Pharmacology
From leech biology to three FDA-approved pharmaceuticals
Drug-vs-leech distinction
Bivalirudin, lepirudin, desirudin (hirudin-derived) and dabigatran (synthetic)
- Approval:
- FDA-approved drugs (NDA/BLA pathways)
- Indication:
- PCI anticoagulation, atrial fibrillation, HIT, VTE
- Derived from:
- Hirudin from Hirudo medicinalis (bivalirudin, lepirudin, desirudin); dabigatran is synthetic and not leech-derived
Hirudo medicinalis / Hirudo verbana
- FDA status:
- FDA-cleared medical device (H. medicinalis: K040187, 2004; H. verbana: K132958, 2014)
- Cleared indication:
- Venous congestion in surgical flaps and replanted tissue
These are two distinct regulatory contexts. The drug above is a recombinant or synthetic pharmaceutical analog regulated under FDA NDA/BLA pathways. The whole-leech therapy is regulated as a medical device. Clinical claims for the drug do NOT extend to whole-leech therapy, and vice versa.
200 compounds catalogued in ASH Compound Reference
Each compound page distinguishes whole-leech therapy from purified / recombinant / synthetic-analog pharmaceutical derivatives, with explicit clinical-translation-limit statements preventing mechanism-to-claim leakage.
Medicinal leech biology has directly inspired three FDA-approved direct thrombin inhibitors and the injectable direct thrombin inhibitors hirudin and bivalirudin originated from the observation that leech salivary extracts prevent blood clotting (Coppens et al., Circ Res, 2012; PMID: 22982873) (bivalirudin is widely used in primary PCI; Stone et al., N Engl J Med, 2008; PMID: 18499566). The leech accounts for two approved venom-derived drugs (bivalirudin and desirudin).
Important Distinction
The Translational Pipeline
Topics
Direct Thrombin Inhibitors
The DTI drug class: from native hirudin to bivalirudin and dabigatran — a four-decade journey.
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Bivalirudin
Class I, Level B-R recommendation for STEMI PCI (2025 ACC/AHA). HORIZONS-AMI: 43% lower 1-year cardiac mortality (2.1% vs 3.8%, HR 0.57). Peak revenue ~$636M (2014, pre-generic; The Medicines Company / Angiomax).
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Oral Anticoagulants
Dabigatran and the DOAC revolution — a synthetic thrombin inhibitor designed from NAPAP, related to leech hirudin by target, not by descent.
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Leech Extracts
Piyavit and whole-extract formulations: international pharmacology, not FDA-approved.
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Drug Pipeline
Destabilase, decorsin, saratin, eglin C — next-generation candidates from the leech secretome.
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Laboratory Effects
APTT, INR, platelet monitoring, and laboratory parameter changes during hirudotherapy.
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By the Numbers
3
FDA-Approved DTIs
$636M
Peak Bivalirudin Revenue
189
Salivary proteins identified in H. medicinalis
99%+
Unexploited as Drug Leads