In a previous post (Extended data with entecavir & annotated HBV management …) good news on the long term use of entecavir was reported. Another large study indicates that entecavir (ETV) monotherapy generally produces equivalent results to combination therapy with tenofovir (TDF) (Gastroenterol 2012; 143: 619-28).
The authors report their experience with a randomized open-label multi center study with 379 nucleos(t)ide-naive patients; 264 were HBeAg-positive and 115 were HBeAg-negative. At week 96, among all patients, virology response defined as HBV DNA <50 IU/mL was 76.4% in the ETV group and 83.2% in the ETV-TDF group.
In multiple comparisons, the combination group tended to have better virological response except in the HBeAg-negative group (91.1% ETV vs. 89.8% in ETV-TDF). The other comparisons included the HBeAg-positive group (69.8% ETV vs. 80.4% ETV-TDF), low baseline HBV DNA (<10 to the 8th IU/mL) (83% in both groups), and the high baseline HBV DNA (62.0% ETV vs. 78.8% ETV-TDF). Yet, the only group where this was statistically significant was those with high baseline HBV DNA, n= 164 (>10 to the 8th IU/mL).
Biological response was greater in the ETV monotherapy, 81.9% compared with 69% in the combination group. Among HBeAg+ patients, loss of e antigen was comparable: 38.9% in ETV compared with 29.7% in ETV-TDF. In this group, seroconversion to HBeAb+ occurred in 32.5% of ETV compared with 21.7% of combination patients.
Safety: five patients in combination group and two patients in ETV monotherapy group discontinued treatment due to adverse events. Three deaths occurred in the combination group (either on treatment or during followup), with the following causes: cardiac arrest, bile duct tumor, and liver failure. In the patient with liver failure, she had responded to therapy but experienced a breakthrough at week 48. At week 100, she was switched to commercial treatment. Five days later she was hospitalized and died within 1 week. No resistance to either drug was identified. Thus, the authors speculate that nonadherence was an important factor. Also, during the course of the study, five malignancies were diagnosed, including 3 with HCC.