Azathioprine

證據等級: L5

預測適應症: 10 個

Azathioprine: From Immunosuppressive Therapy to Inflammatory Bowel Disease Maintenance

One-Sentence Summary

Azathioprine is a thiopurine-class immunosuppressant with decades of established use in autoimmune and transplant-related settings. Among the candidate indications generated by the TxGNN model, Inflammatory Bowel Disease (Crohn's disease / Ulcerative Colitis) is the only prediction backed by substantial real-world evidence, supported by multiple completed Phase 3 RCTs, Cochrane systematic reviews, and dozens of clinical trials and publications. The drug is currently not marketed in Norway.

Quick Overview

Item	Content
Original Indication	Not specified in the evidence pack (Data Gap — no `original_indications` on file). Azathioprine is a long-established thiopurine immunosuppressant historically used for renal transplant rejection prophylaxis and rheumatoid arthritis.
Predicted New Indication	Inflammatory Bowel Disease (Crohn's disease / Ulcerative Colitis)
TxGNN Prediction Score	99.52% (internal disease rank #5344)
Evidence Level	L1
Norway Market Status	✗ Not marketed
Number of Authorizations	0
Recommended Decision	Proceed with Guardrails

Note on candidate selection: The evidence pack's single highest TxGNN-scored prediction (colobomatous microphthalmia-rhizomelic dysplasia syndrome, 99.9999%) and several other top-ranked items (rank 2–4, 6, 8, 10) are congenital/genetic or primary immunodeficiency syndromes with zero supporting trials or literature, and in some cases (e.g. WHIM syndrome, chronic granulomatous disease) immunosuppression would be mechanistically inappropriate or harmful. These were all scored L5 / Hold by the internal scoring model. This report therefore focuses on Inflammatory Bowel Disease, the highest-evidence, guideline-relevant candidate (L1 / "Proceed with Guardrails"); Ulcerative Colitis (rank 9, also L1/S3) is a closely related subtype supported by largely overlapping evidence.

Why is This Prediction Reasonable?

Detailed mechanism-of-action data for azathioprine is not available in this evidence pack. Based on well-established pharmacology, azathioprine is a prodrug metabolized to 6-mercaptopurine and active 6-thioguanine nucleotides, which inhibit purine synthesis and suppress proliferation of T- and B-lymphocytes. This immunomodulatory action is directly relevant to chronic immune-mediated inflammatory diseases of the gut.

Azathioprine's use in inflammatory bowel disease is not a novel repurposing hypothesis — it is longstanding, guideline-endorsed clinical practice (thiopurines have been used in IBD maintenance therapy for over 50 years). The TxGNN model's prediction essentially re-discovers an already well-validated drug-disease relationship, which is reflected in the depth of supporting evidence: multiple Cochrane systematic reviews, large Phase 3 RCTs (including trials establishing combination therapy with anti-TNF agents), and an extensive real-world/pharmacogenomic literature base (e.g., TPMT/NUDT15-guided dosing to reduce thiopurine-induced leukopenia).

This strong internal consistency — a mechanistically plausible, clinically confirmed indication receiving a high TxGNN score with dense supporting evidence — stands in clear contrast to the model's spurious top-ranked predictions for rare congenital syndromes, and supports treating IBD as the credible repurposing candidate from this evidence pack.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT03101800	Phase 3	Unknown	84	Low-dose azathioprine + allopurinol vs. azathioprine monotherapy in ulcerative colitis; addresses AZA treatment-failure/adverse-event rates
NCT03464136	Phase 3b	Completed	386	Ustekinumab vs. adalimumab in biologic-naïve Crohn's disease patients who failed conventional therapy including azathioprine
NCT00094458	Phase 3	Completed	508	Infliximab vs. infliximab+azathioprine vs. azathioprine alone in immunomodulator/biologic-naïve Crohn's disease (landmark SONIC-type design)
NCT02177071	Phase 4	Completed	211	Infliximab + antimetabolite (AZA) combination vs. antimetabolite monotherapy for maintaining steroid-free remission in Crohn's disease
NCT01015391	N/A	Unknown	100	T2 vs. azathioprine for maintaining clinical/endoscopic remission in Crohn's disease after surgical resection
NCT02929706	N/A	Unknown	400	NUDT15 genotype-guided thiopurine dose optimization to reduce thiopurine-induced leukopenia in IBD
NCT05456776	N/A	Completed	35	Azathioprine associated with impaired postoperative intestinal epithelial regeneration in Crohn's disease
NCT00113503	Phase 2	Terminated	50	Multi-site trial comparing weight-based vs. metabolite-guided azathioprine dosing in Crohn's disease
NCT07248644	Phase 4	Not yet recruiting	304	Switching to mesalazine monotherapy vs. continuing thiopurines in elderly UC patients in sustained remission
NCT04196920	N/A	Unknown	200	Methotrexate- vs. azathioprine-based anti-TNF combination therapy in chronic IBD (building on SONIC trial findings)

Literature Evidence

PMID	Year	Type	Journal	Key Findings
29293971	2018	Review	Journal of Crohn's & Colitis	Comprehensive clinical review of thiopurine treatment and research in IBD
16048561	2005	PK/PGx study	J Gastroenterol Hepatol	Azathioprine/6-MP pharmacogenetics and metabolite monitoring in IBD
10499471	1999	Review	Scand J Gastroenterol Suppl	Update on clinical efficacy and safety of azathioprine in IBD
33305616	2021	Review	Pharmacogenomics	Pharmacogenetics of IBD, including thiopurine genetic predictors
15177535	2004	Review	Gastroenterol Clin North Am	Treatment of IBD with azathioprine and 6-mercaptopurine
22072847	2011	Review	World J Gastroenterol	Optimizing 6-MP/azathioprine therapy in IBD management
24117596	2013	Systematic review + meta-analysis	Aliment Pharmacol Ther	Mercaptopurine as a safe strategy in azathioprine-intolerant IBD patients
19072367	2008	Review	Expert Rev Gastroenterol Hepatol	Molecular insights into azathioprine's mechanism and clinical implications in IBD
37586320	2023	Translational study	Cell Reports Medicine	Gut commensal bacteria (Blautia wexlerae) linked to azathioprine therapy failure in IBD
39921705	2025	Real-world retrospective study	Expert Rev Clin Pharmacol	Effectiveness/safety of thiopurines in IBD patients with NUDT15 polymorphism

Norway Market Information

Azathioprine currently holds no active marketing authorizations in Norway (0 licenses on record; market status: Not Marketed). No product-level dosage form or approved-indication data is available.

Safety Considerations

Please refer to the package insert for safety information.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale:

Inflammatory bowel disease is supported by L1-level evidence — multiple completed Phase 3 RCTs and Cochrane systematic reviews — reflecting azathioprine's status as an established, guideline-endorsed maintenance therapy rather than a speculative repurposing candidate. However, the drug is not currently marketed in Norway, and critical drug-level data are missing.

To proceed, the following is needed:

Norwegian/TFDA-equivalent package insert data (warnings, contraindications) — currently a Blocking data gap that prevents any S1 safety pre-assessment (DG001)
Confirmed mechanism-of-action documentation from DrugBank or equivalent source (DG002, High severity)
A defined regulatory pathway assessment, since azathioprine has zero existing marketing authorizations in Norway
TPMT/NUDT15 genotyping and myelosuppression-monitoring protocol, given the recurring theme in the literature of thiopurine-induced leukopenia risk
Clarification of the original approved indication(s), which are absent from the current evidence pack
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.