NV Castelle et al. Clin Gastroenterol Hepatol 2022; 20: 465-467. Open Access: Patients With Low Drug Levels or Antibodies to a Prior Anti-Tumor Necrosis Factor Are More Likely to Develop Antibodies to a Subsequent Anti-Tumor Necrosis Factor
Design: Retrospective case-control study in 5828 patients (2171 cases, 1445 controls). Subjects needed to have consecutively orders of 2 anti-TNF therapies (infliximab (IFX) prior to adalimumab (ADM) or vice versa).
- Before switch from IFX to ADM, median (interquartile range) IFX serum concentrations were lower in cases versus control subjects (1.0 μg/mL [1.0–1.0] vs 11.7 μg/mL [4.2–27.1]; P < .0001).
- As noted in figure below, prior antidrug antibodies ADAb) to anti-TNF agent was associated with development of ADAb with 2nd anti-TNF agent. This risk was >2-fold higher when switching from IFX to ADM (B in Figure) and even more when switching from ADM to IFX (D in Figure)
- Increasing concentrations of ADAb to IFX were associated with higher proportions of patients developing ADAb to ADM (P < .0001). In contrast, increasing concentrations of ADAb to ADM did not result in a significantly higher proportion of patients developing ADAb to IFX.
- In my experience, many patients with subtherapeutic anti-TNF levels, even those with ADAb, can remain on initial anti-TNF with more frequent dosing and often with combination therapy. So before jumping off the initial treatment, make sure it has been optimized.
- In those who do start a 2nd anti-TNF agent, the authors recommend using combination therapy (with an immunomodulator) which “leads to lower rates of clinical failure and more favorable pharmacokinetics, compared with monotherapy.”
- “Alternatively, a strategy with optimized monotherapy using proactive TDM may be effective as well, but remains to be assessed in a prospective manner.”
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