Efficacy and safety of ixekizumab in a randomized, double-blinded, placebo-controlled phase IIIb study of patients with moderate-to-severe genital psoriasis.

BACKGROUND: Genital psoriasis (GenPs) is a common, debilitating and difficult-to-treat manifestation of plaque psoriasis. However, few controlled, interventional studies of GenPs exist. OBJECTIVES: To determine the efficacy of ixekizumab vs. placebo in patients with moderate-to-severe GenPs with ≥ 1% involved body surface area (BSA). METHODS: Patients with moderate-to-severe GenPs, defined as a baseline static Physician's Global Assessment of Genitalia (sPGA-G) score of ≥ 3, with BSA ≥ 1% were randomized 1 : 1 to receive placebo (n = 74) or the recommended dosing of ixekizumab (n = 75). Major outcomes included the percentage of patients achieving 0 or 1 scores on the sPGA-G (primary end point), overall sPGA, GenPs Sexual Frequency Questionnaire (GenPs-SFQ) item 2, and ≥ 3-point improvement from baseline on the GenPs itch numerical rating scale. RESULTS: At week 12, ixekizumab was superior to placebo for sPGA-G 0/1 (73% vs. 8%, P < 0·001), overall sPGA 0/1 (73% vs. 3%, P < 0·001), GenPs-SFQ item 2 score of 0 or 1 (78% vs. 21%, P < 0·001) and genital itch (60% vs. 8%, P < 0·001). No candidiasis was reported, no deaths occurred and one (1%) serious adverse event was reported in a patient receiving placebo. CONCLUSIONS: Ixekizumab was superior to placebo for the treatment of moderate-to-severe GenPs with BSA ≥ 1%. The safety profile of ixekizumab was consistent with previous studies in moderate-to-severe plaque psoriasis.

Extension of ustekinumab maintenance dosing interval in moderate-to-severe psoriasis: results of a phase IIIb, randomized, double-blinded, active-controlled, multicentre study (PSTELLAR).

BACKGROUND: Phase III studies showed that some patients maintained response for ≥ 6 months following ustekinumab discontinuation. OBJECTIVES: To assess clinical responses with extended ustekinumab maintenance dosing intervals. METHODS: Adults with moderate-to-severe plaque psoriasis received ustekinumab at weeks 0, 4 and 16 during open-label treatment. Patients achieving a week-28 Physician's Global Assessment (PGA) score of cleared/minimal (PGA = 0/1) were randomized 1 : 4 to group 1 [approved every 12 weeks (q12 wk) maintenance] or group 2 (q12-24 wk; response-based dosing determined by time to loss of PGA = 0/1). Key end points included the number of visits with PGA = 0/1 (primary end point) and ≥ 75% improvement in Psoriasis Area and Severity Index (PASI 75) between weeks 88 and 112, and PGA/PASI responses between weeks 28 and 112. RESULTS: Overall, 378 patients achieved PGA = 0/1 at week 28 and were randomized to group 1 (n = 76) or group 2 (n = 302). Patients in group 1 had numerically greater mean numbers of visits with PGA = 0/1 than group 2 and also with PASI 75 from week 88 to 112. A higher proportion of patients in group 1 (55%) than group 2 (39%) had PGA = 0/1 at all seven visits from week 88 to 112. Maintenance of response was observed with dose-interval extension beyond q12 wk in a subset of patients. Extending the dosing interval did not affect antibody development or safety. CONCLUSIONS: Efficacy was better maintained among week-28 PGA responders randomized to continue q12 wk ustekinumab vs. extending maintenance dosing based on clinical response, although some patients maintained high levels of efficacy with up to q24 wk dosing.

Phase 3, open-label, randomized study of the pharmacokinetics, efficacy and safety of ixekizumab following subcutaneous administration using a prefilled syringe or an autoinjector in patients with moderate-to-severe plaque psoriasis (UNCOVER-A).

BACKGROUND: The efficacy of ixekizumab, an anti-interleukin-17A (anti-IL-17A) monoclonal IgG4 antibody, was demonstrated in moderate-to-severe psoriasis patients when administered via prefilled syringe (PFS). OBJECTIVE: To evaluate the effect of two drug delivery devices on the pharmacokinetics (PK) of ixekizumab as well as efficacy and safety with both devices. METHODS: In the first 12 weeks of an open-label, phase 3 study, moderate-to-severe psoriasis patients were randomized to ixekizumab delivery via PFS or autoinjector device. Randomization was stratified by weight (<80 kg, 80-100 kg, >100 kg), injection assistance (yes/no) and injection site (arm, thigh or abdomen). Following a 160-mg initial dose at week 0, patients received subcutaneous 80-mg ixekizumab as a single injection every 2 weeks for 12 weeks. Blood samples were collected following the initial 160-mg dose on days 2, 4, 7, 10 and 14 for PK analysis. Primary PK parameters were maximum concentration (Cmax ) and area under the curve (AUC0-tlast ) where tlast is the time of last sample (14 days ± 24 h). Efficacy was assessed by percent improvement on the Psoriasis Area and Severity Index (PASI) at week 12. Adverse event reporting, vital signs and clinical laboratory data were used to evaluate safety. RESULTS: Of 204 randomized patients, 192 were included in the PK analysis (PFS: 94; autoinjector: 98). The PFS and autoinjector showed similar geometric mean Cmax (90% CI) [15.0 µg/mL (13.9-16.1) vs. 14.8 µg/mL (13.8-15.9)] and geometric mean AUC0-tlast (90% CI) [157 µg × day/mL (147-168) vs. 154 µg × day/mL (144-165)]. When comparing Cmax and AUC0-tlast of the autoinjector to PFS, the geometric LS mean ratios were 0.97. At week 12, mean percent PASI improvement (via modified baseline observation carried forward) was similar with the PFS (89.3%) and autoinjector (86.9%). Both devices had safety results that were consistent with the known safety profile of ixekizumab. CONCLUSION: The PK, efficacy and safety of ixekizumab administered subcutaneously by PFS and autoinjector were similar. Clinicaltrials.gov number: NCT01777191 https://clinicaltrials.gov/ct2/show/NCT01777191.

Plaque thickness and morphology in psoriasis vulgaris associated with therapeutic response.

BACKGROUND: The Utah Psoriasis Initiative (UPI) is an expanding database that is being used to identify and characterize phenotypic variants of psoriasis and explore genotype-phenotype relationships. We recently reported distinct morphological variants of psoriasis that are characterized by thickness of lesions (induration) in the untreated state. OBJECTIVES: To explore the clinical relevance of these morphological variants. METHODS: For these analyses, we used the phenotypic data from 282 additional subjects gathered at enrollment into the UPI and compared their phenotype with that of the original 500 patients reported previously. The analysis was further expanded via a longitudinal follow-up of 286 subjects from the original 500 case cohort. RESULTS: Firstly, the initial findings were confirmed. Expansion of the cohort used for the original observation by about 50% and reanalysis showed that there was no alteration in the proportions of patients expressing thin- and thick-plaque disease phenotypes. Secondly, analysis of the larger cohort showed that this morphological phenotype had clinical relevance: those patients with thin-plaque disease were more likely to report a complete therapeutic response to topical corticosteroids and phototherapy. In contrast, plaque thickness did not appear to be a factor in response to systemic agents. CONCLUSIONS: Using a patient's baseline plaque morphology to choose a primary treatment modality may result in earlier disease improvement and reduce the cost of therapy.

Detailed genetic characterization of the interleukin-23 receptor in psoriasis.

Using a multi-tiered, case-control association design, scanning 25 215 gene-centric SNPs, we previously identified two psoriasis susceptibility genes: IL12B and IL23R. These results have recently been confirmed. To better characterize the IL23R psoriasis-association, we used a fine mapping strategy to identify 59 additional IL23R-linked SNPs, which were genotyped in our three independent, white North American sample sets (>2800 individuals in toto). A sliding window of haplotype association demonstrates colocalization of psoriasis susceptibility effects within the boundaries of IL23R across all sample sets, thereby decreasing the likelihood that neighboring genes, particularly IL12RB2, are driving the association at this region. Additional haplotype work identified two 5-SNP haplotypes with strong protective effects, consistent across our three sample sets (OR(common)=0.67; P(comb)=4.32E-07). Importantly, heterogeneity of effect was extremely low between sample sets for these haplotypes (P(Het)=0.961). Together, these protective haplotypes attain a frequency of 16% in controls, declining to 11% in cases. The characterization of association patterns within IL23R to specific predisposing/protective variants will play an important role in the elucidation of psoriasis etiology and other related phenotypes. Further, this work is essential to lay the foundation for the role of IL23R genetics in response to pharmaceutical therapy and dosage.

Variants in the 5q31 cytokine gene cluster are associated with psoriasis.

A multitiered genetic association study of 25 215 single-nucleotide polymorphisms (SNPs) in three case-control sample sets (1446 patients and 1432 controls) identified three IL13-linked SNPs (rs1800925, rs20541 and rs848) associated with psoriasis. Although the susceptibility effects at these SNPs were modest (joint allelic odds ratios (ORs): 0.76 to 0.78; P(comb): 1.3E-03 to 2.50E-04), the association patterns were consistent across the sample sets, with the minor alleles being protective. Haplotype analyses identified one common, susceptible haplotype CCG (joint allelic OR=1.27; P(comb)=1.88E-04) and a less common, protective haplotype TTT (joint allelic OR=0.74; P(comb)=7.05E-04). In combination with the other known genetic risk factors, HLA-C, IL12B and IL23R, the variants reported here generate an 11-fold psoriasis-risk differential. Residing in the 5q31 cytokine gene cluster, IL13 encodes an important T-cell-derived cytokine that regulates cell-mediated immunity. These results provide the foundation for additional studies required to fully dissect the associations within this cytokine-rich genomic region, as polymorphisms in closely linked candidate genes, such as IRF1, IL5 or IL4, may be driving these results through linkage disequilibrium.