Table 1.

Randomised clinical trials, extension studies and observational studies of switching from originator TNF-α inhibitors to biosimilars in inflammatory rheumatic diseases.

Reference study	Patients (n)	Disease	Reference product/biosimilar	Primary endpoint	Clinical results	Immunogenicity (presence of ADAb)
NIkiphorou¹⁴	39	RA (38%) AS and ReA (39%) PsA (18%) JIA (5%)	IFX/CT-P13	PROs (HAQ, pain, fatigue and morning stiffness) Disease activity (VAS patient)	Patient symptoms and disease activity were similar during IFX and CT-P13.	ND
PLANETRA Extension study¹⁵	302 Maintenance: 158 Switch IFX originator to CT-P13: 144	RA	IFX/CT-P13	ACR20 at week 102	Maintenance: 71.7% Switch: 71.8%	Maintenance: 40.3% Switch: 44.8%
PLANETAS Extension study¹⁶	174 Maintenance CT-P13: 88 Switch IFX originator to CT-P13: 86	AS	IFX/CT-P13	ASAS20 week 102	Maintenance group: 80.7% Switch group: 76.9%	Maintenance: 23.3% Switch: 27.4%
SB4 extension study²⁰	245 Maintenance SB4: 126 Switch originator to SB4: 119	RA	ETA/SB4	ACR20 week 100	Maintenance group: 80% Switch group: 80%	ND
SB2 transition study¹⁸	Switch IFX to SB2: 94 Maintenance SB2: 101 Maintenance IFX: 201	RA	IFX/SB2	Change in DAS28 at week 78	Comparable change between the three groups	Switch IFX to SB2: 14.6 Maintenance SB2: 14.1 Maintenance IFX:14.9
SB5 transition study²¹	Maintenance SB5: 254 Switch ADL to SB5: 125 Maintenance ADL: 129	RA	ADL/SB5	ACR20 week 42	Maintenance SB5: 76.9 Switch ADL to SB5: 81.1 Maintenance ADL:71.2	Maintenance SB5: 15.7 Switch ADL to SB5: 16.8 Maintenance ADL: 18.3
NOR-SWITCH²²	481 Maintenance originator IFX: 241 Switch: 240	RA: 77 SpA: 91 PsA: 30 Other (CD, UC, Pso): 283	IFX/CT-P13	Worsening of the disease according to specific clinical endpoint	Maintenance: 26.2% Switch: 29.6%	Maintenance: 7.1% Switch: 7.9%
DANBIO²³	768 All switch	RA: 364 SpA: 256 PsA: 119 Other: 29	IFX/CT-13	Disease flare at month 3	Unchanged disease and flare 3 months prior to versus 3 months after switch	No difference of ADAb positivity between baseline and at 6 months after switching
DANBIO²⁴	1548	RA: 891 SpA: 322 PsA: 335	ETA/SB4	Disease flare at month 3	Unchanged disease and incidence of flare prior versus after switch	ND

ACR20, American College of Rheumatology 20; ADL, adalimumab; ADAb, antidrug antibodies; AS, ankylosing spondylitis; ASAS20, Assessement in Anlylosing Spondylitis; CD, Crohn’s disease; DAS28, disease activity score 28 joints; DANBIO, a nationwide registry of biological therapies in Denmark; HAQ, Health Assessment Questionnaire;

IFX, infliximab; ETA, etanercept; JIA, juvenile idiopathic arthritis; ND, not determined; NOR-SWITCH, Switching from originator infliximab to biosimilar CT-P13 compared with maintained treatment with originator infliximab; PLANETRA, A randomised, double-blind, parallel-group study to demonstrate equivalence in efficacy and safety of CT-P13 compared with innovator infliximab when coadministered with methotrexate in patients with active rheumatoid arthritis; PLANETAS, A randomised, double-blind, multicentre, parallel-group, prospective study comparing the pharmacokinetics, safety, and efficacy of CT-P13 and innovator infliximab in patients with ankylosing spondylitis; PRO, patient-reported outcome; PsA, psoriatic arthritis; Pso, psoriasis; RA, rheumatoid arthritis; ReA, reactive arthritis; SpA, spondyloarthritis; TNF-α, tumour necrosis factor-α; UC, ulcerative colitis; VAS, Visual Analogue Scale.