Novel Plasmin-independent Thrombolytic Agent for Pulmonary Embolism

Pulmonary embolism (PE) is the leading preventable cause of death among hospitalized patients, yet current thrombolytic therapies are hindered by significant limitations, including high bleeding risks and incomplete clot resolution. The high incidence and life-threatening nature of PE highlight the critical need for safer and more effective thrombolytic solutions. Despite decades of research, the available thrombolytics remain exclusively plasmin-based. These therapies activate plasminogen to plasmin, an enzyme that indiscriminately degrades essential hemostatic proteins, such as fibrinogen, necessary for clot stability and wound healing. This lack of specificity not only increases the risk of severe bleeding complications but also restricts the clinical applicability, leaving a substantial unmet need for innovative alternatives to address PE effectively and safely. SNJ Pharma, Inc. has developed a novel plasmin-independent thrombolytic enzyme, High-Temperature Requirement A1 (HtrA1), as a promising alternative to current plasmin-based therapies. The recombinant form of HtrA1 (rHtrA1) exhibits robust fibrinolytic activity, effectively dissolving intravascular clots while sparing essential hemostatic proteins, such as fibrinogen. This unique mechanism avoids plasmin generation, enabling rHtrA1 to selectively degrade pathological thrombi without increasing bleeding risk, a common limitation of traditional thrombolytics. In mouse models of PE, rHtrA1 demonstrated exceptional efficacy, completely dissolving clots and achieving a 100% survival rate. Building on this success, the proposed study will further evaluate the therapeutic potential of rHtrA1 in a murine PE model, focusing on establishing a dose-response relationship and determining the effective dose. Successful completion of this research will lay the groundwork for a groundbreaking therapeutic approach, addressing critical unmet needs in the thrombolytic treatment of PE while minimizing bleeding complications. Project Number: 1R43HL182336-01 | Fiscal Year: 2025 | NIH Institute/Center: National Heart Lung and Blood Institute (NHLBI) | Principal Investigator: Hyeon Jin Kim | Institution: SNJ PHARMA INC., TORRANCE, CA | Award Amount: $499,882 | Activity Code: R43 | Study Section: Special Emphasis Panel[ZHL1 CSR-E (M2)] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R43HL18233601