Tocilizumab biosimilars

Humanised IgG1 kappa monoclonal antibody of about 148 kDa, produced in Chinese hamster ovary cells, directed against the interleukin-6 receptor rather than the cytokine itself.

Binds both soluble and membrane-bound IL-6 receptors and blocks IL-6 from initiating signalling through gp130, suppressing the acute-phase response, B-cell differentiation and T-cell activation that IL-6 drives. Blocking the receptor rather than the ligand means it neutralises IL-6 activity regardless of cytokine concentration.

Non-linear, target-mediated pharmacokinetics: half-life rises from about 6 days at low concentrations to 13 days at steady state with 8 mg/kg every four weeks. The subcutaneous 162 mg presentation given weekly or every two weeks reaches similar exposure.

Intravenous: 8 mg/kg every four weeks for rheumatoid arthritis, weight-based for juvenile arthritis and a single dose for cytokine release syndrome, from 80 mg, 200 mg and 400 mg vials at 20 mg/mL. Subcutaneous: 162 mg weekly or every two weeks by pre-filled syringe or pen.

• Rheumatoid arthritis
• Giant cell arteritis
• Polyarticular and systemic juvenile idiopathic arthritis
• Cytokine release syndrome after CAR-T cell therapy
• Systemic sclerosis-associated interstitial lung disease (United States)
• COVID-19 in hospitalised adults receiving corticosteroids (2021 onward)

Anti-tocilizumab antibodies occur in a small proportion of patients and are rarely neutralising or clinically relevant. Comparative programmes use analytical similarity, a pharmacokinetic study in healthy volunteers with the intravenous presentation, and a comparative efficacy study in rheumatoid arthritis with DAS28 or ACR20 at week 24, with the subcutaneous presentation supported by a separate PK bridge.

RoActemra was authorised in the EU on 16 January 2009 (EMEA/H/C/000955) and Actemra licensed by FDA on 8 January 2010 (BLA 125276), with the subcutaneous presentation following in 2013 and 2014. Demand surged in 2021 when it was authorised for severe COVID-19, and Indian regulators granted emergency-use permission to a domestic biosimilar in October 2021 to relieve shortages. The first biosimilars, Tyenne in the EU (September 2023) and Tofidence in the US (September 2023), followed the expiry of the core patents.

Sources: Purple Book (S016), EMA medicines data (S017), CDSCO lists (S011, S013).

Tocilizumab is a newer biosimilar market with three US products, four EU products and a fourth EU name from Gedeon Richter in April 2026. Both intravenous and subcutaneous presentations matter, and Celltrion's Avtozma is the only US product interchangeable in both. India's experience is unusual: the pandemic produced a restricted emergency permission for a domestic product in 2021 before any biosimilar was approved in the West. The UAE has no biosimilar registered yet, only Actemra.