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Entecavir Study Continues to Show Low Incidence of Resistance Through Five Years of Treatment
In lamivudine-refractory patients who received BARACLUDE after treatment with lamivudine failed, the cumulative probability of genotypic BARACLUDE resistance was 51 percent through the fifth year. This finding is consistent with prior observations that the pre-existence of lamivudine-resistant mutations results in an increase in the rate of BARACLUDE resistance.
"Many chronic hepatitis B patients require long-term treatment. Unfortunately, the initial benefits of therapy can be lost after the development of resistance. These five-year BARACLUDE data that demonstrate long-term minimal resistance at 1.2 percent in nucleoside-naive patients can be of great importance for patients," said Professor Ching-Lung Lai, Chief, Division of Gastroenterology and Hepatology, University of Hong Kong.
Drug resistance occurs when the hepatitis B virus (HBV) mutates, thereby avoiding the effects of the medication. This can decrease the efficacy of the current medication and may compromise future treatment options. To date, studies have shown that multiple mutations are required to develop BARACLUDE(R) (entecavir) resistance.
"These long-term BARACLUDE data continue to support the observations seen in the first years of treatment and are reflective of BARACLUDE's high genetic barrier to resistance," said Helena Brett-Smith, M.D., Group Director of Clinical Research at Bristol-Myers Squibb. "More importantly, we believe the data support BARACLUDE as an important initial treatment choice for chronic hepatitis B, which is a disease that results in a large global health burden."
About the Analysis
More than 700 patients across six studies initiated therapy on BARACLUDE and were monitored for treatment response and resistance.
The year five analysis expands upon previous analyses, adding in information on patients who received treatment with BARACLUDE during the fifth year of follow-up (n=108 for patients in nucleoside-naive studies and n=33 for patients in lamivudine-refractory studies).
In this comprehensive analysis, all patients enrolled in Bristol-Myers Squibb clinical trials ETV-014, -015, -022, -027, -026 and -901 who experienced a virologic breakthrough(1) or whose virus had not yet reached undetectable levels(2) at weeks 48, 96, 144, 192, 240 or end of dosing, were sequenced to determine if any changes occurred in the genetic code of the virus that would result in resistance or loss of effectiveness of BARACLUDE.
Nucleoside-naive patients in this analysis were initially treated with BARACLUDE 0.5 mg in studies ETV-022 and -027 and continued treatment with BARACLUDE 1 mg by enrolling in study ETV-901 with a treatment gap of less than or equal to 35 days. Lamivudine-refractory patients in this analysis initiated therapy on BARACLUDE 1 mg in studies ETV-014, -015, and -026 and continued treatment in study ETV-901 with a treatment gap of less than or equal to 35 days.
Viral load reduction in chronic hepatitis B patients treated with BARACLUDE(R) (entecavir) in nucleoside-naive and lamivudine-refractory studies was also evaluated.
Results from these studies prior to this year five analysis were previously announced on April 14, 2007.
-- The incidence of BARACLUDE resistance in patients in nucleoside-naive studies over time is low, with a cumulative probability of genotypic BARACLUDE resistance of 1.2 percent through five years.
-- No nucleoside-naive patient developed resistance (n=108) in year five.
-- 93 percent of the nucleoside-naive patients taking BARACLUDE were able to achieve and maintain an undetectable viral load (HBV DNA Lamivudine-refractory data
-- The results in lamivudine-refractory patients in years one through five were consistent with the finding that the pre-existence of lamivudine-resistant substitutions resulted in an increase in the emergence of BARACLUDE resistance, with a cumulative probability of genotypic resistance of 51 percent through five years.
-- In year five, 43 percent of lamivudine-refractory patients had virologic breakthrough with BARACLUDE resistance (n=33).
-- During this resistance monitoring program, 68 of the 187 lamivudine-refractory patients achieved undetectable viral load (
Source: Bristol-Myers Squibb