Efficacy and safety of next-generation tick transcriptome-derived direct thrombin inhibitors

Despite their limitations, unfractionated heparin (UFH) and bivalirudin remain standard-of-care parenteral anticoagulants for percutaneous coronary intervention (PCI). We discovered novel direct thrombin inhibitors (DTIs) from tick salivary transcriptomes and optimised their pharmacologic activity. The most potent, ultravariegin, inhibits thrombin with a Ki of 4.0 pM, 445-fold better than bivalirudin. Unexpectedly, despite their greater antithrombotic effect, variegin/ultravariegin demonstrated less bleeding, achieving a 3-to-7-fold wider therapeutic index in rodent thrombosis and bleeding models. When used in combination with aspirin and ticagrelor in a porcine model, variegin/ultravariegin reduced stent thrombosis compared with antiplatelet therapy alone but achieved a 5-to-7-fold lower bleeding time than UFH/bivalirudin. Moreover, two antibodies screened from a naïve human antibody library effectively reversed the anticoagulant activity of ultravariegin, demonstrating proof-of-principle for antidote reversal. Variegin and ultravariegin are promising translational candidates for next-generation DTIs that may reduce peri-PCI bleeding in the presence of antiplatelet therapy.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Ultravariegin from tick salivary transcriptomes inhibits thrombin with a Ki of 4.0 pM (445-fold better than bivalirudin), achieves 3-to-7-fold wider therapeutic index than UFH/bivalirudin in rodent and porcine models, and is antibody-reversible.

Leech-derived molecules this paper discusses, each with a full profile in the ASH compound registry:

Узнайте, как это исследование связано с клинической практикой

More peer-reviewed studies in Разработка лекарственных препаратов.

• Novel Leech Antimicrobial Peptides — Hirunipins — Kumar et al. (2025)
• Medicinal Leech Genome Assembly — Anticoagulant Gene Catalog — Kvist et al. (2020)
• Effects of hirudotherapy on liver functions, lipid profile, and insulin sensitivity in rats with metabolic syndrome — Bilden A et al. (2026)
• Hirudotherapy in Medicine and Dentistry — Jha K et al. (2015)
• Medicinal leech therapy (hirudotherapy): a brief overview — Singh A (2010)
• HIRUDOTHERAPY IN PRESBYACUZIS PRAECOX IN CLEAN-UP WORKERS AFTER THE CHORNOBYL ACCIDENT DURING THE POST-CATASTROPHE YEARS — Zabolotnyi D, Mishchanchuk N (2019)
• Investigation of oxidant-antioxidant status in patients treated with hirudotherapy: an experimental study — Sarikan I, Savas H (2024)
• Leech therapeutic applications — Abdualkader A et al. (2013)
• Non-Occlusive Mesenteric Ischemia Due to Hirudotherapy: A Case Report — Akalın Ç, Ekmen N (2020)
• Leech therapy: a history — Hyson J (2005)

Browse all ASH-analysed research →