To investigate the influence of interferon-free antivirus therapy on lipid profiles in chronic hepatitis C virus genotype 1b (HCV1b) infection.

Interferon-free antiviral agents were used to treat 276 patients with chronic HCV1b infection, and changes in serum lipids of those who achieved sustained virologic response (SVR) were examined. The treatment regimen included 24 wk of daclatasvir plus asunaprevir (DCV + ASV) or 12 wk of sofosbuvir plus ledipasvir (SOF + LDV). SVR was achieved in 121 (85.8%) of 141 patients treated with DCV + ASV and 132 (97.8%) of 135 patients treated with SOF + LDV. In the two patient groups (DCV + ASV-SVR and SOF + LDV-SVR), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides were measured at baseline during treatment and at 4 and 12 wk after treatment. Then, longitudinal changes in lipid profiles were analyzed.

Serum levels of TC, LDL-C, and HDL-C were significantly increased throughout the observation period in both the DCV + ASV-SVR and SOF + LDV-SVR groups. During antivirus treatment, the increases in TC and LDL-C were significantly greater in the SOF + LDV-SVR group than in the DCV + ASV-SVR group (P < 0.001). At 4 and 12 wk after the therapy, serum levels of TC and LDL-C were similar between the two groups and were significantly greater than those at baseline. Approximately 75%-80% of the increase in TC was derived from an increased LDL-C. In multiple regression analysis, the difference in therapy protocol (DCA + ASV or SOF + LDV) was an independent predictor that was significantly associated with the increase in TC and LDL-C at 4 wk of therapy.

Serum cholesterol significantly increased during SOF + LDV treatment. After treatment, HCV elimination was associated with a similar increase in cholesterol regardless of the therapy protocol.

Hepatitis C virus (HCV) is one of the most harmful viruses to human health[1,2]. Chronic HCV infection causes sustained inflammation of the liver, which can progress to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma[3,4]. Until just a few years ago, anti-HCV therapy was limited to interferon (IFN)-based regimens, which can cause severe side effects and result in an unsatisfactory cure rate[5,6]. However, several oral anti-HCV drugs (direct acting antivirals; DAAs) have been developed over the last several years[7-10]. The combination of DAAs brought a revolutionary change to anti-HCV therapy. Now, HCV can be eliminated from the infected host within 12 wk of DAA combination therapy without noticeable side effects with tremendously high probability. The sustained viral response (SVR) rate in chronic HCV genotype 1b (HCV1b) infection is now reported to be 95%-100%[10].

Several critical steps of the HCV life cycle are closely associated with lipid metabolism[11-13]. HCV particles in the peripheral blood are coated with lipids. About 10⁸ HCV particles are assumed to be secreted from the liver into peripheral blood every 24 h[14]. This finding suggested that lipid metabolism is somewhat shifted towards the production of HCV particles. Therefore, HCV may interfere with host lipid metabolism in order to enhance the replication process.

Many studies of serum lipid profiles in chronic HCV infection reported significant decreases in serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), while some reported a decrease in high-density lipoprotein cholesterol (HDL-C)[15-19]. Meanwhile, a decrease in serum triglycerides (TG) in chronic HCV infection remains an issue of debate[15]. Serum cholesterol levels in patients who achieved SVR with IFN-based therapy were reported to increase after therapy[16-18]. However, the change in cholesterol metabolism during IFN-based therapy is not easily defined because the nutritional state is worsened as a side effect of IFN-based therapy that may severely influence serum lipid levels[6]. On the contrary, IFN-free DAA combination therapy had no influence on the nutritional state of the host. Therefore, the change in serum lipid profiles during and after therapy are more clearly defined in DAA combination therapy.

A few recent reports suggested that serum cholesterol level is increased soon after initiation of sofosbuvir plus ledipasvir (SOF + LDV) therapy and is decreased from the baseline level after treatment failure[19]. However, these changes were not reported in other DAA combination regimens. Sofosbuvir is a nucleotide analog that inhibits HCV NS5B polymerase. Other DAAs inhibit the activities of NS3-4 HCV protease, the NS5A HCV replication complex, or NS5B polymerase. Changes in serum cholesterol in response to DAA combination therapy may indicate cancellation of the suppressive effect of HCV proliferation. Moreover, DAA by itself may impact lipid metabolism.

In this retrospective study, longitudinal changes in serum lipid profiles were examined in chronic HCV1b patients who were treated with a combination of daclatasvir and asunaprevir (DCA + ASV) or SOF + LDV and achieved SVR. Then, the differences in serum lipid profiles between the two regimens were clarified.

In this study, we observed the impact of IFN-free antiviral regimens on lipid metabolism as indicated by changes in serum cholesterol in patients with chronic HCV1b infection. Comparisons of serum lipid profiles after treatment showed similar increases in TC and LDL-C levels between the DCV + ASV-SVR and SOF + LDV-SVR groups. The increase in TC at P12W was 22.01 mg/dL in the DCV + ASV-SVR group and 18.52 mg/dL in the SOF + LDV-SVR group. Similar increases in TC levels of patients who achieved SVR with IFN-based therapy were reported[16-18]. Thus, an increase in TC of about 20 mg/dL was considered to be derived by clearance of HCV, regardless of the therapy regimen[16-18]. It is well known that lipid metabolism is disrupted by chronic HCV infection[20,21]. Therefore, cancellation of the suppressive effect of chronic HCV infection on lipid metabolism may have brought about the increase in TC of 20 mg/dL[16-18]. Additionally, these data indicated LDL-C was the major contributor (75%-80%) to the increase in TC. This finding suggested that the increase in cholesterol in this situation is considered to be primarily caused by an increase in LDL-C.

Meanwhile, the increases in cholesterol levels during treatment were dependent on the treatment regimen[22]. Although the increases in TC and LDL-C levels were features of both DCV + ASV and SOF + LDV treatment, the increase in cholesterol during treatment was much greater in the SOF + LDV-SVR group than in the DCV + ASV-SVR group[22]. The differences in the increase in cholesterol between DCV + ASV-SVR and SOF + LDV-SVR groups may not be simply explained by cancellation of disturbed lipid metabolism caused by HCV. In our patients, rapid virological response (no serum HCV RNA detected) rate at 4W was 89.3% in the DCV + ASV-SVR group and 87.9% in the SOF + LDV-SVR group. There was no difference in the rapid virological response rate between groups. Serum HCV RNA at 8W was not detected in any of the patients. Moreover, at the time of therapy termination, when HCV was completely abolished from hepatocytes, serum cholesterol remained significantly higher in SOF + LDV-SVR group. Therefore, the difference in anti-viral efficacy between the two regimens was not likely to be involved in the extent of the increase in serum cholesterol.

Interestingly, the behavior of serum cholesterol differed between the SOF + LDV-SVR and DCV + ASV-SVR groups. The increases in TC and LDL-C levels were slight during the therapy in the DCV + ASV-SVR group. Then, further increases in TC and LDL-C levels were observed after therapy termination at P4W and P12W. This finding suggested that DCV + ASV therapy somewhat inhibited the increase in serum cholesterol. In contrast, TC and LDL-C levels were greatly increased from the early stage of SOF + LDV therapy till the end of treatment. Thereafter, TC and LDL-C levels rapidly decreased. Therefore, SOF-LDV is believed to accelerate the increase in serum cholesterol. After therapy termination, similar degree of increase in cholesterol was observed regardless of the DAA regimen.

These findings suggested that elimination of HCV was not the sole factor contributing to the changes in serum cholesterol during DAA therapy. Instead, DAAs by themselves may have pharmacological actions on lipid metabolism[22]. This hypothesis that DAAs have pharmacological effects on lipid metabolism was strengthened by the changes in the serum cholesterol in DCV + ASV-nSVR group. In this group, serum cholesterol did not increase during the therapy, but it transiently increased at P4W. The behavior of serum cholesterol in this group differed from that in DCV + ASV-SVR group. This finding further suggested that DCV + ASV therapy suppressed the increase in serum cholesterol during therapy because transient increase in cholesterol was evoked despite replication of activated HCV after removal of DCV + ASV. However, relatively small number of patients in the DCV + ASV-nSVR group may limit the value of this supplemental study.

Using multiple linear regression analysis of factors contributing to the degree of the increase in TC and LDL-C levels at 4W of therapy, the choice of therapy regimen was elucidated as a strong contributing factor to the increase in TC and LDL-C levels. Thus, selection of the therapy regimen had a deep impact on the change in serum cholesterol during anti-HCV treatment. As mentioned above, the therapy regimen (DCV + ASV vs SOF + LDV) was not associated with the difference in final virological efficacy in these patients because we selected only the SVR patients in this retrospective study. From this finding, we concluded that SOF + LDV therapy strongly induced an increase in serum cholesterol, especially LDL-C, while the pharmacological effect of DCV + ASV may result in a suppression of increase in serum cholesterol. In this study, no further change in cholesterol was observed in the mid or late stage of SOF + LDV or DCV + ASV therapy. This finding may indicate that there was a limitation of SOF + LDV or DCV + ASV action on serum cholesterol.

Although the mechanisms underlying the opposite effects of SOF + LDV and DCV + ASV on serum cholesterol levels remain unclear, there is a difference in the inhibitory manner on HCV proliferation. Both DCV and LDV are inhibitors of the NS5A protein[23,24]; ASV is an inhibitor of the NS3/4A protease[25], while SOF is a nucleotide analog that inhibits the activity of NS5B polymerase[26,27], which might affect the viral kinetics during the very early phase of treatment in different way. In addition, the potency of each drug exerts different inhibitory effects. SOF has been used as a backbone in many regimens and has shown to be stronger in viral inhibition. Therefore, SOF-LDV had shorter treatment time with better efficacy.

The viral kinetic of DCV was biphasic, with decline phase of HCV starting from the first 12 h of the treatment. In the second phase, decline of HCV slowed down[28]. However, more prominent suppression of HCV could be expected at 2 d of therapy in SOF-combination. Thus, the potency of SOF could rapidly eradicate HCV. This may be related to prominent increase in the cholesterol in SOF + LDV therapy because with earlier viral reduction, a better reduction of hepatic inflammation could be seen in SOF based combination therapy[29,30]. As cholesterol is an indicator of liver function, cholesterol levels were decreased in HCV-related chronic hepatitis. Therefore, the more prominent increase in serum cholesterol in the SOF + LDV-SVR group might represent faster improvement in liver pathology or inflammation in the SOF + LDV-SVR group than in the DCV + ASV-SVR group. This hypothesis is particularly well applied for the differences in the cholesterol between the early stage of SOF + LDV and DCV + ASV therapy.

However, increase in cholesterol was still significantly higher at the time of therapy termination in the SOF + LDV-SVR group than in the DCV + ASV-SVR group. In addition, using this mechanism, it might be difficult to explain the transient elevation in cholesterol shortly after the therapy termination in the DCV + ASV-nSVR group. These findings suggested that there might be novel pharmacological effects of DAAs on the cholesterol metabolism. This issue remains to be solved in the future.

Hashimoto et al[22] recently examined factors affecting the increase in LDL-C in the early stage of DCV + ASV or SOF + LDV treatment and reported that factors promoting an increase in LDL-C of 25 mg/dL or more at 4 wk of therapy were therapy regimen (SOF + LDV) and change in the quantity of the HCV core antigen. The greater the decrease in the amount of HCV core antigen, the greater the increase in LDL-C.

In the present study, factors promoting an increase in TC at 4W were therapy regimen (SOF + LDV) and baseline quantity of HCV RNA. As HCV RNA was not detected in the majority of patients, the decrease in HCV RNA at 4W was approximately the same as the baseline quantity of HCV RNA. Therefore, our data was quite similar to those reported by Hashimoto et al[22]. However, factors positively affecting the increase in LDL-C were therapy regimen (SOF + LDV) and baseline TG, but not baseline quantity of HCV RNA. The difference between the precedent study and our study may be due to differences in patient classification, methods to quantify HCV activity, or the statistical methods used to evaluate the factors affecting the increase in LDL-C.

In summary, the increase in serum cholesterol was different between the SOF + LDV and DCV + ASV therapies. SOF + LDV therapy strongly increased cholesterol, while DCV + ASV may have suppressive effect on increase in cholesterol. The potency of eradication of HCV with SOF + LDV may be associated with more prominent increase in cholesterol during treatment. In addition, SOF + LDV or DCV + ASV therapy might have its own pharmacological effects on serum cholesterol during the process of HCV eradication. In order to clarify the mechanisms of DAAs in serum cholesterol, further investigations are required.

In conclusion, SOF + LDV and DCV + ASV therapies had different influences on serum cholesterol levels.

We thank the faculty and staff of Jikei University Katsushika Medical Center for excellent assistance.