A comparison of clevudine and entecavir for treatment-naïve patients with chronic hepatitis B: results after 2 years of treatment

Adverse events of nucleos(t)ide analogues for chronic hepatitis B: a systematic review

Nucleos(t)ide analogues (NAs) are the main drug category used in chronic hepatitis B (CHB) treatment. Despite the fact that NAs have a favourable safety profile, undesired adverse events (AEs) may occur during the treatment of CHB. Given the eminent number of patients currently receiving NAs, even a small risk of any of these toxicities can represent a major medical issue. The main objective of this review was to analyse information available on AEs associated with the use of NAs in published studies. We choose the following MesH terms for this systematic review: chronic hepatitis B, side effects and treatment. All articles published from 1 January 1990 up to 19 February 2018 in MEDLINE of PubMed, EMBASE, the Cochrane Library and LILACS databases were searched. A total of 120 articles were selected for analysis, comprising 6419 patients treated with lamivudine (LAM), 5947 with entecavir (ETV), 3566 with tenofovir disoproxil fumarate (TDF), 3096 with telbivudine (LdT), 1178 with adefovir dipivoxil (ADV) and 876 with tenofovir alafenamide (TAF). The most common AEs in all NAs assessed were abdominal pain/discomfort, nasopharyngitis/upper respiratory tract infections, fatigue, and headache. TAF displays the highest density of AEs per patient treated among NAs (1.14 AE/treated patient). In conclusion, treatment of CHB with NAs is safe, with a low incidence of AEs. Despite the general understanding TAF being safer than TDF, the number of patients treated with TAF still is too small in comparison to other NAs to consolidate an accurate safety profile. PROSPERO Registration No. CRD42018086471.

Clevudine Induced Mitochondrial Myopathy

Clevudine was approved as an antiviral agent for hepatitis B virus, which showed marked, rapid inhibition of virus replication without significant toxicity. However, several studies have reported myopathy associated with clevudine therapy. Also, we experienced seven patients who suffered from myopathy during clevudine therapy. To characterize clevudine-induced myopathy, we collected previously reported cases of clevudine myopathy and analyzed all the cases including our cases. We searched electronic databases that were published in English or Korean using PubMed and KoreaMed. Ninety-five cases with clevudine myopathy, including our seven cases, were selected and analyzed for the demographic data, clinical features, and pathologic findings. The 95 patients with clevudine-induced myopathy comprised 52 women and 43 men aged 48.9 years (27-76 years). The patients received clevudine therapy for about 14.2 months (5-24 months) before the development of symptoms. Weakness mainly involved proximal extremities, especially in the lower extremities, and bulbar and neck weakness were observed in some cases (13.7%). Creatine kinase was elevated in the majority of patients (97.9%). Myopathic patterns on electromyography were observed in most patients examined (98.1%). Muscle biopsy presented patterns compatible with mitochondrial myopathy in the majority (90.2%). The weakness usually improved within about 3 months after the discontinuation of clevudine. Though clevudine has been known to be safe in a 6-month clinical trial, longer clevudine therapy for about 14 months may cause reversible mitochondrial myopathy. Careful clinical attention should be paid to patients with long-term clevudine therapy.

Efficacy of switching from adefovir to tenofovir in chronic hepatitis B patients who exhibit suboptimal responses to adefovir-based combination rescue therapy due to resistance to nucleoside analogues (SATIS study)

Background/Aims

It remains to be determined whether switching from adefovir (ADV) to tenofovir (TDF) provides better virological outcomes in patients exhibiting suboptimal responses to ADV plus nucleoside analogue (ADV+NA) therapy for NA-resistant chronic hepatitis B (CHB).

Methods

In this prospective trial, patients who showed partial responses (defined as serum hepatitis B virus [HBV] DNA >60 IU/mL) to ADV+NA therapy for NA resistance were randomly allocated to receive TDF plus NA (TDF+NA group, n=16) or to continue their current therapy (ADV+NA group, n=16). The primary end point was the proportion of patients with complete virological response (CVR, defined as serum HBV DNA <60 IU/mL) at 48 weeks.

Results

The median age was 52 years (16 men), and 28 were positive for hepatitis B e antigen (HBeAg). The baseline characteristics did not differ significantly between the two groups. The proportion with CVR was significantly higher in the TDF+NA group than in the ADV+NA group at 24 weeks (81.3% vs. 25.0%, P=0.001) and 48 weeks (87.5% vs. 37.5%, P=0.002). Furthermore, a decrease in the serum HBV DNA level of >2log₁₀ IU/mL was more likely in the TDF+NA group at both 24 and 48 weeks (68.8% vs. 56.3%, P=0.014 vs. 81.3% vs. 56.3%, P=0.001, respectively). During the follow-up, the rate of HBeAg seroconversion was higher in the TDF+NA group than the ADV+NA group (12.5% vs. 6.25%, P=0.640), as was that for the hepatitis B surface antigen (6.25% vs. 0%, P=0.080). No serious adverse events due to antiviral agents occurred.

Conclusion

In patients exhibiting suboptimal responses to ADV+NA therapy for NA-resistant CHB, switching from ADV to TDF might provide better virological outcomes.

Molecular diagnosis and treatment of drug-resistant hepatitis B virus

Oral antiviral agents have been developed in the last two decades for the treatment of chronic hepatitis B (CHB). However, antiviral resistance remains an important challenge for long-term CHB therapy. All of the clinically available oral antiviral agents are nucleoside or nucleotide analogues that target the activity of viral reverse transcriptase (RT), and all are reported to have resistant mutations. Since the hepatitis B virus (HBV) RT, like other viral polymerases, lacks proofreading activity, the emergence of drug-resistance occurs readily under selective pressure from the administration of antiviral agents. The molecular diagnosis of drug-resistant HBV is based on sequence variations, and current diagnostic methods include sequencing, restriction fragment polymorphism analysis, and hybridization. Here, we will discuss the currently available molecular diagnosis tools, in vitro phenotypic assays for validation of drug-resistant HBV, and treatment options for drug-resistant HBV.