Sodium taurocholate cotransporting polypeptide (NTCP) polymorphisms may influence HDV RNA load and early response to bulevirtide

Background & Aims Sodium taurocholate cotransporting peptide (NTCP) genetic polymorphisms have been described, but their role in untreated and treated patients with Chronic Hepatitis Delta (CHD) remains unknown. Virological response (VR) to NTCP inhibitor Bulevirtide (BLV) was achieved at week 48 by >70% of CHD patients, but nearly 15% experienced virological nonresponse (VNR) or partial response (PR). This study aimed to evaluate whether NTCP genetic polymorphisms affect baseline HDV RNA load and response to BLV in CHD patients. Methods Untreated and BLV treated patients were enrolled in a retrospective cross-sectional and longitudinal study. Clinical and virological characteristics were collected at baseline and up to 96 weeks in the BLV-treated patients. NTCP genetic polymorphisms were identified by Sanger sequencing. Results Of the 6 NTCP polymorphisms studied in 209 CHD untreated patients, carriers of rs17556915 TT/CC (N=142) compared to CT (N=67) genotype presented higher median HDV RNA levels (5.39 vs. 4.75 log10 IU/mL, p=0.004). 76 out of 209 patients receiving BLV monotherapy at 2 mg/day were evaluated at week 24 and 40 of them up to week 96. Higher mean baseline HDV RNA levels were confirmed in TT/CC (N=43) compared to CT (N=33) carriers (5.38 vs. 4.72 log10 IU/mL, p=0.010). Although 24-week VR was comparable between TT/CC and CT carriers (25/43 vs. 17/33, p=0.565), the former group presented VNR more often than PR (9/11 vs. 9/23, p=0.02) at week 24. 7/9 TT/CC genotype carriers remained VNR at week 48 of BLV treatment. Conclusions The NTCP rs17556915 C>T genetic polymorphisms may influence baseline HDV RNA load both in untreated and BLV treated patients with CHD and may contribute to identify patients with different early virological responses to BLV.