Combination Oral Antivirals Are Now Unnecessary for Chronic HBV Infection

Combination Oral Antivirals Are Now Unnecessary for Chronic HBV Infection

Atif Zaman, MD, MPH reviewing Gordon SC et al. Hepatology 2013 Aug.

Tenofovir suppressed the virus in nearly all patients, even those with high pretreatment viral loads.

Atif Zaman, MD, MPH

With the availability of potent antiviral agents (e.g., entecavir, tenofovir), the majority of hepatitis B virus (HBV)-infected patients will achieve successful viral suppression. But is this also true for patients with high viral load (HVL)? Or do they require an additional anti-HBV medication to achieve suppression and prevent the development of resistance?

To answer this question, researchers analyzed virologic response (HBV DNA <400 copies/mL) in patients with and without HVL (baseline viral load ≥9 log10 copies/mL) who had been followed for 240 weeks as part of two previous registration trials comparing tenofovir disoproxil fumarate (TDF) and adefovir for treating HBV infection. The trials included both hepatitis B e antigen (HBeAg)-positive and HBeAg-negative patients and both treatment-experienced and treatment-naive patients. At week 48, patients on adefovir were switched to TDF. Patients with persistent viremia (never achieving HBV DNA <400 copies/mL) at week 72 were given the option of continuing TDF alone or adding emtricitabine.

Of 641 patients enrolled, 129 (20%) had HVL. By week 240, virologic response was achieved in 98.3% of patients with HVL and 99.2% of patients without HVL. Patients with HVL took longer to achieve response, but by week 96, rates were similar between the two groups. Notably, in patients with HVL, adding emtricitabine to TDF did not affect virologic response rates. No patient with HVL at week 240 had persistent viremia or developed TDF resistance. Of 13 instances of viral breakthrough, 62% were attributed to noncompliance.

Comment

This study highlights several key features of modern therapy with antivirals for hepatitis B virus infection. First, although patients with high viral loads take longer (up to 96 weeks) to achieve undetectability, eventually all will achieve it. Second, while awaiting HBV DNA undetectability, resistance development is not a worry. Third, the main cause of viral breakthrough is noncompliance. Finally, combination therapy does not improve HBV response or outcomes.

Editor Disclosures at Time of Publication
Disclosures for Atif Zaman, MD, MPH at time of publication Speaker’s bureau Bristol-Myers Squibb; Genentech; Gilead; Kadmon; Merck; Salix; Vertex

Citation(s):
Gordon SC et al. Efficacy of tenofovir disoproxil fumarate at 240 weeks in patients with chronic hepatitis B with high baseline viral load. Hepatology 2013 Aug; 58:505. (http://dx.doi.org/10.1002/hep.26277)

PubMed abstract (Free)

Source- http://www.jwatch.org/na31904/2013/08/08/combination-oral-antivirals-are-now-unnecessary-chronic#sthash.8NE8nL9O.dpuf