Blisibimod is a selective peptibody

Fusion protein

Fusion proteins or chimeric proteins are proteins created through the joining of two or more genes which originally coded for separate proteins. Translation of this fusion gene results in a single polypeptide with functional properties derived from each of the original proteins...

 antagonist of B-cell activating factor

B-cell activating factor

B-cell activating factor also known as tumor necrosis factor ligand superfamily member 13B is a protein that in humans is encoded by the TNFLSF13B gene...

 (BAFF, also known as B-Lymphocyte Stimulator or BLyS), being developed by Anthera Pharmaceuticals

Anthera Pharmaceuticals

Anthera Pharmaceuticals, Inc. is a pharmaceutical company that specializes in developing treatments for serious cardiovascular and autoimmune diseases...

 as a treatment for systemic lupus erythematosus

Systemic lupus erythematosus

Systemic lupus erythematosus , often abbreviated to SLE or lupus, is a systemic autoimmune disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage...

. It is currently under active investigation in clinical trials.

Mechanism

Blisibimod is a peptibody consisting of four novel BAFF binding domains fused to the N-terminus of the fragment crystallizable region

Fragment crystallizable region

The fragment crystallizable 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 system...

 (Fc) of a human antibody

Antibody

An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...

.

BAFF is involved in B-cell survival, activation, and differentiation. Elevated levels of BAFF have been associated with several B-cell mediated autoimmune diseases, including systemic lupus erythematosus, lupus nephritis

Lupus nephritis

Lupus nephritis is an inflammation of the kidney caused by systemic lupus erythematosus , a disease of the immune system. Apart from the kidneys, SLE can also damage the skin, joints, nervous system and virtually any organ or system in the body....

, rheumatoid arthritis

Rheumatoid arthritis

Rheumatoid arthritis is a chronic, systemic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints. The process produces an inflammatory response of the synovium secondary to hyperplasia of synovial cells, excess synovial fluid, and the development...

, multiple sclerosis

Multiple sclerosis

Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...

, Sjögren’s syndrome, Graves’ disease, and Hashimoto's thyroiditis

Hashimoto's thyroiditis

Hashimoto's thyroiditis or chronic lymphocytic thyroiditis is an autoimmune disease in which the thyroid gland is gradually destroyed by a variety of cell- and antibody-mediated immune processes. It was the first disease to be recognized as an autoimmune disease...

. Blisibimod binds to BAFF and inhibits

Enzyme inhibitor

An enzyme inhibitor is a molecule that binds to enzymes and decreases their activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. They are also used as herbicides and pesticides...

 interaction with BAFF receptors, 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

Amgen Inc. is an international biotechnology company headquartered in Thousand Oaks, California. Located in the Conejo Valley, Amgen is the world's largest independent biotech firm. The company employs approximately 17,000 staff members. Its products include Epogen, Aranesp, Enbrel, Kineret,...

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

Placebo

A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...

 treatments. Blisibimod was acquired by Anthera Pharmaceuticals, who in 2010 initiated a global Phase II study entitled PEARL-SC to investigate the efficacy, safety, and tolerability of blisibimod in subjects with systemic lupus erythematosus. As of 2011, this study is ongoing.