Table 1.

Examples of FDA approved Fc-fusion proteins.^*

Name (trade name; sponsoring companies)	Effector protein	Impact of Fc domain on PK	Targets	Disease	Proposed mechanisms of action	Reference
Alefacept (Amevive; Astellas)	Human leukocyte function antigen-3 (LFA-3)	Prolong half-life	CD2	Plaque psoriasis	Inhibition of CD2-dependent lymphocyte activation	89
Etanercept (Enbrel; Amgen/Pfizer)	p75 TNFαR	Prolong half-life	TNFα	RA, JIA, PA, AS and plaque psoriasis	Neutralization of TNFα activity	55
Abatacept (Orencia; Bristol-Myers Squibb)	Cytotoxic T-lymphocyte antigen-4 (CTLA-4)	Prolong half-life	CD80 and CD86	RA and JIA	Inhibition of CD80/86-dependent T cell activation	90
Romiplostim (Nplate; Amgen)	Peptide	Prolong half-life	Thrombo-poietin receptor	Thrombocytopaenia in patients with idiopathic thrombocytopaenic purpura	Activation of thrombopoietin receptor	91
Rilonacept (Arcalyst; Regeneron)	Ligand-binding domains of IL-1 receptor and IL-1 receptor accessory protein (IL-1RAcP)	Prolong half-life	IL-1	CAPS	Neutralization of IL-1 activity	56
Belatacept (Nulojix; tol-Myers Squibb)	Cytotoxic T-lymphocyte antigen-4 (CTLA-4)	Prolong half-life	CD80 and CD86	prophylaxis of organ rejection in adult patients receiving a kidney transplant	Inhibition of CD80/86-dependent T cell activation	8
Aflibercept (Eylea; Regeneron)	Vascular endothelial growth factor receptor 1 and 2 (VEGFR 1 and 2)	Prolong half-life	VEGF-A, VEGF-B, PIGF	neovascular (Wet) age-related macular degeneration	Neutralization of VEGF activity	9

^*Abbreviation: AS, ankylosing spondylitis; CAPS, cryopyrin-associated periodic syndrome; Fc, crystallizable fragment; IL, interleukin; JIA, juvenile idiopathic arthritis; PA, psoriatic arthritis; PIGF, placental growth factor; RA, rheumatoid arthritis; TNFα, tumor necrosis factor-α; VEGF, vascular endothelial growth factor.