Hepatitis B surface antigen quantification as a predictor of seroclearance during treatment in HIV-hepatitis B virus coinfected patients from Sub-Saharan Africa

Background and Aim: In Sub-Saharan Africa, seroclearance of hepatitis B surface antigen (HBsAg) and hepatitis B "e" antigen (HBeAg), including their quantifiable markers, have rarely been evaluated during long-term antiviral treatment among patients coinfected with HIV and hepatitis B virus (HBV). Methods: In this prospective cohort study from two randomized-control trials in Côte d'Ivoire, 161 antiretroviral-naïve HIV-HBV coinfected patients starting lamivudine (n=76) or tenofovir/emtricitabine (n=85) containing antiretroviral therapy were included. HBV DNA was quantified using an in-house assay (detection limit=12copies/mL) and HBsAg quantification (qHBsAg) using the Elecsys assay. Results: Overall, 33 (20.5%) patients were HBeAg positive, 121 (75.2%) had detectable HBV DNA, and 92/93 (98.9%) harbored HBV genotype E. Median treatment duration was 35.5months (interquartile range: 24.3-36.4). Among HBeAg-positive patients, cumulative proportion with HBeAg seroclearance was 46.3% (n=14). Overall, cumulative proportion of HBsAg seroclearance was 6.6% (n=10). Lower baseline qHBsAg levels and strong 12-month declines in qHBsAg were significantly associated with HBsAg seroclearance for both HBeAg-negative and HBeAg-positive patients. When taken at certain levels, these determinants provided moderate sensitivity (Se) and specificity (Sp) in predicting HBsAg seroclearance at month 36 (≤1000IU/mL at baseline, Se=0.80, Sp=0.80; ≥1.0log10IU/mL drop at month 12, Se=0.57, Sp=1.00). Instead, qHBsAg levels ≤100 or ≤10IU/mL at month 12 were optimal (both Se=0.90 and Sp=1.00). Detectable HBV-DNA provided fairly high Se and Sp when evaluated at baseline (Se=1.00, Sp=0.80), but not at month 12 (Se=0.80, Sp=0.40). Conclusions: HBsAg seroclearance rates are not common in patients from Sub-Saharan Africa treated with anti-HBV containing antiretroviral therapy. qHBsAg levels at 12months of treatment may accurately predict HBsAg seroclearance.