Withdrawal of Prostacyclin Pathway Therapy in Patients With Pulmonary Arterial Hypertension Recei… (NCT07700303) | Clinical Trial Compass
Not Yet RecruitingNot Applicable
Withdrawal of Prostacyclin Pathway Therapy in Patients With Pulmonary Arterial Hypertension Receiving Sotatercept (WATERLOO)
Canada78 participantsStarted 2026-09-30
Plain-language summary
Pulmonary arterial hypertension (PAH) is a rare lung disease that leads to elevated blood pressure in the lungs and strain on the right side of the heart. For many years, treatments for PAH have included drugs that target the prostacyclin pathway using intravenous, subcutaneous, oral, and inhaled drugs. These drugs help widen the blood vessels in the lungs so the heart does not have to work as hard. However, these medicines can cause side effects such as jaw pain, flushing, diarrhea, and nausea, and the pump therapy can be very hard to manage day-to-day.
A newer medicine called sotatercept works in a different way. It helps fix some of the root causes of PAH. Early reports suggest that some people do very well on sotatercept and may not need to keep taking their prostacyclin therapy. However, investigators do not yet know if it is safe to stop prostacyclin therapies or how to do so. This study, called WATERLOO, is designed to find out whether slowly stopping prostacyclin therapy while the participant is doing well on sotatercept is safe. Investigators will compare people who stop their prostacyclin therapy to people who keep taking it. This study is being done at PAH expert centres in Canada and Europe.
Who can participate
Age range
18 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Adults ≥ 18 years old diagnosed with PAH.
. Treatment with sotatercept for ≥6 months.
. Background therapy with ≥2 PAH vasodilator therapies, one of which is a parenteral prostacyclin or selexipag.
. At low or intermediate-low risk, defined using the 2022 ESC/ERS guidelines 4-strata risk assessment tool (Table 1).
. RHC at screening or historical within 8 weeks of screening, and after at least 6 months of sotatercept treatment, demonstrating a mPAP ≤40 mmHg and PVR ≤5 WU
. The ability to adhere to the study visit schedule and to comprehend and comply with all protocol requirements.
. Ability to provide informed consent.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in Mean Pulmonary Arterial Pressure (mPAP) From Baseline to 24 Weeks
Timeframe: Baseline to 24 weeks
Trial details
NCT IDNCT07700303
SponsorUniversity of Alberta
Sponsor typeOTHER
Study typeINTERVENTIONAL
Primary completion2028-03-30
Contact for this trial
Canadian VIGOUR Centre Clinical Trial Project Lead
. A RHC at screening or historical within 8 weeks of screening and after ≥6 months of sotatercept treatment demonstrating mPAP \> 40 mmHg or PVR \> 5 WU.
. Hospitalization for worsening PAH or right heart failure within the 3 months prior to screening.
. Active listing for lung or heart/lung transplantation.
. Metastatic cancer or any other condition with a life expectancy \< 6 months,
. Female patients who are pregnant or who are of childbearing age and are unwilling to use contraception during the study.
. History of ≥ 3 interruptions or missed doses of sotatercept for any reason within the previous 6 months prior to screening.
. Patients who received any investigational medication within 1 month prior to screening (unless known to be placebo) or who are scheduled to receive another investigational drug during the course of this study.