Cardurion Pharmaceuticals Completes Enrollment in Phase 2 CYCLE Trials Evaluating CRD-750, a Novel PDE9 inhibitor, in Heart Failure
- CRD-750 is the first clinical-stage PDE9 inhibitor to be evaluated in patients in both types of chronic heart failure
- The CYCLE-1-REF trial is evaluating patients with heart failure with reduced ejection fraction (HFrEF), and the CYCLE-2-PEF trial is evaluating patients with heart failure with preserved ejection fraction (HFpEF)
BURLINGTON, Mass., Aug. 06, 2025 (GLOBE NEWSWIRE) -- Cardurion Pharmaceuticals, Inc. (“Cardurion”), a clinical-stage biotechnology company discovering and developing new therapeutic approaches for the treatment of patients with cardiovascular diseases, today announced that it has completed enrollment in two global, multi-center, Phase 2 clinical trials assessing the safety and efficacy of CRD-750 in both types of chronic heart failure (HFrEF and HFpEF).
CRD-750 is an orally-administered phosphodiesterase 9 (PDE9) inhibitor that represents a new mechanism to enhance the natriuretic peptide signaling (NPS) pathway, a clinically-validated pathway for the treatment of patients with heart failure. Cardurion is the first company to bring a PDE9 inhibitor into clinical development for the treatment of chronic heart failure.
The CYCLE-1-REF trial (NCT06215911) enrolled approximately 560 patients with HFrEF and is evaluating three doses of CRD-750 compared to placebo. CYCLE-2-PEF (NCT06215586) enrolled approximately 300 patients with HFpEF and is evaluating one dose of CRD-750 compared to placebo. The primary endpoint of both CYCLE clinical trials is the change in N-terminal pro-B-type natriuretic peptide (NT-proBNP), a peptide that is released by the heart in the setting of heart failure. Reduction in NT-proBNP has been used as a biomarker to measure the treatment effect in clinical trials of other approved heart failure therapies. The trials are also evaluating secondary endpoints, including additional biomarkers and the Kansas City Cardiomyopathy Questionnaire (KCCQ), a patient-reported outcomes scale.
“The clinical community eagerly awaits the results of the CYCLE clinical trials. Despite recent approvals, a large unmet medical need persists and patients with heart failure continue to experience high rates of morbidity and mortality. PDE9 inhibition is a promising new mechanism in the NPS pathway that may offer an opportunity to improve the standard of care treatment for the millions of patients with both types of chronic heart failure,” said James Udelson, MD, Chief of Cardiology at Tufts Medical Center and Principal Investigator for the CYCLE-1-REF and CYCLE-2-PEF trials.
“Completion of enrollment in the CYCLE trials represents a major milestone in our CRD-750 clinical program. Since the founding of Cardurion, our team has believed that the upregulation of PDE9 that occurs in heart failure is a critical element limiting the beneficial clinical effects of the highly validated NPS pathway. Our progress brings us closer to our goal of leveraging PDE9 inhibition to address unmet needs for patients,” said Howard Surks, MD, Chief Medical and Scientific Officer of Cardurion. “It is gratifying for us to implement this large, global clinical program in partnership with the cardiovascular treatment community. We look forward to receiving the Phase 2 results from these clinical trials and presenting them at a future medical meeting.”
About PDE9 Inhibition
Phosphodiesterase (PDE) 9 is an enzyme whose elevated activity in patients with heart failure reduces the beneficial effects of the natriuretic peptide signaling (NPS) pathway. The NPS pathway plays an important and protective role in cardiac function and its activation has been shown to confer outcomes benefit for patients with heart failure. PDE9 is significantly upregulated in patients with chronic heart failure, causing disruption in the NPS pathway. Cardurion is the first company to demonstrate clinical proof-of-mechanism for PDE9 inhibition in patients with chronic heart failure with its PDE9 program.
About Heart Failure
Heart failure is a prevalent and growing condition that is responsible for substantial morbidity and mortality. Approximately 6.7 million adults in the United States suffer from heart failure, and approximately 50 percent of these patients die from the condition within five years of diagnosis. One in five patients with heart failure are hospitalized annually, and approximately 25 percent of these patients are re-admitted within a month of discharge. Approximately half of all patients with chronic heart failure have reduced ejection fraction (HFrEF) and half have preserved ejection fraction (HFpEF), categorized as different diseases based on the pumping ability of the heart. Unmet medical needs remain in heart failure, despite the reductions in morbidity and mortality from currently approved treatments for heart failure.
About Cardurion Pharmaceuticals
Cardurion Pharmaceuticals is a clinical-stage biotechnology company discovering and developing new therapeutic approaches to address cardiovascular diseases. Cardurion has extensive expertise in cardiovascular biology, signaling pathways and drug discovery and development, and it translates that expertise into potentially groundbreaking therapeutics with the promise to address the unmet needs of patients. Cardurion’s clinical-stage pipeline consists of product candidates targeting phosphodiesterase-9 (PDE9) and calcium/calmodulin-dependent protein kinase II (CaMKII). Cardurion is the first company to advance product candidates against these novel and important targets into clinical testing for the treatment of cardiovascular disease. Cardurion is headquartered in Burlington, Massachusetts, with discovery sciences and research facilities in Shonan, Japan. For more information, please visit Cardurion’s website at https://cardurion.com and follow us on LinkedIn.

Contacts Investors: Dan Ferry LifeSci Advisors daniel@lifesciadvisors.com 617-430-7576 Media Contact: Barbara Yates The Yates Network LLC 781-258-6153 barbara@theyatesnetwork.com
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