Abatacept (Orencia) is a novel drug recently approved in the United States and European countries for the treatment of autoimmune rheumatic diseases like Rheumatoid Arthritis.
Abatacept drug class:
It belongs to the class of medicine that inhibits the activation of T cells by binding to CD 80 and CD 86 present on the APC (antigen-presenting cells). It is a selective costimulation modulator
(Abatacept) Orencia indications:
- It may be used as a monotherapy or in combination with other anti-rheumatic drugs in patients Rheumatoid arthritis.
 - Abatacept should not be used along with TNF-blocking agents (like adalimumab, etanercept, and infliximab, etc) and anakinra.
 - It can also be used alone or in conjunction with methotrexate to treat mild to severe juvenile idiopathic arthritis.
 
Abatacept in Psoriatic arthritis:
- The FDA has approved abatacept for treating psoriatic arthritis. NSAIDs, Methotrexate, Sulfasalazine, cyclosporin, and leflunomide are effective in the treating peripheral arthritis in patients with psoriasis.
 - However, none of these drugs have proven roles in modifying disease progression and halting joint destruction.
 - Abatacept in clinical trials was found effective in 39% of the patients compared to placebo (22%).
 - It has also been found effective in patients with axial involvement in psoriatic arthritis, enthesitis, and dactylitis.
 
Abatacept in Juvenile idiopathic arthritis:
- Additionally, it has been licenced for use in children with moderately to highly active juvenile idiopathic arthritis as a monotherapy or in combination with methotrexate.
 
(Abatacept) Orencia dose:
Abatacept (Orencia) should be administered via an intravenous infusion initially
Adult patients with upto 60 kg body weight:
Dose via intravenous infusion:
- 3 doses of 500 mg every 15 days
 - 500 mg every month by intravenous infusion
 
Otherwise it can be infused by a subcutaneous injection:
- 125 mg once a week, with the first dosage administered subcutaneously one day after the intravenous loading dose;
 - Patients who are unable to get an intravenous infusion may begin subcutaneous abatacept treatment without first receiving an intravenous loading dose.
 
Adult patients with a body-weight of 60 – 100 kgs:
- A Loading Dose via an intravenous infusion:
	
- 750 mg every 15 days for 3 doses
 - followed by intravenous infusions 750 mg monthly.
 
 
Alternatively by subcutaneous injection:
- 125 mg once weekly, the first subcutaneous dose should be given within 1 day of the intravenous loading dose;
 - (patients who are unable to receive an infusion may initiate subcutaneous abatacept without receiving an intravenous loading dose)
 
101 kg and above weighing adults:
Loading dose via intravenous infusion: 3 doses of 1000mg for 15 days
- 1000 mg every month by intravenous infusion
 
Alternatively by subcutaneous injection:
- The first subcutaneous dose of 125 mg once weekly should be administered one day after the intravenous loading dose;
 - (patients who are unable to receive an infusion may initiate subcutaneous abatacept without receiving an intravenous loading dose).
 
Intravenous Dose of Orencia (Abatacept) in Children:
Children 6 years of age or older and weighing less than 75 kgs:
- 10 mg/kg
 - The dose is repeated at 2 weeks and 4 weeks after the initial dose and every 4 weeks thereafter
 
Children 6 years or older and weighing more than 75 kgs:
- Follow the Usual adult dosing with a maximum dose of up to 1000 mg
 - Following the initial dose, the dose is repeated at 2 weeks, 4 weeks, and then every 4 weeks after that.
 
Dose in Kidney disease:
- The manufacturer has not provided any dose adjustment in patients with kidney disease.
 
Dose in Liver Disease:
- The manufacturer has not provided any dose adjustment in patients with liver disease.
 
How to administer Abatacept (Orencia)?
Intravenous infusion of Orencia:
- Infuse for 30 minutes.
 - Inject using 0.2-1.2 micron low protein-binding filter
 
Subcutaneous administration of Orencia:
- Before injecting, let the prefilled syringe warm at room temperature for 30 to 60 minutes.
 - Preferably inject into front thigh, or the abdomen but not close to the navel (keep a distance of about three fingers from the navel), or the outer upper arms (the least preferred site).
 - Do not inject into an inflamed area i.e. tender, bruised, red, or hard skin.
 - Always rotate the injection sites
 
Pregnancy Risk Category: C
It may be used if benefits outweigh the risks
- Pregnancy Implications Pregnant females have not been tested with Abatacept. Animal studies have not shown any teratogenic effects.
 - Lactation It is not known if abatacept is found in breast milk.
 
Considerations for Breastfeeding
- Breastfeeding is not recommended due to the adverse effects on the developing immune system
 
Side effects of Abatacept:
Abatacept is contraindicated in patients allergic to it, HIV, and immunocompromised patients who are at risk of infection and sepsis.
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Hypersensitivity reactions:
- Hypersensitivity reactions may involve anaphylactic reactions resulting in hypotension that may occur during the infusion and within 24 hours of the infusion.
 - Epinephrine, fluids, and steroids must be available while infusing the medicine.
 
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Infections:
- Patients are also at risk of developing serious infections such as the reactivation of tuberculosis, pneumocystis pneumonia, and other bacterial and viral infections.
 - Screening must be done for hepatitis B infections and immunized prior to initiating the treatment in patients.
 
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Malignancies:
- The risks of malignancies such as lymphoma and lung cancer have been associated with its use.
 - However, these cancers are more common in patients with rheumatoid arthritis and the data is scarce regarding the associations of cancers with abatacept use.
 
 
Common side effects of Abatacept (Orencia):
- Abdominal pain
 - Vomiting
 - Nausea
 - Flushing
 - Conjunctivitis
 - Infection
 - Cough
 - Stomatitis
 - Fatigue
 - Paraesthesia
 - Headache
 - Diarrhea
 - Pain in extremities
 - Dizziness
 - Hypertension
 - Dyspepsia
 - Fatigue
 
Uncommon adverse effects of Orencia:
- Psoriasis
 - Weight gain
 - Dyspnoea
 - Gastritis
 - Palpitation
 - Alopecia
 - Bradycardia
 - Hypotension
 - Anxiety
 - Dry eye
 - Visual disturbance
 - Tachycardia
 - Arthralgia
 - Thrombocytopenia
 - Basal and squamous cell carcinoma
 - Dry skin
 - Skin papilloma
 - Depression
 - Bronchospasm
 - Hypertension
 - Sleep disorder
 - Bruising
 - Depression
 - Hyperhidrosis
 - Menstrual disturbances
 
Rare side effects of Abatacept:
- Lung cancer
 - lymphoma
 
Mechanism of Action (MOA) of Orencia (Abatacept):
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The drug abatacept modulates costimulation. It binds to CD80 on antigen-presenting cells to prevent T-cell (T-lymphocyte) activation (APC).
 - 
	
This prevents the necessary CD28 interaction between T cells and APCs. T cells that have been activated are present in the synovium of rheumatoid arthritis patients.
 
Pharmacodynamics/Kinetics of Orencia:
- Half-life elimination: 8-25 days
 
Monitoring Parameters
- Signs and symptoms that indicate infection. It is recommended that you screen for TB and hepatitis before starting therapy.
 
International Brand Names of Abatacept:
- Orencia
 
Currently, it is not available in Pakistan.
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