Importance: Previous research showed a differential response to ustekinumab therapy based on HLA-C*06:02 status in patients with psoriasis but consisted mostly of small (and sometimes inconclusive) cohort studies.
Objective: To assess whether HLA-C*06:02 status is associated with a differential response to ustekinumab therapy in patients with psoriasis through a systematic review and a meta-analysis of available data.
Data sources: A comprehensive search was conducted using MEDLINE, Embase, the Cochrane Library, Web of Science, and gray literature sources. Databases were searched from January 1, 2000, to May 14, 2018. Search strategies included terms and synonyms for psoriasis, HLA-C, and ustekinumab. Languages were restricted to English, French, German, and Dutch.
Study selection: Studies were included if they reported the association between HLA-C*06:02 status and 75% improvement in Psoriasis Area and Severity Index (PASI75) response to ustekinumab therapy in patients with plaque psoriasis after 6 and/or 3 months of treatment. Randomized clinical trials and observational studies were included. Screening and selection were performed independently by 2 reviewers.
Data extraction and synthesis: HLA-C*06:02 genotype status and PASI75 response rates were extracted by 2 reviewers. Data were pooled using random-effects models. Heterogeneity was assessed using the τ2 and I2 statistic. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines were followed.
Main outcome and measure: The primary outcome was the risk difference of achieving PASI75 after 6 months of ustekinumab therapy between HLA-C*06:02-positive and HLA-C*06:02-negative patients.
Results: A total of 8 studies were reviewed; 1048 patients were included for meta-analyses, and 937 patients were included for the primary analysis of PASI75 response after 6 months of treatment. Random-effects meta-analysis showed a risk difference of 0.24 (95% CI, 0.14-0.35; P < .001) in favor of HLA-C*06:02-positive patients. The median PASI75 response rate in the HLA-C*06:02-positive group was 92% (pooled, 89%; range, 62%-98%). For HLA-C*06:02-negative patients, the median response rate was 67% (pooled, 62%; range, 40%-84%). Substantial heterogeneity may have been present, with an I2 of 82%.
Conclusions and relevance: The meta-analysis showed a differential response to ustekinumab therapy based on HLA-C*06:02 status in patients with psoriasis. Although HLA-C*06:02-positive patients had high PASI75 response rates after 6 months, the PASI75 response rate was also high in the HLA-C*06:02-negative group. There appears to be no rationale for excluding patients from ustekinumab treatment based on a negative HLA-C*06:02 status.