Tremelimumab is a fully human

Human

Humans are the only living species in the Homo genus...

 IgG2 monoclonal antibody produced by Pfizer

Pfizer

Pfizer, Inc. is an American multinational pharmaceutical corporation. The company is based in New York City, New York with its research headquarters in Groton, Connecticut, United States...

. It binds to the protein CTLA-4

CTLA-4

CTLA4 also known as CD152 is a protein that plays an important regulatory role in the immune system...

, which is expressed on the surface of activated T lymphocytes. Tremelimumab blocks the binding of the antigen-presenting cell ligands B7.1 and B7.2 to CTLA-4, resulting in inhibition of B7-CTLA-4-mediated downregulation of T-cell activation; subsequently, B7.1 or B7.2 may interact with another T-cell surface receptor protein, CD28

CD28

CD28 is one of the molecules expressed on T cells that provide co-stimulatory signals, which are required for T cell activation. CD28 is the receptor for CD80 and CD86 . When activated by Toll-like receptor ligands, the CD80 expression is upregulated in antigen presenting cells...

, resulting in a B7-CD28-mediated T-cell activation unopposed by B7-CTLA-4-mediated inhibition.

Tremelimumab is thought to stimulate patients’ immune systems to attack their tumors. It has been shown to induce durable tumor responses in patients with metastatic melanoma in Phase 1 and Phase 2 clinical studies.

On April 2, 2008, Pfizer announced that it has discontinued a Phase III clinical trial for patients with advanced melanoma

Melanoma

Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye...

 after the review of interim data showed that the trial would not demonstrate superiority to standard chemotherapy. Studies for other tumors are planned , namely for prostate cancer

Prostate cancer

Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, there are cases of aggressive prostate cancers. The cancer cells may metastasize from the prostate to other parts of the body, particularly...

 and bladder cancer

Bladder cancer

Bladder cancer is any of several types of malignant growths of the urinary bladder. It is a disease in which abnormal cells multiply without control in the bladder. The bladder is a hollow, muscular organ that stores urine; it is located in the pelvis...

.

On October 4, 2011, MedImmune

MedImmune

MedImmune, LLC, headquartered in Gaithersburg, Maryland, became a wholly owned subsidiary of AstraZeneca in 2007. Since being acquired, MedImmune has remained a Maryland-based biotechnology development enterprise...

 LLC gained worldwide rights on Tremelimumab to develop and commercialize the drug for treatment of cancer, while Pfizer retains all rights for combination therapies.

Similar drugs

, there are two fully human anti CTLA-4 monoclonal antibodies in advanced clinical trials, tremelimumab and ipilimumab

Ipilimumab

Ipilimumab , marketed as Yervoy, is a drug used for the treatment of melanoma, a type of skin cancer. It is a U.S...

 (from Medarex

Medarex

Medarex is an American biotechnology company owned by Bristol Myers Squibb and based in Princeton, New Jersey. The company has manufacturing facilities in Bloomsbury and Annandale, New Jersey, and research facilities in Milpitas and Sunnyvale, California. Medarex specializes in therapeutic...

 and Bristol-Myers Squibb

Bristol-Myers Squibb

Bristol-Myers Squibb , often referred to as BMS, is a pharmaceutical company, headquartered in New York City. The company was formed in 1989, following the merger of its predecessors Bristol-Myers and the Squibb Corporation...

).