HepatologyVolume 51, Issue 2 p. 422-430 Viral HepatitisFree Access Entecavir treatment for up to 5 years in patients with hepatitis B e antigen–positive chronic hepatitis B†‡§ Ting-Tsung Chang, Corresponding Author Ting-Tsung Chang [email protected] Medical College, National Cheng Kung University, Tainan, Taiwan, ROC fax: +886-6-209-5233138 Sheng-Li Road, Tainan, 70428, Taiwan, Republic of China===Search for more papers by this authorChing-Lung Lai, Ching-Lung Lai Queen Mary Hospital, Hong Kong, ChinaSearch for more papers by this authorSeung Kew Yoon, Seung Kew Yoon Kangnam St. Mary Hospital, The Catholic University of Korea, Seoul, KoreaSearch for more papers by this authorSamuel S. Lee, Samuel S. Lee Foothills Provincial General Hospital, University of Calgary, Calgary, CanadaSearch for more papers by this authorHenrique Sergio M. Coelho, Henrique Sergio M. Coelho Hospital Universitario Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, BrazilSearch for more papers by this authorFlair Jose Carrilho, Flair Jose Carrilho Department of Gastroenterology, University of São Paulo School of Medicine, São Paulo, SP, BrazilSearch for more papers by this authorFred Poordad, Fred Poordad Department of Hepatology and Liver Transplantation, Cedars-Sinai Medical Center, Los Angeles, CASearch for more papers by this authorWaldemar Halota, Waldemar Halota Department of Infectious Diseases and Hepatology, Nicolaus Copernicus University, Bydgoszcz, PolandSearch for more papers by this authorYves Horsmans, Yves Horsmans Department of Hepatology and Gastroenterology, Cliniques St Luc, Brussels, BelgiumSearch for more papers by this authorNaoky Tsai, Naoky Tsai University of Hawaii, Honolulu, HISearch for more papers by this authorHui Zhang, Hui Zhang Bristol-Myers Squibb Co. (BMS), Research and Development, Wallingford, CTSearch for more papers by this authorDaniel J. Tenney, Daniel J. Tenney Bristol-Myers Squibb Co. (BMS), Research and Development, Wallingford, CTSearch for more papers by this authorRicardo Tamez, Ricardo Tamez Bristol-Myers Squibb Co., Research and Development, Princeton, NJSearch for more papers by this authorUchenna Iloeje, Uchenna Iloeje Bristol-Myers Squibb Co. (BMS), Research and Development, Wallingford, CTSearch for more papers by this author Ting-Tsung Chang, Corresponding Author Ting-Tsung Chang [email protected] Medical College, National Cheng Kung University, Tainan, Taiwan, ROC fax: +886-6-209-5233138 Sheng-Li Road, Tainan, 70428, Taiwan, Republic of China===Search for more papers by this authorChing-Lung Lai, Ching-Lung Lai Queen Mary Hospital, Hong Kong, ChinaSearch for more papers by this authorSeung Kew Yoon, Seung Kew Yoon Kangnam St. Mary Hospital, The Catholic University of Korea, Seoul, KoreaSearch for more papers by this authorSamuel S. Lee, Samuel S. Lee Foothills Provincial General Hospital, University of Calgary, Calgary, CanadaSearch for more papers by this authorHenrique Sergio M. Coelho, Henrique Sergio M. Coelho Hospital Universitario Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, BrazilSearch for more papers by this authorFlair Jose Carrilho, Flair Jose Carrilho Department of Gastroenterology, University of São Paulo School of Medicine, São Paulo, SP, BrazilSearch for more papers by this authorFred Poordad, Fred Poordad Department of Hepatology and Liver Transplantation, Cedars-Sinai Medical Center, Los Angeles, CASearch for more papers by this authorWaldemar Halota, Waldemar Halota Department of Infectious Diseases and Hepatology, Nicolaus Copernicus University, Bydgoszcz, PolandSearch for more papers by this authorYves Horsmans, Yves Horsmans Department of Hepatology and Gastroenterology, Cliniques St Luc, Brussels, BelgiumSearch for more papers by this authorNaoky Tsai, Naoky Tsai University of Hawaii, Honolulu, HISearch for more papers by this authorHui Zhang, Hui Zhang Bristol-Myers Squibb Co. (BMS), Research and Development, Wallingford, CTSearch for more papers by this authorDaniel J. Tenney, Daniel J. Tenney Bristol-Myers Squibb Co. (BMS), Research and Development, Wallingford, CTSearch for more papers by this authorRicardo Tamez, Ricardo Tamez Bristol-Myers Squibb Co., Research and Development, Princeton, NJSearch for more papers by this authorUchenna Iloeje, Uchenna Iloeje Bristol-Myers Squibb Co. (BMS), Research and Development, Wallingford, CTSearch for more papers by this author First published: 25 January 2010 https://doi.org/10.1002/hep.23327Citations: 447 † Potential conflicts of interest: Ting-Tsung Chang: Research support from Bristol-Myers Squibb; Ching-Lung Lai: Research support and consultancy fees from Bristol-Myers Squibb. SeungKew Yoon: Nothing to disclose. Samuel S. Lee: Consultancy fees from Roche, Gilead, Bristol-Myers Squibb, and Novartis. Speakers' bureau for Roche, Gilead, and Bristol-Myers Squibb. Henrique Sergio M Coelho: Nothing to disclose. Flair Jose Carrilho: Research support from Bristol-Myers Squibb. Fred Poordad: Research support, speakers' bureau fees, and consultancy fees from Bristol-Myers Squibb. Waldemar Halota: Nothing to disclose. Yves Horsmans: Consultancy fees from Bristol-Myers Squibb. Naoky Tsai: Research support, speakers' bureau fees, and consultancy fees from Bristol-Myers Squibb. Hui Zhang: BMS employee. Daniel J. Tenney: BMS employee. Ricardo Tamez: BMS employee. Uchenna Iloeje: BMS employee. ‡ In addition to the authors, the following investigators participated in the study: Asia/Pacific: Nurul Akbar, Marilyn Arguillas, You-Chen Chao, Su-Kiun Chin, Kwang-Hyub Han, Simon Huang, Ian Kronborg, Alice Lee, Jacob George, Sik-To Lai, Shou-Dong Lee, Yun-Fan Liaw, Chee Chian Lim, Gin-Ho Lo, Yiu Wing Luk, George Marinos, Ismail Merican, Rosmawati Mohamed, Eng Keat Ooi, Stuart Roberts, William Sievert, Jose Sollano, Chee Kiat Tan, Judy Lao-Tan, Tawesak Tanwandee, Shun-Sheng Wu, Felix Zano. Europe and Middle East: Edward Antuch, Yucel Batur, Anna Boron-Kaczmarska, Pavel Chalupa, Isabelle Colle, Andrzej Gladysz, Barbara Gocman, Zbigniew Gonciarz, Markus H. Heim, Vasily Isakov, Ran Tur-Kaspa, Sabahattin Kaymakoglu, Wieslaw Kryczka, Jan Kuydowicz, Yoav Lurie, Tomasz Mach, Francesco Mazzotta, Roma Modrzewska, Beat Muellhaupt, Assy Nimer, Court Pedersen, Vladimir Rafalsky, Maria Raptopoulou-Gigi, Daniel Shouval, Marian Sikora, Cihan Yurdaydin, Konstantin Zhdanov. USA and Canada: Frank H. Anderson, Thomas Boyer, Robert Brown, Robert G. Gish, Anna Lok, Gerald Minuk, Raymond Rubin, Eugene Schiff, Morris Sherman. Latin America: Antonio A. Barone, Fernando Bessone, Hugo Cheinquer, Laura E. Cisneros Garza, Luiz Guilherme Costa Lyra, Hugo Fainboim, Jorge Ferrandiz, Maria Lucia Ferraz, Fernando L. Goncales, Jr, Mario Pessoa, Marcelo Silva, Ruben Terg. § The sponsor designed the study in collaboration with expert hepatologists. The sponsor also collected the data, monitored study conduct, performed the statistical analyses, and coordinated writing of the article with all authors. AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract Sustained virologic suppression is a primary goal of therapy for chronic hepatitis B (CHB). In study entecavir (ETV)-022, 48 weeks of entecavir 0.5 mg was superior to lamivudine for virologic suppression for hepatitis B e antigen (HBeAg)-positive CHB. A total of 183 entecavir-treated patients from ETV-022 subsequently enrolled in study ETV-901. We present the results after up to 5 years (240 weeks) of continuous entecavir therapy. The entecavir long-term cohort consists of patients who received ≥1 year of entecavir 0.5 mg in ETV-022 and then entered ETV-901 with a treatment gap ≤35 days. In ETV-901 the entecavir dose was 1.0 mg daily. For patients with samples available at Year 5, proportions with hepatitis B virus (HBV) DNA <300 copies/mL, normal alanine aminotransferase (ALT) levels, HBeAg loss, and HBeAg seroconversion were determined. In all, 146 patients met criteria for inclusion in the entecavir long-term cohort. At Year 5, 94% (88/94) had HBV DNA <300 copies/mL and 80% (78/98) had normal ALT levels. In addition to patients who achieved serologic responses during study ETV-022, 23% (33/141) achieved HBeAg seroconversion and 1.4% (2/145) lost hepatitis B surface antigen (HBsAg) during study ETV-901. Through 5 years, entecavir resistance emerged in one patient. The safety profile of entecavir was consistent with previous reports. Conclusion: Extended therapy with entecavir through 5 years maintained or increased rates of HBV DNA suppression and ALT normalization. Additional patients also achieved HBeAg loss and seroconversion. Entecavir provides sustained viral suppression with minimal resistance during long-term treatment of HBeAg-positive CHB. (HEPATOLOGY 2010.) Chronic hepatitis B (CHB) affects over 350 million people worldwide. Long-term complications of infection include cirrhosis and hepatocellular carcinoma (HCC), which together cause over 500,000 deaths annually.1, 2 CHB patients with an elevated viral load (ongoing viral replication) have the highest risk of progressing to these life-threatening complications.3, 4 To avoid or minimize liver disease progression, CHB treatment recommendations now stress the importance of long-term maintenance of hepatitis B virus (HBV) DNA suppression.5-7 Medications currently approved for the treatment of hepatitis B e antigen (HBeAg)-positive CHB include standard interferon-α, pegylated interferon-α, lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate. Treatment with standard or pegylated interferon has been shown to result in durable serologic responses (HBeAg seroconversion) in HBeAg-positive patients, but these therapies are limited by the need for parenteral administration and a high incidence of adverse events.8-10 Lamivudine has demonstrated efficacy and safety, but the benefits of treatment have limited durability as resistance reaches ≈70% after 4 years of therapy.11 Current CHB treatment guidelines recommend against the use of lamivudine as first-line therapy due to its high rate of resistance.5, 6 Although telbivudine demonstrated greater suppression of HBV DNA than lamivudine, monitoring in patients with virologic breakthrough showed that resistance exceeds 20% among HBeAg-positive patients treated for 2 years.12, 13 Treatment with adefovir for 48 weeks resulted in HBV DNA suppression to <400 copies/mL in only 13% of HBeAg-positive patients,14 and resistance has been shown to develop in 20% of HBeAg-positive patients after 5 years.15 Tenofovir treatment for HBeAg-positive CHB achieves high levels of virologic suppression, but at this time, efficacy and resistance data have only been reported through 96 weeks (2 years).16, 17 Entecavir demonstrated superior histologic, virologic, and biochemical benefit compared to lamivudine after 48 weeks in entecavir (ETV)-022, a study conducted in nucleoside-naïve HBeAg-positive CHB patients.18 In a blinded extension of this study, which evaluated continued entecavir or lamivudine treatment through 96 weeks, increasing numbers of entecavir-treated patients experienced virologic, biochemical, and HBeAg serologic responses, with a safety profile comparable to that of lamivudine.19 The current report presents efficacy and safety results for HBeAg-positive patients who received a minimum of 52 weeks of blinded entecavir treatment in study ETV-022 (www.clinicaltrials.gov identifier: NCT00036608), and subsequently received open-label entecavir in rollover study ETV-901 for a cumulative total duration of up to 5 years (240 weeks). Abbreviations ALT, alanine aminotransferase; bDNA, branched DNA; CHB, chronic hepatitis B; ETV, entecavir; HBeAg, hepatitis B e antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; PCR, polymerase chain reaction; ULN, upper limit of normal. Patients and Methods Study Design. Study ETV-022 was a randomized, double-blind comparison of entecavir and lamivudine for up to 96 weeks in nucleoside-naïve patients with HBeAg-positive CHB.18, 19 A total of 715 patients were enrolled at 137 centers worldwide between December 2001 and September 2002. Patients were randomized to receive entecavir 0.5 mg or lamivudine 100 mg once daily for a minimum of 52 weeks. Patients classified as responders (HBV DNA <0.7 MEq/mL and HBeAg loss) or nonresponders (HBV DNA ≥0.7 MEq/mL) at Week 48 discontinued therapy at Week 52. Responders were followed off-treatment for 24 weeks and nonresponders were offered enrollment into rollover study ETV-901 or, at the discretion of the investigator, alternative off-study anti-HBV therapy. Patients who achieved a protocol-defined virologic response (serum HBV DNA <0.7 MEq/mL [≈700,000 copies/mL] by branched DNA [bDNA] assay [Bayer Diagnostics, formerly Chiron Diagnostics], but remained HBeAg-positive) at Week 48 were offered continued blinded treatment through Week 96 or until loss of HBeAg. During the second year of treatment (Weeks 52-96) any virologic responders (HBV DNA <0.7 MEq/mL) who became responders or nonresponders discontinued study therapy. Study ETV-901 is an ongoing multinational rollover study designed to provide open-label entecavir to patients from 10 Phase II or Phase III entecavir studies. For patients in the ETV-022 study, the following subgroups of patients could enter ETV-901: 1) virologic responders at Week 48 (Year 1) who opted not to continue to a second year in study ETV-022; 2) virologic responders at Week 96 (Year 2); 3) nonresponders from either the first or second year of blinded treatment; and 4) responders from either the first or second year of blinded treatment who experienced virologic relapse (defined as serum HBV DNA ≥0.7 MEq/mL and/or detection of HBeAg on two occasions ≥2 weeks apart) during off-treatment follow-up. The nucleoside-naïve HBeAg-positive entecavir long-term cohort (hereafter called the entecavir long-term cohort) consists of entecavir-treated patients from study ETV-022 who had ≤35-day off-treatment gap between the last entecavir dose in study ETV-022 and the first entecavir dose in study ETV-901, and includes all patients who satisfy this definition regardless of treatment response achieved in ETV-022. Initially, due to ongoing blinding of Phase II/III studies, patients enrolling in ETV-901 received entecavir plus lamivudine. The protocol was subsequently amended so that patients received only entecavir (1.0 mg daily). Duration of treatment in study ETV-901 was at the discretion of the investigator; patients could continue until study closure if the investigator judged that continued treatment was in the patient's best interest or discontinue at any time. All patients who discontinued treatment in ETV-901 were required to be followed for at least 24 weeks postdosing to assess safety. The studies were conducted in accordance with the ethical principles of the Declaration of Helsinki and in adherence to the laws and regulatory requirements of all participating countries. Written informed consent was obtained from all study participants. Patients. Complete inclusion criteria for enrollment in the ETV-022 study have been described.18 Eligible patients were 16 years or older and had HBeAg-positive CHB and compensated liver function. Patients were required to have detectable hepatitis B surface antigen (HBsAg) for at least 6 months and evidence of chronic hepatitis on a baseline liver biopsy completed within 1 year of randomization. At screening, patients were required to have serum HBV DNA ≥3 MEq/mL (≈3 million copies/mL) by bDNA assay, and alanine aminotransferase (ALT) 1.3-10 times the upper limit of normal (ULN). Exclusion criteria included coinfection with hepatitis C virus, hepatitis D virus, or human immunodeficiency virus (HIV), prior treatment with lamivudine for >12 weeks, and exposure to other antiviral agents within 6 months of randomization. Patients treated in study ETV-022 who were eligible to enter study ETV-901 are described above in Study Design. Time on Treatment. For the HBeAg-positive entecavir long-term cohort, time on treatment for efficacy analyses was defined as the total duration in weeks from the first dose in ETV-022 to the last date of dosing up to Week 240 (Year 5) in ETV-901. Safety analyses were based on exposure during ETV-901. Efficacy Analyses. In ETV-901, serum HBV DNA was determined by polymerase chain reaction (PCR) assay at 12-week intervals during the first year and at 24-week intervals thereafter while treatment continued. HBV serologies were obtained every 12 weeks during the first and second year of open-label treatment. Efficacy assessments for the cohort include proportions of patients at 48, 96, 144, 192, and 240 weeks (Years 1, 2, 3, 4, and 5, respectively) who met the following endpoints: HBV DNA <300 copies/mL, HBeAg loss, HBeAg seroconversion, and normal ALT (≤1.0 × ULN). Mean serum levels of HBV DNA and ALT for the cohort were also determined at baseline and at 24-week intervals through Year 5. Safety Analyses. Safety analyses for the HBeAg-positive entecavir long-term cohort included the following events occurring on-treatment during study ETV-901: adverse events, serious adverse events, treatment discontinuations due to adverse events or laboratory abnormalities, and ALT flares. Deaths that occurred on-treatment in study ETV-901 or during off-treatment follow-up are also described. The results of safety analyses for study ETV-022 have been reported.18, 19 Resistance Analysis. Genotypic analyses20, 21 were performed to assess and characterize any emerging entecavir resistance substitutions among HBV isolates from patients who had HBV DNA ≥300 copies/mL at Years 1, 2, 3, 4, and 5, and from patients who discontinued treatment for any reason prior to Year 5 (end of dosing) and had HBV DNA ≥300 copies/mL at the time of treatment discontinuation. Genotypic and phenotypic analyses20, 21 were also performed on isolates from all patients experiencing virologic breakthrough (≥1 log10 increase from nadir) at the time breakthrough occurred. Statistical Analyses. All data analyses are descriptive. Tabulations by treatment group are presented for each of the efficacy and safety variables. Continuous variables are summarized using the mean, median, minimum, and maximum values. Binary variables are summarized by counts and percentages. Efficacy endpoints were assessed among patients with available samples. An additional sensitivity analysis using the last observation carried forward method (LOCF) was conducted for the endpoint of HBV DNA <300 copies/mL at Week 240 (Year 5). In this analysis, the last observed HBV DNA levels were carried forward for those patients without Year 5 measurements, i.e., patients who had either discontinued prior to Year 5 or who were still on study but had a missing HBV DNA measurement at Year 5. Safety analyses for the cohort include all adverse events that occurred on-treatment in study ETV-901 and all deaths that occurred on-study (during treatment in ETV-901 or during off-treatment follow-up). Assay Methodology. Serum HBV DNA was quantified by a central laboratory using the Roche COBAS Amplicor PCR assay (v. 2.0; lower limit of quantification 300 copies/mL [57 IU/mL]; Pleasanton, CA). In study ETV-022, HBV serologies (HBsAg, anti-HBs, HBeAg, anti-HBe) were assessed in a central laboratory using the Abbott AxSYM microparticle enzyme immunoassay (Abbott Laboratories, North Chicago, IL) and DiaSorin enzyme immunoassay. In study ETV-901, HBV serologies were assessed in local laboratories using available methodologies. ALT was assessed by local laboratories in studies ETV-022 and ETV-901. Genotyping of HBV DNA involved PCR amplification of the HBV reverse transcriptase domain, followed by nucleotide sequence analysis. In phenotypic analyses, substitutions that emerged on-treatment were cloned into HBV expression vectors, which were transfected into HepG2 hepatoma cells in the presence of entecavir. The amounts of replicated, encapsulated HBV DNA was immunocaptured from the culture media and quantified to determine the susceptibility to entecavir.20-22 Role of the Funding Source. The study was designed by the sponsor in collaboration with expert hepatologists. The sponsor collected the data, carried out the statistical analyses, and coordinated the writing of the article with all authors. Results Study Population. Of the 354 patients who were randomized to treatment with entecavir 0.5 mg in the ETV-022 study, 183 enrolled in the ETV-901 study (11 responders, 151 virologic responders, and 21 nonresponders; Fig. 1). Of these, 146 patients (one responder, 126 virologic responders, and 19 nonresponders) had a treatment gap of ≤35 days between the last study dose in ETV-022 and the first study dose in ETV-901 and were considered continuously treated. These 146 patients constituted the nucleoside-naïve HBeAg-positive entecavir long-term cohort. Figure 1Open in figure viewerPowerPoint Study design and protocol-defined outcomes: origin of entecavir long-term cohort. Among the 146 patients in the entecavir long-term cohort, 68% (99/146) received entecavir through 5 years. Forty-seven patients discontinued treatment prior to the Year 5 visit. The reasons for treatment discontinuation were: completion of treatment in the opinion of the investigator (12), progression of CHB (1); death (5); loss to follow-up (2); patient noncompliance (1); withdrawal of consent (14); minimal virologic response (3); and other (9). Mean time on therapy for the entecavir long-term cohort (n = 146) through studies ETV-022 and ETV-901 was 248 weeks. Of the 146 patients, 132 received entecavir in ETV-022 and entecavir together with lamivudine in study ETV-901, and 14 received only entecavir through both studies. Of the 132 patients who received entecavir with lamivudine in study ETV-901, 12 received the combined regimen only (mean exposure to lamivudine was 26.4 weeks) and 120 received entecavir without lamivudine after initially receiving both (mean exposure to entecavir and lamivudine were 169 and 25.5 weeks, respectively). Baseline (pretreatment) demographic and disease characteristics for the entecavir long-term cohort are presented in Table 1. The majority of patients in the cohort were male (80%) and Asian (64%), with a mean age of 36 years. Mean baseline levels of HBV DNA and ALT were 9.9 log10 copies/mL and 122 IU/L, respectively. Infection with HBV genotype A (26%), B (27%), or C (30%) accounted for most patients; 4% were infected with HBV genotype D. Table 1. Baseline Demographic and Disease Characteristics of the Nucleoside-Naïve HBeAg-Positive Entecavir Long-Term Cohort (n=146) Characteristic Entecavir (n=146) Age, years; mean (SE) 36 (1.1) Male sex, n (%) 117 (80) Race, n (%) Asian 94 (64) White 49 (34) Black/African American 3 (2) Genotype, n (%) A 38 (26) B 39 (27) C 44 (30) D 6 (4) Other 19 (13) HBV DNA by PCR (log10 copies/mL), mean (SE) 9.91 (0.182) Hepatitis B surface antigen-positive, n (%) 146 (100) Hepatitis B e antigen-positive, n (%) 146 (100) Hepatitis B e antibody-negative, n (%) 144 (99) Hepatitis B e antibody-positive, n (%) 2 (1) Alanine aminotransferase (IU/L), mean (SE) 121.8 (7.04) Abbreviation: SE, standard error. Virologic Endpoints. HBV DNA was suppressed early in therapy and extended treatment increased or maintained viral suppression through Year 5 (Fig. 2). Mean change from baseline in HBV DNA at Year 5 was −7.2 log10 copies/mL. Fifty-five percent of patients in the cohort had achieved HBV DNA <300 copies/mL at Year 1 of the Phase III study (ETV-022; Fig. 3). The proportion of patients in the entecavir long-term cohort achieving HBV DNA <300 copies/mL increased from 55% in Year 1 to 83% in Year 2. Among 116 patients who had HBV DNA <300 copies/mL at Year 2, 109 (94%) achieved this response while receiving entecavir 0.5 mg daily in study ETV-022 and the other seven achieved the endpoint while receiving entecavir 1.0 mg ± lamivudine (in study ETV-901). Continuous treatment through Years 3, 4, and 5 resulted in increasing proportions of patients achieving and maintaining HBV DNA <300 copies/mL, with 94% (88/94) of patients achieving or maintaining this endpoint at Year 5. Figure 4 shows the distribution of patients according to HBV DNA level at Year 5; only one patient had HBV DNA >105 copies/mL. Figure 2Open in figure viewerPowerPoint HBV DNA suppression through Year 5 in the entecavir long-term cohort (ETV-022 to ETV-901). Figure 3Open in figure viewerPowerPoint Proportions of patients achieving HBV DNA <300 copies/mL through 5 years of therapy. Figure 4Open in figure viewerPowerPoint Distribution of patients by HBV DNA level following 5 years of entecavir therapy. Five additional patients who remained on-treatment at Year 5 had missing HBV DNA measurements: four had HBV DNA <300 copies/mL at their last observation prior to the Year 5 analyses; one had detectable HBV DNA and had ETV resistant virus emerge during Year 3, as described below. Of the 47 patients in the cohort who discontinued treatment during study ETV-901 prior to Year 5, 79% (37/47) had HBV DNA <300 copies/mL on their last HBV DNA measurement. The sensitivity analysis was conducted based on the intention-to-treat (ITT) population. The last observed HBV DNA levels for all patients who were either still on study but had a missing PCR test at Year 5 (n = 5) or who had discontinued prior to Year 5 (n = 47) were carried forward; this maintained the total number of patients in this cohort intact (n = 146). When the Year 5 HBV DNA endpoint is calculated using this method, 88% (129/146) of patients had HBV DNA <300 copies/mL at Year 5. Biochemical Endpoints. As with virologic response, results for ALT normalization among patients in the entecavir long-term cohort at Year 1 were consistent with results of the overall ETV-022 patient population (Fig. 5). Sixty-five percent (95/146) of patients in the entecavir long-term cohort achieved ALT ≤1 × ULN at Year 1. Treatment in Year 2 resulted in increasing proportions achieving the endpoint (78%, 109/140), and continuous treatment through Years 3, 4, and 5 resulted in maintenance of ALT normalization (80% 78/98 at Year 5; Fig. 5). At Year 5, the mean ALT level for the entecavir long-term cohort was 33 IU/L, a decrease from the mean level of 122 IU/L at baseline. Figure 5Open in figure viewerPowerPoint Proportions of patients achieving normal ALT (≤1 × ULN) through 5 years of therapy. Serologic Endpoints. During study ETV-022, 31% (110/354) and 5% (18/354) of patients achieved HBeAg seroconversion and HBsAg loss, respectively, through up to Year 2 of treatment plus up to 24 weeks of posttreatment follow-up. Due to protocol-defined management criteria, most patients who achieved HBeAg loss or HBeAg seroconversion during ETV-022 discontinued study therapy (as responders), did not enroll in ETV-901, and thus were not part of the entecavir long-term cohort. Among 146 patients in the entecavir long-term cohort, two achieved HBeAg seroconversion during ETV-022 but did not meet the virologic criterion for response (HBV DNA <0.7 MEq/mL), and three experienced seroreversion after HBeAg seroconversion during ETV-022 and therefore enrolled in ETV-901. Continued treatment in ETV-901 resulted in 33 additional patients (23%, 33/141) achieving HBeAg seroconversion on-treatment. One patient in the entecavir long-term cohort achieved HBsAg loss during ETV-022 and two additional patents (1.4%, 2/145) achieved HBsAg loss during continued treatment in ETV-901. Resistance and Virologic Breakthrough. Genotypic testing of isolates from patients with HBV DNA ≥300 copies/mL at Years 1, 2, 3, 4, and 5 identified one patient (1/146) with entecavir resistance that emerged during Year 3, and has been reported.22, 23 This patient received 16 weeks of lamivudine plus entecavir prior to being switched to entecavir alone (per protocol amendment), showed the simultaneous emergence of L180M/M204V (associated with lamivudine resistance) and S202G (associated with entecavir resistance) at Week 139, and had virologic breakthrough at Week 148. Of the 47 patients who discontinued treatment prior to Year 5, 10 had HBV DNA ≥300 copies/mL at the last on-treatment measurement. Genotypic testing of isolates from these 10 patients found no evidence of entecavir resistance. Safety. The safety profile for this cohort during treatment with open-label entecavir (study ETV-901) is summarized in Table 2. During ETV-901, no patient in this cohort discontinued entecavir due to an adverse event (Table 2). Adverse events occurring in ≥10% of patients are shown in Table 3. The most common serious adverse events were increased ALT and liver abscess, both occurring in two (1%) patients. One patient, who stopped study medication 172 weeks after initially starting on entecavir, experienced an ALT flare that was associated with a ≥2-log increase in HBV DNA. This patient was subsequently lost to follow-up at Week 176. The safety profile for the entecavir long-term cohort during study ETV-901 was consistent with the safety profile reported for all entecavir-treated patients through 2 y
