Warfarin
| Evidence Level: L5 | Predicted Indications: 7 |
Table of Contents
Warfarin: Heparin cofactor 2 deficiency
One-Sentence Summary
Warfarin is a vitamin K antagonist anticoagulant, originally used to treat pulmonary embolism, thrombotic disease and intracranial embolism. The TxGNN model predicts it may be useful for heparin cofactor 2 deficiency, an inherited thrombophilia, but this is supported only by 3 older case or family reports (1990-2001) and no clinical trials. The evidence is weak, and the prediction largely extends the existing thrombosis indication rather than opening a new therapeutic area.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Heparin cofactor 2 deficiency |
| TxGNN Prediction Score | 0.9987 |
| Evidence Level | L5 |
| India Market Status | Listed in a compiled Indian medicine price dataset (18 of 18) – CDSCO approval status is not included in this data |
| Number of Listed Products | 18 (valid: 18) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Warfarin is known to be a vitamin K antagonist that lowers the vitamin K-dependent clotting factors (II, VII, IX and X). Its efficacy in thrombosis and embolism is established.
Heparin cofactor II deficiency is an inherited thrombophilia in which patients can develop recurrent venous thrombosis. Long-term anticoagulation after a thrombotic event is therefore mechanistically plausible. This is the same mechanism as the approved thrombosis indications, not a new one.
The supporting literature is limited to three case or family reports. One describes a right ventricular thrombus in a patient with familial deficiency. Another describes a patient with a congenital deficiency state and pulmonary infarction who was treated with warfarin for 7 years. The third describes a family with multiple thromboses, including children treated with warfarin.
Other predictions fall into three groups.
- Thrombophilia (rank 4): Warfarin is effectively used on-label here, but the evidence is indirect (see below).
- Factor V excess and antithrombin deficiency type 2 (ranks 2 and 3): These are plausible extensions of the thrombosis use, with little or no direct evidence.
- Rheumatoid arthritis, fibrocystic breast disease and benign mammary dysplasia (ranks 5-7): These are likely false-positive signals driven by drug-interaction associations (for example danazol-warfarin), not therapeutic links.
Clinical Trial Evidence
Currently no clinical trials are registered for heparin cofactor 2 deficiency.
For the broader category of thrombophilia (predicted rank 4), one trial is relevant:
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00895505 | Phase 3 | Unknown | 300 | D-dimer-guided strategy to decide how long to extend secondary VTE prophylaxis after unprovoked DVT; a duration-strategy trial, not a warfarin efficacy trial, and no results were provided |
For rheumatoid arthritis (rank 5), four Phase 1 trials (NCT01311622, NCT04246762, NCT01636557, NCT05392127) exist. They are drug-interaction studies that use warfarin only as a probe substrate. They are not evidence of efficacy for repurposing.
Literature Evidence
Evidence for heparin cofactor 2 deficiency (all case reports):
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 2214444 | 1990 | Case report | Kyobu Geka | Right ventricular thrombus in a 14-year-old with familial heparin cofactor II deficiency, initially mistaken for a myxoma |
| 2033902 | 1991 | Case report | Nihon Kyobu Shikkan Gakkai Zasshi | Congenital antithrombin deficiency with repeated thrombosis and pulmonary infarction; treated with warfarin for 7 years, then switched to heparin |
| 11570053 | 2001 | Case report (family study) | Journal of UOEH | Family with multiple thromboses, including infant death from vena cava thrombosis; a sibling was started on warfarin but had recurrent DVT |
Context from the related thrombophilia prediction:
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 33141212 | 2020 | Review | JAMA | Diagnosis and treatment of lower extremity VTE; recurrence of 20% to 36% over 10 years |
| 39233011 | 2024 | Review | J Thromb Haemost | ISTH communication on DOACs for secondary VTE prevention in severe thrombophilia; evidence limited to cohort and single-centre studies |
| 39244017 | 2024 | Review | Presse Med | Impact of thrombophilia on VTE management |
India Market Information
18 valid single-ingredient registrations exist. The licence records contain no approved-indication text. Main authorisations:
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 204631 | Sofarin 5mg Tablet (Samarth Life Sciences) | Strip of 10 tablets | Not stated in licence record |
| 241473 | Warf 3 Tablet (Cipla) | Strip of 30 tablets | Not stated in licence record |
| 231513 | Uniwarfin 2mg Tablet (Torrent) | Strip of 10 tablets | Not stated in licence record |
| 45437 | Cofarin 2mg Tablet (East West Pharma) | Strip of 10 tablets | Not stated in licence record |
| 141666 | Mywarf Tablet (Parnasa Mediworld) | Strip of 15 tablets | Not stated in licence record |
All products are oral tablets.
Safety Considerations
- Contraindications flagged in the knowledge graph (not label text): hypertension, liver failure and liver disease, cholestasis, congestive heart failure, hypothyroidism, nephrotic syndrome, impaired renal function, blood coagulation disease, anaemia, hyperlipidaemia, psychotic and other mental disorders, substance abuse or dependence, connective tissue and bone disease, gallbladder disease, and chronic diarrhoeal disease.
- Drug interactions: 865 interactions are recorded. Examples include:
- Major: acetylsalicylic acid (aspirin) and metronidazole.
- Moderate: ranitidine, rabeprazole, doxycycline, metformin, amoxicillin, bupropion, aprepitant, mesalazine, and corticosteroids (hydrocortisone, dexamethasone, betamethasone, budesonide, triamcinolone).
- Other literature signals: warfarin-induced skin necrosis is rare (0.01-0.1%). Danazol and leflunomide have been reported to raise the anticoagulant effect of warfarin.
Package insert warnings and contraindications were not available for this report, so please consult the product labelling.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence for heparin cofactor 2 deficiency is three older case reports with no trials. The mechanism is the same as for the existing thrombosis indications, so it is plausible but not new. The model score is very high (0.9987), yet it is not matched by clinical evidence. Among the other predictions, only thrombophilia reaches L3, and even that relies on indirect evidence. The rheumatoid arthritis and breast disease signals are interaction artefacts and should not be pursued.
To proceed, the following is needed:
- Package insert warnings and contraindications for the Indian-licensed products, and the approved indication text
- Mechanism of action data from DrugBank
- Prospective or registry data on warfarin in heparin cofactor II deficiency and other inherited thrombophilias, including comparison with DOACs
- Evidence on bleeding risk and INR monitoring for the target population
- Route compatibility assessment (oral tablets only are available)
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.