Quantification of plasma hdv rna in untreated and bulevirtide-treated patients with chd: a comparison between robogene 2.0 and eurobioplex

Background and Aim Accurate HDV-RNA quantification is crucial for diagnosis and management of chronic hepatitis Delta, yet variability between assays exist. We compared three methods to quantify HDV-RNA in untreated and Bulevirtide (BLV)-treated CHD patients. Methods Frozen plasma from untreated and BLV–treated CHD patients were tested in a single-center retrospective study: Robogene HDV-RNA Quantification Kit 2.0 (Roboscreen GmbH; LOD 6 IU/mL on 7500 Fast Real-Time PCR System [Applied Byosystem]), EurobioPlex HDV PCR quantitative (Eurobio Scientific, LOD 100 IU/m) on CFX96™ real-time PCR detection system [Bio-Rad]) and AltoStar HDV RT-PCR Kit 1.5 (Altona Diagnostics; RUO test, estimated LOD <10 IU/mL). Results Overall, 429 plasma samples from 130 CHD (69 untreated and 61 BLV-treated) patients were studied. Median HDV-RNA were higher with Robogene than EurobioPlex [3.78 (0.70-7.99) vs. 4.69 (2.00-8.19) Log IU/mL, p<0.0001]. Compared to Robogene 2.0, EurobioPlex reported similar HDV-RNA (Δ ± 0.5 Log) in 66 (28%) patients but higher >0.5 Log in 160 (69%). Viremia was lower with Robogene than AltoStar [3.32 (0.70-7.37) vs. 3.91 (0.19-7.54) Log IU/mL, p<0.0001]. AltoStar reported HDV-RNA levels >0.5 Log in 127 (52%). Virological response at week 24 (Robogene vs. Eurobio and AltoStar) and 48 (Robogene vs. AltoStar) did not differ. HDV-RNA undetectability rates at week 24 were 11% vs. 33% with Robogene vs. EurobioPlex, and 11% vs. 3% Robogene vs. AltoStar. At week 48, 18% vs. 4% Robogene vs. AltoStar. 47 on-treatment samples were analyzed with the three tests: HDV-RNA levels were 3.04 (0.70-6.20) IU m/l vs. 3.62 (2.00-7.12) vs. 3.37 (0.28-6.45) IU/mL with Robogene vs. EurobioPlex vs. AltoStar, respectively (p=0.36). At week 72 HDV-RNA was undetectable in 42%, 83% and 25% of patients, respectively. Conclusions HDV-RNA levels quantified by EurobioPlex and Altostar were 1 and 0.5 logs higher than Robogene 2.0, respectively. HDV-RNA undetectability rates during BLV differed according to the method.