Assessing therapeutics

Tumor necrosis factor (TNF) blockers, such as adalimumab (Humira^®), infliximab (Remicade^®), and the infliximab biosimilar infliximab-dyyb (Inflectra^®), are used to treat inflammatory bowel disease (IBD; Crohn disease, ulcerative colitis) and rheumatic diseases (eg, rheumatoid arthritis, plaque psoriasis, psoriatic arthritis, ankylosing spondylitis).^1-3

TNF blockers have had a major impact on the course of treatment for these conditions, but response rates vary by indication and other factors (eg, dose, smoker vs nonsmoker, etc.). While some patients respond to treatment, many others are refractory to treatment, showing either nonresponse during induction (primary failure) or response during induction followed by loss of efficacy (secondary failure).

When treatment fails, a physician may need to consider other treatment options, such as adjusting dose or dosing intervals, switching to a different TNF blocker, or switching to a non–TNF blocker. Measuring TNF blocker drug levels can help differentiate pharmacodynamic from possible pharmacokinetic conditions associated with treatment failure. 

The American Gastroenterology Association (AGA) suggests a testing-based strategy when control of active IBD is suboptimal.⁴

Individuals suitable for testing:

• Individuals with IBD who have recently started treatment with adalimumab, infliximab, or the biosimilar infliximab (baseline testing)
• Individuals who experience treatment failure with any of these drugs

Individuals suitable for testing:

• Individuals with a rheumatic disease who have experienced failure of treatment with adalimumab, infliximab, or the infliximab biosimilar infliximab