Current af filiation: Korea National Evidence-based healthcare Collaborating Agency
Editor: Tai-Chung Tseng, National Taiwan University College of Medicine, Taiwan
Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphonate, shows potent antiviral activity against hepatitis B virus. Our previous 48-week trial revealed that BSV has comparable antiviral efficacy to tenofovir disoproxil fumarate (TDF) and better safety profiles in terms of improved renal and bone safety. This extension study evaluated the prolonged efficacy and safety of BSV in treatment-naive chronic hepatitis B patients.
Patients continued to participate in an open-label BSV study after an initial 48-week double-blind comparison of BSV and TDF treatment. The antiviral efficacy and drug safety was evaluated up to 192 weeks in two groups: patients continuing BSV treatment (BSV-BSV) and patients switching from TDF to BSV after 48 weeks (TDF-BSV).
Among 197 patients receiving randomized treatments, 170 (86%) entered the open-label phase and 152 (77%) entered the 192-week extension study. Virological response rates over 192 weeks were 92.50% and 93.06% in the BSV-BSV and TDF-BSV groups, respectively (
BSV maintained potent antiviral efficacy after 192 weeks and showed no evidence of drug resistance. BSV was safe, well tolerated, and effective in patients who switched from TDF to BSV. Trial Registration Number: NCT01937806 (date: 10 Sep 2013).
• BSV maintained prolonged potent antiviral efficacy without drug resistance in HBeAg-positive and HBeAg-negative patients throughout 192 weeks of treatment.
• Approximately 93% of patients had HBV DNA <69 IU/mL after 192-week BSV treatment.
• Long-term BSV treatment is tolerable and safe in terms of renal function and BMD.
Hepatitis B is a major global health concern with 350 million people suffering from chronic hepatitis B (CHB) and 600,000 deaths per year due to related diseases [
Tenofovir disoproxil fumarate (TDF) has potent antiviral effects and very high genetic barriers against resistance [
Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphate, has potent antiviral efficacy and was approved for the treatment of CHB patients in Korea in May 2017 following the results of a 48-week randomized, controlled, phase 3 trial (NCT01937806). The results revealed that BSV and TDF showed similar antiviral efficacy at 48 weeks [
This was a 192-week study, including 48 weeks of randomized controlled trial, with an extension period for the treatment of hepatitis B patients in Korea. The initial 48-week period comprised a double-blind, randomized, multi-center, non-inferiority, controlled trial comparing BSV (Ildong Pharmaceutical Co, Ltd., Seoul, Korea) with TDF (Gilead Sciences, Foster City, CA, USA), and the remaining 144 weeks comprised an open-label trial with BSV administration only. The present study was conducted in 22 institutions and obtained approval from each institution’s Institutional Review Board and the Human Research Ethics Committee. Further details are described elsewhere [
CHB patients were enrolled from November 2013 to February 2016 (NCT01937806). Details of the eligibility criteria are described in our previous study [
Participants were randomly assigned to two groups in a 1:1 ratio and received either BSV (150 mg) plus L-carnitine (660 mg) or TDF (300 mg) alone for initial 48 weeks. In this period, to ensure double-blinding, participants in the BSV plus L-carnitine group also received placebo TDF, whereas those in the TDF group received placebo BSV plus placebo L-carnitine supplements. Thereafter, in the extension study, participants who had received BSV plus L-carnitine in the initial phase were administered the same regimen and those who had received TDF were switched to BSV plus L-carnitine, and the treatment was continued until week 192.
The primary endpoint was virological response (VR), defined as HBV DNA <69 IU/mL at week 192. Other efficacy endpoints were HBV DNA <20 IU/mL, HBsAg or HBeAg seroconversion, ALT normalization, and drug resistance. Safety evaluation included monitoring of adverse events (AEs), glomerular filtration rate (GFR), BMD, and carnitine concentration.
All laboratory tests, including hematological analysis, serum chemistry tests, lipid parameters, and renal function measurements, were performed at a central laboratory (GC laboratory, Yongin, Korea) at 12-week intervals. HBV DNA quantification was performed using the COBAS AmpliPrep/TaqMan test (Roche Diagnostics, Indianapolis, IN, USA), with 20 IU/mL as the lower level detection limit. Other laboratory tests were performed as previously described [
BMD measurements of the lumbar spine (L1–4) and the total hip were performed using dual-energy X-ray absorptiometry scan and conducted at each institution. GFR was calculated using the Modification of Diet in Renal Disease (MDRD) method using the formula: 175 × serum creatinine (mg/dL) – 1.154 × age (years) – 0.203 (× 0.742 for females). BMD and GFR measurements were performed at baseline and weeks 48, 96, 144, and 192.
Population sequencing was performed in all participants at baseline and at weeks 48, 96, 144, and 192 in participants with HBV DNA levels >1,724 IU/mL. DNA sequencing was performed at the investigator’s discretion to confirm drug adherence if virological breakthrough (increase of >1 log10 IU/mL from HBV DNA nadir) developed. An in vitro drug susceptibility assay was performed at the central laboratory (Department of Pharmacology and Center for Cancer Research and Diagnostic Medicine, IBST, School of Medicine, Konkuk University, Seoul, Korea) when virological breakthrough was observed from two continuous visits and when changes were detected in the reverse transcriptase sequence [
HBV DNA was extracted from the sera of the patients using a QiAamp MinElute Virus Spin Kit (Qiagen, Hilden, Germany) according to the manufacturer’s protocol. To characterize the HBV RT gene, the RT gene was amplified by PCR and cloned into the HBV1.2mer replicon using the pGEM-4Z vector (Promega, Madison, WI, USA) and sequenced, as described previously [
The primary efficacy endpoints, study designs, and sample size estimates were performed as described previously [
Among 197 participants (86%) who enrolled in the initial randomized study, 170 participated in the BSV monotherapy extension study. Of these patients, 152 participated in the extended treatment period III (144–192 weeks, 4 years) and two (1.32%) dropped out owing to non-adherence (one in BSV-BSV and one in TDF-BSV group) (
Among the total study population, 65.1% (99/152) were male, and the rate of HBeAg-positive patients was 62.5% in the BSV–BSV group and 55.6% in the TDF-BSV group. The most common HBV genotype was type C (98.0%). The baseline characteristics were similar between the two groups, with an average HBV DNA of 6.31 log10 IU/mL and 6.55 log10 IU/mL in the BSV-BSV and TDF-BSV groups, respectively (
At week 192, the cumulative incidence rates of HBV DNA <69 IU/mL and <20 IU/mL were 92.5% and 87.5% in the BSVBSV group and 93.1% and 87.5% in the TDF-BSV group, respectively, and there was no significant difference between the two groups in terms of VR in the FAS (
At week 192, the rates of HBeAg loss and HBeAg seroconversion were 32.7% and 10.2%, respectively, in the BSV-BSV group and 35.0% and 12.5%, respectively, in the TDF-BSV group. These rates did not differ statistically between the two groups (
None of the participants in the BSV-BSV group showed HBsAg loss and/or seroconversion until week 192, whereas one participant in the TDF-BSV group showed HBsAg loss at week 48 and seroconversion at week 144 (
At week 192, 88.8% of participants in the BSV-BSV group and 93.1% of participants in the TDF-BSV group showed serum ALT normalization (
It was previously shown that resistance to BSV did not develop until 144 weeks [
The virological, serological, and biochemical responses were further evaluated according to HBeAg status (
During 192 weeks, 69/80 (86.3%) AEs were reported in the BSV-BSV group and 57/72 (79.2%) were reported in the TDF-BSV group. During this period, there were 12/80 (15.0%) SAEs reported in the BSV-BSV group and 9/72 (12.5%) in the TDF-BSV group (
Among the reported SAEs, serious adverse drug reactions (SADRs) included one case each of muscle spasm and biochemical breakthrough due to non-adherence in the BSV-BSV group and one case each of sudden hearing loss and arthralgia in the TDF-BSV group. All patients who had experienced SADR recovered, but the one with biochemical breakthrough finally dropped out (
Hip and spine BMD decreased during the 48 weeks in the TDF group (mean percent change: -0.62 vs. 0.28,
The median changes in GFR at 192 weeks were 6.0 mL/min (interquartile range [IQR]: -1.60, 12.90) and 0 (IQR: -2.30, 15.25) in the BSV-BSV and TDF-BSV groups, respectively (
A decrease in L-carnitine levels was observed in seven patients (two patients in the BSV-BSV group and five patients in the TDF-BSV group) at week 192 without any clinical symptoms associated with carnitine deficiency. During the next visit, we will check the safety in patients with decreased levels of L-carnitine using follow-up laboratory tests.
The present study reports the four-year outcome of a study scheduled for eight years in HBeAg-positive and HBeAg-negative CHB patients. Long-term BSV treatment showed a stable and potent virological, biochemical, and serologic response. In addition, no viral resistance against BSV was found during the 4 years. BSV therapy was tolerable, none of the patients discontinued its use due to AEs, and the risk of BSV-induced renal and bone complications were low.
Our previous study revealed that BSV has antiviral effects comparable to those of TDF during 48 weeks. Furthermore, the antiviral effect was maintained for up to 144 weeks when TDF was switched to BSV [
In this study, HBeAg loss and seroconversion rate were lower than those in other studies for patients receiving NA [
Emergence of resistance to NAs is related to reduced antiviral efficacy, hepatitis flares, disease progression, and poor outcomes [
Despite its potent antiviral efficacy and low resistance, reduction in BMD due to long-term use of TDF is an important problem. A previous study revealed that the incidence rates of osteoporosis and osteopenia were 8.2% and 31.6%, respectively, after 96 weeks of TDF [
TDF has potential nephrotoxic effects such as decreased GFR or tubular injury [
Carnitine deficiency is the most common side effect of BSV [
TAF, which is an orally bioavailable prodrug of tenofovir, has been developed to reduce AEs of TDF, such as renal or bone complications. In a TDF-TAF switching study, changes in GFR and BMD showed a similar pattern to those seen with switching from TDF to BSV [
The present study has several limitations. First, the sample size was relatively small and only Asian patients were enrolled. Therefore, further studies with large sample sizes and race diversity are required. Second, although 4-year BSV treatment was effective and tolerable, further studies are required to confirm its long-term antiviral efficacy and safety. Third, although renal AE was not observed after BSV treatment, the present study did not measure biomarkers for renal function, such as urinary albumin, fractional excretion of uric acid, and urinary beta-2 microglobulin. Similarly, markers for bone turnover to detect bone formation or resorption were not evaluated. Fourth, while levels of total cholesterol and triglyceride were measured every 48 weeks, other lipid profiles, such as low-density lipoprotein cholesterol or high-density lipoprotein cholesterol, were not evaluated. Finally, only qualitative HBsAg was measured; therefore, the present study could not assess the reducing effect of antiviral medication on HBsAg titers, which might represent their impact on intrahepatic covalently closed circular HBV DNA. Despite these limitations, to the best of our knowledge, this is the first study to report on the safety profiles of renal function and bone density in long-term BSV therapy.
In conclusion, BSV treatment for 192 weeks showed potent viral reduction without the development of drug resistance. BSV treatment also demonstrated favorable safety profiles without reducing BMD and eGFR. As the safety profile is a major consideration in the selection of medication, BSV is a potentially novel treatment for CHB, especially in patients at high risk of developing renal and bone-related diseases.
D.S.S. wrote the manuscript and performed the formal analysis and critical revision. S.H.U. was involved in the study conception, design, and supervision. All the other authors contributed to data acquisition and revision of the manuscript.
This study was financially supported by Ildong Pharmaceutical Co. Ltd., Korea.
adverse event
alanine aminotransferase
antiviral therapy
bone mineral density
besifovir dipivoxil maleate
chronic hepatitis B
estimated glomerular filtration rate
entecavir
full analysis set
glomerular filtration rate
hepatitis B envelop antigen
hepatitis B surface antigen
hepatitis B virus
hepatocellular carcinoma
interquartile range
nucleos(t)ide analog
per protocol set
serious adverse drug reactions
tenofovir alafenamide fumarate
tenofovir disoproxil fumarate
upper limit of normal
virological response
Supplementary material is available at Clinical and Molecular Hepatology website (
HBV RT mutations identified in a besifovir-treated patient
Virological, biochemical response according to the presence of cirrhosis (FAS)
Virological, serological, and biochemical responses by baseline HBeAg status (PPS)
Serious adverse events
(A) Mean HBV DNA level (log IU/mL). (B) HBV DNA change from baseline (log IU/mL). BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; HBV, hepatitis B virus; ANOVA, analysis of variance.
ALT normalization at 192 weeks. ALT, alanine aminotransferase; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate.
Proportion of patients with HBV DNA <69 IU/mL at 192 weeks by FAS in (A) HBeAg-positive patients and (B) HBeAg-negative patients. Bars represent 95% confidence intervals. HBeAg, hepatitis B envelope antigen; HBV, hepatitis B virus; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; FAS, full analysis set.
Proportion of patients with HBV DNA <20 IU/mL at 192 weeks by FAS in (A) HBeAg-positive patients and (B) HBeAg-negative patients. Bars represent 95% confidence intervals. HBeAg, hepatitis B envelope antigen; HBV, hepatitis B virus; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; FAS, full analysis set.
Patient disposition. BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; HCC, hepatocellular carcinoma; CPK, creatinine phosphokinase; F/U, follow up; FAS, full analysis set; PPS, per protocol set; IP, investigational product.
Viral suppression by study visit. (A) Proportions of patients with HBV DNA <69 IU/mL as determined by FAS. (B) Proportions of patients with HBV DNA <20 IU/mL as determined by FAS. Bars represent 95% confidence intervals. HBV, hepatitis B virus; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; FAS, full analysis set.
Changes in BMD. (A) Mean percentage changes in the hip at week 48, 96, 144, and 192 of treatment. Bars represent 95% confidence intervals. (B) Mean percentage changes in the spine at week 48, 96, 144, and 192 of treatment. Bars represent 95% confidence intervals. BMD, bone mineral density; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate.
Median changes from baseline in eGFR (MDRD) by study week. Data are presented as median (Q1, Q3) values (mL/min). BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; eGFR, estimated glomerular filtration rate; MDRD, modification of diet in renal disease.
Baseline characteristics of the study participants
BSV-BSV (n=80) | TDF-BSV (n=72) | ||
---|---|---|---|
Male | 53 (66.3) | 46 (63.9) | 0.76 |
Age (years) | 46.16 (10.8) | 44.04 (9.9) | 0.21 |
HBeAg positive | 50 (62.5) | 40 (55.6) | 0.38 |
HBV genotype | 0.86 | ||
A | 1 (1.3) | 0 | |
C | 78 (97.5) | 71 (98.6) | |
D | 0 (0.0) | 1 (1.4) | |
Not determined | 1 (1.3) | 0 (0.0) | |
HBV DNA (log10 IU/mL) | 6.31 (1.7) | 6.55 (1.5) | 0.35 |
ALT (U/L) | 105.6 (102.1) | 127.4 (143.7) | 0.38 |
ALT normal |
4 (5.0) | 6 (8.3) | 0.52 |
BMI (kg/m2) | 0.05 | ||
Normal, <25 kg/m2 | 53 (66.3) | 49 (68.1) | |
Overweight, ≥25 to ≥30 kg/m2 | 25 (31.3) | 15 (20.8) | |
Obese, >30 kg/m2 | 2 (2.5) | 8 (11.1) | |
eGFR by MDRD (mL/min) | 89.5 (14.6) | 92.4 (13.9) | 0.22 |
Creatinine (mg/dL) | 0.86 (0.2) | 0.83 (0.1) | 0.31 |
Phosphate (mg/dL) | 3.53 (0.5) | 3.45 (0.6) | 0.56 |
Fib-4 score | 2.14 (2.08) | 1.91 (1.14) | 0.98 |
Total hip BMD clinical status |
0.88 | ||
Normal, T-score ≥-1.0 | 57 (82.6) | 46 (83.6) | |
Osteopenia, -2.5≤ T-score <-1.0 | 12 (17.4) | 9 (16.4) | |
Osteoporosis, T-score <-2.5 | 0 (0.0) | 0 (0.0) | |
Data not collected | 11 | 17 | |
Spine BMD clinical status | 0.71 | ||
Normal, T-score ≥-1.0 | 49 (68.1) | 39 (65.0) | |
Osteopenia, -2.5≤ T-score <-1.0 | 19 (26.4) | 19 (31.7) | |
Osteoporosis, T-score <-2.5 | 4 (5.6) | 2 (3.3) | |
Data not collected | 8 | 12 | |
Concurrent medical history | |||
Mild renal impairment |
44 (55.0) | 33 (45.8) | 0.26 |
Cirrhosis | 19 (23.8) | 13 (18.1) | 0.39 |
Diabetes mellitus | 10 (12.5) | 3 (4.2) | 0.07 |
Hypertension | 10 (12.5) | 9 (12.5) | 1.00 |
Prior antiviral therapy | 0 | 1 (1.4) | 0.47 |
Values are presented as number (%), n/N (%), or mean (standard deviation) unless otherwise stated.
BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; HBeAg, hepatitis B e antigen; HBV, hepatitis B virus; ALT, alanine aminotransferase; BMI, body mass index; eGFR, estimated glomerular filtration rate; MDRD, modification of diet in renal disease; Fib-4, fibrosis-4; BMD, bone mineral density.
33 U/L for females, 41 U/L for males.
For BMD, some data were not collected.
50≤ eGFR <90 (mL/min).
Virological, serological, and biochemical responses
FAS |
PPS |
|||||
---|---|---|---|---|---|---|
BSV-BSV (n=80) | TDF-BSV (n=72) | BSV-BSV (n=77) | TDF-BSV (n=67) | |||
HBV DNA <69 IU/mL | 74 (92.5) | 67 (93.1) | 0.90 | 73 (94.8) | 63 (94.0) | 1.00 |
HBV DNA <20 IU/mL | 70 (87.5) | 63 (87.5) | 1.00 | 69 (89.6) | 59 (88.1) | 0.77 |
HBeAg loss |
16/49 (32.7) | 14/40 (35.0) | 0.82 | 14/47 (29.8) | 14/37 (37.8) | 0.44 |
HBeAg seroconversion |
5/49 (10.2) | 5/40 (12.5) | 0.75 | 3/47 (6.4) | 5/37 (13.5) | 0.29 |
HBsAg loss |
0/79 (0.0) | 1/72 (1.4) | 0.48 | 0/77 (0.0) | 1/67 (1.5) | 0.47 |
HBsAg seroconversion |
0/79 (0.0) | 1/72 (1.4) | 0.48 | 0/77 (0.0) | 1/67 (1.5) | 0.47 |
ALT normalization |
71 (88.8) | 67 (93.1) | 0.36 | 69 (89.6) | 62 (92.5) | 0.54 |
Values are presented as n/N (%) or number (%).
FAS, full analysis set; PPS, per protocol set; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; HBV, hepatitis B virus; HBeAg, hepatitis B envelope antigen; HBsAg, hepatitis B surface antigen; ALT, alanine aminotransferase.
Among HBeAg-seropositive patients at baseline.
Patients with missing data were excluded following statistical analysis plan.
Among HBsAg-seropositive patients at baseline.
Among patients with baseline ALT levels above the central laboratory normal range (0–41 U/L for males and 0–33 U/L for females).
Virological, serological, and biochemical responses by baseline HBeAg status (FAS)
HBeAg-positive patients (n=90) |
HBeAg-negative patients (n=62) |
|||||
---|---|---|---|---|---|---|
BSV-BSV (n=50) | TDF-BSV (n=40) | BSV-BSV (n=30) | TDF-BSV (n=32) | |||
HBV DNA <69 IU/mL | 44 (88.0) | 35 (87.5) | 1.00 | 30 (100.0) | 32 (100.0) | – |
HBV DNA <20 IU/mL | 40 (80.0) | 32 (80.0) | 1.00 | 30 (100.0) | 31 (96.9) | 1.00 |
HBeAg loss |
16/49 (32.7) | 14/40 (35.0) | 0.82 | – | – | – |
HBeAg seroconversion |
5/49 (10.2) | 5/40 (12.5) | 0.75 | – | – | – |
HBsAg loss |
0/49 (0) | 1/40 (2.5) | 0.45 | 0/30 (0) | 0/32 (0) | – |
HBsAg seroconversion |
0/49 (0) | 1/40 (2.5) | 0.45 | 0/30 (0) | 0/32 (0) | – |
ALT normalization |
42 (84.0) | 37 (92.5) | 0.33 | 29 (96.7) | 30 (93.8) | 1.00 |
Values are presented as n/N (%) or number (%).
HBeAg, hepatitis B envelope antigen; FAS, full analysis set; BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; HBV, hepatitis B virus; HBsAg, hepatitis B surface antigen; ALT, alanine aminotransferase.
Among HBeAg-seropositive patients at baseline.
Patients with missing data were excluded following statistical analysis plan.
Among HBsAg-seropositive patients at baseline.
Among patients with baseline ALT levels above the central laboratory normal range (0–41 U/L for males and 0–33 U/L for females).
Safety data
Variable | 0–192 weeks |
||
---|---|---|---|
BSV-BSV (n=80) | TDF-BSV (n=72) | ||
Adverse events | 69 (86.3) | 57 (79.2) | 0.25 |
Adverse drug reactions | 38 (47.5) | 35 (48.6) | 0.89 |
Serious adverse events | 12 (15.0) | 9 (12.5) | 0.66 |
Serious adverse drug reactions | 2 (2.5) | 2 (2.8) | 1.00 |
Serious adverse events leading to drug discontinuation | 1 (1.3) | 0 (0.0) | 1.00 |
Death | 0 (0.0) | 0 (0.0) | - |
Adverse drug reaction recorded in ≥3% of all patients | |||
Nasopharyngitis | 2 (2.5) | 3 (4.2) | 0.67 |
Dyspepsia | 3 (3.8) | 6 (8.3) | 0.31 |
Osteopenia | 1 (1.3) | 5 (6.9) | 0.10 |
Alanine aminotransferase increased | 4 (5.0) | 3 (4.2) | 1.00 |
Headache | 4 (5.0) | 1 (1.4) | 0.37 |
Dizziness | 3 (3.8) | 0 (0.0) | 0.25 |
Somnolence | 3 (3.8) | 1 (1.4) | 0.62 |
Fatigue | 2 (2.5) | 4 (5.6) | 0.42 |
Pruritus | 1 (1.3) | 4 (5.6) | 0.19 |
Benign hepatic nodules | 3 (3.8) | 1 (1.4) | 0.62 |
Hypertension | 5 (6.3) | 0 (0.0) | 0.06 |
Renal related adverse events | |||
Proteinuria | 0 (0.0) | 1 (1.4) | 0.47 |
Phosphate <2.5 mg/dL | 10 (12.5) | 15 (20.8) | 0.17 |
eGFR <50 mL/min | 1 (1.3) | 2 (2.8) | 0.60 |
Serum creatinine increase ≥0.5 mg/dL above baseline | 0 (0.0) | 1 (1.4) | 0.47 |
Bone-related adverse events | |||
Fracture | |||
Spontaneous |
1 (1.3) | 0 (0.0) | 1.00 |
Traumatic | 4 (5.0) | 1 (1.4) | 0.37 |
Dyslipidemia | |||
Triglyceride, above 300 mg/dL | 0 (0.0) | 0 (0.0) | - |
Total cholesterol, above 300 mg/dL | 0 (0.0) | 0 (0.0) | - |
Total carnitine level at week 192 |
|||
Low | 2 (2.5) | 5 (6.9) | 0.26 |
High | 10 (12.5) | 7 (9.7) | 0.59 |
Values are presented as number (%).
BSV, besifovir dipivoxil maleate; TDF, tenofovir disoproxil fumarate; eGFR, estimated glomerular filtration rate.
Spontaneous fracture from postmenopausal osteoporosis.
Lab normal range (male, 51–98; female, 37–81).