For people with Prader-Willi syndrome (PWS) and excessive daytime sleepiness.

Consider the TEMPO clinical study.

*Posed by models, not actual patient.

About the TEMPO study

This clinical study is assessing an investigational medication for excessive daytime sleepiness in people 6 years of age or older with PWS and is seeking volunteers.

A person may qualify to participate in the TEMPO study if they:

  • Are 6 years of age or older
  • Have a diagnosis of PWS
  • Have excessive daytime sleepiness

This is not a complete list of study requirements. The study doctor will review all the requirements with you.

Per the National Organization of Rare Disorders, PWS affects males and females in equal numbers and occurs in all ethnic groups and geographic regions around the world.

For this reason, it is important to study the investigational medication in a wide range of people with PWS. We are looking for ALL types of people with PWS to enroll—including children, teens, and adults who are of any race, ethnic origin, or gender.

Source: National Organization for Rare Disorders, last updated 7/12/2023,

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Download the study brochure

The study brochure provides information similar to the information on this website to help you discuss participation in the TEMPO study with your care recipient's doctor or that you can share with someone that may want to learn about the study.

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Study site locations

Find the TEMPO study site nearest you.

Assistance with study-related travel expenses may be available to eligible participants. Even if there is no study site nearby, you may still be able to participate. Additional sites will be opening throughout the year. Please check back if you do not see a site that works for you, or email to see if there is a site opening soon in your area.

We were unable to find any sites within 1500 miles of your location

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Eligibility questionnaire

Use our Eligibility Questionnaire to check if a care recipient may be eligible for the TEMPO study. Please note that the questionnaire is not a complete list of eligibility requirements and completing the questionnaire does not mean that a care recipient agrees to participate in the study.

Go to questionnaire
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Why consider the TEMPO study?

More medicines are needed to help treat the symptoms of PWS, but they must first be evaluated in clinical studies. This study depends on volunteers to participate to help researchers learn more about the use of this investigational medication in people with PWS to see if it may help their excessive daytime sleepiness.

The study doctor and staff understand that you or the person in your care has special needs, and they may be able to help with any questions or concerns you have with participating.

Why is the TEMPO study important?

As you likely already know, PWS is a rare genetic disorder, meaning that people are born with it. So even though there is no “cure,” there are some common symptoms—like excessive daytime sleepiness (feeling very sleepy during the day)—that may be able to be managed or even treated. Research studies like this one are key to developing medicines that may help.

What is the purpose of the TEMPO study?

This study will assess whether an investigational medication is safe and effective compared to placebo (a tablet/pill with no medicine in it). Researchers want to assess its impact on the severity of excessive daytime sleepiness in people 6 years of age or older who have PWS. They also want to assess its impact on the severity of irritable and disruptive behaviors and on hyperphagia (excessive eating).

What can I expect if I decide to participate?

The plan is to enroll 134 people in this study, which will consist of:

  • A Screening/Baseline Period of up to about 45 days (to make sure volunteers qualify to enroll).
  • An 11-week Treatment Period (during which time study participants will take their assigned study drug [i.e., placebo OR the investigational medication, pitolisant]).
  • An Open-Label Extension Period during which eligible participants will have the option to continue in the study and all will receive the investigational medication, pitolisant, as their study drug.
  • A Follow-Up Period consisting of 2 telehealth video visits within a month after the last study drug dose to see how participants are doing.

Study participation will last up to about 22 weeks (6 months), including Screening/Baseline Period and 30-day Follow-Up Period, during which time there will be 5 visits and up to 3 telehealth video visits.

For those who continue on to the Open-Label Extension Period, total participation will last closer to 74 weeks (or about a year and a half).

Image: Study participation chart

What about the study participant’s private health information?

The study doctor and staff will handle all personal health information in a confidential manner. Personal health information includes both a participant’s study data and original medical records. To protect privacy, participant and/or caregiver name and other personal information will not be identified unless necessary for study purposes. Instead, the participant and/or caregiver will be identified only by a code.

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About clinical studies

What is a clinical trial?

A clinical trial, also called a clinical research study, is conducted to learn whether an investigational medication is safe and effective for use in people with the medical condition being studied.

Clinical trials/studies are required to follow strict scientific standards to help ensure the safety of the participants while researchers learn more about the investigational medication.

What is an investigational medication?

An investigational medication is a substance that is being tested in clinical studies. An ethics committee has reviewed the clinical study for testing in people, and the investigational medication may or may not be approved by the United States Food and Drug Administration (FDA) for treatment for the condition being studied.