Infliximab biosimilars

Chimeric mouse-human IgG1 kappa monoclonal antibody of about 149 kDa, murine variable regions on human constant regions, produced in a murine myeloma (Sp2/0) cell line.

Binds soluble and transmembrane tumour necrosis factor alpha with high affinity, neutralising its activity and, through Fc-mediated effects on TNF-expressing cells, contributing to its efficacy in inflammatory bowel disease. That Fc contribution is why regulators asked early biosimilars for comparative data in bowel disease as well as arthritis.

Intravenous infusion; half-life about 8 to 10 days, with maintenance infusions every eight weeks. Concomitant immunomodulators reduce clearance and antibody formation. A subcutaneous 120 mg formulation of one biosimilar (Remsima SC) is authorised in the EU and registered in the UAE.

3 mg/kg (rheumatoid arthritis) or 5 mg/kg (other indications) at weeks 0, 2 and 6, then every eight weeks, as lyophilised powder in 100 mg vials reconstituted for infusion. The subcutaneous presentation is given every two weeks after intravenous induction.

• Rheumatoid arthritis
• Crohn's disease (adult and paediatric)
• Ulcerative colitis (adult and paediatric)
• Ankylosing spondylitis
• Psoriatic arthritis
• Plaque psoriasis

Antibodies to infliximab develop in a substantial minority of patients, particularly without concomitant methotrexate or azathioprine, and are associated with infusion reactions and loss of response. Comparative programmes use analytical similarity, a pharmacokinetic study, and comparative efficacy studies in rheumatoid arthritis and ankylosing spondylitis; the NOR-SWITCH trial in Norway later provided switching evidence across indications that shaped interchangeability policy in Europe.

Remicade was licensed by FDA on 24 August 1998 (BLA 103772) and authorised in the EU on 13 August 1999 (EMEA/H/C/000240). Celltrion's CT-P13, as Remsima and Inflectra, became the first monoclonal antibody biosimilar authorised by EMA in September 2013 and the first approved by FDA in April 2016. Inflectra's EU authorisation was withdrawn by Pfizer in May 2026, leaving Remsima as the sole EU name for CT-P13.

Sources: Purple Book (S016), EMA medicines data (S017), CDSCO lists (S013, S014).

Infliximab is the molecule on which the regulatory model for antibody biosimilars was built, and Europe's experience with it, especially the Norwegian tender and NOR-SWITCH, is the evidence base behind the EU's position on interchangeability. The market has matured: four US products, three active EU products, and in the UAE Celltrion's Remsima in both intravenous and subcutaneous forms. India has one domestic manufacturer permitted, Reliance Life Sciences, alongside imports of the Celltrion and Biocad products.