ADAGEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ADAGEN (ADAGEN).
ADAGEN (pegademase bovine) is a modified form of the enzyme adenosine deaminase (ADA). It catalyzes the deamination of adenosine and 2'-deoxyadenosine to inosine and 2'-deoxyinosine, respectively, thereby reducing the accumulation of toxic metabolites (deoxyadenosine triphosphate) that cause lymphotoxicity in patients with severe combined immunodeficiency disease (SCID) due to ADA deficiency.
| Metabolism | ADAGEN is a pegylated bovine adenosine deaminase; it is catabolized by proteolysis into amino acids. There is no specific cytochrome P450 metabolism. The polyethylene glycol (PEG) component is expected to be eliminated renally. |
| Excretion | Renal: approximately 40-60% of administered dose as intact polyethylene glycol conjugate; the remainder undergoes enzymatic degradation or biliary excretion. Fecal elimination is minimal. |
| Half-life | Terminal elimination half-life is approximately 3-6 days (mean ~3.5 days) in patients with ADA-SCID, allowing for weekly intramuscular dosing. |
| Protein binding | Not extensively protein-bound; less than 20% bound to plasma proteins (likely albumin and alpha-2-macroglobulin). |
| Volume of Distribution | Volume of distribution is approximately 0.3-0.5 L/kg, indicating distribution primarily in extracellular fluid and vascular space, with limited tissue penetration. |
| Bioavailability | Intramuscular: nearly 100% bioavailability. |
| Onset of Action | Intramuscular injection: clinical and biochemical improvement (e.g., reduction in toxic metabolites) typically observed within 1-2 weeks; full immune reconstitution may take months. |
| Duration of Action | Duration of effect corresponds to the dosing interval of once weekly; sustained ADA activity declines slowly over the week, maintaining metabolite detoxification. |
30 U/kg intramuscularly or subcutaneously once weekly; adjust dose based on adenosine deaminase (ADA) activity and clinical response.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustments are recommended for renal impairment; however, monitor for adverse effects as renal function declines. |
| Liver impairment | No specific dose adjustments are recommended for hepatic impairment; caution advised in severe hepatic impairment due to potential altered pharmacokinetics. |
| Pediatric use | Same as adult dosing (30 U/kg once weekly); weight-based dosing is used without additional age-specific adjustments. |
| Geriatric use | No specific dose adjustments recommended; monitor for adverse effects and ADA activity, as elderly may have decreased physiological reserve. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ADAGEN (ADAGEN).
| Breastfeeding | Excretion in human milk unknown; caution advised. M/P ratio not determined. |
| Teratogenic Risk | No adequate human studies; animal studies not conducted. Use only if clearly needed. First trimester: unknown risk. Second/third trimester: unknown risk. |
| Fetal Monitoring | Monitor pregnancy outcome; no specific fetal monitoring required. |
■ FDA Black Box Warning
None
| Serious Effects |
["Known hypersensitivity to pegademase bovine or any component of the product.","Patients with severe thrombocytopenia or coagulopathy that precludes intramuscular injection.","Do not use in patients who are suitable candidates for or have undergone successful bone marrow transplantation."]
| Precautions | ["Hypersensitivity reactions including anaphylaxis have been reported; monitor patients during infusion.","Thrombocytopenia and hemolytic anemia have been observed; monitor platelet counts and hemoglobin.","Neutralizing antibodies may develop, leading to loss of efficacy; monitor ADA antibody titers and drug levels.","PEG antibodies may develop; consider cross-reactivity with other PEGylated drugs.","Not for intravenous administration; administer intramuscularly only.","Use caution in patients with active infection or bleeding disorders."] |
| Food/Dietary | No specific food interactions reported. Maintain a balanced diet to support immune function. Avoid grapefruit juice if taking concurrent medications metabolized by CYP3A4 (though ADAGEN is not metabolized by CYP450). |
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| Fertility Effects | No known effect on fertility. |
| Clinical Pearls | ADAGEN (pegademase bovine) is used for enzyme replacement therapy in patients with severe combined immunodeficiency disease (SCID) due to adenosine deaminase (ADA) deficiency. Monitor plasma ADA activity and deoxyadenosine nucleotide (dAXP) levels to guide dosing. Avoid concomitant use with other immunosuppressive therapies unless necessary. Administer intramuscularly; rotate injection sites. Premedicate with acetaminophen and diphenhydramine if infusion reactions occur. |
| Patient Advice | ADAGEN is given as an injection into a muscle, typically once weekly. · You may experience injection site reactions (pain, redness, swelling) that usually resolve. · Report signs of infection (fever, chills, persistent cough) immediately. · Regular blood tests are needed to monitor enzyme levels and immune function. · Do not receive live vaccines during treatment due to potential risk of infection. · Inform your healthcare provider about all medications, including over-the-counter drugs and supplements. · Pregnancy and breastfeeding considerations: Discuss risks and benefits with your doctor. |