Takeaway
- Higher serum concentrations of ustekinumab (Stelara) at 4 weeks are correlated with clinical response in patients with moderate to severe psoriasis.
Why this matters
- Serum drug concentration may help identify underexposed patients, but prior results were contradictory for ustekinumab.
Key results
- At 4 weeks, ustekinumab concentration was negatively correlated with absolute Psoriasis Area and Severity Index (PASI) score (P=.032) and positively correlated with change in PASI score (P=.024) up to 5.9 μg/mL.
- Optimal responders (PASI≤2) had higher ustekinumab concentration compared with suboptimal responders (PASI>2; 4.0 vs 2.8 μg/mL; P=.036).
- An ustekinumab concentration threshold of 3.6 μg/mL was associated with optimal response (area under the curve, 0.71; sensitivity, 86%; specificity, 63%; P=.036).
- 1 patient (2%) was positive for anti-ustekinumab antibodies.
- Psoriatic arthritis was associated with higher ustekinumab concentration in multivariate analysis (P=.048).
Study design
- 49 patients with moderate to severe psoriasis treated with ustekinumab were included.
- Funding: Research Foundation-Flanders, Belgium.
Limitations
- Small patient sample size.
- Cross-sectional study.
References
References