studies to understand the safety and effectiveness of a new treatment. Phase IV is composed of observational studies to understand the long-term impacts of a new treatment.

Clinical trial phases

Treatments developed by pharmaceutical and biotechnology companies go through clinical trials under the supervision of physicians and other research professionals.

All phases of clinical trial testing involves human participants or volunteers. Each phase is different depending on who can participate, how long the trial takes and what type of information the researchers are trying to understand.

There are also different ways that a clinical trial can be designed. A common design is called a randomized double-blind, placebo-controlled trial. This means that participants in the trial are split into two groups at random. One group will be given a placebo (an inactive pill, liquid or powder that has no treatment value). The other group will be given the treatment that is being studied.

In this type of study, the participants and the researchers will not know who is receiving the placebo and who is receiving the studied treatment until the end of the study. When a placebo is used during a trial, generally it only happens for a limited time at the beginning of the study. Then it’s often followed by a period of time where all participants receive an active treatment.

There are also studies that use a double-blind design that compares a new potential treatment with a currently approved treatment.

Clinical trial phases include:

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Who can participate?

About 20 to 100 healthy participants

How long is this phase?

Several months

What is being studied?

How the body processes a treatment

Side effects at different dosage levels

What happens next?

About 70% of drugs pass this phase and go onto Phase II


Who can participate?

Hundreds of patient participants

How long is this phase?

Several months to two years

What is being studied?

How safe and effective a new treatment is compared to a currently approved treatment

What happens next?

About 33% of drugs pass this phase and go onto Phase III


Who can participate?

300 to 3,000 patient participants

How long is this phase?

1 to 4 years

What is being studied?

How safe and effective a new treatment is compared to a currently approved treatment

More understanding about benefits and possible side effects

What happens next?

About 25% to 30% of drugs pass this phase and request FDA approval



There are also Phase IV studies (often called Post Marketing Surveillance Trials) after a drug or treatment has been approved and is on the market. These are different from other clinical trial phases because they are observational – they compare the treatment with others on the market and monitor long-term effectiveness and safety. Phase IV studies often involve several thousand patient participants.


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Pros and cons of participating in a clinical trial

You can weigh the pros and cons of participating in a clinical trial just as you might weigh the pros and cons of a specific treatment. For example, when making any type of treatment decision, you might consider your disease severity, your reactions to previous treatments and other health conditions you might be coping with.

Some of the pros and cons of participating in a clinical trial include:



  • Help others by contributing to medical research

  • Receive free treatment and access to a treatment before it is widely available

  • Obtain free medical care during the trial, including appointments and lab work

  • Possibly get paid for participating or for costs of travel

  • Experience improvement or even remission of psoriatic disease symptoms

  • Play an active role in your health care



  • As with all treatments, possibly experience a side effect or risk

  • Might receive a placebo

  • Must discontinue all existing treatments during a “washout” period before the trial begins

  • Experience no improvement or even worsening of psoriatic symptoms

  • May be time-consuming or demanding with regular check-ups

  • May have challenges in accessing the treatment once the trial is complete

Keep in mind that a participant may withdraw from a study at any time for any reason.

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Understanding informed consent

Informed consent is having the right to know and understand what will happen during a clinical trial before agreeing to participate. Understanding what to expect will help you decide whether participating in a clinical trial is best for you.

Giving written consent to participate in a clinical trial means that you acknowledge, understand and accept all aspects of the study. This includes any possible benefits or risks. The physicians and research staff are responsible for helping you understand the information. They should give you enough time to make a decision about participating in the clinical trial. You can always ask questions if you do not understand something about the study or if you have other concerns.

You have the right to the following:

  • Know the purpose of the clinical trial and what will happen during the study
  • Be informed of all of the possible benefits, side effects and risks that might be reasonably expected and any medical treatments available if complications occur during the study
  • Ability to ask questions about the clinical trial before giving consent and at any time during the study
  • Sufficient time to make your decision about participating without pressure to make a decision
  • A signed and dated copy of the informed consent form
  • Ability to refuse to participate for any reason before the trial has started and at any time during the study

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After a clinical trial ends


For you:

You may have some questions or concerns about what will happen to the treatment and your treatment plan after a study has ended. It is important that you speak with the research staff about your concerns.

You can ask:

  • If the treatment is helping, is it possible to stay on it?
  • If you cannot stay on that treatment, what are your next steps for getting onto a new treatment plan?
  • What happens to your data and information?
  • Will you receive results from this study? If so, when and how?
  • Can you or your health care provider access your medical records from the study?

Work with the research staff to help coordinate with your health care provider on a treatment plan after the trial has ended. If you are unable to access health care outside of a clinical trial, speak with the research staff about your treatment options after the trial. Or it may be possible to join another clinical trial.


For the treatment:

All of the data that is collected during a clinical trial is analyzed to determine how safe and effective the treatment is. All data is de-identified so that no one will know an individual’s specific information. Researchers will use these findings to determine whether to stop testing or to move to the next phase of clinical trials. Results from a clinical trial are often published in scientific journals and on

If the clinical trial was a Phase III study, researchers will determine if the findings are medically important. If they are, researchers will submit their findings for publication and to the FDA for approval. The FDA will review all of the data and findings from the clinical trial and make a decision on whether or not to approve the treatment and make it available on the market.

Treatments that become approved may continue to have clinical studies done in order to:

  • Compare the safety, effectiveness and cost of the new treatment with other treatments that are currently available
  • Better understand the long-term safety and efficacy of the new treatment
  • Measure its impact on quality of life for people using the new treatment

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