Psoriasis: antidrug antibodies linked to impaired clinical response to ustekinumab

  • Loeff FC & al.
  • J Invest Dermatol
  • 10 Apr 2020

  • curated by Brian Richardson, PhD
  • Clinical Essentials
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Takeaway

  • Positivity for antidrug antibodies (ADA) is associated with higher Psoriasis Area and Severity Index (PASI) score in patients with psoriasis treated with ustekinumab, according to a cross-sectional study.

Why this matters

  • The varied response of patients to ustekinumab is not well understood.

Key results

  • ADAs were detected in 3.8% of patients by a drug-sensitive radioimmunoassay (RIA) and 10.6% of patients by drug-tolerant (dt) ELISA.
  • ADA positivity vs negativity was associated with lower median ustekinumab levels:
    • RIA: −0.62 μg/mL (95% CI, −1.190 to −0.30 μg/mL). 
    • dtELISA: −0.74 μg/mL (95% CI, −1.09 to −0.47 μg/mL).
  • ADA positivity vs negativity was associated with higher absolute PASI score:
    • RIA: +6.6 (95% CI, 3.0-9.9). 
    • dtELISA: +1.9 (95% CI, 0.4-4.0).
  • Lack of detectable ustekinumab was associated with higher median PASI score (+6.5; 95% CI, 3.9-8.8) compared with detectable ustekinumab.

Study design

  • 340 patients with psoriasis treated with ustekinumab were analyzed for ADAs, ustekinumab levels, and PASI score.
  • Funding: British Association of Dermatologists; others.

Limitations

  • Observational study design.