The drug adalimumab is used very successfully in the treatment of various inflammatory diseases. Yet in some patients, the efficacy of this drug decreases over time. We explain why this is so and how drug monitoring can contribute to long-term therapy success.
Whether for rheumatism, psoriasis, or chronic inflammatory bowel diseases: The drug adalimumab (ADM, trade name Humira®) has considerably improved the therapy options for many patients. As a human monoclonal antibody it is very effective and well tolerated. Like other so-called TNF-α blockers, adalimumab binds to the tumor necrosis factor-alpha (TNF-α), inhibiting its effect. The body therefore excretes fewer inflammation mediators, and the inflammation is ameliorated. Yet in some patients, adalimumab does not work, or its efficacy decreases over time. Sometimes a dosage increase helps in these cases. The cause for the loss of efficacy may also be that the body has formed antibodies against the drug—known as anti-drug antibodies (ADA). These antibodies neutralize the effect of adalimumab. In this case, the only remedy is to change the medication.
Therapeutic drug monitoring (TDM) can assist physicians in making the right therapy decision. Two tests are decisive in this regard:
+ Trough level measurement
To produce the optimum effect, TNF-α blockers like adalimumab must be present in a sufficient concentration in the blood. However, this bioavailability can vary from person to person. As a part of drug monitoring, the trough level concentration in the blood can be tested regularly prior to each new infusion. This testing allows the physician to adjust the dose individually to the patient, ensuring that the drug will produce the optimum effect.
+ Antibody measurement
If the measured trough level indicates that the adalimumab concentration is less than the therapeutically effective level (< 1 µg/mL), the blood should also be tested for anti-ADM antibodies. The therapy can then be adjusted according to the antibody count: If the concentration of anti-ADM antibodies is low, the dose should be increased or the interval between doses should be reduced. In contrast, patients with a high anti-ADM antibody count should be treated with another medication.
The trough level and the antibody count give the physician information that is decisive in the further success of therapy. Accordingly we have expanded our portfolio, and, in addition to RIDASCREEN® ADM Monitoring (Art. No. G09043), we now offer RIDASCREEN® Anti-ADM Antibodies (Art. No. G09044).
Do you have further questions concerning adalimumab and therapeutic drug monitoring? We will be happy to support you!