AuthorisedTherapeutic exploratory (Phase II)Interventional

A randomized, placebo-controlled trial to assess the efficacy, tolerability, and pharmacokinetics of clemastine in children and adults with Pitt-Hopkins syndrome

This study is looking at a medicine called clemastine to see if it can help children and adults who have Pitt-Hopkins syndrome. This is an early-stage study, called Phase II, meaning researchers are trying to find out if the medicine works, if it's safe, and how the body uses it. Participants will receive either the clemastine medicine or a dummy pill (placebo) to fairly compare the effects. The main thing researchers want to know is how caregivers feel about any changes in their loved one's condition. They will also look at other things like how tired people are, their mood, sleep patterns, and any seizures. This research aims to understand if clemastine could be a helpful treatment option in the future.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Amsterdam UMC Stichting

Enrolment target

Start

13 Apr 2026

Pitt-Hopkins syndrome

What is this study about?

This research study is focused on Pitt-Hopkins syndrome, a rare genetic condition. The main goal is to explore a medicine called clemastine (sometimes known by the brand name Tavegyl) to see if it could help people with this syndrome. Clemastine is an type of antihistamine, and researchers are interested in whether it can improve some of the symptoms associated with Pitt-Hopkins syndrome.

This is a "Phase II" study. This means it's an important early step where scientists are primarily checking if the medicine is effective, how well people tolerate it (are there many side effects?), and how the body processes the medicine. They want to make sure it's safe to use and to get a better idea of how it works before potentially moving on to larger studies. Participants will be given either the active medicine or a "placebo," which looks exactly the same but contains no medicine, so researchers can fairly compare results.

The research team will be looking at several things to see if clemastine makes a difference. The most important measure is how caregivers feel about their loved one's overall condition and any changes they notice. They'll also be checking for improvements in tiredness, mood, sleep, digestion problems, and even things like seizure frequency and movement abilities. This detailed information will help researchers understand if clemastine has a positive impact on the daily lives of people with Pitt-Hopkins syndrome.

Key takeaways

This is an early-stage study testing a medicine called clemastine for Pitt-Hopkins syndrome.
It aims to see if clemastine is safe and helps with symptoms like tiredness, sleep, and mood.
Participants will receive either the study medicine or a dummy pill (placebo).
Caregivers' observations of changes will be a key part of how the medicine's effects are measured.
The study is for adults aged 18 and over, with a confirmed diagnosis of Pitt-Hopkins syndrome.

Who may be eligible?

This study is looking for adults who are 18 years old or older. Both men and women are welcome to take part.

Since this study is specifically for Pitt-Hopkins syndrome, participants must have a confirmed diagnosis of this condition. There might be other health requirements or medicines you're taking that could affect if you can join, but those details would be discussed with the study team.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Are you 18 years old or older?
Do you have a confirmed diagnosis of Pitt-Hopkins syndrome?
Are you able to attend appointments at the study clinic?
Are you, or your caregiver, able to complete questionnaires as part of the study?

Answer every question to see your result.

What does participation involve?

If you join this study, you would be given either the active study medicine (clemastine) or a placebo (a dummy pill) to take regularly, as instructed by the study team. You wouldn’t know which one you are getting. You would have several visits to the study clinic where the research team would carry out various assessments. These could include questionnaires – some filled out by you and some by your caregiver – to understand how you are feeling, your mood, sleep, and overall well-being. They might also check things like your breathing, how tired you feel, and possibly even your brain activity using a special test called an EEG (which involves placing sensors on your head).

Additionally, there might be physical tests, like walking for a certain amount of time, and some blood tests to see how your body is handling the medicine. These visits would be spread out over a period that the study team will explain, and the total duration of your participation in the study will be clearly communicated to you and your family.

Potential risks and benefits

Taking part in any medical study has potential benefits and risks. You might benefit from the study medicine if it helps with your Pitt-Hopkins syndrome symptoms, or you could simply benefit from the close medical attention you receive. However, there's also a chance the medicine might not work for you, or it could cause side effects, similar to any medicine. These side effects, if they occur, will be carefully monitored by the study team. You have the right to withdraw from the study at any time, for any reason, without it affecting your medical care.

Locations (1)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

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Unverified
Netherlands

Common questions

What is Pitt-Hopkins syndrome?

Pitt-Hopkins syndrome is a rare genetic condition that can affect many parts of the body, leading to developmental delays, breathing problems, and other unique features.

What is clemastine?

Clemastine is a type of antihistamine, a medicine often used for allergies. In this study, scientists are exploring if it could help with symptoms related to Pitt-Hopkins syndrome.

What is a placebo?

A placebo is a 'dummy' pill that looks just like the real medicine but contains no active ingredients. It helps researchers compare the effects of the actual medicine fairly.

Will I know if I'm getting the real medicine or the placebo?

No, this is a 'blinded' study, meaning neither you, your caregiver, nor the study doctors will know if you are receiving the active medicine or the placebo until after the study ends.

What kind of tests will happen during the study?

You might have questionnaires about your mood, sleep, and energy levels, along with physical checks, some activity tests, and possibly blood samples or an EEG (a brain activity test).