HBV DNA levels guide antiviral treatment in chemotherapy setting

By Shreeya Nanda, Senior medwireNews Reporter

Pretreatment levels of hepatitis B virus (HBV) DNA could inform the withdrawal of pre-emptive antiviral therapy in chronic HBV patients undergoing cytotoxic chemotherapy for cancer, indicate research findings published in Digestive Diseases and Sciences.

The team from Samsung Medical Center in Seoul, South Korea, explains that prophylactic nucleos(t)ide analogue therapy is recommended for patients positive for hepatitis B surface antigen (HBsAg) who are candidates for chemotherapy, but that limited data are available to guide the discontinuation of antiviral therapy.

Of 95 HBsAg-positive patients diagnosed with cancer who received nucleos(t)ide analogue treatment during cytotoxic chemotherapy, just over half (54.7%) achieved a sustained off-treatment virological response (SOVR), defined as HBV DNA levels maintained below 2000 IU/mL for a minimum of a year after discontinuation of antivirals.

Only baseline levels of HBV DNA were significantly associated with SOVR in a multivariate analysis, with 2000 IU/mL as the cutoff (p=0.027). Participants with HBV DNA levels at and above the cutoff (n=34) had an SOVR rate of 23.5% while those below the cutoff had an SOVR rate of 72.1% (n=61), a significant difference (p<0.001).

The SOVR rate varied significantly when study participants were further stratified by pretreatment HBV DNA levels (p<0.001), at 5.0% for those with levels of at least 20,000 IU/mL, and rising to a respective 50.0%, 68.9% and 81.3% for patients with HBV DNA levels between 2000 IU/mL and 19,999 IU/mL, between 13 IU/mL and 1999 IU/mL, and below 12 IU/mL.

In the subgroup of patients with HBV DNA levels of at least 2000 IU/mL, hepatitis B e antigen (HBeAg) status was additionally linked to SOVR (p=0.035) – no patient positive for HBeAg antigen achieved SOVR whereas 42.1% of those negative for the antigen did.

And among participants with HBV DNA levels below 2000 IU/mL, no other factor showed a significant association with SOVR, although duration of consolidation therapy showed a trend towards significance.

Researcher Dong Hyun Sinn and colleagues say that their findings “demonstrate the importance of baseline HBV DNA level in the course of patients who discontinued preemptive [antiviral therapy].”

And they add: “Clinicians should weigh and discuss the risk–benefit of withdrawing preemptive [antiviral therapy] according to each patient’s situation; our data would help risk stratify patients.”

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