Faculty Bibliography

The lower limit of detection of most polymerase chain reaction (PCR) assays for hepatitis C virus (HCV) RNA is 50 IU/ml, compared to 5 IU/ml for the transcription-mediated amplification (TMA) method. We retrospectively reviewed 57 patients to assess the predictive value of a positive TMA in the setting of a negative PCR during antiviral therapy. Patients were divided into (1) PCR-/TMA+ (discordant; n=21) and (2) PCR-/TMA-(concordant; n=36). Sustained virologic response (SVR) was decreased in the discordant group (48% vs. 75%; P=0.04). In discordant patients, SVR was more frequent in patients who had one positive TMA than in those who had two or more positive TMAs or one positive TMA and recurrent HCV RNA detectability by PCR during treatment (78% vs. 25%; P=0.03). Breakthrough occurred more frequently in discordant patients (24% vs. 3%; P=0.02). A positive TMA on two or more occasions in patients who have become PCR-negative on therapy indicates a high likelihood of treatment failure.

UNLABELLED: This prospective, multicenter, community-based and academic-based, open-label, investigator-initiated, U.S. study evaluated efficacy and safety of pegylated interferon (PEG-IFN) alfa-2b plus a flat or weight-based dose of ribavirin (RBV) in adults with chronic hepatitis C. Patients (n = 5027) were randomly assigned to receive PEG-IFN alfa-2b 1.5 microg/kg/week plus flat-dose (800 mg/day) or weight-based (800-1400 mg/day) RBV for 48 weeks (patients with genotype 1, 4, 5, or 6) and for 24 or 48 weeks (genotype 2/3 patients). Primary end point was sustained virologic response (undetectable [<125 IU/mL] serum hepatitis C virus RNA at 24-week follow-up). Sustained virologic response, but not end-of-treatment, rates were significantly higher with weight-based than with flat-dose RBV (44.2% versus 40.5%; P = 0.008). Sustained virologic response rates by intention-to-treat analysis were 34.0% and 28.9%, respectively, in genotype 1 patients (P = 0.005) and 31.2% and 26.7%, respectively, in genotype 1 patients with high baseline viral load (P = 0.056). In genotype 2/3 patients, rates were not significantly different (61.8% and 59.5%, respectively) regardless of treatment duration. Besides greater hemoglobin reductions with weight-based RBV, safety profiles were similar across RBV dosing groups, including the 1400-mg/day group. CONCLUSION: PEG-IFN alfa-2b plus weight-based RBV is more effective than flat-dose RBV, particularly in genotype 1 patients, providing equivalent efficacy across all weight groups. RBV 1400 mg/day is appropriate for patients 105 to 125 kg. For genotype 2/3 patients, 24 weeks of treatment with flat-dose RBV is adequate; no evidence of additional benefit of extending treatment to 48 weeks was demonstrated.

UNLABELLED: WIN-R (Weight-based dosing of pegINterferon alfa-2b and Ribavirin) was a multicenter, randomized, open-label, investigator-initiated trial involving 236 community and academic sites in the United States, comparing response to pegylated interferon (PEG-IFN) alfa-2b plus a flat or weight-based dose of ribavirin (RBV) in treatment-naive patients with chronic hepatitis C and compensated liver disease. Patients were randomized to receive PEG-IFN alfa-2b at 1.5 microg/kg/week plus flat-dose (800 mg/day) or weight-based-dose RBV (800 mg/day for weight <65 kg, 1000 mg/day for 65-85 kg, 1200 mg/day for >85-105 kg, or 1400 mg/day for >105-<125 kg). Sustained virologic response (SVR; undetectable [<125 IU/mL] hepatitis C virus [HCV] RNA at end of follow-up) in patients > or =65 kg was the primary end point. Low SVR rates have been reported among African American individuals, in whom there is a preponderance of HCV genotype 1. This subanalysis of WIN-R was conducted to evaluate the efficacy of weight-based dosing among African American individuals with genotype 1 infection enrolled in the trial. Of 362 African American patients in the primary efficacy analysis, 188 received RBV flat dosing and 174 received weight-based dosing. SVR rates were higher (21% versus 10%; P = 0.0006) and relapse rates were lower (22% versus 30%) in the weight-based-dose group than in the flat-dose group. Safety and rates of drug discontinuation were similar between the 2 groups. CONCLUSION: Weight-based dosing of RBV is more effective than flat dosing in combination with PEG-IFN alfa-2b in African American individuals with HCV genotype 1. Even with weight-based dosing, response rates in African American individuals are lower than reported in other ethnic groups.

An international group of experienced hepatologists and virologists conducted a single-day workshop to review the management of patients with chronic hepatitis B receiving treatment with oral nucleosides or nucleotides. Guidelines regarding on-treatment management and available published data on the importance of serum hepatitis B virus (HBV) DNA as a marker of outcomes were reviewed. On-treatment monitoring strategies to define early virologic responses that might be predictive of better outcomes and a reduced risk of viral resistance were proposed for further study. This treatment plan, labeled the roadmap concept, recommends monitoring of serum HBV DNA levels to identify outcomes of therapy. Primary treatment failure was defined as a reduction of serum HBV DNA levels by less than 1 log10 IU/mL from baseline at week 12. Measurement of the HBV DNA level at week 24 was considered essential to characterize virologic responses as complete, partial, or inadequate. Complete virologic response was defined as negative HBV DNA by a sensitive assay (<60 IU/mL or <300 copies/mL); partial virologic response was defined as HBV DNA levels less than 2000 IU/mL (4 log10 copies/mL), and inadequate virologic response was defined as HBV DNA levels of 2000 IU/mL or greater (4 log10 copies/mL). Strategies are proposed for managing patients in each of these categories, depending in part on the rapidity with which HBV DNA suppression is achieved and the emergence of genotypic mutations that reduce the effectiveness of a specific drug. Future studies of the use of the roadmap concept in improving outcomes of chronic hepatitis B are warranted

As our understanding of the natural history of hepatitis B virus (HBV) infection increases, so do the patient circumstances for which anti-HBV therapy is considered. For example, patients with chronic HBV infection that is negative for hepatitis B surface antigen can experience hepatitis flares during or after cytotoxic chemotherapy and thus are potential candidates for anti-HBV therapy. Also, although passive-active immunoprophylaxis is highly effective in preventing the vertical transmission of HBV, high maternal serum HBV DNA concentrations have been associated with the failure of immunoprophylaxis; for this reason, clinicians may consider administering anti-HBV therapy during pregnancy. However, prophylactic anti-HBV therapy can be both complex and controversial. A satellite symposium conducted during the 57th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD) in Boston, Massachusetts, presented approaches to treating HBV infection in patients who are pregnant and in those who are preparing to receive chemotherapy.

The 2007 American Association for the Study of Liver Diseases (AASLD) practice guidelines for managing chronic hepatitis B virus (HBV) infection recommend pharmacologic therapy for patients with alanine aminotransferase (ALT) activity higher than 2 times the upper limit of normal and serum HBV DNA concentration higher than 20,000 IU/mL. Findings reported over the past several years, however, indicate that HBV infection associated with ALT activity and serum HBV DNA concentrations below these treatment thresholds can progress to serious liver disease, such as cirrhosis or hepatocellular carcinoma. These findings suggest that these treatment thresholds may be too conservative. Moreover, emerging data suggest that, in some patient populations, the appropriate goal of therapy may be sustained suppression of HBV DNA with maintenance antiviral therapy. A satellite symposium conducted during the 57th Annual Meeting of the AASLD in Boston, Massachusetts, presented new findings relative to the course of HBV infection.

As of October 2006, 6 medications are approved in the United States for the management of chronic hepatitis B virus (HBV) infection: 2 formulations of interferon and 4 oral nucleos(t)ide analogues. For the treating practitioner, tailoring the pharmaceutical regimen according to patient features and clinical circumstances can be a challenge. First-line therapeutic regimens for the management of HBV infection include monotherapy with a U.S. Food and Drug Administration-approved agent that has potent on-treatment viral response and low rates of resistance; in the future, these regimens may include a combination of more than one nucleos(t)ide analogue or a combination of a nucleos(t)ide analogue and pegylated interferon. The oral nucleos(t)ide analogues are generally better tolerated than interferon; however, they can be expensive when administered for lengthy periods and can also lead to medication resistance. Lamivudine, the first approved nucleoside analogue for the treatment of HBV infection, has a very high resistance profile; in fact, lamivudine exposure increases viral resistance to other commercially available nucleos(t)ide analogues: entecavir, telbivudine, and adefovir. For these reasons, the 2007 American Association for the Study of Liver Diseases (AASLD) guidelines no longer recommend lamivudine as first-line therapy for the management of HBV infection. A satellite symposium conducted during the 57th Annual Meeting of the AASLD in Boston, Massachusetts, presented approaches to customizing the management of chronic HBV infection. The presentation highlighted recent findings suggesting that early, profound, and sustained viral suppression improves the probability of sustained virologic response and reduces the likelihood of nucleos(t)ide resistance.