Tocilizumab

Evidence Level: L3

Predicted Indications: 5

Tocilizumab

Pharmacist Assessment Report

Tocilizumab: From Rheumatoid Arthritis to 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 18 publications retrieved are mostly reviews and case reports.

Quick Overview

Item	Content
Original Indication	Rheumatoid arthritis (the ARTG entry in the data compiled for this report has no indication text)
Predicted New Indication	Ankylosing spondylitis
TxGNN Prediction Score	0.9999
Evidence Level	L3
Australia Market Status	Listed on the PBS Schedule (1 of 1 items) – TGA (ARTG) registration status is not included in this data
Number of PBS Items	1 (valid: 1)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the data compiled for this report. Based on known information, tocilizumab blocks the IL-6 receptor. IL-6 contributes to systemic inflammation and bone remodelling.

Ankylosing spondylitis is an inflammatory spondyloarthropathy, and spondyloarthropathy is already among tocilizumab’s listed original indications. This overlap supports the prediction. However, the two Phase 3 placebo-controlled trials were terminated. The literature also indicates tocilizumab has not shown the efficacy seen with TNF or IL-17 inhibitors in this disease. The mechanistic rationale is therefore plausible but not clinically confirmed.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrolment	Key Findings
NCT01209689	Phase 3	Terminated	113	Placebo-controlled trial of tocilizumab 4 or 8 mg/kg IV every 4 weeks in AS after inadequate response to TNF antagonists; no confirmed efficacy result available
NCT01209702	Phase 2/3	Terminated	306	Seamless placebo-controlled trial in TNF-naïve AS patients who failed NSAIDs; no confirmed efficacy result available
NCT01965132	N/A	Recruiting	10,000	Korean registry of biologics in RA, AS and PsA; observational and not specific to tocilizumab in AS
NCT07138898	Phase 2	Recruiting	80	Perioperative immunosuppressant management in rheumatology patients having shoulder arthroplasty; no AS efficacy data

Literature Evidence

PMID	Year	Type	Journal	Key Findings
23765873	2014	Randomised trials (BUILDER-1/2)	Ann Rheum Dis	Assessed short-term symptomatic efficacy and safety of tocilizumab in AS
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
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
29290076	2018	Meta-analysis	Clin Rheumatol	Serious infection risk with biologics in AS and nr-axSpA
33981717	2021	Case report	Front Med	Two cases of AA amyloidosis in AS treated successfully with tocilizumab
28413099	2017	Review	Semin Arthritis Rheum	Second-line biologic optimisation in RA, PsA and AS
29278210	2017	Review	Curr Pharm Biotechnol	Overview of biologics in inflammatory arthritis

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
ARTG 10056G	Actemra	Concentrate for injection 200 mg in 10 mL	Not stated in the data compiled for this report

Safety Considerations

Drug Interactions: 100 interactions were identified. The listed ones include:
- Major: deferiprone
- Moderate: warfarin, apixaban, rivaroxaban, dicoumarol, simvastatin, rosuvastatin, hydroxychloroquine, chloroquine, metronidazole, tinidazole, naltrexone, disulfiram, lidocaine, secnidazole, benznidazole
- Minor: zinc salts (sulfate, acetate, gluconate, chloride)
Other considerations from the literature: IL-6 inhibition raises infection risk, including tuberculosis, so pre-treatment screening is advisable. A tocilizumab-associated vasculitis-like reaction and severe liver injury have been reported in case reports.

Please refer to the TGA-approved Product Information (PI) for warnings and contraindications.

Conclusion and Next Steps

Decision: Hold

Rationale:

Both Phase 3 AS trials were terminated with no confirmed efficacy result. The literature suggests tocilizumab is less effective than TNF or IL-17 inhibitors in AS, so the high TxGNN score is not backed by clinical confirmation.

To proceed, the following is needed:

Full results from the terminated BUILDER-1 and BUILDER-2 trials (NCT01209689, NCT01209702), including reasons for termination
Mechanism of action data
The TGA Product Information, including approved indications, warnings and contraindications
Evidence showing a role for tocilizumab in patients who have failed TNF or IL-17 inhibitors

Other Predicted Indications (Brief)

Predicted Indication	Evidence Level	Decision	Comment
Polyarticular juvenile rheumatoid arthritis	L1	Proceed with Guardrails	Completed Phase 3 withdrawal trial (NCT00988221, n=188). This confirms an already-listed use rather than a novel repurposing finding.
RF-positive polyarticular JIA	L3	Proceed with Guardrails	Evidence is inherited from the broader pJIA programme; no subtype-specific trials.
Rheumatoid vasculitis	L4	Research Question	Case reports only, plus a vasculitis-like reaction safety signal.
Inflammatory spondylopathy	L5	Hold	Overlaps with AS; same terminated trials.
Spondyloarthropathy, susceptibility to	L5	Hold	Genetic susceptibility entity; only an in vitro study.
Hypermobility of coccyx, Kummell disease, vertebral disease	L5	Hold	No mechanistic rationale or relevant clinical evidence.
MSMD due to complete IL12B deficiency	L5	Hold	Potentially harmful given the infection risk of immunosuppression.

Disclaimer

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