AuthorisedTherapeutic exploratory (Phase II)Interventional

A Phase 2, randomized, double-blind, placebo-controlled trial to evaluate the efficacy, safety, and tolerability of CRD-4730 in patients with heart failure with reduced ejection fraction (HFREF) (CALIBRATE-HF)

Heart failure happens when the heart muscle cannot pump blood around the body as well as it should. This clinical trial, called CALIBRATE-HF, is testing a new medicine called CRD-4730. Researchers want to find out if this medicine is safe and if it can improve how the heart works. Adults aged 18 and older who have heart failure with reduced pumping power can take part. Everyone who joins will be randomly chosen to take either CRD-4730 tablets or a dummy pill (placebo) alongside their usual heart care. Neither the participants nor their doctors will know which one they receive. The trial lasts for about 24 weeks. During this time, the study team will monitor heart health using blood tests, heart scans (ultrasounds), and symptom questionnaires. The goal is to see if CRD-4730 can improve heart strength, relieve symptoms, and safely protect heart health in the future.

At a glance

Status

Authorised

Phase

Therapeutic exploratory (Phase II)

Sponsor

Cardurion Pharmaceuticals Inc.

Enrolment target

369

Start

14 Aug 2026

heart failure

What is this study about?

Heart failure is a long-term condition where the heart muscle becomes too weak or stiff to pump blood efficiently around the body. For people with 'reduced ejection fraction', the left side of the heart is not squeezing out as much blood with each beat as a healthy heart would. This can lead to tiredness, breathlessness during simple activities, and swelling in the legs and ankles. While modern treatments have improved life for many people, doctors are still searching for new options that can help the heart muscle pump better and ease daily struggles.

This trial, called CALIBRATE-HF, is investigating an experimental tablet named CRD-4730. In this Phase 2 study, researchers want to discover whether CRD-4730 can reduce strain on the heart, improve its shape and pumping strength, and help people feel better in their day-to-day lives. They also want to check for any unwanted side effects and find out how well the human body tolerates the drug over six months.

To make sure the results are fair and reliable, this is a 'placebo-controlled' study. This means some people will receive the new medicine, while others receive a matching dummy tablet with no active medicine. Finding new ways to support failing hearts is vital, and the results from this study could help guide better treatments for thousands of people living with heart conditions across the UK and the world.

Key takeaways

Tests a new daily tablet called CRD-4730 for heart failure.
Aimed at adults aged 18 and older with reduced heart pumping power.
Compares the new drug against an inactive dummy pill (placebo) over 24 weeks.
Includes regular heart scans, blood checks, and symptom reviews.
Participation is completely voluntary and added on top of your usual care.

Who may be eligible?

This trial is open to men and women aged 18 and over who have been diagnosed with heart failure with reduced ejection fraction. This means your doctor has confirmed that your heart muscle is pumping blood with less force than normal.

To join, you should be willing to take study tablets regularly and attend scheduled hospital clinic visits for tests. You will also need to complete questionnaires about how your heart symptoms affect your day-to-day activities.

You might not be able to take part if you have certain other serious health issues, very unstable heart symptoms, or if your kidneys or liver are severely unwell. The trial team will carefully review your medical history and current medicines to make sure it is completely safe for you to participate.

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.

I am aged 18 or older.
I have been diagnosed with heart failure with reduced pumping function.
I am able to attend regular hospital or clinic appointments over six months.
I am happy to take a daily study tablet and undergo routine heart scans and blood tests.
My current heart condition is reasonably stable on my everyday medicines.

Answer every question to see your result.

What does participation involve?

Taking part in this trial lasts for at least 24 weeks (around six months). If you join, you will be asked to take a tablet by mouth every day. You will have a 50-50 chance of receiving either the active study drug (CRD-4730) or a dummy tablet (placebo), taken in addition to your standard heart medications.

You will need to visit the study clinic several times, notably at the start, at 12 weeks, and at 24 weeks. During these visits, doctors will check your blood pressure, pulse, and general health. You will have blood tests to measure heart stress markers, non-invasive heart ultrasound scans (echocardiograms) to see how well your heart pumps, and quick heart rhythm traces (ECGs).

You will also fill out short symptom questionnaires to share how you are feeling in your daily life. After 24 weeks, the study team will conduct a final safety follow-up to ensure you remain well.

Potential risks and benefits

Taking part may not directly improve your heart health, particularly if you are given the dummy tablet. However, the trial gives you frequent, thorough health checks with heart specialists, and the findings could help improve heart failure treatments for many people in the future. As with any new medicine, there is a risk of side effects, which the medical team will watch for closely. Joining the trial is entirely voluntary. You can choose to leave the study at any point without giving a reason, and your regular NHS care and relationship with your doctors will not be affected in any way.

Locations (10)

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

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Unverified
Latvia
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Unverified
Slovakia
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Unverified
Lithuania
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Unverified
Hungary
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Unverified
Italy
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Unverified
Netherlands
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Unverified
Spain
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Unverified
Poland
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Unverified
Bulgaria
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Unverified
Czechia

Common questions

What is a placebo and why is it used?

A placebo looks and tastes just like the real medicine, but contains no active ingredients. Researchers use it to compare the study medicine against dummy pills to prove whether changes in health are truly caused by the drug.

Will I have to stop taking my regular heart tablets?

No. The study medication or placebo is taken alongside your standard, proven heart failure medicines so your normal heart care is not compromised.

Do I have to pay to take part?

No. The trial medication, clinic visits, and all heart scans are provided free of charge, and trial organisers often help cover reasonable travel expenses to the clinic.

What happens if I experience side effects?

You will be given contact details for the study team to report any problems. If side effects are troublesome, doctors can adjust your treatment or take you off the study immediately to protect your safety.

Can I leave the study early if I change my mind?

Yes. You have the right to withdraw from the trial at any time. Doing so will not affect your normal medical treatment or your relationship with your healthcare team.