Desirudin

What is Desirudin?

Desirudin is a recombinant version of hirudin, the anticoagulant medicinal leeches inject to keep blood flowing while they feed. It is a 65-amino-acid protein of about 6,964 daltons held in shape by three disulfide bridges, produced in Saccharomyces cerevisiae and differing from the natural molecule only by the absence of a sulfate group on tyrosine 63 — which is where the name comes from, desulfatohirudin. It was approved in Europe as Revasc in 1997 and in the United States as Iprivask in 2003, for prevention of deep vein thrombosis after elective hip or knee replacement, given as 15 mg subcutaneously twice daily starting before surgery. The reason the page exists is not that the drug is in use — it is not — but that its clinical record is unusually strong for a product that vanished, and that record is worth preserving accurately.

What Desirudin Is Investigated For

Desirudin's evidence base is small in number of trials and large in number of patients, and it points consistently one way. The 1997 trial in the Journal of Bone and Joint Surgery randomised 445 hip replacement patients against unfractionated heparin with centrally assessed bilateral venograms: deep vein thrombosis in 7% on desirudin versus 23% on heparin, and proximal thrombosis in 3% versus 16%, both at p<0.0001, with no difference in bleeding. The same year a 2,079-patient trial in the New England Journal of Medicine compared it against enoxaparin — the drug that went on to dominate this indication for the next two decades — and desirudin again came out ahead, with total deep vein thrombosis of 18.4% versus 25.5% (p=0.001) and proximal thrombosis of 4.5% versus 7.5% (p=0.01), again with similar safety. A later post hoc analysis of that trial found the advantage was concentrated in patients with stage 3B chronic kidney disease, where major venous thromboembolism occurred in 3.4% on desirudin versus 11.1% on enoxaparin. Everything after that is small: an open-label 516-patient single-arm safety study, a 16-patient pilot against argatroban in suspected heparin-induced thrombocytopenia, and pharmacokinetic work on renal dosing. The useful reading is that this drug was never shown to fail — it was simply never adopted, in an era when low-molecular-weight heparins were established, convenient and familiar, and then direct oral anticoagulants arrived and made the question moot.

History & Discovery

Hirudin has the longest lead time of any peptide drug in this catalogue. Medicinal leeches were used therapeutically for centuries before anyone asked why the bleeding did not stop, and the anticoagulant principle in leech saliva was identified in the nineteenth century. The modern pharmacology belongs largely to Friedrich Markwardt, who worked on the molecule in Erfurt from the 1950s and published the first human pharmacokinetic and anticoagulant data in 1984. His own retrospective account makes the limiting factor plain: native hirudin was an antithrombotic agent of high quality whose clinical use remained limited because it could not be obtained in adequate amounts. Extracting it from leeches was never going to supply a drug. Recombinant DNA solved the supply problem in the 1980s. Expressing hirudin in yeast produced material in quantity, with one unavoidable difference — yeast cannot sulfate tyrosine 63, so the product is desulfatohirudin, which is where desirudin gets both its name and a modest reduction in thrombin affinity relative to the native molecule. Ciba-Geigy developed it as CGP 39393, and a second recombinant hirudin, lepirudin, was developed in parallel by Hoechst for heparin-induced thrombocytopenia. The clinical programme ran through the mid-1990s and delivered two positive venographic trials in hip replacement, published in the same year against two different comparators. The European Commission authorised Revasc on 9 July 1997. The FDA approved Iprivask on 4 April 2003. What happened next is the part worth remembering. The European product was never marketed in any European country, and the authorisation was voluntarily withdrawn for commercial reasons on 18 July 2014 — seventeen years of a live authorisation and no sales. In the United States the product passed through several owners, ending with Bausch, and is recorded in Drugs@FDA as Discontinued. A small group of investigators kept trying to find it a niche through 2010 to 2014, in heparin-induced thrombocytopenia, in renal impairment, in critically ill medical patients, and the DESIR-ABLE studies read as exactly that — a search for a use case. By then rivaroxaban and apixaban were arriving, and injectable orthopaedic prophylaxis was becoming a smaller question. Desirudin's legacy is in what it proved about the class: bivalirudin borrowed hirudin's bivalent binding strategy, and dabigatran eventually took direct thrombin inhibition oral.

How It Works

Thrombin is the enzyme at the end of the clotting cascade — it turns dissolved fibrinogen into the fibrin mesh that holds a clot together. Leeches evolved a protein that wraps around thrombin and shuts it down completely, so blood keeps flowing while they feed. Desirudin is that protein, made in yeast instead of grown in a leech, and it blocks thrombin the same way.

Desirudin is a direct thrombin inhibitor, meaning it acts on thrombin itself rather than through antithrombin as heparins do. Hirudins are bivalent inhibitors: the molecule's globular N-terminal domain occupies thrombin's active site while its acidic C-terminal tail binds exosite 1, the fibrinogen-recognition site, so the enzyme is blocked both catalytically and in its ability to find its substrate. The resulting complex is extraordinarily tight — hirudin is the most potent natural thrombin inhibitor known — and for practical purposes irreversible, which is the reason there is no antidote. That two-point binding has consequences heparin does not share. Heparin-antithrombin complexes are large and cannot reach thrombin already bound inside a clot; direct inhibitors can, so clot-bound thrombin is inhibited as well as circulating thrombin. Direct inhibitors are also independent of antithrombin levels and are not neutralised by platelet factor 4, which is what makes the class relevant in heparin-induced thrombocytopenia. The molecule itself is 65 amino acids and about 6,964 daltons, cyclised by three disulfide bridges between cysteines 6–14, 16–28 and 22–39, expressed in Saccharomyces cerevisiae. It differs from natural leech hirudin only by lacking the sulfate group on tyrosine 63 — the recombinant expression system cannot perform that modification — which reduces thrombin affinity somewhat relative to the native molecule without compromising clinical activity. Pharmacokinetically it was straightforward and that was part of the pitch. Given subcutaneously at 15 mg every 12 hours to steady state, peak concentrations were 35 nmol/L in people with normal renal function and 47 nmol/L in moderate impairment, and desirudin concentration bears a linear relationship to the aPTT ratio when the square root of concentration is plotted (r² = 0.76). Elimination is renal, which is both the drug's simplicity and its constraint. The fixed-dose, no-monitoring regimen that the 1997 hip trial emphasised was a genuine advantage at a time when unfractionated heparin required aPTT titration — though by the time desirudin reached the US market, low-molecular-weight heparins had already removed that advantage.

Evidence Snapshot

Research Gaps & Open Questions

What the current literature has not yet settled about Desirudin:

• 01Whether the venographic advantage over enoxaparin would have produced fewer symptomatic events. Asymptomatic venographic thrombosis is a validated surrogate but it is a surrogate, and no trial of desirudin was ever powered for symptomatic deep vein thrombosis, pulmonary embolism or death.
• 02Whether the chronic kidney disease finding is real. A post hoc subgroup analysis showing major venous thromboembolism at 3.4% versus 11.1% in stage 3B patients is the most interesting result in the whole programme and the least reliable, because it was not prespecified.
• 03Whether the 10% antihirudin antibody rate would have mattered at scale. The study that measured it detected no clinical consequence and said plainly that it was too small to exclude rare severe effects; lepirudin's experience suggests those effects exist.
• 04Whether it had a genuine role in heparin-induced thrombocytopenia. A 16-patient open-label pilot against argatroban is not evidence of anything beyond feasibility, and the appeal — fixed-dose subcutaneous dosing rather than a titrated infusion — was real enough to justify a proper trial that never happened.
• 05Why a drug that beat the standard of care in a 2,079-patient trial was never marketed in Europe at all. The public record says commercial reasons and nothing more, and the counterfactual — what orthopaedic prophylaxis would look like if it had been adopted — is unanswerable.
• 06Whether a reversal agent could have been developed. The absence of an antidote was always hirudin's structural weakness, and idarucizumab eventually solved the equivalent problem for dabigatran; nothing comparable was ever attempted for the hirudins.

Forms & Administration

Subcutaneous injection, supplied as a lyophilised powder in 15 mg single-dose vials for reconstitution. The approved regimen was 15 mg every 12 hours, with the first dose 5 to 15 minutes before surgery but after induction of regional block if one was used, continued for 9 to 12 days. No routine coagulation monitoring was required in patients with normal renal function; the labelling called for dose reduction and aPTT monitoring in renal impairment. There was never an oral, intravenous or extended-release form approved for this indication, and no product of any kind is currently marketed — the description above is of a regimen that no longer exists in practice.

Dosing & Protocols

The ranges below reflect protocols commonly discussed in the literature and by clinicians — not a prescription. Actual dosing for any individual should be determined by a qualified healthcare provider who knows the patient.

Desirudin is discontinued in the United States and its European authorisation was withdrawn in 2014. It is a direct thrombin inhibitor with no reversal agent. Nothing described here is available or should be sought from any source, and material offered as desirudin outside a regulated supply chain should be treated as unsafe.

Timeline of Effects

Monitoring & Measurement

Common Questions

Who Desirudin Is NOT For

Drug & Supplement Interactions

The interactions that mattered were pharmacodynamic and entirely predictable: anything that impairs haemostasis adds to the bleeding risk. Antiplatelet agents including aspirin and clopidogrel, non-steroidal anti-inflammatory drugs, other anticoagulants, thrombolytics and dextran all fall into that category, and in the surgical setting where desirudin was used, perioperative analgesia with NSAIDs was a routine consideration rather than a theoretical one. Pharmacokinetic interactions were essentially absent. Desirudin is a 65-amino-acid protein cleared renally and degraded by peptidases; it does not engage cytochrome P450 enzymes or drug transporters, and no clinically significant metabolic interaction was described. The variable that governed exposure was renal function, not co-medication — so a drug that reduces glomerular filtration, such as an NSAID in a volume-depleted postoperative patient, could raise desirudin exposure indirectly. Two laboratory interactions are worth recording. Desirudin prolongs the aPTT in a concentration-dependent way, which was how it was monitored when monitoring was required, but that also means it confounds aPTT-based interpretation of anything else. And thrombin itself interferes with immunological assays for hirudin-specific antibodies, which complicated the immunogenicity work and is a reason to read antibody-incidence figures in this class with some care.

Safety Profile

Legal Status

Regulatory status changes over time. Verify current local rules with a qualified professional.

Myths & Misconceptions