A Genome-Wide Association Study Identifying SVEP1 Variant as a Predictor of Response to Tolvaptan for Cirrhotic Ascites

Abstract

Background and Aims: Tolvaptan, an orally active vasopressin V2-receptor antagonist, has been used for patients with difficult-to-treat ascites in Japan. In this study, we conducted a genome-wide association study (GWAS) in the Japanese population to identify genetic variants associated with tolvaptan’s efficacy for patients with hepatic ascites. Methods: From 2014 through 2018, genomic DNA samples were obtained from 550 patients who were treated with tolvaptan. Of those, 80 cases (non-responder; increase of body weight [BW]) and 333 controls (responder; > 1.5 kg decrease of BW) were included in the GWAS and replication study. Results: GWAS showed 5 candidate SNPs around the miR818, KIAA1109, and SVEP1 genes. After validation and performing a replication study, an SNP (rs2991364) located in the SVEP1 gene was found to have a significant genome-wide association (OR = 3.55, P = 2.01 x 10− 8). Univariate and multivariate analyses showed that blood urea nitrogen (BUN) and SVEP1 SNP were significantly associated with the response (OR = 1.03, p = 0.02 and OR = 4.24, p < 0.0001, respectively). Based on a prediction model of logistic regression analysis in a population with the rs2991364 risk allele, the failure probability (= exp (score: 22.234 + BUN*0.077 + Na*-0.179) (1 + exp (score)) was determined for the detection of non-responders. Assuming a cutoff of failure probability at 38.6%, sensitivity was 84.4%, specificity was 70% and AUC was 0.774. Conclusion: SVEP1 rs2991364 was identified as the specific SNP for the tolvaptan response. The prediction score can identify tolvaptan non-responders and help to avoid a lengthy period of futile treatment.