Tocilizumab
| Evidence Level: L3 | Predicted Indications: 5 |
Table of Contents
Tocilizumab: Ankylosing spondylitis
One-Sentence Summary
Tocilizumab is an IL-6 receptor antibody originally used for rheumatoid arthritis, juvenile idiopathic arthritis, temporal arteritis and Castleman disease. The TxGNN model predicts it may be effective for ankylosing spondylitis, but the evidence is weak: 2 Phase 3 trials were both terminated, and the literature consists mainly of reviews and case reports. The only top-10 prediction with solid trial support is polyarticular juvenile idiopathic arthritis, which largely overlaps with an existing indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Ankylosing spondylitis |
| TxGNN Prediction Score | 0.9999 |
| Evidence Level | L3 |
| Canada Market Status | Marketed (marketed DINs: 15 of 15) |
| Number of DINs | 15 (marketed: 15) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the data compiled for this report. Based on known information, tocilizumab is a humanized monoclonal antibody that blocks the interleukin-6 receptor. Its efficacy in rheumatoid arthritis and juvenile idiopathic arthritis is established, and mechanistically it may be applicable to inflammatory spine and joint disease.
IL-6 contributes to systemic inflammation and bone turnover, so blocking it is biologically plausible in axial spondyloarthritis. However, the two Phase 3 trials in ankylosing spondylitis were terminated and did not establish clinical efficacy. TNF and IL-17 inhibitors remain the standard of care. The prediction is therefore best treated as a hypothesis, not a validated new use.
Other predicted indications (top 10), for context:
| Predicted Indication | Evidence Level | Assessment |
|---|---|---|
| Polyarticular juvenile idiopathic arthritis | L1 | Completed Phase 3 withdrawal trial plus extensions. Largely overlaps with an existing indication, so it is closer to on-label use than true repurposing. Proceed with Guardrails |
| RF-positive polyarticular JIA | L2 | Inferred from the broader pJIA trials. Proceed with Guardrails |
| Inflammatory spondylopathy | L5 | Same terminated AS trials. Hold |
| Rheumatoid vasculitis | L4 | Case reports only, including reports of tocilizumab-induced vasculitis. Research question |
| Vertebral disease | L4 | Indirect evidence only. Hold |
| Hypermobility of coccyx, Kummell disease, spondyloarthropathy susceptibility | L5 | Prediction only, with no mechanistic rationale or direct evidence. Hold |
| Mendelian susceptibility to mycobacterial disease (IL12B deficiency) | L5 | Prediction only. Immunosuppression and infection risk make use likely inappropriate. Hold |
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT01209689 | Phase 3 | Terminated | 113 | Placebo-controlled study of tocilizumab 4 or 8 mg/kg in AS patients with inadequate response to TNF antagonists |
| NCT01209702 | Phase 2/3 | Terminated | 306 | Placebo-controlled seamless study in NSAID-failure, TNF-naïve AS patients, assessing symptoms and structural damage |
| NCT01965132 | N/A | Recruiting | 10,000 | Korean biologics registry (RA, AS, PsA), observational safety data |
| NCT07138898 | Phase 2 | Recruiting | 80 | Perioperative immunosuppressant management before shoulder arthroplasty; not an AS efficacy trial |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 23765873 | 2014 | RCT analysis (BUILDER-1/2) | Ann Rheum Dis | Assessed short-term symptomatic efficacy of tocilizumab in AS from the two placebo-controlled trials |
| 26986130 | 2016 | Systematic review / network meta-analysis | Medicine | Comparative effectiveness of biologic regimens for AS |
| 36260501 | 2022 | Systematic review | RMD Open | Informs consensus on efficacy and safety of IL-6 pathway inhibition in immune-mediated diseases |
| 33981717 | 2021 | Case report | Front Med | Two cases of AA amyloidosis in AS treated successfully with tocilizumab |
| 22452603 | 2012 | Review | Inflamm Allergy Drug Targets | Short review of IL-6 antagonism in AS |
| 22450391 | 2012 | Review | Curr Opin Rheumatol | Alternatives for AS patients refractory to TNF inhibition |
| 25488787 | 2014 | Review | Best Pract Res Clin Rheumatol | Spondyloarthritis treatment beyond TNF blockade |
| 28413099 | 2017 | Review | Semin Arthritis Rheum | Second-line biologic optimization in RA, PsA and AS |
| 29290076 | 2018 | Meta-analysis | Clin Rheumatol | Serious infection risk with biologics in AS and nr-axSpA |
| 31852268 | 2020 | Systematic review (safety) | Expert Rev Clin Immunol | Infection risk of biologics versus non-biologics in inflammatory arthritis |
Canada Market Information
| DIN | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 02350092 | ACTEMRA | Not listed | Not listed |
| 02350114 | ACTEMRA | Not listed | Not listed |
| 02350106 | ACTEMRA | Not listed | Not listed |
| 02424770 | ACTEMRA | Not listed | Not listed |
| 02483327 | ACTEMRA | Not listed | Not listed |
All 15 licences are valid single-ingredient products. The other brands are TYENNE (5 DINs) and AVTOZMA (5 DINs), which are biosimilars of tocilizumab.
Safety Considerations
Drug Interactions: 100 interactions were identified in the interaction database. Examples from the retrieved list:
- Major: Deferiprone
- Moderate: Warfarin, apixaban, rivaroxaban, dicoumarol, simvastatin, rosuvastatin, hydroxychloroquine, chloroquine, metronidazole, lidocaine, naltrexone, disulfiram
- Minor: Zinc salts (sulfate, acetate, gluconate, chloride)
Class-related cautions from the literature: Serious infections (including tuberculosis and herpes zoster), liver enzyme elevation (a severe liver injury case is reported in rheumatoid vasculitis), neutropenia, and lipid changes. Paradoxical vasculitis-like reactions have also been reported.
Please refer to the package insert for full warnings and contraindications.
Conclusion and Next Steps
Decision: Hold (for ankylosing spondylitis)
Rationale:
- Both Phase 3 AS trials were terminated without a confirmed efficacy readout, and TNF and IL-17 inhibitors remain standard. Tocilizumab should not be advanced for AS on the model prediction alone.
- Among the top-10 predictions, polyarticular JIA and RF-positive pJIA support “Proceed with Guardrails” because of Phase 3 evidence. They largely overlap with existing indications and are not new repurposing opportunities.
To proceed, the following is needed:
- Review of the terminated AS trial results (NCT01209689, NCT01209702) to understand why they stopped and whether any efficacy signal exists
- Health Canada package insert warnings and contraindications (not yet available, which blocks safety screening)
- Mechanism of action data
- For pJIA: a monitoring plan covering TB screening, liver enzymes, neutrophils and platelets, and lipids
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.