Abatacept

Abatacept is a prescription drug used for reducing signs and symptoms in adult patients with active rheumatoid arthritis (RA). It is also used for reducing signs and symptoms in children six years of age and older with active juvenile idiopathic arthritis (JIA).

Other Names
Abatacept is marketed as Orencia by Bristol-Myers Squibb.

Uses
Abatacept is used for reducing the signs and symptoms of:
 * active rheumatoid arthritis (RA) in adults
 * active juvenile idiopathic arthritis (JIA) in children over six years of age

How Abatacept is Taken
Abatacept is available in a 250-mg vial.

Adults with rheumatoid arthritis (RA)
For adult patients with RA, Abatacept is initially administered as a 30-minute intravenous (IV) infusion.

Following the initial dosing, Abatacept should be given at two weeks and then at four weeks after the first infusion. It then should be dosed every four weeks thereafter.

Children with juvenile idiopathic arthritis (JIA)
The recommended dose of Abatacept for patients 6-17 years of age with juvenile idiopathic arthritis who weigh less than 75 kg is 10 mg/kg calculated based on body weight.

Children weighing 75 kg or more receive the adult dosing regimen, not to exceed a maximum dose of 1000 mg.

How Abatacept Works
Abatacept inhibits the activation of white blood cells called T lymphocytes by binding to the surface proteins CD80 and CD86, thereby blocking interaction with CD28 (another surface protein). This interaction provides a signal necessary for full activation of T lymphocytes. So, by blocking this interaction, abatacept prevents the full activation of T lymphocytes.

Activated T lymphocytes are involved in the development of rheumatoid arthritis (RA) and several other autoimmune disorders.

How the Body Affects Abatacept
At the standard 10 mg/kg dose, circulating levels appeared to reach a steady-state after 60 days. There is no data available on the metabolism and excretion of abatacept.

Side Effects
The most common side effects (&gt;3% of treated patients) observed with Orencia use are: People with chronic obstructive pulmonary disease (COPD) may have a higher incidence of side effects.
 * Headache
 * Nasopharyngitis (sore throat, runny nose, nasal congestion, sneezing and cough)
 * Dizziness
 * Cough
 * Back pain
 * Hypertension
 * Dyspepsia (indigestion)
 * Urinary tract infection

Hypersensitivity
Severe allergic reactions have occurred with Abatacept use.

Infections
Infections may arise in patients with a history of recurrent infections, underlying conditions which may predispose them to infections, or chronic, latent, or localized infections.

Abatacept can reactivate tuberculosis (TB) in people who have been previously infected with TB. Before starting treatment, patients should be screened with a tuberculin skin test, chest X-ray, and the QuantiFERON Gold TB test. If any tests are positive, the latent TB should be treated prior to starting Orencia.

Immunizations
Live vaccines are not to be received while taking Orencia or within three months after taking Orencia.

Diabetes
Because Abatacept contains maltose, patients with diabetes may develop abnormally high blood sugar levels while taking Orencia.

TNF antagonists
Abatacept is not to be used concurrently with a TNF antagonist, such as adalimumab, etanercept, and infliximab. This combination may increase their risk for infections.

Other biologic RA therapies
The use of Abatacept with other biologic RA therapies, such as anakinrais,is not recommended.

Effectiveness
The effectiveness of Abatacept was studied in two trials: Both trials demonstrated sustained improvements in physical function for RA patients treated with Orencia through two years.[1]
 * AIM (Abatacept in Inadequate responders to Methotrexate)
 * ATTAIN (Abatacept Trial in Treatment of Anti-TNF Inadequate Responders)