Validation of a stopping rule at week 12 using HBsAg and HBV DNA for HBeAg-negative patients treated with peginterferon alfa-2a

Abstract

It was recently demonstrated that none of the hepatitis B e antigen (HBeAg)-negative patients without any serum hepatitis B surface antigen (HBsAg) decline and with <2log hepatitis B virus (HBV) DNA decline at week 12 of a 48-week peginterferon alfa-2a (PEG-IFN) treatment course achieved a sustained response (SR). We aimed at validating this stopping rule in two independent trials. HBeAg-negative patients receiving 48 or 96 weeks of PEG-IFN in the phase III registration trial (N=85) and PegBeLiver study (N=75) were stratified according to the presence of any HBsAg decline and/or 2log HBV DNA decline at week 12. SR was defined as HBV DNA <2000IU/ml and normal alanine aminotransferase 24 weeks after treatment. The original PARC trial included 102 patients (genotype A/D/other: 14/81/7), 25 (25%) had an SR. The validation dataset consisted of 160 patients (genotype A/B/C/D/other: 10/18/34/91/7), 57 (36%) achieved an SR. The stopping rule performed well across the two studies (p=0.001) and its negative predictive value [NPV] was 95% in the validation dataset harbouring genotypes A-D. Its performance was best for genotype D. Moreover, among the 34 patients treated for 96 weeks, none of the 7 (21%) without HBsAg decline and with <2log HBV DNA decline at week 12 achieved an SR (NPV 100%). We confirmed in two independent studies that the combination of HBsAg and HBV DNA levels at week 12 identifies HBeAg-negative patients with a very low chance of SR to either 48 or 96 weeks of PEG-IFN therapy.