Predictors of successful nucleo(s)tide analogue (NA) therapy withdrawal remain elusive. We studied the relationship between end-of-treatment levels of hepatitis B core-related antigen (HBcrAg) and hepatitis B surface antigen (HBsAg) and outcome after therapy cessation.
Patients who discontinued NA therapy in centers in Asia and Europe were enrolled. HBcrAg and HBsAg were measured at treatment cessation, and associations with off-treatment outcomes were explored. The SCALE-B score was calculated as previously reported. End points included sustained virologic response (VR; hepatitis B virus DNA level <2000 IU/mL), HBsAg loss, and alanine aminotransferase (ALT) flares (>3× upper limit of normal). Re-treated patients were considered nonresponders.
We analyzed 572 patients, 457 (80%) were Asian and 95 (17%) were hepatitis B e antigen positive at the start of NA therapy. The median treatment duration was 295 weeks. VR was observed in 267 (47%), HBsAg loss was observed in 24 (4.2%), and ALT flare was observed in 92 (16%). VR (67% vs 42%) and HBsAg loss (15% vs 1.5%) was observed more frequently in non-Asian patients (P < .001). Lower HBcrAg levels were associated with higher rates of VR (odds ratio [OR], 0.701; P < .001) and HBsAg loss (OR, 0.476; P < .001), and lower rates of ALT flares (OR, 1.288; P = .005). Similar results were observed with HBsAg (VR: OR, 0.812; P = .011; HBsAg loss: OR, 0.380; P < .001; and ALT flare: OR, 1.833; P < .001). Lower SCALE-B scores were associated with higher rates of VR, HBsAg loss, and lower rates of ALT flares in both Asian and non-Asian patients (P < .001).
In this multicenter study, off-treatment outcomes after NA cessation varied with ethnicity. Lower levels of HBcrAg and HBsAg were associated with favorable outcomes. A risk score comprising both factors can be used for risk stratification.