Entecavir is significantly better at suppression of viral load to undetectable levels than lamivudine in two types of patients with chronic hepatitis B infection, according to a pair of presentations at Digestive Disease Week.

Study ETV-027 was a large-scale, multinational, Phase III clinical trial of 638 HBe antigen-negative chronic hepatitis B patients who had not previously received nucleoside treatment. In the study, 235 patients received entecavir 0.5 mg once daily and 313 received lamivudine 100 mg once daily for a minimum of 52 weeks. At Week 52, patients were categorized based on evaluations at Week 48: non-responders, who discontinued treatment; responders, who discontinued treatment and were followed for 24 weeks off-treatment; and virologic responders, who received blinded treatment up to Week 96.

In a cumulative analysis of all patients treated through 96 weeks, 94 percent of patients in the entecavir treatment group had virologic suppression to undetectable levels compared with 77 percent of patients given lamivudine. Additionally, the proportion of patients achieving or maintaining liver enzyme level normalization was 89 percent for entecavir compared with 84 percent for lamivudine.

No evidence of BARACLUDE resistance was identified in patients treated for up to 96 weeks who had no prior lamivudine-resistance substitutions at baseline.

As part of Study ETV-026, a multinational Phase III clinical trial, 286 lamivudine-refractory, 141 HBe antigen-positive chronic hepatitis B patients were randomized to receive entecavir 1.0 mg once daily and 145 to continued lamivudine 100 mg once daily for a minimum of 52 weeks.

At Week 52, patients were categorized based on evaluations at Week 48: non-responders discontinued treatment; responders discontinued treatment and were followed for 24 weeks off-treatment; virologic responders received blinded treatment up to Week 96.

In a cumulative analysis of all patients treated through 96 weeks, 30 percent of entecavir patients compared to less than 1 percent of lamivudine patients achieved an undetectable viral load. The difference was statistically significant . Additionally, 17 percent of entecavir patients compared with 6 percent of lamivudine patients experienced HBe Antigen seroconversion. The proportion of patients achieving liver enzyme normalization was significantly greater for patients treated with entecavir (85 percent) than for lamivudine (29 percent).

Viral rebound due to entecavir resistance mutations occurred in 9 percent of lamivudine-refractory patients during the second year of treatment.

"It is increasingly recognized that hepatitis B viral load is an important evaluation tool for physicians when assessing, monitoring, and managing patients," said Morris Sherman, MD, an entecavir study investigator and associate professor of medicine at the University of Toronto.