26217 Adalimumab Quantitative with Reflex to Antibody, Serum (ADALX)

​Humira

​If the result is 8.0 mcg/mL or less, then adalimumab antibody test will be performed at an additional charge.

​Patient Preparation: For 12 hours before specimen collection, it is recommended that the patient not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Tumor necrosis factor (TNF) measurement is not the analyte of choice for monitoring therapy with TNF inhibitors (such as adalimumab or infliximab), since TNF testing would not distinguish between free TNF and TNF bound to the monoclonal antibody, either in the extracellular or membrane-bound form of the cytokine.

Toxicity effects other than acute hypersensitivity infusion reactions have not been described nor correlated with high adalimumab concentrations.

Optimal therapeutic concentrations of adalimumab may vary according to the disease.(11-13) For adults with active inflammatory bowel disease, a concentration of 7.5 mcg/mL or greater is considered therapeutic.(5)

For patients taking biotin supplements, it is recommended to wait at least 12 hours after the last ingestion of biotin to collect a blood sample for this test. 

Therapeutic drug monitoring of adalimumab concentration

HIGHLIGHTS:

Adalimumab (brand name Humira) is a fully human therapeutic monoclonal antibody targeting tumor necrosis factor alpha, a proinflammatory cytokine that is upregulated in several autoimmune inflammatory states.

Adalimumab is FDA-approved for treatment of rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis; ankylosing spondylitis, pediatric and adult Crohn disease, ulcerative colitis, plaque psoriasis, hidradenitis suppurativa and uveitis. Adalimumab is a subcutaneous injection, usually self-administered every other week at a fixed dose of 40 mg in adults, although dosing can vary.

Testing for adalimumab concentration and presence of anti-adalimumab antibodies is helpful to adjust therapeutic strategies for patients starting therapy (proactive monitoring), and to adjust dosing or treatment strategy when partial response or loss of response to therapy is observed, manifested as recurrence of symptoms. 

​If the result is 8.0 mcg/mL or less, then adalimumab antibody test will be performed at an additional charge.

Currently, adalimumab quantitation is one of the most commonly tested monoclonal antibodies in routine clinical practice; this testing is generally performed in conjunction with immunogenicity assessment for antibodies to adalimumab (ATA). Most often, this testing is ordered for patients with inflammatory bowel disease (IBD) who are on adalimumab therapy and who are experiencing loss of response (reactive monitoring),(5) but the testing may be ordered for anyone on adalimumab-even when treatment is going well (proactive monitoring).(6-8)

Results from adalimumab and ATA testing play an important role in patient management. In the setting of loss of response to adalimumab therapy, for adults with active inflammatory bowel disease (IBD), a clinical decision tool from the American Gastroenterology Association(9,10) suggests the following scenarios for a blood draw that occurred at trough, immediately before the next injection dose:

For patients who have undetectable or low concentrations of adalimumab (<8 mcg/mL) but no detectable ATA, the patient care team may choose to increase the dose of adalimumab in an attempt to increase the amount of the drug in circulation.

If the patient has subtherapeutic adalimumab concentrations (<8 mcg/mL) in the presence of an ATA, in many cases, the patient care team may switch the patient to another TNF inhibitor.

For patients with increased trough concentrations of adalimumab (therapeutic or greater), whether an ATA is present or not, it may be necessary to switch the patient to a therapy with a different mechanism of action such as the anti-alpha4-beta-7-integrin antibody vedolizumab or the IL12/IL23 antibody ustekinumab.

Low trough concentrations may be correlated with loss of response to adalimumab. For adalimumab trough concentrations of 8.0 mcg/mL or less, testing for ATA is suggested. 

For adalimumab trough concentrations above 8.0 mcg/mL, the presence of ATA is unlikely; patients experiencing loss of response to adalimumab may benefit from a therapy with a different mechanism of action such as the anti-alpha4-beta-7-integrin antibody vedolizumab or the IL12/IL23 antibody ustekinumab.

Adalimumab concentration results above 35 mcg/mL are suggestive of a blood draw at a time-point in treatment other than trough.

Test interpretation relies on clinical presentation and may differ from the statements above, which were designed for adults with IBD experiencing loss of response. For individuals on adalimumab therapy for other conditions such as rheumatoid arthritis, or pediatric patient populations or proactive monitoring, drug concentration therapeutic targets and patient management decision may be individualized.