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Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection
Journal Pre-proof Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection Hong Zhang, Jingrui Liu, Xiaoxue Zhu, Xiaojiao Li, Weili Jin, Hong Chen, Min Wu, Cuiyun Li, Chengjiao Liu, JunqiNiu, Yanhua Ding PII:
S0166-3542(19)30500-5
DOI:
https://doi.org/10.1016/j.antiviral.2019.104693
Reference:
AVR 104693
To appear in:
Antiviral Research
Received Date: 30 August 2019 Revised Date:
15 November 2019
Accepted Date: 11 December 2019
Please cite this article as: Zhang, H., Liu, J., Zhu, X., Li, X., Jin, W., Chen, H., Wu, M., Li, C., Liu, C., JunqiNiu, , Ding, Y., Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection, Antiviral Research (2020), doi: https://doi.org/10.1016/j.antiviral.2019.104693. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier B.V.
Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection
Running title: Pradefovir for chronic hepatitis B infection
Hong Zhang1, Jingrui Liu1, Xiaoxue Zhu1, Xiaojiao Li1, Weili Jin3, Hong Chen1, Min Wu1, Cuiyun Li1, Chengjiao Liu1, JunqiNiu2, Yanhua Ding1
1 Phase I Clinical Research Center, The First Hospital of Jilin University, Jilin, China 2 Department of Hepatology, The First Hospital of Jilin University, Jilin, China 3 Xi'an Xintong Pharmaceutical Research Co., Ltd.
Corresponding Author: Dr. Yanhua Ding, Phase I Clinical Trial Unit, The First Hospital, Jilin University, Changchun 130021, China; Tel/Fax: +86-431-88782705; Email: [email protected] Dr. JunqiNiu, Department of Hepatology, The First Hospital, Jilin University, Changchun 130021, China; Tel/Fax: +86-431-88782705; Email: [email protected]
1
Abstract Background & Aims: Pradefovir is a liver targeted novel prodrug of adefovir (PMEA) developed to provide higher antiviral activity with reduced systemic toxicities. This study evaluated the tolerability, pharmacokinetics, and antiviral activity of pradefovir in patients with chronic hepatitis B (CHB) virus infection. Methods: Non-cirrhotic, treatment-naïve subjects with CHB were divided into five groups (10 patients each) and randomized within each group in a ratio of 6:2:2 to receive an ascending dose of 30, 60, 75, 90, or 120 mg pradefovir, 10 mg adefovir dipivoxil (ADV), or 300 mg tenofovir disoproxil fumarate (TDF) once a day for 28 days. Results: A total of 51 subjects were randomized and 49 subjects completed the study. The groups were well matched and included 39 males, of whom 71% were hepatitis B e-antigen-negative with a mean hepatitis B virus (HBV) DNA level of 6.4–7.16 log10 IU/mL. No subject experienced a serious adverse event or nephrotoxicity. The most frequently reported adverse event was asymptomatic reduction in blood cholinesterase levels in the pradefovir group which recovered without any treatment about 13±7 days after drug discontinuation. This adverse event was not observed in the ADV and TDF groups. The mean changes in serum HBV DNA were -2.78, -2.77, -3.08, -3.18, -3.44, -2.34, and -3.07 log10 IU/mL at 30, 60, 75, 90, and 120 mg pradefovir, 10 mg ADV and 300 mg TDF, respectively, with plateau levels reached with 60 mg pradefovir. Pradefovir and its metabolite PMEA showed linear pharmacokinetics proportional to the dose. The half-life of PMEA in the pradefovir group was 11.47–17.63 h.
2
Conclusions: Short-term use of pradefovir was well tolerated. A decline in HBV DNA levels was superior to TDF at higher doses of pradefovir. 30–60 mg pradefovir is recommended for CHB treatment.
Clinical trial number: CTR20150224 Keywords: Prodrug; pharmacokinetics; safety; Viral hepatitis; Clinical Trial
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Introduction Chronic hepatitis B (CHB) virus infection affects more than 350 million individuals worldwide, with a high prevalence in Asian and Sub-Saharan African countries [1–2]. Persistent viral replication is an independent risk factor for the development of cirrhosis, hepatocellular carcinoma, and liver-related mortality [3–6]. Adefovir dipivoxil (ADV), a diester prodrug of the active moiety adefovir (PMEA) is effective in lamivudine-resistant CHB patients [7-8]. Long-term ADV use helps achieve and maintain viral suppression, regression of fibrosis, and reversal of cirrhosis in most patients [9], However, PMEA is actively transported into the renal proximal tubules and causes nephrotoxicity at ADV doses of 30–120 mg/day [10]. Hence, ADV, is used at submaximal dose of 10 mg because of it’s renal toxicity. Pradefovir, a hepatic targeted novel prodrug of PMEA developed by utilizing the HepDirectTM patented technology, enhances the delivery of PMEA to the liver. Different from ADV, the majority of pradefovir is metabolized to PMEA in the hepatocytes; it remains unchanged until penetration in to the hepatocytes, after which it is converted to PMEA by cytochrome P450 isozyme 3A4 [11-13]. This selectively liver-activated prodrug enhances liver levels of the active metabolite adefovir diphosphate (ADV-DP) and decreases serum and renal concentrations. These features lead to a high PMEA concentration in the liver and very low concentration in the serum which reduces the renal and bone toxicities associated with ADV [14]. The molecular weight of pradefovir is similar to that of ADV.
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The well-tolerated oral single dose of pradefovir varies between 10 and 120 mg and does not cause significant kidney impairment in healthy subjects and the maximum concentration (Cmax) and area under the plasma concentration-time curve from time 0 to 48 h (AUC0–48) of serum PMEA ranges from 18 to 312 ng/mL and 72 to 1095 ng*h/mL, respectively [15]. The clinical trials with pradefovir are currently on going. This phase Ib study is the first study conducted in China evaluating the efficacy and safety of pradefovir in CHB subjects.
Methods Study design This study was a randomized, active-controlled, open-label, phase 1b trial (Chinese Drug Trial Identifier: CTR20150224), and was conducted at the Phase I Clinical Research Center, The First Hospital of Jilin University (Jilin, China) between April 2015 and February 2017. A total of 50 CHB subjects were randomized (6:2:2) to receive pradefovir of 30, 60, 75, 90, or 120 mg respectively, 300mg TDF or 10mg ADV under fasting condition in an open labeled fashion. 10 subjects each group was in each block were randomized using the PLAN procedure of SAS software. Six patients received an ascending dose of 30, 60, 75, 90, or 120 mg pradefovir, and two patients were given 10 mg ADV, and the remaining two patients in each group were prescribed 300 mg TDF once a day for 28 days. One subject withdrawn from the study due to personal reason in the 60 mg pradefovir group was replaced. An ascending oral dose strategy for pradefovir was used, in which each group receives assigned dose only after reviewing the safety data from the previous group in the study.
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Serum beta HCG levels were checked during screening and enrollment to rule out pregnancy. Pradefovir was administered in the clinical research center on days 1–15. On the remaining days, the participants were advised to take the study medication at the same condition (Supplement Fig. 1). The study protocol was approved by the Ethics Committee of First Hospital of Jilin University. All patients provided written informed consent for participation in the trial. After screening, the subjects who met the requirements of the protocol (inclusion/exclusion criteria) were enrolled and a random number was assigned. If any clinical or laboratory abnormality was detected such as uncontrolled hypertension, hyperglycemia, etc, or the subject refuses to continue in the trial due to personal reasons before the first dose of the drug, then the original subject was replaced by a backup subject and 100 was added to the allotted random number for confirmation (eg random number was changed from 11 to 111). If the subjects fail to follow the protocol due to personal reasons during the clinical trial, the sponsor and the investigator will discuss whether to re-select a qualified subject to replace the subject with poor compliance. If so, then 100 was added to the allotted random number for confirmation.
Patient selection The following main selection criteria were used. Inclusion criteria were: 1) adult subjects aged 18 to 65 years; 2) non pregnant and nonlactating females; 3) chronic HBV infection (HBsAg(+) and HBsAg/HBV DNA(+)) > 6 months, and serum HBV DNA ≥ 1×105 IU/mL
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for hepatitis B e-antigen (HBeAg)(+) or HBV DNA ≥ 1×104 IU/mL for HBeAg(-); 4) alanine aminotransferase (ALT) between 2 and 10× upper limit of normal (ULN); 5) creatinine clearance (CrCl) rate≥ 70 mL/min. 5) treatment-naïve or terminated interferon or nucleos(t)ide analogue treatment at least 6 months before screening. Exclusion criteria were: 1) serum Cr ≥ 1.5× ULN; 2) Child-Pugh score of B or C; 3) co-infection
with
human
immunodeficiency
virus
and/or
hepatitis
C
virus;
4)
alpha-fetoprotein > 100 ng/mL; and 8) within 14 days of the trial, had used antacids, immunosuppressants, or drugs that affect the pharmacokinetics (PK) or safety evaluation of drugs in this trial.
Study drug and administration method Pradefovir was synthesized by Xi'an Xintong Research Co. Ltd. (Batch No. 150302; Shaanxi Sheng, China). ADV was synthesized by GlaxoSmithKline (Batch No. 15015095, Tianjin, China). TDF was synthesized by Gilead Sciences Co. Ltd. (Batch No. A842261; California, USA). All of the drugs were provided by Xi'an Xintong research Co. Ltd. The study drug was administered orally once daily in the morning with 240 mL water. The drugs were stored at room temperature until use.
Safety and tolerability Drug tolerability was regularly assessed by routine clinical examination, vital signs, laboratory tests, electrocardiograms, abdominal ultrasound, and chest X-ray. AEs were
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encoded using the Medical Dictionary for Regulatory Activities (MedDRA, version 16; MedDRA MSSO, McLean, VA, USA). The severity of the AEs and the grade of laboratory abnormalities were assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) 4.03. a 24 h urine samples were collected before the study drug doesed ; and a 0–24 h urine samples were collected as well on days 1, 7, 14, and 28; and they were analyzed for trace levels of albumin, α1-microglobulin, β2-microglobulin, glucosamine anhydride enzyme, glutathione transferase, and retinol-binding protein. Serum inorganic phosphorus and Cr were detected at pre-dose; day 1, 2, 8,15, and day 29.
Efficacy The primary endpoint was log change in serum HBV DNA from day 1 (baseline) to day 29. Blood samples were collected at baseline, 2, 4, 8, 24, and 48 h after first dose, on days 8, 15, and 22 pre-dose, and on day 29. Other endpoints included the log change in serum HBsAg and HBeAg from baseline and change in serum ALT. Blood samples were collected at baseline, on days 8 and 22 pre-dose, and on day 29.
PK study Blood samples for pradefovir and adefovir (PMEA) kinetic analyses were collected between 0- 24h post-dose, on days 1 and 14, pre-dose on days 3, 8, 12, 13, 15, and 22, and on day 29. Blood samples were collected and placed in a vacutainer without an anticoagulant, clotted for 30 min, and centrifuged at 3,500 rpm for 10 min at 4°C. Urine samples at 0, 0–6, 6–12, and
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12–24 h for pradefovir and PMEA were collected on days 1 and 14.
Detection methods HBV DNA level was quantified using Roche’s COBAS TaqMan Kit (Basel, Switzerland). The undetectable level was 20 IU/mL or less. HBsAg, anti-HBs, HBeAg, anti–HBe, and anti-HBc were tested using the chemiluminescence method. Serum concentrations of pradefovir and PMEA were determined by a validated high-performance liquid chromatography-tandem mass spectrometry method at Covance Laboratories (Shanghai, China). Nephrotoxicity factors were analyzed with an enzyme-linked immunoassay or using an automated biochemical detection instrument from Covance Laboratories or the First Hospital of Jilin University.
Statistical methods Serum PK parameters including maximum observed concentration (Cmax), time to maximum observed concentration (Tmax), area under the concentration-time curve from time of dosing (zero hour) to the last time point with measurable concentration (AUC0-t), AUC from time of dosing (zero hours) extrapolated to infinity (AUC0-∞), as well as terminal elimination half-life of the drug in serum (t½), clearance (CLz/F), volume (Vz/F) at first dose and Css max, AUCss0-t, AUCss0-∞, tss ½, Tss max, CLz/F ss, Vz/F ss, accumulation index (AI) and degree of fluctuation (Df) at last dose, were estimated based on the observed concentration-time data by the noncompartmental PK approach using WinNonlin version 6.4 (Pharsight Corporation,
9
Mountain View, CA). Descriptive statistics were used for presenting the PK parameters of pradefovir and PMEA. Dose proportionality of pradefovir and PMEA was determined using a power model and a linear fixed effects model. The relationship between reduction in log10 IU/mL of serum HBV DNA, and the time-weighted average change in HBV DNA (DAVG) [16] from baseline to day 29 and AUC0–24,ss was analyzed using Lowess curve fitting (local regression), linear regression, and the Emax model. Other variables were analyzed with the Student’s t-test, the Kruskal–Wallis test, regression analysis, or correlation analysis using SAS 9.1 software (Cary, NC, USA). P < 0.05 in two-sided tests was considered statistically significant.
Results A total of 51 subjects were enrolled and randomized in this study. Two subjects withdrew from the study due to the personal reasons and fracture (not related to the study drug) in the 60 mg pradefovir and TDF group respectively and the subject in the 60 mg pradefovir group was replaced. Subject no. 44 in TDF group had a road traffic accident with fracture on the 15th day during the clinical trial and was withdrawn from the clinical trial. Ultimately, 49 subjects completed the study. The flow diagram of patient recruitment in each group is shown in Supplement Figure 1. In general, the groups were well matched for demographics and disease characteristics (Table 1). The majority of subjects were males (76%) and HBeAg-negative (71%) with a mean HBV DNA level between 6.4 and 7.16 log10 IU/mL at
10
baseline. The baseline quantitative HBsAg and HBV DNA and ALT levels were comparable among the different treatment groups (P>0.05, Table 1).
Antiviral activity HBV DNA levels were variable on day 1 with no clear trend, but showed a steady decline from days 2 to 29. The lowest HBV DNA levels were seen on day 29. At week 4 (day 29), the mean changes in HBV DNA were -2.78, -2.64, -3.08, -3.18, -3.29, -2.34, and -3.07 log10 IU/mL with pradefovir doses of 30, 60, 75, 90, and 120 mg, 10 mg ADV, 300 mg TDF, respectively. The decline in HBV DNA levels was greater in the pradefovir group (30–120 mg) than in the ADV group. The mean decline in HBV DNA level was greater in the pradefovir group (75–120 mg) than in the TDF group (Fig. 1). When antiviral activity was assessed by DAVG and by the slope of viral decay over 4 weeks, there were no notable differences between the TDF and pradefovir group, but activity was significantly greater than in the ADV group (Table 2). Due to the small sample size, there were no significant differences in changes in the HBV DNA levels, DAVG22 and DAVG29 between each group on ANOVA statistical test. Viral decay slope was lesser in the adefovir dipivoxil group than other groups except 60mg pradefovir (P<0.05, Table 2). The viral declines were similar between the 30-60mg groups, and between the 75-120mg groups, which were slightly more than those of 30-60mg groups. Meanwhile the plateau phase for anti-HBV activity as measured by DAVG29 was achieved with a pradefovir dose of
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60 mg. Indeed, there was no dose dependent decline in HBV DNA levels with increasing doses of pradefovir. One subject in the TDF group had undetectable HBV DNA levels on day 29, with an HBV DNA level of 5.27 log10 IU/mL at baseline, which was relatively lower compared with the other subjects. There were no significant differences in HBV DNA levels between HBeAg-negative with and HBe-Ag-positive subjects in each group (Fig. 1). HBsAg and HBeAg levels did not significantly change after 28 days of treatment. None of the treated patients had HBsAg-negative conversion, HBeAg serum conversion, or HBsAg serum conversion. The ALT and AST levels showed a decreasing trend and the mean change was similar across all treatment groups (Fig. 2). The normalization of ALT and AST levels was similar among groups (Table 2).
PK analysis
Serum drug concentration analysis
Pradefovir was rapidly absorbed and eliminated, which contributed to the very low trough concentration. Pradefovir and PMEA steady state was achieved in about 3 days, and its serum concentrations increased in proportion to the doses (Fig. 3). The serum PK parameters of pradefovir and PMEA are shown in Tables 3 and Supplement Table 1. The peak time (Tmax) of pradefovir was between 0.25 and 0.625 h and the mean value of t1/2 was 1.91–4.27 h in each dose group, which indicated that the absorption and elimination were similar in each 12
dosage group. The Tmax of PMEA in the ADV group was 0.25–3.0 h, which was longer than that of the pradefovir group (0.25–1.5 h). The elimination of PMEA in ADV group (t1/2=7.09–7.44 h) was slightly faster than that in the pradefovir group (t1/2=11.47–17.63 h). The PK parameters (Tmax and t1/2) of pradefovir and PMEA were similar between days 1 and 14 in each dosage group. The Cmax of PMEA in the 10 mg ADV group was lower than that of the pradefovir group, and the exposure of PMEA (AUC) in the 10 mg ADV group was similar to that of 40–45 mg pradefovir according to Lowess regression analysis (Supplement Fig. 2). After repeated administration, there was slight accumulation, and the mean AIs of AUC and Cmax of pradefovir and PMEA were close to 1, with the exception of the AI of Cmax of PMEA in the ADV group (AI=2.3).
Urine drug concentration analysis
The renal clearance rate (CLr), urine accumulation excretion (ae0–24h), and urine accumulation excretion rate (fe0–24h%) of pradefovir and PMEA are shown in Supplement Figure 3. With the increase in dosage, the ae0–24h of pradefovir in urine increased, and the fe0–24h% of pradefovir was close in each dosage group. The CLr of pradefovir ranged from 26 to 54 L/h, and the CLr of PMEA of pradefovir group ranged from 13.0 to 19.8 L/h, with no significant difference in each dosage group. The fe0–24hr% of these groups was much higher than the glomerular filtration rate (~7.5 L/h). There was no significant difference in CLr, ae0–24h and fe0–24h% between days 1 and 14. The CLr of PMEA of the 10 mg ADV
13
group ranged from 10.4 to 14.0 L/h, with no significant difference between the pradefovir and ADV groups.
Analysis of linear correlation between exposure and pradefovir dosage
Over the range of pradefovir and PMEA exposure (Cmax and AUC) for each dosage group of pradefovir on days 1 and 14, the slope (90% confidence interval) in the power model was very close to 1 (regression coefficient for the power model: 0.93-1.07), which indicated that the linear PK and the Cmax and AUC of pradefovir and PMEA increased with an increase in dose (Supplement Fig. 2A).
Analysis of PK and pharmacodynamics
Greater antiviral activity was associated with a higher dosage and serum PMEA exposure. The relationship between reduction in log10 IU/mL of serum HBV DNA from baseline to day 29 and AUC0–24,ss could not be analyzed appropriately by linear regression and the Emax model. Only Lowess regression could be used to describe the relationship trend, which showed a platform trend after 60 mg pradefovir (Supplement Fig. 2).
Safety
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Pradefovir was generally safe and well tolerated over the 28 days of treatment. Overall, 47/51 subjects (92.2%) experienced 210 AEs, 45/51 (88.2%) experienced 164 adverse reactions, and 21/51 (41.2%) experienced 40 AEs of CTC Grade ≥ 2. One subject in the TDF group reported one severe AE (fracture not related to the study drug). No AEs related to death occurred. AEs occurred in both the pradefovir and control groups (ADV or TDF) with a similar frequency (Supplement Table 2). Most AEs were mild or moderate in intensity. The most frequently reported AEs were reductions in blood cholinesterase (ChE) levels in the pradefovir group and recovered without treatment about 13±7 days after drug discontinuation, which did not occurred in the ADV and TDF groups (Supplement Fig. 4). However, their total bilirubin (TBIL), retinol-conjugated protein and prealbumin level did not significantly change and only showed some fluctuations (Fig. 2). No subject experienced grade 4 laboratory abnormalities.
There were no significant differences in serum Cr levels and
serum CrCl rate among the different days or different groups (Fig. 2). Over the 28 days of treatment, no differences were observed among different treatment groups with regard to changes in serum inorganic phosphorus and serum Cr levels, and urine nephrotoxicity markers (Fig. 2 and Supplement Fig. 5).
Discussion
In this phase 1b trial, we found that pradefovir was as effective as TDF in the short-term period, and 4–4.5 fold reduced systemic levels of PMEA with better antiviral activity in the
15
pradefovir group compared to the ADV group [17–18]. The log10 change in serum HBV DNA levels (primary endpoint) revealed a consistent antiviral effect across the pradefovir treatment groups (Fig. 1). On day 29, the mean change in HBV DNA was approximately -3.09–-3.30 log10 IU/mL, with no significant difference in the 75–120 mg doses. However, similar results were observed with 60–120 mg pradefovir when the change in HBV DNA was evaluated by DAVG4, a metric with that is sensitive enough to detect even small differences among treatment groups [16]. On evaluation of the treatment effect by slope of viral decline over 28 days (decay slope≈ -1), no significant differences were observed. The change in HBV DNA in the 60–120mg pradefovir group was similar to that of the 300 mg TDF group. The short-term viral decline observed with TDF in this study was comparable to the results of previous studies (mean decline of about −2.9 log10 IU/mL with no significant difference between the HBeAg-positive and HBeAg-negative groups) [19]. Quantitative HBsAg and HBeAg levels remained essentially unchanged as anticipated [8,19–20]. In a previous study conducted in the United States, after 24 weeks treatment, the median log HBV decline was 3.66 for 10 mg ADV, and 3.32-5.07 for pradefovir at doses of 5-30 mg, respectively. PK/pharmacodynamic analyses indicated that 30 mg pradefovir achieved 98% of the Emax [21]. However, in this study, 60 mg was the most effective saturated dose.
In CHB patients, the PK of pradefovir were dose-proportional with efficient absorption (Tmax < 1 h) and rapid serum elimination (mean t1/2 < 4.27 h). Concentrations of pradefovir were undetectable in serum 6–8 h after treatment in all groups. Circulating serum PMEA
16
levels in patients of the pradefovir group were lower than those in the ADV group, which proved that the HepDirect TM patented technology for pradefovir was successful [22]. The PK of PMEA were dose-proportional, with efficient transformation from pradefovir (median Tmax, 0.5–0.75 h) and relatively slow serum elimination (mean t1/2, 11.47–17.82 h). The AI of PMEA was low, which supports QD dosing of pradefovir [21,23]. The Tmax was similar and the t1/2 was shorter than those in healthy subjects (Tmax: 0.87–0.82 h; t1/2: 19–312 h) [15]. The rates of clearance of pradefovir and its metabolite PMEA were much higher than the glomerular filtration rate (~7.5 L/h), suggesting that there was active tubular secretion along with glomerular filtration as shown in a previous study of pradefovir in American HBV patients [23].
The 28-day therapy of pradefovir, ADV and TDF were safe and well tolerated. No renal AEs were observed in this study such as urine nephrotoxicity markers and CrCl rate [24-27]. However, the impairment of renal function (renal toxicity) may occur with long term treatment for 2-5 years. Hence, future long-term phase II-IV trials are required to verify our results [15]. Previous clinical reports of HBV-infected patients treated with ADV have suggested the potential association between higher PMEA serum levels (i.e., elevated trough serum levels) and renal toxicity characterized by a gradual rise in serum Cr accompanied by decrease in serum phosphorus level with a rising dose of ADV from 30 to 120 mg [28].
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ChE is an enzyme synthesized by hepatocytes and its serum levels reflect the synthetic function of liver [29]. Serum bilirubin, albumin, prothrombin time, and MELD score were all normal and only ChE level decreased with pradefovir therapy in this study, which spontaneously returned to normal after stopping the pradefovir. However, none of the patients developed any symptom associated with CHE reduction such as tremors, blurring of vision, urine and fecal incontinence. In a near complete phase II clinical study of 48-week pradefovir treatment in China, CHE was similarly reduced, and the subjects had no symptoms of CHE reduction or abnormalities of liver functions (serum bilirubin, albumin, prothrombin time, and MELD score, data not shown). Therefore, we analyzed that pradefovir did not affect synthetic function of liver. Moreover, when pradefovir was added to the blood of healthy subjects, the ChE level did not change in vitro (-72±172 μmol/L). Thus, we speculate that CHE reduction may be due to interference of the pradefovir metabolites in the blood CHE quantification process. Also, the CHE levels could spontaneously recover after pradefovir metabolites are cleared from the body, especially in the liver. Because pradefovir is a diester prodrug of PMEA, despite low serum PMEA concentration, other metabolites may also persist in the hepatocytes. The recovery period of about 13 days, which is 9 days longer than the lasting time of serum PMEA (5× t1/2 of PMEA) could support the above [30]. Finally, we hypothesize that pradefovir and its metabolite-PMEA do not affect CHE level detection, but other unknown metabolites may affect CHE level detection.
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Although PMEA is not an active metabolite, it indirectly reflects the exposure of the active anti-HBV metabolite. The clinical therapeutic dose for ADV is 10 mg, which corresponds to a pradefovir dose of 40–45 mg by PMEA exposure (Supplement Fig. 2). Thus, the phase II clinical trial dosage could be increased to 45 mg QD of pradefovir [30]. The plateau phase for anti-HBV activity as measured by DAVG29 was achieved with a pradefovir dose of 60 mg. So, we believe that this should be the optimum dose used in future trials [30]. ADV nephrotoxicity occurred at 30 mg, which corresponded to PMEA exposure of 692.4 ng*h/mL (230.8×3 from 10 mg ADV at Table 3) and a pradefovir dose of about 90 mg. Therefore, 90 mg pradefovir could be used in the future studies, and if nephrotoxicity is a concern due to other reasons, the pradefovir dosage could be reduced to 75 mg QD [8,30]. In conclusion, this phase Ib trial found that 28 days of therapy with pradefovir, a new PMEA prodrug, was safe and well tolerated by CHB patients. The antiviral activity of pradefovir was similar to that of TDF over a wide range of doses. Moreover, pradefovir was associated with significantly reduced serum PMEA levels compared to ADV. Based on the above findings, we found that the clinical therapeutic dose of ADV-10 mg is equal to pradefovir dose 40–45 mg. A dose close to 45mg was selected for the subsequent phase II clinical trial. Later 30, 45 and 60 mg QD pradefovir was recommended to be an appropriate dosage in phase II clinical trial.
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Acknowledgements
The authors would like to thank all the patients in this study.
Funding
This work was financially supported by the National Major Scientific and Technological Special Project for Significant New Drug Development during the Thirteenth Five-Year PlanPeriod of China (Project: 2017ZX09304004, 2017ZX09101001-002-004), the National Natural Science Foundation of China (Project: 81602897) and Xi'an Xintong research Co Ltd.,.
Authors’ contributions
Yanhua Ding, JunqiNiu and Hong zhang contributed to the conception and design of the study, data acquisition, and data analysis and interpretation. Hong Chen, Xiaojiao Li, Xiaoxue Zhu and Min Wu contributed to the data acquisition, data analysis, and interpretation. Hong Zhang, Weili Jin, Cuiyun Li, Jingrui Liu and Chengjiao Liu contributed to the data analysis and interpretation. All authors made critical revisions to the draft versions of the manuscript and approved the final manuscript.
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Conflict of interest
The authors declare that they have no conflicts of interests.
Compliance with ethical standards
Ethical approval The study was performed in accordance with Good Clinical Practice and the Declaration of Helsinki principles for ethical research. The study protocol was approved by the independent central ethics committee of The First Hospital of Jilin University. Written informed consent was obtained from each participant. Chinese Drug Trial Identifier: CTR20150224. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 (5). Informed consent Informed consent was obtained from all patients for being included in the study.
21
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[14] Agarwal K, Brunetto M, Seto WK, Lim YS, Fung S, Marcellin P, Ahn SH, Izumi N8, Chuang WL, Bae H, Sharma M, Janssen HLA, Pan CQ, Çelen MK, Furusyo N, Shalimar D, Yoon KT, Trinh H, Flaherty JF, Gaggar A, Lau AH, Cathcart AL, Lin L, Bhardwaj N, Suri V, Mani Subramanian G, Gane EJ, Buti M2, Chan HLY. 96 weeks treatment of tenofovir alafenamide vs. tenofovir disoproxil fumarate for hepatitis B virus infection. J Hepatol. 2018, 68(4):672-681. [15]
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Int. 2017,11(4):390-400. [16] Zolopa AR1, Berger DS, Lampiris H, Zhong L, Chuck SL, Enejosa JV, Kearney BP, Cheng AK. Activity of elvitegravir, a once-daily integrase inhibitor, against resistant HIV Type 1: results of a phase 2, randomized, controlled, dose-ranging clinical trial.J Infect Dis. 2010,201(6):814-22. [17] Peters MG, Hann Hw Hw, Martin P, Heathcote EJ, Buggisch P, Rubin R, Bourliere M, Kowdley K, Trepo C, Gray Df Df, Sullivan M, Kleber K, Ebrahimi R, Xiong S, Brosgart CL. Adefovir dipivoxil alone or in combination with lamivudine in patients with lamivudine-resistant chronic hepatitis B. Gastroenterology. 2004,126(1):91-101. [18]Perrillo R, Hann HW, Mutimer D, Willems B, Leung N, Lee WM, Moorat A, Gardner S, Woessner M, Bourne E, Brosgart CL, Schiff E.Adefovir dipivoxil added to ongoing
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lamivudine in chronic hepatitis B with YMDD mutant hepatitis B virus.Gastroenterology. 2004, 126(1):81-90. [19]Kaneko S, Kurosaki M, Tamaki N, Itakura J, Hayashi T, Kirino S, Osawa L, Watakabe K, Okada M, Wang W, Shimizu T, Higuchi M, Takaura K, Yasui Y, Tsuchiya K, Nakanishi H, Takahashi Y, Watanabe M, Izumi N.Tenofovir alafenamide for hepatitis B virus infection including switching therapy from tenofovir disoproxil fumarate.J Gastroenterol Hepatol. 2019.[Epub ahead of print]
[20]Chan HL, Fung S, Seto WK, Chuang WL, Chen CY Kim HJ6, Hui AJ, Janssen HL, Chowdhury A, Tsang TY, Mehta R, Gane E, Flaherty JF, Massetto B, Gaggar A, Kitrinos KM, Lin L, Subramanian GM, McHutchison JG, Lim YS, Acharya SK, Agarwal K; GS-US-320-0110 Investigators.Tenofovir alafenamide versus tenofovir disoproxil fumarate for the treatment of HBeAg-positive chronic hepatitis B virus infection: a randomised, double-blind, phase 3, non-inferiority trial.Lancet Gastroenterol Hepatol. 2016,1(3):185-195. [21] Lin, C., Xu, C.,Yeh, L. Pharmacokinetics and pharmacodynamics of pradefovir, a liver-targeting prodrug of PMEA in HBV patients. JOURNAL OF HEPATOLOGY.2006,44: S16-S16. [22] Agarwal K, Fung SK, Nguyen TT, Cheng W, Sicard E, Ryder SD, Flaherty JF, Lawson E, Zhao
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[23]Lee, K. S, Lim, S. G, Chuang, W. L. Safety, tolerability and antiviral activity of pradefovir mesylate in patients with chronic hepatitis B virus infection: 48-week analysis of a phase 2 study. JOURNAL OF HEPATOLOGY. 2006,44: S274-S274. [24] Chan A, Park L, Collins LF, Cooper C, Saag M, Dieterich D, Sulkowski M, Naggie S.Correlation Between Tenofovir Drug Levels and the Renal Biomarkers RBP-4 and ß2M in the ION-4 Study Cohort. Open Forum Infect Dis.2019, 6(1):ofy273. [25] Li Z, Shen C, Wang Y, Wang W, Zhao Q, Liu Z, Wang Y, Zhao C. Circulating kidney injury molecule-1 is a novel diagnostic biomarker for renal dysfunction during long-term adefovir therapy in chronic hepatitis B. Medicine (Baltimore). 2016 Nov;95(44):e5264. [26] Wang BF, Wang Y, Wang BY, Sun FR, Zhang D, Chen YS. Osteomalacia and Fanconi's syndrome caused by long-term low-dose adefovir dipivoxil. J Clin Pharm Ther. 2015, 40(3):345-8. [27] Rodríguez-Nóvoa S, Labarga P, D'avolio A, Barreiro P, Albalate M, Vispo E, Solera C, Siccardi
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Impairment in kidney tubular function in patients receiving tenofovir is associated with highe rtenofovir plasma concentrations.AIDS. 2010, 24(7):1064-6. [28] FDA Advisory Committee Briefing Document: Adefovir dipivoxil for the treatment of chronic hepatitis B. NDA 21-449 Gilead Sciences, Foster City, Calif. July 2002. Available at: http://www.fda.gov/ohrms/dockets/ac/02/briefing/3885B1_01_Gilead.pdf. Accessed February 12, 2003.
26
[29]
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Figure Legends Figure 1. HBV DNA levels at different time points during the course of treatment (all were compared to values at baseline, the dotted line represents HBeAg-negative and the solid line represents HbeAg-positive). (A–E) 30–120 mg pradefovir, (F) 10 mg ADV (G) 300 mg TDF and (H) the mean change in HBV DNA levels in each group. Figure 2. Changes in mean serum biochemical index of the groups at different time points during the treatment. Mean ALT levels (A); mean AST levels (B); mean γ-glutamyl transpeptidase levels (C); mean Cr levels (D); mean cholinesterase levels (E); mean TBIL levels (F); mean inorganic phosphorus levels (G); mean retinol-conjugated protein levels (H); mean prealbumin levels (I); mean serum ClCr levels (J). Figure 3. Mean values of serum pradefovir and adefovir (PMEA) concentration-time profiles in each treatment group Mean (±SD) pradefovir plasma concentration-time profiles (A) and Mean (±SD) adefovir (PMEA) plasma concentration-time profiles (B); Mean (±SD) pradefovir plasma 27
concentration-time profiles (log value, C) and Mean (±SD) adefovir (PMEA) plasma concentration-time profiles (log value, D).
28
Table 1. Baseline demographics and disease characteristics. pradefovir tenofovir
30mg
60mg
75mg
90mg
120mg
adefovir dipivoxil 10mg
(N=6)
(N=7)
(N=6)
(N=6)
(N=6)
(N=10)
(N=10)
Age, mean(SD),Year
40(8.94)
36.4(5.97)
33(5.76)
32.2(6.46)
47.2(8.45)
43.4(13.72)
38.1(8.72)
Gender,male/female,n
5/1
6/1
6/0
6/0
4/2
6/4
6/4
BMI,mean(SD),kg/m2
22.68(2.73)
24.16(2.71)
23.65(3.69)
23.55(2.58)
24.25(3.61)
22.83(3.74)
23.8(2.23)
Ethnicity (Han/Other)
5/1
5/2
6/0
6/0
5/1
10/0
9/1
HBV DNA, mean(SD), log10 IU/mL
6.90(1.86)
7.16(1.24)
6.40(1.21)
6.60(1.38)
6.95(2.21)
6.66(1.01)
6.77(1.24)
HBsAg,mean(SD),
2.84(1.45)
4.11(0.45)
3.61(0.82)
3.65(0.74)
3.46(1.29)
3.36(0.95)
3.13(1.21)
HBeAg positive/negative
2/4
1/6
2/4
1/5
2/4
4/6
3/7
ALT, mean(SD),U/L
184.6(53.9)
99.9(51.2)
159.1(96.0)
225.2(153.3)
184.1(101.1)
149.7(77.2)
129.0(47.8)
Baseline parameter
log10 IU/mL
disoproxil 300mg
29
Table 2. Summary of measures for antiviral activity(Mean± ±SD) pradefovir
P
Endpoint
The change from baseline to day 22 in HBV DNA, log10IU/mL The change from baseline to
30mg(N=6)
60mg(N=7)
75mg(N=6)
90mg(N=6)
120mg(N=6)
-2.44(0.987)
-2.47(0.317)
-2.80(0.398)
-2.85(0.454)
-3.08(1.261)
adefovir dipivoxil
tenofovir disoproxil
10mg(N=10)
300mg(N=10) 0.27
-2.10(0.596)
-2.49(0.958) 0.36
-2.79(1.180)
-2.65(0.386)
-3.09(0.391)
-3.18(0.544)
-3.30(1.308)
-2.35(0.722)
-3.07(1.157)
DAVG22, log10 IU/ml
-1.42 (0.666)
-2.14 (1.423)
-1.71 (0.346)
-1.74 (0.360)
-2.10 (0.945)
-1.16 (0.457)
-1.64 (0.813)
0.20
DAVG29, log10 IU/ml
-1.72 (0.764)
-2.25 (1.596)
-2.02 (0.352)
-2.06 (0.380)
-2.12 (0.833)
-1.43 (0.499)
-2.06 (1.078)
0.55
Viral decay slope from baseline to day 29
-1.09 (0.155)
-0.94 (0.128)
-1.18 (0.160)
-1.22 (0.163)
-1.23 (0.186)
-0.85 (0.103)
-1.06 (0.123)
ALT normalization, n
1
1
2
2
1
1
3
AST normalization, n
1
0
3
1
1
0
4
day 29 in HBV DNA, log10IU/mL
<0.05*
HBV, hepatitis B virus; NA, not applicable; *: Viral decay slope was lesser in adefovir dipivoxil group than other group except 60 mg pradefovir (P<0.05); HBV DNA was set to 15 IU/mL if the observed value was less than the lower limit of quantification (20 IU/mL), when deriving changes from baseline.
30
Table 3. PK parameters of adefovir (PMEA) between the first dose and steady state in each treatment group (geomean(cv%)). dose
Cmax
Tmax*
AUC0-24
t1/2
CL/F
VZ/F
Df
AI
AI
(ng/mL)
(h)
(ng*h/mL)
(h)
(L/h)
(L)
(%)
AUC
Cmax
31
day1 adefovir
222.7(26.3 222.7 21.4(23.3) 21.4
dipivoxil10mg(N=10)
1.25(0.25-3)
7.44(15.3) 7.44
22.7(26.3) 22.7
244.6(34.3) 244.6
9.4(35.0) 9.4
97.7(55.1) 97.7
1119.8() 1119.8
) 167.5(38.2 167.5
30mg(N=6)
50.4(46.1) 50.4 0.875(0.5-1.5) 111.5(31.6 111.5
60mg(N=7)
) 325.5(15.4 325.5
10.62(27.8 10.62
0.75(0.50.75(0.5-0.75)
1279.4(19. 1279.4 85.8(16.8) 85.8
)
)
)
8)
130.6(20.6 130.6
346.7(22.3 346.7
11.25(42.7 11.25
105.1(32.3 105.1
1540.3(28. 1540.3
)
)
)
2)
429.9(13.6 429.9
10.59(24.9 10.59
75mg(N=6) )
0.50(0.5-1.5)
134.3(24.5 134.3
97.7(14.9) 97.7
90mg(N=6)
Pradefovir
1463.8(20. 1463.8
)
0.625(0.5-1)
)
)
2)
233.4(44.7 233.4
0.875(0.5-1.0
714.9(31.1 714.9
11.63(28.9 11.63
1319.0(16. 1319.0
)
0)
)
)
120mg(N=6)
86.1(39.0) 86.1 1)
day14 32
adefovir
41.6(154.6
0.75(0.25-3.0
230.8(23.8
416.2(161. 7.09(26.2)
dipivoxil10mg(N=10)
)
0)
11.47(43.0
1345.6(30. 89.9(44.9) 89.9(44.9)
118.4(25.7
126.0(50.0
3)
)
419.4(20.1
17.82(40.7
1932.3(36.
1.3(13.6 642.9(16.9)
122.8(43.9
)
7)
)
420.0(27.0
13.94(40.7
1861.8(24.
1.2(16.5 658.3(29.1)
)
4)
)
515.1(26.9
13.54(35.3
1880.6(45.
1.2(16.9
96.3(21.2) 0.625(0.5-1)
206.3(63.9 120mg(N=6)
521.5(23.5)
0.9(21.7)
)
)
5)
)
813.0(44.4
17.63(32.4
2074.8(18.
1.1(21.5
0.625(0.50.625(0.5-1.5) )
0.9(35.6)
)
90mg(N=6) )
1.2(35.0)
)
99.9(27.3) 99.9(27.3) 0.75(0.25-1.5)
1.0 (30.9)
)
75mg(N=6) )
1.2(21.4 552.0(16.4)
78.1(23.2) 0.75(0.5-0.75)
)
)
60mg(N=6) )
1.1(5.5) 4)
48.7(41.0) 0.5(0.5-1)
Pradefovir
244.4(27.9)
) 197.3(30.4
30mg(N=6)
24.5(25.6)
2.3(180.6
89.2(38.1) )
)
553.2(29.8) 1)
1.0(45.0) )
accumulation index: AI; fluctuation: Df *: median (min-max).
33
Highlights Pradefovir was associated with reduced serum PMEA levels compared to ADV. The antiviral activity of pradefovir was greater after pradefovir than ADV, and it was similar to that of TDF. pradefovir demonstrated a favorable safety profile and excellent anti-HBV activity. pradefovir could be a promising anti-HBV drug.
S0166-3542(19)30500-5
DOI:
https://doi.org/10.1016/j.antiviral.2019.104693
Reference:
AVR 104693
To appear in:
Antiviral Research
Received Date: 30 August 2019 Revised Date:
15 November 2019
Accepted Date: 11 December 2019
Please cite this article as: Zhang, H., Liu, J., Zhu, X., Li, X., Jin, W., Chen, H., Wu, M., Li, C., Liu, C., JunqiNiu, , Ding, Y., Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection, Antiviral Research (2020), doi: https://doi.org/10.1016/j.antiviral.2019.104693. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier B.V.
Safety, efficacy, and pharmacokinetics of pradefovir for the treatment of chronic hepatitis B infection
Running title: Pradefovir for chronic hepatitis B infection
Hong Zhang1, Jingrui Liu1, Xiaoxue Zhu1, Xiaojiao Li1, Weili Jin3, Hong Chen1, Min Wu1, Cuiyun Li1, Chengjiao Liu1, JunqiNiu2, Yanhua Ding1
1 Phase I Clinical Research Center, The First Hospital of Jilin University, Jilin, China 2 Department of Hepatology, The First Hospital of Jilin University, Jilin, China 3 Xi'an Xintong Pharmaceutical Research Co., Ltd.
Corresponding Author: Dr. Yanhua Ding, Phase I Clinical Trial Unit, The First Hospital, Jilin University, Changchun 130021, China; Tel/Fax: +86-431-88782705; Email: [email protected] Dr. JunqiNiu, Department of Hepatology, The First Hospital, Jilin University, Changchun 130021, China; Tel/Fax: +86-431-88782705; Email: [email protected]
1
Abstract Background & Aims: Pradefovir is a liver targeted novel prodrug of adefovir (PMEA) developed to provide higher antiviral activity with reduced systemic toxicities. This study evaluated the tolerability, pharmacokinetics, and antiviral activity of pradefovir in patients with chronic hepatitis B (CHB) virus infection. Methods: Non-cirrhotic, treatment-naïve subjects with CHB were divided into five groups (10 patients each) and randomized within each group in a ratio of 6:2:2 to receive an ascending dose of 30, 60, 75, 90, or 120 mg pradefovir, 10 mg adefovir dipivoxil (ADV), or 300 mg tenofovir disoproxil fumarate (TDF) once a day for 28 days. Results: A total of 51 subjects were randomized and 49 subjects completed the study. The groups were well matched and included 39 males, of whom 71% were hepatitis B e-antigen-negative with a mean hepatitis B virus (HBV) DNA level of 6.4–7.16 log10 IU/mL. No subject experienced a serious adverse event or nephrotoxicity. The most frequently reported adverse event was asymptomatic reduction in blood cholinesterase levels in the pradefovir group which recovered without any treatment about 13±7 days after drug discontinuation. This adverse event was not observed in the ADV and TDF groups. The mean changes in serum HBV DNA were -2.78, -2.77, -3.08, -3.18, -3.44, -2.34, and -3.07 log10 IU/mL at 30, 60, 75, 90, and 120 mg pradefovir, 10 mg ADV and 300 mg TDF, respectively, with plateau levels reached with 60 mg pradefovir. Pradefovir and its metabolite PMEA showed linear pharmacokinetics proportional to the dose. The half-life of PMEA in the pradefovir group was 11.47–17.63 h.
2
Conclusions: Short-term use of pradefovir was well tolerated. A decline in HBV DNA levels was superior to TDF at higher doses of pradefovir. 30–60 mg pradefovir is recommended for CHB treatment.
Clinical trial number: CTR20150224 Keywords: Prodrug; pharmacokinetics; safety; Viral hepatitis; Clinical Trial
3
Introduction Chronic hepatitis B (CHB) virus infection affects more than 350 million individuals worldwide, with a high prevalence in Asian and Sub-Saharan African countries [1–2]. Persistent viral replication is an independent risk factor for the development of cirrhosis, hepatocellular carcinoma, and liver-related mortality [3–6]. Adefovir dipivoxil (ADV), a diester prodrug of the active moiety adefovir (PMEA) is effective in lamivudine-resistant CHB patients [7-8]. Long-term ADV use helps achieve and maintain viral suppression, regression of fibrosis, and reversal of cirrhosis in most patients [9], However, PMEA is actively transported into the renal proximal tubules and causes nephrotoxicity at ADV doses of 30–120 mg/day [10]. Hence, ADV, is used at submaximal dose of 10 mg because of it’s renal toxicity. Pradefovir, a hepatic targeted novel prodrug of PMEA developed by utilizing the HepDirectTM patented technology, enhances the delivery of PMEA to the liver. Different from ADV, the majority of pradefovir is metabolized to PMEA in the hepatocytes; it remains unchanged until penetration in to the hepatocytes, after which it is converted to PMEA by cytochrome P450 isozyme 3A4 [11-13]. This selectively liver-activated prodrug enhances liver levels of the active metabolite adefovir diphosphate (ADV-DP) and decreases serum and renal concentrations. These features lead to a high PMEA concentration in the liver and very low concentration in the serum which reduces the renal and bone toxicities associated with ADV [14]. The molecular weight of pradefovir is similar to that of ADV.
4
The well-tolerated oral single dose of pradefovir varies between 10 and 120 mg and does not cause significant kidney impairment in healthy subjects and the maximum concentration (Cmax) and area under the plasma concentration-time curve from time 0 to 48 h (AUC0–48) of serum PMEA ranges from 18 to 312 ng/mL and 72 to 1095 ng*h/mL, respectively [15]. The clinical trials with pradefovir are currently on going. This phase Ib study is the first study conducted in China evaluating the efficacy and safety of pradefovir in CHB subjects.
Methods Study design This study was a randomized, active-controlled, open-label, phase 1b trial (Chinese Drug Trial Identifier: CTR20150224), and was conducted at the Phase I Clinical Research Center, The First Hospital of Jilin University (Jilin, China) between April 2015 and February 2017. A total of 50 CHB subjects were randomized (6:2:2) to receive pradefovir of 30, 60, 75, 90, or 120 mg respectively, 300mg TDF or 10mg ADV under fasting condition in an open labeled fashion. 10 subjects each group was in each block were randomized using the PLAN procedure of SAS software. Six patients received an ascending dose of 30, 60, 75, 90, or 120 mg pradefovir, and two patients were given 10 mg ADV, and the remaining two patients in each group were prescribed 300 mg TDF once a day for 28 days. One subject withdrawn from the study due to personal reason in the 60 mg pradefovir group was replaced. An ascending oral dose strategy for pradefovir was used, in which each group receives assigned dose only after reviewing the safety data from the previous group in the study.
5
Serum beta HCG levels were checked during screening and enrollment to rule out pregnancy. Pradefovir was administered in the clinical research center on days 1–15. On the remaining days, the participants were advised to take the study medication at the same condition (Supplement Fig. 1). The study protocol was approved by the Ethics Committee of First Hospital of Jilin University. All patients provided written informed consent for participation in the trial. After screening, the subjects who met the requirements of the protocol (inclusion/exclusion criteria) were enrolled and a random number was assigned. If any clinical or laboratory abnormality was detected such as uncontrolled hypertension, hyperglycemia, etc, or the subject refuses to continue in the trial due to personal reasons before the first dose of the drug, then the original subject was replaced by a backup subject and 100 was added to the allotted random number for confirmation (eg random number was changed from 11 to 111). If the subjects fail to follow the protocol due to personal reasons during the clinical trial, the sponsor and the investigator will discuss whether to re-select a qualified subject to replace the subject with poor compliance. If so, then 100 was added to the allotted random number for confirmation.
Patient selection The following main selection criteria were used. Inclusion criteria were: 1) adult subjects aged 18 to 65 years; 2) non pregnant and nonlactating females; 3) chronic HBV infection (HBsAg(+) and HBsAg/HBV DNA(+)) > 6 months, and serum HBV DNA ≥ 1×105 IU/mL
6
for hepatitis B e-antigen (HBeAg)(+) or HBV DNA ≥ 1×104 IU/mL for HBeAg(-); 4) alanine aminotransferase (ALT) between 2 and 10× upper limit of normal (ULN); 5) creatinine clearance (CrCl) rate≥ 70 mL/min. 5) treatment-naïve or terminated interferon or nucleos(t)ide analogue treatment at least 6 months before screening. Exclusion criteria were: 1) serum Cr ≥ 1.5× ULN; 2) Child-Pugh score of B or C; 3) co-infection
with
human
immunodeficiency
virus
and/or
hepatitis
C
virus;
4)
alpha-fetoprotein > 100 ng/mL; and 8) within 14 days of the trial, had used antacids, immunosuppressants, or drugs that affect the pharmacokinetics (PK) or safety evaluation of drugs in this trial.
Study drug and administration method Pradefovir was synthesized by Xi'an Xintong Research Co. Ltd. (Batch No. 150302; Shaanxi Sheng, China). ADV was synthesized by GlaxoSmithKline (Batch No. 15015095, Tianjin, China). TDF was synthesized by Gilead Sciences Co. Ltd. (Batch No. A842261; California, USA). All of the drugs were provided by Xi'an Xintong research Co. Ltd. The study drug was administered orally once daily in the morning with 240 mL water. The drugs were stored at room temperature until use.
Safety and tolerability Drug tolerability was regularly assessed by routine clinical examination, vital signs, laboratory tests, electrocardiograms, abdominal ultrasound, and chest X-ray. AEs were
7
encoded using the Medical Dictionary for Regulatory Activities (MedDRA, version 16; MedDRA MSSO, McLean, VA, USA). The severity of the AEs and the grade of laboratory abnormalities were assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) 4.03. a 24 h urine samples were collected before the study drug doesed ; and a 0–24 h urine samples were collected as well on days 1, 7, 14, and 28; and they were analyzed for trace levels of albumin, α1-microglobulin, β2-microglobulin, glucosamine anhydride enzyme, glutathione transferase, and retinol-binding protein. Serum inorganic phosphorus and Cr were detected at pre-dose; day 1, 2, 8,15, and day 29.
Efficacy The primary endpoint was log change in serum HBV DNA from day 1 (baseline) to day 29. Blood samples were collected at baseline, 2, 4, 8, 24, and 48 h after first dose, on days 8, 15, and 22 pre-dose, and on day 29. Other endpoints included the log change in serum HBsAg and HBeAg from baseline and change in serum ALT. Blood samples were collected at baseline, on days 8 and 22 pre-dose, and on day 29.
PK study Blood samples for pradefovir and adefovir (PMEA) kinetic analyses were collected between 0- 24h post-dose, on days 1 and 14, pre-dose on days 3, 8, 12, 13, 15, and 22, and on day 29. Blood samples were collected and placed in a vacutainer without an anticoagulant, clotted for 30 min, and centrifuged at 3,500 rpm for 10 min at 4°C. Urine samples at 0, 0–6, 6–12, and
8
12–24 h for pradefovir and PMEA were collected on days 1 and 14.
Detection methods HBV DNA level was quantified using Roche’s COBAS TaqMan Kit (Basel, Switzerland). The undetectable level was 20 IU/mL or less. HBsAg, anti-HBs, HBeAg, anti–HBe, and anti-HBc were tested using the chemiluminescence method. Serum concentrations of pradefovir and PMEA were determined by a validated high-performance liquid chromatography-tandem mass spectrometry method at Covance Laboratories (Shanghai, China). Nephrotoxicity factors were analyzed with an enzyme-linked immunoassay or using an automated biochemical detection instrument from Covance Laboratories or the First Hospital of Jilin University.
Statistical methods Serum PK parameters including maximum observed concentration (Cmax), time to maximum observed concentration (Tmax), area under the concentration-time curve from time of dosing (zero hour) to the last time point with measurable concentration (AUC0-t), AUC from time of dosing (zero hours) extrapolated to infinity (AUC0-∞), as well as terminal elimination half-life of the drug in serum (t½), clearance (CLz/F), volume (Vz/F) at first dose and Css max, AUCss0-t, AUCss0-∞, tss ½, Tss max, CLz/F ss, Vz/F ss, accumulation index (AI) and degree of fluctuation (Df) at last dose, were estimated based on the observed concentration-time data by the noncompartmental PK approach using WinNonlin version 6.4 (Pharsight Corporation,
9
Mountain View, CA). Descriptive statistics were used for presenting the PK parameters of pradefovir and PMEA. Dose proportionality of pradefovir and PMEA was determined using a power model and a linear fixed effects model. The relationship between reduction in log10 IU/mL of serum HBV DNA, and the time-weighted average change in HBV DNA (DAVG) [16] from baseline to day 29 and AUC0–24,ss was analyzed using Lowess curve fitting (local regression), linear regression, and the Emax model. Other variables were analyzed with the Student’s t-test, the Kruskal–Wallis test, regression analysis, or correlation analysis using SAS 9.1 software (Cary, NC, USA). P < 0.05 in two-sided tests was considered statistically significant.
Results A total of 51 subjects were enrolled and randomized in this study. Two subjects withdrew from the study due to the personal reasons and fracture (not related to the study drug) in the 60 mg pradefovir and TDF group respectively and the subject in the 60 mg pradefovir group was replaced. Subject no. 44 in TDF group had a road traffic accident with fracture on the 15th day during the clinical trial and was withdrawn from the clinical trial. Ultimately, 49 subjects completed the study. The flow diagram of patient recruitment in each group is shown in Supplement Figure 1. In general, the groups were well matched for demographics and disease characteristics (Table 1). The majority of subjects were males (76%) and HBeAg-negative (71%) with a mean HBV DNA level between 6.4 and 7.16 log10 IU/mL at
10
baseline. The baseline quantitative HBsAg and HBV DNA and ALT levels were comparable among the different treatment groups (P>0.05, Table 1).
Antiviral activity HBV DNA levels were variable on day 1 with no clear trend, but showed a steady decline from days 2 to 29. The lowest HBV DNA levels were seen on day 29. At week 4 (day 29), the mean changes in HBV DNA were -2.78, -2.64, -3.08, -3.18, -3.29, -2.34, and -3.07 log10 IU/mL with pradefovir doses of 30, 60, 75, 90, and 120 mg, 10 mg ADV, 300 mg TDF, respectively. The decline in HBV DNA levels was greater in the pradefovir group (30–120 mg) than in the ADV group. The mean decline in HBV DNA level was greater in the pradefovir group (75–120 mg) than in the TDF group (Fig. 1). When antiviral activity was assessed by DAVG and by the slope of viral decay over 4 weeks, there were no notable differences between the TDF and pradefovir group, but activity was significantly greater than in the ADV group (Table 2). Due to the small sample size, there were no significant differences in changes in the HBV DNA levels, DAVG22 and DAVG29 between each group on ANOVA statistical test. Viral decay slope was lesser in the adefovir dipivoxil group than other groups except 60mg pradefovir (P<0.05, Table 2). The viral declines were similar between the 30-60mg groups, and between the 75-120mg groups, which were slightly more than those of 30-60mg groups. Meanwhile the plateau phase for anti-HBV activity as measured by DAVG29 was achieved with a pradefovir dose of
11
60 mg. Indeed, there was no dose dependent decline in HBV DNA levels with increasing doses of pradefovir. One subject in the TDF group had undetectable HBV DNA levels on day 29, with an HBV DNA level of 5.27 log10 IU/mL at baseline, which was relatively lower compared with the other subjects. There were no significant differences in HBV DNA levels between HBeAg-negative with and HBe-Ag-positive subjects in each group (Fig. 1). HBsAg and HBeAg levels did not significantly change after 28 days of treatment. None of the treated patients had HBsAg-negative conversion, HBeAg serum conversion, or HBsAg serum conversion. The ALT and AST levels showed a decreasing trend and the mean change was similar across all treatment groups (Fig. 2). The normalization of ALT and AST levels was similar among groups (Table 2).
PK analysis
Serum drug concentration analysis
Pradefovir was rapidly absorbed and eliminated, which contributed to the very low trough concentration. Pradefovir and PMEA steady state was achieved in about 3 days, and its serum concentrations increased in proportion to the doses (Fig. 3). The serum PK parameters of pradefovir and PMEA are shown in Tables 3 and Supplement Table 1. The peak time (Tmax) of pradefovir was between 0.25 and 0.625 h and the mean value of t1/2 was 1.91–4.27 h in each dose group, which indicated that the absorption and elimination were similar in each 12
dosage group. The Tmax of PMEA in the ADV group was 0.25–3.0 h, which was longer than that of the pradefovir group (0.25–1.5 h). The elimination of PMEA in ADV group (t1/2=7.09–7.44 h) was slightly faster than that in the pradefovir group (t1/2=11.47–17.63 h). The PK parameters (Tmax and t1/2) of pradefovir and PMEA were similar between days 1 and 14 in each dosage group. The Cmax of PMEA in the 10 mg ADV group was lower than that of the pradefovir group, and the exposure of PMEA (AUC) in the 10 mg ADV group was similar to that of 40–45 mg pradefovir according to Lowess regression analysis (Supplement Fig. 2). After repeated administration, there was slight accumulation, and the mean AIs of AUC and Cmax of pradefovir and PMEA were close to 1, with the exception of the AI of Cmax of PMEA in the ADV group (AI=2.3).
Urine drug concentration analysis
The renal clearance rate (CLr), urine accumulation excretion (ae0–24h), and urine accumulation excretion rate (fe0–24h%) of pradefovir and PMEA are shown in Supplement Figure 3. With the increase in dosage, the ae0–24h of pradefovir in urine increased, and the fe0–24h% of pradefovir was close in each dosage group. The CLr of pradefovir ranged from 26 to 54 L/h, and the CLr of PMEA of pradefovir group ranged from 13.0 to 19.8 L/h, with no significant difference in each dosage group. The fe0–24hr% of these groups was much higher than the glomerular filtration rate (~7.5 L/h). There was no significant difference in CLr, ae0–24h and fe0–24h% between days 1 and 14. The CLr of PMEA of the 10 mg ADV
13
group ranged from 10.4 to 14.0 L/h, with no significant difference between the pradefovir and ADV groups.
Analysis of linear correlation between exposure and pradefovir dosage
Over the range of pradefovir and PMEA exposure (Cmax and AUC) for each dosage group of pradefovir on days 1 and 14, the slope (90% confidence interval) in the power model was very close to 1 (regression coefficient for the power model: 0.93-1.07), which indicated that the linear PK and the Cmax and AUC of pradefovir and PMEA increased with an increase in dose (Supplement Fig. 2A).
Analysis of PK and pharmacodynamics
Greater antiviral activity was associated with a higher dosage and serum PMEA exposure. The relationship between reduction in log10 IU/mL of serum HBV DNA from baseline to day 29 and AUC0–24,ss could not be analyzed appropriately by linear regression and the Emax model. Only Lowess regression could be used to describe the relationship trend, which showed a platform trend after 60 mg pradefovir (Supplement Fig. 2).
Safety
14
Pradefovir was generally safe and well tolerated over the 28 days of treatment. Overall, 47/51 subjects (92.2%) experienced 210 AEs, 45/51 (88.2%) experienced 164 adverse reactions, and 21/51 (41.2%) experienced 40 AEs of CTC Grade ≥ 2. One subject in the TDF group reported one severe AE (fracture not related to the study drug). No AEs related to death occurred. AEs occurred in both the pradefovir and control groups (ADV or TDF) with a similar frequency (Supplement Table 2). Most AEs were mild or moderate in intensity. The most frequently reported AEs were reductions in blood cholinesterase (ChE) levels in the pradefovir group and recovered without treatment about 13±7 days after drug discontinuation, which did not occurred in the ADV and TDF groups (Supplement Fig. 4). However, their total bilirubin (TBIL), retinol-conjugated protein and prealbumin level did not significantly change and only showed some fluctuations (Fig. 2). No subject experienced grade 4 laboratory abnormalities.
There were no significant differences in serum Cr levels and
serum CrCl rate among the different days or different groups (Fig. 2). Over the 28 days of treatment, no differences were observed among different treatment groups with regard to changes in serum inorganic phosphorus and serum Cr levels, and urine nephrotoxicity markers (Fig. 2 and Supplement Fig. 5).
Discussion
In this phase 1b trial, we found that pradefovir was as effective as TDF in the short-term period, and 4–4.5 fold reduced systemic levels of PMEA with better antiviral activity in the
15
pradefovir group compared to the ADV group [17–18]. The log10 change in serum HBV DNA levels (primary endpoint) revealed a consistent antiviral effect across the pradefovir treatment groups (Fig. 1). On day 29, the mean change in HBV DNA was approximately -3.09–-3.30 log10 IU/mL, with no significant difference in the 75–120 mg doses. However, similar results were observed with 60–120 mg pradefovir when the change in HBV DNA was evaluated by DAVG4, a metric with that is sensitive enough to detect even small differences among treatment groups [16]. On evaluation of the treatment effect by slope of viral decline over 28 days (decay slope≈ -1), no significant differences were observed. The change in HBV DNA in the 60–120mg pradefovir group was similar to that of the 300 mg TDF group. The short-term viral decline observed with TDF in this study was comparable to the results of previous studies (mean decline of about −2.9 log10 IU/mL with no significant difference between the HBeAg-positive and HBeAg-negative groups) [19]. Quantitative HBsAg and HBeAg levels remained essentially unchanged as anticipated [8,19–20]. In a previous study conducted in the United States, after 24 weeks treatment, the median log HBV decline was 3.66 for 10 mg ADV, and 3.32-5.07 for pradefovir at doses of 5-30 mg, respectively. PK/pharmacodynamic analyses indicated that 30 mg pradefovir achieved 98% of the Emax [21]. However, in this study, 60 mg was the most effective saturated dose.
In CHB patients, the PK of pradefovir were dose-proportional with efficient absorption (Tmax < 1 h) and rapid serum elimination (mean t1/2 < 4.27 h). Concentrations of pradefovir were undetectable in serum 6–8 h after treatment in all groups. Circulating serum PMEA
16
levels in patients of the pradefovir group were lower than those in the ADV group, which proved that the HepDirect TM patented technology for pradefovir was successful [22]. The PK of PMEA were dose-proportional, with efficient transformation from pradefovir (median Tmax, 0.5–0.75 h) and relatively slow serum elimination (mean t1/2, 11.47–17.82 h). The AI of PMEA was low, which supports QD dosing of pradefovir [21,23]. The Tmax was similar and the t1/2 was shorter than those in healthy subjects (Tmax: 0.87–0.82 h; t1/2: 19–312 h) [15]. The rates of clearance of pradefovir and its metabolite PMEA were much higher than the glomerular filtration rate (~7.5 L/h), suggesting that there was active tubular secretion along with glomerular filtration as shown in a previous study of pradefovir in American HBV patients [23].
The 28-day therapy of pradefovir, ADV and TDF were safe and well tolerated. No renal AEs were observed in this study such as urine nephrotoxicity markers and CrCl rate [24-27]. However, the impairment of renal function (renal toxicity) may occur with long term treatment for 2-5 years. Hence, future long-term phase II-IV trials are required to verify our results [15]. Previous clinical reports of HBV-infected patients treated with ADV have suggested the potential association between higher PMEA serum levels (i.e., elevated trough serum levels) and renal toxicity characterized by a gradual rise in serum Cr accompanied by decrease in serum phosphorus level with a rising dose of ADV from 30 to 120 mg [28].
17
ChE is an enzyme synthesized by hepatocytes and its serum levels reflect the synthetic function of liver [29]. Serum bilirubin, albumin, prothrombin time, and MELD score were all normal and only ChE level decreased with pradefovir therapy in this study, which spontaneously returned to normal after stopping the pradefovir. However, none of the patients developed any symptom associated with CHE reduction such as tremors, blurring of vision, urine and fecal incontinence. In a near complete phase II clinical study of 48-week pradefovir treatment in China, CHE was similarly reduced, and the subjects had no symptoms of CHE reduction or abnormalities of liver functions (serum bilirubin, albumin, prothrombin time, and MELD score, data not shown). Therefore, we analyzed that pradefovir did not affect synthetic function of liver. Moreover, when pradefovir was added to the blood of healthy subjects, the ChE level did not change in vitro (-72±172 μmol/L). Thus, we speculate that CHE reduction may be due to interference of the pradefovir metabolites in the blood CHE quantification process. Also, the CHE levels could spontaneously recover after pradefovir metabolites are cleared from the body, especially in the liver. Because pradefovir is a diester prodrug of PMEA, despite low serum PMEA concentration, other metabolites may also persist in the hepatocytes. The recovery period of about 13 days, which is 9 days longer than the lasting time of serum PMEA (5× t1/2 of PMEA) could support the above [30]. Finally, we hypothesize that pradefovir and its metabolite-PMEA do not affect CHE level detection, but other unknown metabolites may affect CHE level detection.
18
Although PMEA is not an active metabolite, it indirectly reflects the exposure of the active anti-HBV metabolite. The clinical therapeutic dose for ADV is 10 mg, which corresponds to a pradefovir dose of 40–45 mg by PMEA exposure (Supplement Fig. 2). Thus, the phase II clinical trial dosage could be increased to 45 mg QD of pradefovir [30]. The plateau phase for anti-HBV activity as measured by DAVG29 was achieved with a pradefovir dose of 60 mg. So, we believe that this should be the optimum dose used in future trials [30]. ADV nephrotoxicity occurred at 30 mg, which corresponded to PMEA exposure of 692.4 ng*h/mL (230.8×3 from 10 mg ADV at Table 3) and a pradefovir dose of about 90 mg. Therefore, 90 mg pradefovir could be used in the future studies, and if nephrotoxicity is a concern due to other reasons, the pradefovir dosage could be reduced to 75 mg QD [8,30]. In conclusion, this phase Ib trial found that 28 days of therapy with pradefovir, a new PMEA prodrug, was safe and well tolerated by CHB patients. The antiviral activity of pradefovir was similar to that of TDF over a wide range of doses. Moreover, pradefovir was associated with significantly reduced serum PMEA levels compared to ADV. Based on the above findings, we found that the clinical therapeutic dose of ADV-10 mg is equal to pradefovir dose 40–45 mg. A dose close to 45mg was selected for the subsequent phase II clinical trial. Later 30, 45 and 60 mg QD pradefovir was recommended to be an appropriate dosage in phase II clinical trial.
19
Acknowledgements
The authors would like to thank all the patients in this study.
Funding
This work was financially supported by the National Major Scientific and Technological Special Project for Significant New Drug Development during the Thirteenth Five-Year PlanPeriod of China (Project: 2017ZX09304004, 2017ZX09101001-002-004), the National Natural Science Foundation of China (Project: 81602897) and Xi'an Xintong research Co Ltd.,.
Authors’ contributions
Yanhua Ding, JunqiNiu and Hong zhang contributed to the conception and design of the study, data acquisition, and data analysis and interpretation. Hong Chen, Xiaojiao Li, Xiaoxue Zhu and Min Wu contributed to the data acquisition, data analysis, and interpretation. Hong Zhang, Weili Jin, Cuiyun Li, Jingrui Liu and Chengjiao Liu contributed to the data analysis and interpretation. All authors made critical revisions to the draft versions of the manuscript and approved the final manuscript.
20
Conflict of interest
The authors declare that they have no conflicts of interests.
Compliance with ethical standards
Ethical approval The study was performed in accordance with Good Clinical Practice and the Declaration of Helsinki principles for ethical research. The study protocol was approved by the independent central ethics committee of The First Hospital of Jilin University. Written informed consent was obtained from each participant. Chinese Drug Trial Identifier: CTR20150224. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008 (5). Informed consent Informed consent was obtained from all patients for being included in the study.
21
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Figure Legends Figure 1. HBV DNA levels at different time points during the course of treatment (all were compared to values at baseline, the dotted line represents HBeAg-negative and the solid line represents HbeAg-positive). (A–E) 30–120 mg pradefovir, (F) 10 mg ADV (G) 300 mg TDF and (H) the mean change in HBV DNA levels in each group. Figure 2. Changes in mean serum biochemical index of the groups at different time points during the treatment. Mean ALT levels (A); mean AST levels (B); mean γ-glutamyl transpeptidase levels (C); mean Cr levels (D); mean cholinesterase levels (E); mean TBIL levels (F); mean inorganic phosphorus levels (G); mean retinol-conjugated protein levels (H); mean prealbumin levels (I); mean serum ClCr levels (J). Figure 3. Mean values of serum pradefovir and adefovir (PMEA) concentration-time profiles in each treatment group Mean (±SD) pradefovir plasma concentration-time profiles (A) and Mean (±SD) adefovir (PMEA) plasma concentration-time profiles (B); Mean (±SD) pradefovir plasma 27
concentration-time profiles (log value, C) and Mean (±SD) adefovir (PMEA) plasma concentration-time profiles (log value, D).
28
Table 1. Baseline demographics and disease characteristics. pradefovir tenofovir
30mg
60mg
75mg
90mg
120mg
adefovir dipivoxil 10mg
(N=6)
(N=7)
(N=6)
(N=6)
(N=6)
(N=10)
(N=10)
Age, mean(SD),Year
40(8.94)
36.4(5.97)
33(5.76)
32.2(6.46)
47.2(8.45)
43.4(13.72)
38.1(8.72)
Gender,male/female,n
5/1
6/1
6/0
6/0
4/2
6/4
6/4
BMI,mean(SD),kg/m2
22.68(2.73)
24.16(2.71)
23.65(3.69)
23.55(2.58)
24.25(3.61)
22.83(3.74)
23.8(2.23)
Ethnicity (Han/Other)
5/1
5/2
6/0
6/0
5/1
10/0
9/1
HBV DNA, mean(SD), log10 IU/mL
6.90(1.86)
7.16(1.24)
6.40(1.21)
6.60(1.38)
6.95(2.21)
6.66(1.01)
6.77(1.24)
HBsAg,mean(SD),
2.84(1.45)
4.11(0.45)
3.61(0.82)
3.65(0.74)
3.46(1.29)
3.36(0.95)
3.13(1.21)
HBeAg positive/negative
2/4
1/6
2/4
1/5
2/4
4/6
3/7
ALT, mean(SD),U/L
184.6(53.9)
99.9(51.2)
159.1(96.0)
225.2(153.3)
184.1(101.1)
149.7(77.2)
129.0(47.8)
Baseline parameter
log10 IU/mL
disoproxil 300mg
29
Table 2. Summary of measures for antiviral activity(Mean± ±SD) pradefovir
P
Endpoint
The change from baseline to day 22 in HBV DNA, log10IU/mL The change from baseline to
30mg(N=6)
60mg(N=7)
75mg(N=6)
90mg(N=6)
120mg(N=6)
-2.44(0.987)
-2.47(0.317)
-2.80(0.398)
-2.85(0.454)
-3.08(1.261)
adefovir dipivoxil
tenofovir disoproxil
10mg(N=10)
300mg(N=10) 0.27
-2.10(0.596)
-2.49(0.958) 0.36
-2.79(1.180)
-2.65(0.386)
-3.09(0.391)
-3.18(0.544)
-3.30(1.308)
-2.35(0.722)
-3.07(1.157)
DAVG22, log10 IU/ml
-1.42 (0.666)
-2.14 (1.423)
-1.71 (0.346)
-1.74 (0.360)
-2.10 (0.945)
-1.16 (0.457)
-1.64 (0.813)
0.20
DAVG29, log10 IU/ml
-1.72 (0.764)
-2.25 (1.596)
-2.02 (0.352)
-2.06 (0.380)
-2.12 (0.833)
-1.43 (0.499)
-2.06 (1.078)
0.55
Viral decay slope from baseline to day 29
-1.09 (0.155)
-0.94 (0.128)
-1.18 (0.160)
-1.22 (0.163)
-1.23 (0.186)
-0.85 (0.103)
-1.06 (0.123)
ALT normalization, n
1
1
2
2
1
1
3
AST normalization, n
1
0
3
1
1
0
4
day 29 in HBV DNA, log10IU/mL
<0.05*
HBV, hepatitis B virus; NA, not applicable; *: Viral decay slope was lesser in adefovir dipivoxil group than other group except 60 mg pradefovir (P<0.05); HBV DNA was set to 15 IU/mL if the observed value was less than the lower limit of quantification (20 IU/mL), when deriving changes from baseline.
30
Table 3. PK parameters of adefovir (PMEA) between the first dose and steady state in each treatment group (geomean(cv%)). dose
Cmax
Tmax*
AUC0-24
t1/2
CL/F
VZ/F
Df
AI
AI
(ng/mL)
(h)
(ng*h/mL)
(h)
(L/h)
(L)
(%)
AUC
Cmax
31
day1 adefovir
222.7(26.3 222.7 21.4(23.3) 21.4
dipivoxil10mg(N=10)
1.25(0.25-3)
7.44(15.3) 7.44
22.7(26.3) 22.7
244.6(34.3) 244.6
9.4(35.0) 9.4
97.7(55.1) 97.7
1119.8() 1119.8
) 167.5(38.2 167.5
30mg(N=6)
50.4(46.1) 50.4 0.875(0.5-1.5) 111.5(31.6 111.5
60mg(N=7)
) 325.5(15.4 325.5
10.62(27.8 10.62
0.75(0.50.75(0.5-0.75)
1279.4(19. 1279.4 85.8(16.8) 85.8
)
)
)
8)
130.6(20.6 130.6
346.7(22.3 346.7
11.25(42.7 11.25
105.1(32.3 105.1
1540.3(28. 1540.3
)
)
)
2)
429.9(13.6 429.9
10.59(24.9 10.59
75mg(N=6) )
0.50(0.5-1.5)
134.3(24.5 134.3
97.7(14.9) 97.7
90mg(N=6)
Pradefovir
1463.8(20. 1463.8
)
0.625(0.5-1)
)
)
2)
233.4(44.7 233.4
0.875(0.5-1.0
714.9(31.1 714.9
11.63(28.9 11.63
1319.0(16. 1319.0
)
0)
)
)
120mg(N=6)
86.1(39.0) 86.1 1)
day14 32
adefovir
41.6(154.6
0.75(0.25-3.0
230.8(23.8
416.2(161. 7.09(26.2)
dipivoxil10mg(N=10)
)
0)
11.47(43.0
1345.6(30. 89.9(44.9) 89.9(44.9)
118.4(25.7
126.0(50.0
3)
)
419.4(20.1
17.82(40.7
1932.3(36.
1.3(13.6 642.9(16.9)
122.8(43.9
)
7)
)
420.0(27.0
13.94(40.7
1861.8(24.
1.2(16.5 658.3(29.1)
)
4)
)
515.1(26.9
13.54(35.3
1880.6(45.
1.2(16.9
96.3(21.2) 0.625(0.5-1)
206.3(63.9 120mg(N=6)
521.5(23.5)
0.9(21.7)
)
)
5)
)
813.0(44.4
17.63(32.4
2074.8(18.
1.1(21.5
0.625(0.50.625(0.5-1.5) )
0.9(35.6)
)
90mg(N=6) )
1.2(35.0)
)
99.9(27.3) 99.9(27.3) 0.75(0.25-1.5)
1.0 (30.9)
)
75mg(N=6) )
1.2(21.4 552.0(16.4)
78.1(23.2) 0.75(0.5-0.75)
)
)
60mg(N=6) )
1.1(5.5) 4)
48.7(41.0) 0.5(0.5-1)
Pradefovir
244.4(27.9)
) 197.3(30.4
30mg(N=6)
24.5(25.6)
2.3(180.6
89.2(38.1) )
)
553.2(29.8) 1)
1.0(45.0) )
accumulation index: AI; fluctuation: Df *: median (min-max).
33
Highlights Pradefovir was associated with reduced serum PMEA levels compared to ADV. The antiviral activity of pradefovir was greater after pradefovir than ADV, and it was similar to that of TDF. pradefovir demonstrated a favorable safety profile and excellent anti-HBV activity. pradefovir could be a promising anti-HBV drug.