Trends in ETV resistance mutations
The rates of ETV resistance gradually increased from 6.04% in 2011 to 15.02% in 2017, and the proportion of LAM/LdT resistance was high from 2011 to 2017. Overall, 166 patients with ETV resistance were screened and 72 were included (Figure 1 and Supplementary Figure 1).
Baseline characteristics of patients with ETV resistance
The 72 patients in the ETV/ADV (n = 25), TDF (n = 27), and ETV/TDF groups (n = 20) completed 48 weeks of treatment. The median age was 43, 44, and 46 years in the ETV/ADV, TDF, and ETV/TDF groups, respectively. The proportion of males was 80.00%, 85.19%, and 65.00% in the ETV/ADV, TDF, and ETV/TDF groups, respectively. The median HBV DNA level was 6.31, 5.40, and 6.23 log10IU/mL, respectively. Median duration of previous LMV treatment before ETV treatment was 28(6-110) months in ETV+ADV group, 26(6-64) months in TDF group, 26(6-72) months in TDF+ETV group. No significant differences occurred in the age distribution, male proportion, baseline HBV DNA level, duration of previous LMV treatment or other liver function, and renal function tests (Table 1).
Table 1. Baseline characteristics of patients with ETV-resistance
in different rescue therapy groups
|
|
ETV+ADV
|
TDF
|
TDF+ETV
|
N
|
25
|
27
|
20
|
Age, years
|
43(21-64)
|
44(20-64)
|
46(30-68)
|
Male, n (%)
|
20, 80.00%
|
23, 85.19%
|
13, 65%
|
ALT (IU/L)
|
120.46
|
61.12
|
71.00
|
Normal ALT, n (%)
|
13, 52.00%
|
17, 62.96%
|
10, 50.00%
|
Bilirubin, mg/dL
|
18.93
|
20.67
|
33.86
|
Creatinine, mg/dL
|
78.97
|
90.62
|
75.43
|
HBeAg-positivity, n (%)
|
17, 67.00%
|
23, 85.19%
|
15, 75.00%
|
HBV DNA (log10 IU/mL)
|
6.31
|
5.40
|
6.23
|
Previously exposed NUC, n
|
|
|
|
LMV
|
23
|
14
|
14
|
ADV
|
0
|
6
|
3
|
LDT
|
1
|
2
|
1
|
LMV+ADV
|
1
|
5
|
2
|
Duration of NUC treatments (months)
|
28(6-110)
|
26(6-64)
|
26(6-72)
|
Resistance mutations
|
|
|
|
ETV
|
18
|
22
|
17
|
Multidrug resistance
|
7
|
5
|
3
|
Virologic, biochemical, and serologic responses in the subgroups
Three patients in the ETV/ADV group discontinued because of poor virologic response and switched to ETV/TDF combination therapy. One patient in the TDF group discontinued because of risk of renal injury. Among the patients in the TDF and ETV/TDF groups, no significant difference was found in the rate of achieving virologic response at 48 weeks (74.07% vs 70.00%). The mean level of HBV DNA significantly decreased at 12 weeks, 24 weeks, and 48 weeks, and no virologic breakthrough occurred in these two groups. However, the ETV/ADV group showed a significantly low rate of achieving virologic response at 48 weeks (28%). The residual HBV DNA level was also significantly higher than in the TDF or ETV/TDF groups. Virologic breakthrough occurred in one patient after 40 weeks of ETV/ADV treatment. The patient switched to ETV/TDF, and their HBV DNA declined to negative after 12 weeks of treatment. As for serologic responses, HBeAg seroclearance occurred in 3 patients in the TDF group, 1 patient in the ETV/TDF group, and 0 patients in the ETV/ADV group, with no significant difference (Table 2 and Figure 2). To evaluate whether poor virologic response in the ETV/ADV group was due to the relatively higher rate of multi-drug resistance, we conducted a subgroup analysis of ETV resistance without ADV resistance. We found that in the patients with only ETV resistance, the ETV/ADV group still demonstrated a significantly lower rate of virologic response at 48 weeks, and the residual HBV DNA level was higher than in the other two groups (Table 3).
Table 2
Virologic, biochemical, and serologic responses of ETV-resistance patients with/or without ADV resistance in different rescue therapy at Week 48
|
ETV + ADV
|
TDF
|
TDF + ETV
|
N
|
25
|
27
|
20
|
HBV DNA < 100 IU/mL, n (%)
|
7, 28.00%
|
20, 74.07%
|
14, 70%
|
HBV DNA change from baseline (log10 IU/mL)
|
3.86 ± 1.62
|
4.55 ± 1.81
|
5.33 ± 1.88
|
Residual HBV DNA level (log10 IU/mL)
|
2.44
|
0.86
|
0.8
|
Virologic breakthrough
|
1
|
0
|
0
|
ALT (IU/L)
|
40.56
|
45.33
|
34.82
|
ALT normal, n (%)
|
19, 76.00%
|
23, 85.19%
|
16, 80.00%
|
Abnormal renal function
|
0
|
1
|
1
|
HBeAg seroclearance, n (%)
|
0
|
3
|
1
|
HBeAg seroconversion, n (%)
|
0
|
1
|
1
|
HBsAg seroclearance, n (%)
|
0
|
0
|
0
|
Discontinued
|
3
|
1
|
0
|
Table 3
Subgroup analysis of virologic, biochemical, and serologic responses of patients with only ETV resistance different rescue therapy at Week 48
|
ETV + ADV
|
TDF
|
TDF + ETV
|
N
|
18
|
22
|
17
|
HBV DNA < 100 IU/mL, n (%)
|
5, 27.28%
|
15, 68.18%
|
11, 64.71%
|
HBV DNA change from baseline (log10 IU/mL)
|
4.09
|
4.07
|
5.03
|
Residual HBV DNA level (log10 IU/mL)
|
2.45
|
1.19
|
1.03
|
Virologic breakthrough
|
0
|
0
|
0
|
ALT (IU/L)
|
41.44
|
44.1
|
35.13
|
ALT normal, n (%)
|
13, 72.22%
|
19, 86.36%
|
14, 82.35%
|
Abnormal renal function
|
0
|
0
|
1
|
HBeAg seroclearance, n (%)
|
0
|
3, 13.64%
|
1, 5.88%
|
HBeAg seroconversion, n (%)
|
0
|
1, 4.55%
|
1, 5.88%
|
HBsAg seroclearance, n (%)
|
0
|
0
|
0
|
Discontinued
|
3
|
1
|
0
|
12 weeks HBV DNA level (log10 IU/mL)
|
3.75
|
2.47
|
2.83
|
24 weeks HBV DNA level (log10 IU/mL)
|
2.44
|
1.36
|
1.84
|
48 weeks HBV DNA level (log10 IU/mL)
|
2.45
|
1.19
|
1.03
|
12 weeks HBV DNA < 100 IU/mL, n (%)
|
0.00%
|
27.27%
|
17.65%
|
24 weeks HBV DNA < 100 IU/mL, n (%)
|
16.67%
|
54.55%
|
41.18%
|
48 weeks HBV DNA < 100 IU/mL, n (%)
|
27.78%
|
68.18%
|
64.71%
|
Safety profiles
Regarding the safety of the different treatments, only 1 hepatocellular carcinoma occurred in the ETV/ADV combination group, and no ALT flares occurred in either group. No significant difference occurred in the discontinuation rate due to adverse events in the three groups. As for eGFR measurement, differences in the baseline eGFR level, eGFR at 48 weeks, and eGFR decline from baseline or the rate of eGFR < 90 mL/min/1.73 m2 at 48 weeks demonstrated no significant differences (Table 4 and Supplementary Figure 2). Other detailed parameters were all showed in the raw data (Supplementary file 1).
Table 4
Safety Profiles of patients in different rescue therapy group at 48 weeks
|
ETV+ADV
|
TDF
|
TDF+ETV
|
N
|
25
|
27
|
20
|
HCC
|
1
|
0
|
0
|
cirrhosis
|
0
|
0
|
0
|
Deaths
|
0
|
0
|
0
|
ALT flare
|
0
|
0
|
0
|
Discontinuation due to adverse event
|
2
|
1
|
1
|
baseline eGFR
|
125.82
|
122.75
|
127.71
|
eGFR at 48 weeks
|
103.76
|
112.32
|
110.26
|
eGFR decline from baseline
|
22.06
|
10.43
|
17.45
|
eGFR<90 mL/min/1.73 m2 at 48 weeks, n(%)
|
3, 12.00%
|
1, 3.70%
|
3, 15.00%
|