In this phase 2/3 Japanese trial, CZP treatment resulted in clinically meaningful improvements in the signs and symptoms of PSO at week 16, which were maintained through week 52 across evaluated patient subgroups. In general, a numerically greater response was observed for CZP 400 mg Q2W versus CZP 200 mg Q2W across patient subgroups. High efficacy levels were observed with the CZP 400 mg Q2W dose irrespective of baseline patient factors.
Several studies have reported an increased risk of PSO in patients who are obese [
25,
26], and patients with severe PSO have been found to be more likely to be obese, compared with those with mild PSO [
27]. Similar trends were observed in a Japanese population, where higher prevalence of obesity and higher mean BMI were reported in patients with PSO compared to healthy controls [
28]. Patients who are overweight or obese have an increased amount of visceral fat, which contributes to a higher systemic inflammatory burden [
19]. An increase in body weight may also alter drug distribution and lead to elevated drug clearance [
19,
29,
30]. Since most systemic treatment strategies for PSO do not rely on weight-based dosing, the administered dose may be inadequate for patients with a higher BMI, thus causing a reduced response in this patient subpopulation [
31]. Indeed, BMI has been shown to affect clinical response to PSO treatments, where obese patients tend to have reduced response to some anti-TNFs (such as infliximab, adalimumab and etanercept) [
12,
19,
20] and some anti-IL-17s (such as secukinumab and brodalumab) [
17,
18]. In patients with psoriasis treated with adalimumab, the PASI 75 response at week 16 in the BMI < 25, 25 to < 30 and ≥ 30 kg/m
2 subgroups was reported to be 85.0, 85.7 and 61.3%, respectively [
32]; the PASI 90 response in these patients was 70.0, 53.6 and 35.5%, respectively [
32]. In patients treated with etanercept, the PASI 75 response at week 12 in the BMI ≤ 35 and > 35 kg/m
2 subgroups was 73.7% and 61.2%, respectively [
33]. In the current study, CZP response was comparable across BMI subgroups for the 400 mg Q2W dose. At week 52, 84.2, 85.7 and 80.0% of patients receiving CZP 400 mg Q2W, in the low, intermediate and high BMI subgroups, respectively, achieved a PASI 75 response, and 84.2, 85.7 and 75.0%, respectively, achieved a PASI 90 response.
Some studies have suggested that a high baseline PASI predicts the achievement of PASI 90 response at week 24 [
11,
21]. In this study, PASI 75 response was similar across baseline PASI subgroups. In terms of PASI 90 response in the group treated with CZP 400 mg Q2W, although the week 16 response was 57.1% in patients with low baseline PASI and 84.2% in those with high baseline PASI, the week 52 response rates were similar (85.7% and 84.2%, respectively). Additionally, CZP response was generally comparable among patients with different disease duration and prior biologic treatment histories at baseline. These findings suggests that CZP provides a clinical benefit independent of disease duration and prior biologic treatment history.
The efficacy observed across all subgroups at weeks 16 and 52 was similar to the overall study population [
7,
8]. In general, PASI 75 and PASI 90 responder rates were higher in the CZP 400 mg Q2W group versus the CZP 200 mg Q2W group across patient subgroups, including BMI, baseline PASI, disease duration and prior biologic exposure. A numerically greater response was also observed for the CZP 400 mg Q2W group versus the CZP 200 mg Q2W group in the overall study population. These findings suggest that additional benefits may be obtained from the higher dose.
The results of this Japanese study are comparable to those of the larger global phase 3 studies of CZP in PSO. In the subgroup analysis of the pooled data from the CIMPASI-1 (NCT02326298) and CIMPASI-2 (NCT02326272) trials, efficacy measured by PASI 75, PASI 90 and PGA 0/1 was observed for both the CZP 400 mg Q2W and CZP 200 mg Q2W doses over 48 weeks of treatment across subgroups, including baseline BMI, baseline disease duration, baseline PASI and prior anti-TNF biologic use [
22,
24]. The PASI 75, PASI 90 and PGA 0/1 responder rates in the pooled CIMPASI-1 and CIMPASI-2 analysis were also greater for the CZP 400 mg Q2W group versus the CZP 200 mg Q2W group across most subgroups at week 48 [
22,
24].
Limitations of this trial include the lack of an active comparator and the exclusion of patients with a history of primary failure to biologic therapy. As all clinical trials have strict inclusion and exclusion criteria which may affect the generalisability of these results to clinical practice, there is a need to use real-world data in registries to monitor efficacy of CZP over the longer term. Sample sizes for many of the subgroups were relatively small and caution should be used when interpreting these results. However, the results here are comparable with those from the larger global studies of CZP in PSO patients.