Retension Pharmaceuticals Inc., a clinical-stage biopharmaceutical company, announced the successful completion of a $15 million Series B financing round to advance its lead candidate RTN-001 for patients with uncontrolled and resistant hypertension. The company also received U.S. Patent Number 12,258,350, extending intellectual property protection for RTN-001 through at least 2044.
Novel PDE5 Inhibitor Targets Cardiovascular Arteries
RTN-001 represents a unique approach to hypertension treatment as a PDE5 inhibitor specifically designed to preferentially target central cardiovascular arteries that determine blood pressure. Unlike earlier, first-generation PDE5 therapies, RTN-001 leverages the well-established mechanism of enhancing nitric oxide signaling, which plays a key role in blood pressure regulation.
The drug candidate has been studied in 243 human subjects to date, including two Phase 2 studies in patients with hypertension taking up to four other antihypertensive medications. In these studies, RTN-001 demonstrated clinically significant reductions in blood pressure while maintaining a well-tolerated safety profile.
Phase 2b Trial to Launch in Q4 2025
The Series B proceeds will support the initiation of a multicenter, double-blind, placebo-controlled, randomized Phase 2b clinical study scheduled to commence in the fourth quarter of 2025. The trial will enroll approximately 280 patients across multiple U.S. sites to evaluate the efficacy and safety of a once-daily, modified-release formulation of RTN-001.
The Phase 2b study will assess the drug's effect on systolic and diastolic peripheral blood pressure, as well as central and ambulatory blood pressure over a 12-week treatment period. The modified-release formulation is designed to deliver sustained blood pressure reduction over 24 hours, addressing a key objective for improving adherence and outcomes in this high-risk population.
Addressing Significant Unmet Medical Need
Hypertension affects approximately 120 million adults in the United States and is defined by the American College of Cardiology and the American Heart Association as resting blood pressure above 130/80 mmHg. The condition is acknowledged as one of the most common preventable risk factors for premature death worldwide, with an estimated 20% of the global population suffering from hypertension, including nearly one-half of the adult population in the U.S.
Despite the availability of multiple antihypertensive drugs, many patients fail to achieve blood pressure goals, underscoring the need for therapies with novel mechanisms, strong efficacy, and improved tolerability. Hypertension significantly increases the risk of heart disease, stroke, and kidney disease, among other conditions, while often remaining asymptomatic.
"We are thrilled by the strong support from both new and existing investors who share our commitment to addressing one of the most persistent challenges in cardiovascular medicine," said Eric Keller, Retension Pharmaceuticals' Chief Executive Officer. "This financing enables us to move into mid-stage clinical development with a formulation specifically designed to maintain 24-hour blood pressure control allowing for once-daily dosing, which could offer a meaningful advantage for patients with uncontrolled and resistant hypertension."
Clinical Collaboration with Cleveland Clinic
The Phase 2b study will be conducted in collaboration with the Cleveland Clinic Coordinating Center for Clinical Research and Dr. Luke Laffin. Dr. Laffin, Co-Director of the Center for Blood Pressure Disorders at Cleveland Clinic, emphasized the clinical significance of the development.
"Patients with uncontrolled and resistant hypertension remain at high risk for major adverse cardiovascular events, and current treatment options often fall short in both efficacy and tolerability," said Dr. Laffin. "RTN-001 has the potential to address this unmet need and could represent a meaningful advancement in how we manage treatment-resistant hypertension."
RTN-001 is being developed under an exclusive worldwide license from Sanofi S.A. and is designed to be used in combination with existing hypertension drugs, potentially offering a new therapeutic option for patients who struggle to achieve blood pressure control with current treatments.
