Clinical response to ustekinumab for patients with psoriasis was shown to vary by body region, in which lower extremities were identified as the most difficult to treat.
Lower response rates to ustekinumab were found in the lower extremities of patients with psoriasis, according to study findings published in Annals of Dermatology.
As the standard measurement tool used most often to determine treatment efficacy in clinical trials, the psoriasis area severity index (PASI) evaluates 4 body regions (the head/neck, upper limbs, trunk, and lower limbs) and 3 plaque characteristics (erythema, induration/thickness, and scaling).
Although PASI scores are typically reported as a composite measurement and does not account for results for each individual body region, researchers note that clinical responses across these regions may differentially affect patients’ quality of life and impact communication with patients for formulating their treatment plans.
They sought to assess and compare the characteristics of and clinical responses to ustekinumab, a fully human monoclonal antibody that inhibits interleukin (IL)-12 and IL-23 by binding its p40 subunit, across the 4 PASI regions.
A post-hoc analysis of a prospective, observational, and multicenter study conducted in Korea was performed, which recruited patients aged 18 years or older with psoriasis who were given ustekinumab.
In the study, 581 participants (mean [SD] age, 44.2 [13.29] years; mean [SD] disease duration, 11.3 [9.65] years; 67.3% male) provided demographic variables (age, sex, body mass index [BMI], and smoking/ drinking history), disease-related variables (disease duration, age at diagnosis, comorbidity, and medication history), and disease severity variables (body surface area [BSA], PASI, and physician’s global assessment [PGA]). Data on PASI was collected at baseline and after each patient visit.
“For comparisons of effectiveness between the 4 body regions at each post-baseline visit, the assessment of PASI response (PASI 75, 90, and 100) included only patients with PASI sub-scores of greater than or equal to 1 for the body regions at baseline,” noted the study authors.
“Furthermore, determination of the proportion of patients achieving a score of 0 for each of the clinical signs (erythema [redness], infiltration [thickness], and desquamation [scaliness]) assessed in the PASI included only patients with a baseline score of greater than or equal to 2 (moderate to very marked) for each respective body region.”
At baseline, mean [SD] PASI score and BSA percentage was 18.9 [9.69] and 27.8 [17.83], respectively. Regarding prior treatment, 83.8% (n = 487) of the patients had been treated with phototherapy, 84.7% (n = 492) had received oral agents, and 9.6% (n = 56) had previously used biologics.
Findings indicated that among the 4 PASI regions, the correlation between the PASI sub-scores for the upper and lower extremities was the highest (r = 0.680). Comparison of the mean baseline PASI sub-scores revealed significant differences between the body regions, with the highest being for the lower extremities.
Moreover, PASI 90 and PASI 100 scores were the highest for the head and neck region, indicating the highest response rates, while those for the lower extremities were consistently low at all visits.
“Differences in disease burden by region should be considered when evaluating the overall degree of severity of psoriasis in individual patients,” concluded researchers.
Son SW, Yu DY, Kim Y, et al. Differences in clinical responses to ustekinumab treatment among body regions: Results from a real-world prospective, observational, and multi-center study in Korea. Ann Dermatol. 2022 Feb;34(1):14-21. doi:10.5021/ad.2022.34.1.14