Medicinal leeches: ancient therapy is a source of biotech drugs

Hirudin analogs have been shown to be inhibitors of thrombin with many potential uses. These agents appear to have advantages over conventional anticoagulant agents such as heparin. The hirudin compounds do not require a cofactor to work, have consistent dose-dependent effects, act directly on thrombin, are highly specific, and have little to no toxicity.