Do antivirals lower the risk of Hepatocellular Carcinoma in HBV?

Meaningful endpoints of therapy are often difficult to demonstrate in clinical studies due to the length of followup that may be needed.  For patients infected with hepatitis B virus (HBV), most clinical studies use surrogate biologic, virologic and histologic markers rather than endpoints like hepatocellular carcinoma (HCC) and death.  In addition, long-term randomized trials with untreated controls are difficult to justify given the success of current treatments in improving these surrogate markers.

A recent Japanese study (Hepatology 2013; 58: 98-107 and editorial pg 18) reports data on a large entecavir-treated cohort (n=472) which was matched with a historical control (retrospective control group, n=1143).  The authors used propensity score matching to eliminate any baseline differences.

Findings:

  • Cumulative incidence of HCC rate at 5 years was 3.7% (for entecavir group) and 13.7% (for controls)
  • Using regression analysis and adjusting for known HCC risk factors, patients treated with entecavir had a hazard ratio of 0.37 for developing HCC.
  • Patients with more risk factors for HCC (eg. older, more active disease, cirrhosis) obtained greater benefit from entecavir treatment (shown in Figure 4 in manuscript)
  • The authors also showed that entecavir-treated patients also had less risk of developing HCC than lamivudine-treated patients
  • Entecavir-treated patients had low rates of resistance (0.8%) at 3.2 years of treatment

Take-home message: suppression of viral replication in HBV cirrhosis patients reduces but does not eliminate the risk of HCC.  In noncirrhotic patients, the magnitude of risk reduction is less.  Thus, patients with active disease should be treated.

Causes of Death with Hepatitis B in U.S.

A recent study followed 6,689 patients with hepatitis B virus (HBV) between 1996-2005 and analyzed causes of death (Hepatology 2013; 58: 21-30, editorial pg 6). This study used a large prospectively-collected database.

The patients were all part of Kaiser Permanente Northern California health plan.  Patients were not eligible if they were coinfected with HIV or HCV.  Causes of death were divided into HBV-related (eg. decompensated cirrhosis [DCC], hepatocellular carcinoma [HCC]) and other causes, including cancer and cardiovascular.

Among this cohort, 68.3% were Asian-Pacific Islander (API) descent, and 11.8% were white (non-hispanic); the remainder were other or unknown descent.  The cohort had a mean age of 41 years.

Findings:

  • Males had higher overall 10-year death rates than females for total deaths (8.9% versus 4.1%) and for HBV-related deaths (4.8% versus 1.2%).
  • 46.7% of all deaths were HBV-related.
  • Death rate rose with increasing age; approximately 40% of deaths after age 40 were HBV-related.
  • Among HBV-related deaths, the death rate from HCC was twice the rate of DCC
  • “We did not find that subjects of API descent origin were at higher risk of death from HBV-related complications.”  This was unexpected because presumably “they are often infected in childhood and therefore have disease of longer duration.”
  • Limitations included absence of data on alcohol, cigarettes and coffee.  In addition, the study period occurred when treatment options for HBV were more limited.

The accompanying editorial notes wide variability in mortality outcome data depending on the study setting.   “Studies in patients with incidentally detected HBV infection, mostly conducted in blood donors in Western countries, tend to portray a benign course…with…their incidence of complications of chronic liver disease, HCC, or liver-related mortality is not significantly higher than that in hepatitis B surface antigen-negative healthy controls.”  In China, the lifetime risk for an infected patient to die from an HBV-related cause “has been estimated to be up to 50% in men and 15% in women.”

Related blog posts:

Hepatocellular Carcinoma after the Fontan Procedure

Given the fact that chronic liver disease and cirrhosis can develop in patients after the Fontan procedure, it comes as little surprise that cases of hepatocellular carcinoma (HCC) are being reported as well (NEJM 2013; 368: 1756-57).

This letter to editor describes four patients ages 24 to 42 who developed HCC following a classic Fontan or a variation.  Three of the four had very elevated alpha-fetoprotein levels; the lowest of the four patients was 106 ng/mL.  The letter notes that cirrhosis “may develop…approximately 11 to 15 years after a Fontan procedure; an incidence of cancer of 1.5 to 5.0% per year” is estimated after development of cirrhosis based on previous studies.

The letter also describes difficulties with regard to potential screening and treatment.

Related blog entry/references:

Microtargeting HCV

“Where there is no vision, the people perish.” –King Solomon, Proverbs

A recent study (NEJM 2013; 368: 1685-94) sheds light on a new vision of potential therapies, using microRNAs designed to interfere with the pathogenesis intracellularly.  While this study used this technology to target the Hepatitis C virus (HCV), the same technology has already received FDA approval for a medication (mipomersen) used to treat familial hypercholesterolemia.

With familial hypercholesterolemia, antisense oligonucleotides were developed which inhibit the expression of apolipoprotein B-100 in the liver.  For HCV, miravirsen is a 15-nucleotide antisense oligonucleotide microRNA (miR-122) which binds two highly conserved sites in HCV RNA.  The liver-expressed miR-122 protects HCV from degradation. Thus, the antisense oligonucleotide miravirsen causes degradation of HCV.  All strains of HCV depend on miR-122. (This aspect is reiterated in an associated editorial: NEJM 2013; 368: 1741-43.)

This study enrolled 36 patients from 2010 to 2011 in a randomized, double-blind, placebo-controlled, sequential series, ascending multiple dose-ranging study (7 study sites).  All HCV patients had not received previous therapy and were genotype 1.  Patients received five weekly subcutaneous injections of miravirsen at 3 mg/kg, 5 mg/kg, 7 mg/kg or placebo injections.

Results: In the miravirsen groups, the mean maximum log reduction in HCV RNA level was related to dose: 1.2 in 3 mg/kg cohort, 2.9 in 5 mg/kg cohort, and 3.0 in 7 mg/kg cohort compared with a 0.4 reduction in the placebo cohort.  During 14 weeks of follow-up after completing treatment, HCV RNA was not detected in one patient in the 5 mg/kg group and in four patients in the 7 mg/kg group.

There were no dose-limiting toxic effects or treatment discontinuations because of adverse events.  However, cholesterol levels did decrease by ~25%. No viral resistance was identified.  In addition, during treatment with miravirsen, a sustained decrease in serum alanine aminotransferase was evident.

The authors note that the pharmacologic data from this study indicate that once-monthly regimen would be feasible.  Because miravirsen is not a substrate for P-450, it is not expected to have significant drug-drug interactions.  Further studies are underway.

Potential drawbacks of treatment: miR-122 is a tumor-suppressor gene for hepatocellular carcinoma (HCC).  Thus, treatment with miravirsen could increase the risk of HCC.  Also, in mice that lack miR-122, there is a high risk of fatty liver and fibrosis.

Related blog posts:

Looking for trouble

Although cirrhosis is an infrequent problem in pediatric gastroenterology, there are several important management aspects.  One of these is surveillance for hepatocellular carcinoma (HCC).  In this month’s Hepatology, Poustchi et al describe the “feasibility of a randomized control trial for liver cancer screening” (Hepatology 2012; 54: 1998 & editorial 1898).  Not surprisingly, the authors conclude that such a trial is not possible with informed consent.  As such, the effectiveness and cost-effectiveness may not be determined.  Although the consensus is in favor of screening, there are potential disadvantages like discovering non-cancer nodules leading towards unnecessary invasive investigations.

The AASLD considers screening for HCC worthwhile in patients with cirrhosis.  When HCC is discovered early, treatment can be effective.  For example, if HCC meets Milan criteria–either 1 tumor <5cm or 2-3 < 3 cm each– OLT has 91% 1 yr survival.

Most U.S. physicians (74%) report that they screen all of their patients with cirrhosis; however,  population-based studies of Medicare patients show only 6.6% receive regular surveillance (Hepatology 2010; 52: 132-41) & only 12% of veterans with HCV-infected cirrhosis (Ann Intern Med 2011; 154: 85-93).  Better ways of consolidating screening can bridge this gap & perhaps catch cases of HCC amenable to treatment.  This may be another area where an EMR can help with patient/doctor reminders.

Current practice recommendations for cirrhotic patients: Ultrasound every 6 months (with or without AFP).  This recommendation is supported by the AASLD, EASL, and APASL.  The efficacy of HCC surveillance is reviewed further in the January “Education Practice” article: Clin Gastro & Hepatatol 2012: 10: 16-21.

Additional references:

  • Gastroenterology 2011; 141: 1240. Risk of HCC from HBV related to ALT and HBV DNA levels.
  • NEJM 2011; 365: 1118. Review. For cirrhotics/advanced liver dz, recs U/S & AFP q6-12months.
  • Hepatology 2010; 53: 1020. updated guidelines from AASLD. Suggests U/S as screen q6months.
  • J Pediatr 2011; 159: 617. BA associated with HCC.
  • Hepatology 2010; 51: 1972. NASH cirrhosis pts develop HCC. 12.8% over .32 yrs (compared with 20.3 % of pts with HCV cirrhosis). Alcohol & age were independent variables that increased risk.
  • Gastroenterology 2009; 137: 110, editorial page 26. AFP has at best 66% sensitivity for HCC.
  • Gastroenterology 2009; 136: 138, 39(ed). HCC occuring c HCV ~1%/yr in HALT-C study. prolonged Rx -not helpful. n=1005. Best surveillance is US. Only 60% of pts c HCC received surveillance. Hepatolgy 2005; 42 : 1208.
  • Gastroenterologyo 2008; 135: 111. DM & obesity associated with increase risk of HCC in patients with HBV/HCV.
  • Gastroenterology 2008; 134: 1612. Increasing LTx for HCC affects others on Tx list.
  • Gastroenterology 2007; 132: 2557. review
  • Clin Gastro & Hep 2006; 4: 252 Review.
  • Hepatology 2005; 42: 1208. AASLD guidelines for management.
  • Gastroenterology 2004 (November) 127; supplement 1:S1–S323. Review of HCC. S108: screen with alpha-fetoprotein AND U/S every 6-12 months in individuals with cirrhosis or advanced disease (not needed in individuals with mild disease).
  • Clinical Gastro & Hep 2003; 1: 10-18. Review.
  • Gastroenterology 2004; 126: 1005. HCC survival improved when detected as part of surveillance.