Dose escalation of adalimumab as a strategy to overcome anti-drug antibodies: A case report of infantile-onset inflammatory bowel disease.

Background: Treatment of infantile-onset inflammatory bowel disease (IO-IBD) is often challenging due to its aggressive disease course and failure of standard therapies with a need for biologics. Secondary loss of response is frequently caused by the production of anti-drug antibodies, a well-known problem in IBD patients on biologic treatment. We present a case of IO-IBD treated with therapeutic drug monitoring (TDM)-guided high-dose anti-tumor necrosis factor therapy, in which dose escalation monitoring was used as a strategy to overcome anti-drug antibodies.

Case Summary: A 5-mo-old boy presented with a history of persistent hematochezia from the 10 d of life, as well as relapsing perianal abscess and growth failure. Hypoalbuminemia, anemia, and elevated inflammatory markers were also present. Endoscopic assessment revealed skip lesions with deep colic ulcerations, inflammatory anal sub-stenosis, and deep fissures with persistent abscess. A diagnosis of IO-IBD Crohn-like was made. The patient was initially treated with oral steroids and fistulotomy. After the perianal abscess healed, adalimumab (ADA) was administered with concomitant gradual tapering of steroids. Clinical and biochemical steroid-free remission was achieved with good trough levels. After 3 mo, antibodies to ADA (ATA) were found with undetectable trough levels; therefore, we optimized the therapy schedule, first administering 10 mg weekly and subsequently up to 20 mg weekly (2.8 mg/kg/dose). After 2 mo of high-dose treatment, ATA disappeared, with concomitant high trough levels and stable clinical and biochemical remission of the disease.

Conclusion: TDM-guided high-dose ADA treatment as a monotherapy overcame ATA production. This strategy could be a good alternative to combination therapy, especially in very young patients.