Subcutaneous tocilizumab: recent advances for the treatment of rheumatoid arthritis

ABSTRACT

Introduction: Tocilizumab (TCZ) is a humanized anti-interleukin-6 (IL-6) receptor monoclonal antibody that is widely used to treat rheumatic arthritis (RA). When initially introduced, TCZ was administered by intravenous infusion. Since 2013, subcutaneous administration of TCZ has also been offered. Currently, we can choose the TCZ administration route according to patient preference.

Areas covered: We summarize TCZ therapy and review recent advances of TCZ-SC therapy. Initially, three pre-clinical phase III randomized controlled trials – MUSASHI, SUMMACTA, and BREVACTA – demonstrated the similar effectiveness and safety between subcutaneous TCZ (TCZ-SC) and intravenous TCZ (TCZ-IV). Several real-world TCZ-SC studies further confirmed these findings. These studies also focused on the influence of body weight. Since TCZ-SC is a fixed dose therapy, the efficacy of TCZ-SC 162 mg q2w was sometimes inadequate in high body weight patients. By contrast, TCZ-SC 162 mg qw therapy achieved a higher trough serum concentration of TCZ than TCZ-IV 8 mg/kg q4w. No additional safety concerns were noted. Finally, possible differences between the IL-6 inhibitor and IL-6 receptor inhibitor are discussed.

Expert opinion: There are no appreciable differences between TCZ-SC and TCZ-IV in clinical practice. Thus, TCZ-SC is an attractive option for RA patients.

KEYWORDS:

• Interleukin-6
• rheumatoid arthritis
• subcutaneous administration
• tocilizumab

Article highlights

• The overall effectiveness and safety of subcutaneous tocilizumab are comparable to intravenous tocilizumab.

• The trough concentration of TCZ-SC 162 mg q2w is relatively low and may be insufficient in high body weight patients.

• The serum trough concentration of TCZ during TCZ-SC 162 mg qw is higher than that of TCZ-IV 8 mg/kg q4w.

• Since TCZ can hide IL-6 related infectious symptoms, clinicians should be aware of stealth infections during TCZ therapy.

• IL-6 inhibition and IL-6 receptor inhibition may differ.

This box summarizes key points contained in the article.

Acknowledgments

The authors would like to thank Enago (www.enago.jp) for the English language review.

Declaration of interest

A Ogata received honoraria for speech from Chugai Pharm. Co, Asahi Kasei Pharm. Co, Eli Lilly Japan KK, Pfizer Co, Bristol-Myers Squibb Co, Eisai Co, GlaxoSmithKline KK, and consultant fee from Chugai Pharmaceutical Co. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

A reviewer on this manuscript has declared that they have served as a consultant for Roche and participated as a study coordinator in the ToSpace trial. Peer reviewers on this manuscript have no other relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper was not funded.