Blisibimod (also known as A-623, formerly AMG 623) is a selective antagonist of

B-cell activating factor B-cell activating factor (BAFF) also known as tumor necrosis factor ligand superfamily member 13B and CD257 among other names, is a protein that in humans is encoded by the ''TNFSF13B'' gene. BAFF is also known as B Lymphocyte Stimulator (BLyS) an ...

(BAFF, also known as B-lymphocyte stimulator or BLyS), being developed by Anthera Pharmaceuticals as a treatment for

systemic lupus erythematosus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...

. It is currently under active investigation in clinical trials.

Mechanism of action

Blisibimod is a

fusion protein Fusion proteins or chimeric (kī-ˈmir-ik) proteins (literally, made of parts from different sources) are proteins created through the joining of two or more genes that originally coded for separate proteins. Translation of this ''fusion gene'' r ...

consisting of four BAFF binding domains fused to the

N-terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

of the

fragment crystallizable region The fragment crystallizable region (Fc region) is the tail region of an antibody that interacts with cell surface receptors called Fc receptors and some proteins of the complement system. This property allows antibodies to activate the immune ...

(Fc) of a human

antibody An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and Viral disease, viruses. The antibody recognizes a unique m ...

. BAFF is involved in

B-cell B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted ...

survival, activation, and differentiation. Elevated levels of BAFF have been associated with several B-cell mediated

autoimmune diseases An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...

, including systemic lupus erythematosus,

lupus nephritis Lupus nephritis is an inflammation of the kidneys caused by systemic lupus erythematosus (SLE), an autoimmune disease. It is a type of glomerulonephritis in which the glomeruli become inflamed. Since it is a result of SLE, this type of glomeru ...

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and ...

, multiple sclerosis,

Sjögren syndrome Sjögren syndrome or Sjögren's syndrome (SjS, SS) is a long-term autoimmune disease that affects the body's moisture-producing (lacrimal and salivary) glands, and often seriously affects other organ systems, such as the lungs, kidneys, and nerv ...

Graves' disease Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyr ...

, and

Hashimoto's thyroiditis Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis and Hashimoto's disease, is an autoimmune disease in which the thyroid gland is gradually destroyed. Early on, symptoms may not be noticed. Over time, the thyroid may enlar ...

. Blisibimod binds to BAFF and inhibits interaction with BAFF

receptors Receptor may refer to: *Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a n ...

, thus decreasing B-cell survival and proliferation throughout the body. Improvements in disease activity have been observed in patients with systemic lupus erythematosus and rheumatoid arthritis following treatment with BAFF inhibitors in clinical trials.

Development

Blisibimod was initially developed by

Amgen Amgen Inc. (formerly Applied Molecular Genetics Inc.) is an American multinational biopharmaceutical company headquartered in Thousand Oaks, California. One of the world's largest independent biotechnology companies, Amgen was established in ...

, with Phase I trials demonstrating comparable safety between the blisibimod and

placebo A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like Saline (medicine), saline), sham surgery, and other procedures. In general ...

treatments. It was subsequently acquired by Anthera Pharmaceuticals, who in 2010 initiated a global Phase II study called PEARL-SC to investigate the efficacy, safety, and tolerability of blisibimod in subjects with systemic lupus erythematosus. The PEARL-SC study, completed in April 2012, yielded data that has been published. Blisibimod is currently being tested in a Phase 3 study, CHABLIS-SC1, for systemic lupus erythematosus, and a Phase 2 study, BRIGHT-SC, for

IgA nephropathy IgA nephropathy (IgAN), also known as Berger's disease () (and variations), or synpharyngitic glomerulonephritis, is a disease of the kidney (or nephropathy) and the immune system; specifically it is a form of glomerulonephritis or an inflammati ...

References

{{Cytokine receptor modulators Engineered proteins