What Is Belatacept?

Belatacept is a drug given intravenously or by injection to prevent acute rejection of transplanted kidneys in adult patients. It is a T-cell costimulation blocker that is administered in combination with other immunosuppressants to help keep a new kidney functioning. Taking belatacept can increase a patient’s risk of developing post-transplant lymphoproliferative disorder (PTLD); this risk is greater if the patient has never been exposed to the Epstein-Barr virus (EBV). This treatment was approved by the United States Food and Drug Administration (FDA) in June 2011 and is marketed under the brand name Nulojix®.

Every organ transplant involves the risk of rejection. The human body may recognize the transplanted organ as foreign and mobilize the immune system to attack and attempt to reject it. Administering immunosuppressants helps reduce this risk, although doing so leaves the patient vulnerable to infection and other complications.

The FDA approved belatacept for kidney transplant patients on 15 June 2011. This treatment works in combination with other immunosuppressants and corticosteroids to prevent acute rejection and to keep the transplanted kidney working. Although it can be injected, belatacept is typically administered in 30-minute intravenous infusions.

This drug is a selective T-cell costimulation blocker. It is a fusion protein that selectively blocks T-cell costimulation, a crucial component of effective immune response. By interfering with this process, belatacept impairs the body’s ability to launch an immune system attack generally and helps reduce the risk of acute organ rejection as a foreign object in the body.

Although impairing the immune system may prevent organ rejection, it also leaves the patient vulnerable to infection and disease the body could normally ward off. Patients treated with belatacept are at an increased risk of certain cancers like skin cancer, a brain infection called progressive multifocal leukoencephalophathy, and other diseases, such as tuberculosis. The patient may also contract other serious bacterial, fungal, or viral infections as a result of a weakened immune system response. Consequently, patients taking this medication should avoid sunlight and live vaccines.

Belatacept was evaluated in three trials of more than 1,200 patients before FDA approval. Common side effects reported include anemia, constipation, and bladder or kidney infection. Some patients experience swollen feet, ankles, and legs.

The most troubling potential side effect of this treatment is an increased risk of developing PTLD. PTLD is a type of cancer characterized by rampant white cell growth in response to a transplanted organ. This risk is highest for patients who were not previously exposed to EBV, the virus that causes mononucleosis.

EBV is carried in approximately 80 percent of transplanted organs. As a result, a patient who has not been previously exposed will not be able to mount an effective immune system response if infected post-transplant. Taking belatacept weakens the immune system further, so only patients who have been tested for EBV should undergo this treatment.

As this treatment is administered intravenously, medical professionals can better ensure that transplant patients are taking their medications. This treatment has not been approved for individuals less than 18 years old. Only patients who receive a kidney transplant are candidates for belatacept as of 2011.