CRD-4730
An investigational treatment for Catecholaminergic Polymorphic Ventricular Tachycardia.
Drug facts
The same compound appears under different names depending on the context. Here is how to identify CRD-4730 wherever you encounter it, plus the key facts at a glance.
- Generic name
- CRD-4730
- Development code
- CRD-4730
- Drug class
- CaMKII inhibitor (small molecule)
- Manufacturer
- Cardurion Pharmaceuticals
- How it's taken
- Tablet by mouth, in a trial only
An investigational tablet from Cardurion Pharmaceuticals that blocks CaMKII, an enzyme involved in the calcium leaks behind catecholaminergic polymorphic ventricular tachycardia (CPVT)[4].
- CRD-4730 is in a Phase 2 study (NCT06658899) that gives about 12 adults with RYR2-related CPVT 2 doses of the drug and a placebo in turn.
- The study's main measure is safety, and it also tracks changes in arrhythmias during exercise stress tests[1].
- No results have been published, and ClinicalTrials.gov lists an estimated completion of April 2027[1].
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Where CRD-4730 fits
CRD-4730 is an experimental pill being tested in adults with CPVT caused by RYR2 gene changes, and no CRD-4730 results have been published[1].
- Care for CPVT today rests on beta blockers, flecainide and implantable defibrillators (ICDs), according to a 2025 review from Baylor College of Medicine[8].
- No FDA label names CPVT as an approved use; the nadolol label covers angina and high blood pressure, and the flecainide label covers life-threatening ventricular arrhythmias in general without naming CPVT[10][11].
- CRD-4730 has not been compared with beta blockers, flecainide or any other CPVT treatment, and the study adds it or a placebo on top of the heart rhythm medicine each person already takes[1].
- Whether an RYR2 result and current exercise test findings could make someone a candidate for this study is a question for a cardiologist who treats inherited arrhythmias.
How CRD-4730 works
Each heartbeat depends on calcium. A storage area inside heart muscle cells releases calcium through a channel called the ryanodine receptor (RyR2), then takes it back. In about half of people with CPVT, a change in the RYR2 gene makes this channel leaky, and in a smaller group a change in the CASQ2 gene has a similar effect[9]. Adrenaline from exercise or strong emotion makes the leak worse, and the stray calcium can set off a dangerous fast rhythm from the lower heart chambers, called ventricular tachycardia[9].
CaMKII is an enzyme switched on by adrenaline signals. It tags RyR2 and other calcium proteins with phosphate, and when it is overactive it pushes the calcium cycle further off balance[5][7]. In a 2019 Boston Children's Hospital study, a CaMKII-blocking gene therapy suppressed adrenaline-triggered arrhythmias in CPVT mice, and a CaMKII-blocking peptide calmed abnormal calcium release in heart cells grown from CPVT patients' stem cells[7].
CRD-4730 is designed to block CaMKII as a pill. Whether that helps people with CPVT is what the trials are testing.
Clinical trial results
NCT06658899 is a Phase 2, double-blind, placebo-controlled crossover study, meaning each person takes 2 doses of CRD-4730 and a placebo in random order without knowing which is which. It aims to enroll 12 adults 18 and older with a confirmed disease-causing RYR2 variant and arrhythmias that show up on an exercise test, who have taken a stable dose of at least 1 heart rhythm medicine other than amiodarone, such as a beta blocker, for 4 weeks, unless they could not tolerate these medicines.
The main outcome is side effects through day 101; secondary outcomes are the change in a ventricular arrhythmia score on exercise testing at days 15, 44 and 73 and drug levels in the blood. It began on December 1, 2025 and lists 12 recruiting sites, 5 of them in the US (San Francisco, Morrisville in North Carolina, Houston, Salt Lake City and Madison in Wisconsin), with an estimated completion in April 2027[1].
An earlier, shorter crossover study, NCT06005428, enrolled 7 people between November 2023 and May 2025 and was stopped for business reasons[2]. Cardurion is also testing CRD-4730 in heart failure with reduced ejection fraction in the 525-person CALIBRATE-HF trial (NCT07750873), which began in July 2026[3].
Main registered trial: NCT06658899 on ClinicalTrials.gov. Check it for the current status, sites and contacts before asking about enrollment.
Side effects and safety
Cardurion has not published results for CRD-4730 from any study, so its side effects in people are not known. The Phase 2 CPVT study counts side effects that start during treatment as its main outcome, through day 101[1]. An earlier, shorter crossover study in CPVT enrolled 7 people and ended early; ClinicalTrials.gov says it stopped because of an internal administrative and business decision and not for safety reasons, and no results were posted[2].
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking CRD-4730
Taken by mouth as a tablet[1]. The registry lists 2 doses, called Dose 1 and Dose 2, and a matching placebo tablet without giving the amounts or how often they are taken. In a separate heart failure trial the drug is taken twice daily for 24 weeks[3]. Any approved dose would be set by an FDA label.
Development history
In November 2023 Cardurion said it was starting a Phase 2 trial of its lead CaMKII inhibitor in CPVT[6], and the first CPVT study (NCT06005428) began on November 7, 2023[2]. In July 2024 Cardurion's Series B financing release named CRD-4730 as its lead CaMKII inhibitor, in an ongoing Phase 2 CPVT trial, and called it the first CaMKII inhibitor to reach clinical testing[4].
The first study ended early on May 31, 2025 for business reasons[2], and the repeat-dose CPVT study began on December 1, 2025[1]. The heart failure trial began on July 15, 2026[3]. Cardurion has announced no FDA designations for CRD-4730 in CPVT.
Explore Catecholaminergic Polymorphic Ventricular Tachycardia trials
Common questions about CRD-4730
▸What is CRD-4730?
An investigational tablet from Cardurion Pharmaceuticals that blocks CaMKII, an enzyme involved in the calcium leaks behind catecholaminergic polymorphic ventricular tachycardia (CPVT)[4]. CRD-4730 is in a Phase 2 study (NCT06658899) that gives about 12 adults with RYR2-related CPVT 2 doses of the drug and a placebo in turn. The study's main measure is safety, and it also tracks changes in arrhythmias during exercise stress tests[1]. No results have been published, and ClinicalTrials.gov lists an estimated completion of April 2027[1].
▸How does CRD-4730 work?
Each heartbeat depends on calcium. A storage area inside heart muscle cells releases calcium through a channel called the ryanodine receptor (RyR2), then takes it back. In about half of people with CPVT, a change in the RYR2 gene makes this channel leaky, and in a smaller group a change in the CASQ2 gene has a similar effect[9]. Adrenaline from exercise or strong emotion makes the leak worse, and the stray calcium can set off a dangerous fast rhythm from the lower heart chambers, called ventricular tachycardia[9].
CaMKII is an enzyme switched on by adrenaline signals. It tags RyR2 and other calcium proteins with phosphate, and when it is overactive it pushes the calcium cycle further off balance[5][7]. In a 2019 Boston Children's Hospital study, a CaMKII-blocking gene therapy suppressed adrenaline-triggered arrhythmias in CPVT mice, and a CaMKII-blocking peptide calmed abnormal calcium release in heart cells grown from CPVT patients' stem cells[7]. CRD-4730 is designed to block CaMKII as a pill. Whether that helps people with CPVT is what the trials are testing.
▸What are the side effects of CRD-4730?
Cardurion has not published results for CRD-4730 from any study, so its side effects in people are not known. The Phase 2 CPVT study counts side effects that start during treatment as its main outcome, through day 101[1]. An earlier, shorter crossover study in CPVT enrolled 7 people and ended early; ClinicalTrials.gov says it stopped because of an internal administrative and business decision and not for safety reasons, and no results were posted[2].
▸How is CRD-4730 taken?
▸Is CRD-4730 FDA approved?
CRD-4730 is currently in phase 2 clinical trials for Catecholaminergic Polymorphic Ventricular Tachycardia. It has not yet received FDA approval.
▸Is CRD-4730 FDA approved for CPVT?
No. CRD-4730 is an experimental drug in a Phase 2 study, and the FDA has not approved it for any use.
Stage: Phase 2 crossover study in about 12 adults with RYR2-related CPVT, recruiting since December 2025.
Results: None published; ClinicalTrials.gov lists an estimated completion of April 2027.
Source: ClinicalTrials.gov NCT06658899
▸What does the CRD-4730 CPVT trial measure?
The main measure is safety, counted as side effects through day 101.
Also tracked: Change in an arrhythmia score on exercise stress tests at days 15, 44 and 73, and drug levels in the blood.
Design: Each person takes 2 doses of CRD-4730 and a placebo in random order, without knowing which is which.
Source: ClinicalTrials.gov NCT06658899
▸Who can join the CRD-4730 CPVT study?
Adults 18 and older with CPVT confirmed by an RYR2 gene change and arrhythmias that show up on an exercise test.
Medicines: A stable dose of at least 1 heart rhythm medicine other than amiodarone, such as a beta blocker, for 4 weeks, unless they could not tolerate these medicines.
Gene: The study requires a confirmed RYR2 variant, so CPVT from other genes such as CASQ2 does not meet the entry rule.
Not eligible: People who had an ICD placed or sympathetic denervation surgery in the past 3 months.
US sites: San Francisco, Morrisville (North Carolina), Houston, Salt Lake City and Madison (Wisconsin).
Source: ClinicalTrials.gov NCT06658899
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- ClinicalTrials.gov. A Phase 2 Study of CRD-4730 in CPVT. https://clinicaltrials.gov/study/NCT06658899
- ClinicalTrials.gov. Effectiveness of CRD-4730 in Participants With Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT). https://clinicaltrials.gov/study/NCT06005428
- ClinicalTrials.gov. A Trial of CRD-4730 in HFrEF. https://clinicaltrials.gov/study/NCT07750873
- Cardurion Pharmaceuticals · 2024-07. Cardurion Pharmaceuticals Announces $260 Million Series B Financing to Advance Its Pipeline of Innovative Medicines for Cardiovascular Diseases. https://cardurion.com/cardurion-pharmaceuticals-announces-260-million-series-b-financing-to-advance-its-pipeline-of-innovative-medicines-for-cardiovascular-diseases/
- Cardurion Pharmaceuticals. CaMKII - Cardurion. https://cardurion.com/pipeline/camkii/
- Cardurion Pharmaceuticals · 2023-11-07. Cardurion Pharmaceuticals to Provide Update on CaMKII Inhibitor Program at the American Heart Association's Scientific Sessions 2023. https://cardurion.com/cardurion-pharmaceuticals-to-provide-update-on-camkii-inhibitor-program-at-the-american-heart-associations-scientific-sessions-2023/
- Circulation · 2019-07-30. Gene Therapy for Catecholaminergic Polymorphic Ventricular Tachycardia by Inhibition of Ca(2+)/Calmodulin-Dependent Kinase II. https://pubmed.ncbi.nlm.nih.gov/31155924/
- Current Opinion in Cardiology · 2025-05-01. Genetics, manifestations, and management of catecholaminergic polymorphic ventricular tachycardia. https://pubmed.ncbi.nlm.nih.gov/39835466/
- MedlinePlus, National Library of Medicine. Catecholaminergic polymorphic ventricular tachycardia. https://medlineplus.gov/genetics/condition/catecholaminergic-polymorphic-ventricular-tachycardia/
- U.S. National Library of Medicine, DailyMed · 2024-05. Nadolol tablets: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0a2acdc0-aab6-462e-a377-67a0f3d55ec6
- U.S. National Library of Medicine, DailyMed · 2024-01. Flecainide acetate tablets: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=14e89448-3a18-42e3-8537-2589be1ef94e