— Christine M. Kukka, Project Manager, HBV Advocate
Chemotherapy drugs used to treat cancer and
arthritis weaken the immune system and can cause a reactivation of HBV
infection, even in people who have undetectable viral load and have
cleared the hepatitis B surface antigen.
Unfortunately, many doctors
still don’t screen cancer patients for current or resolved hepatitis B
infections when prescribing rituximab chemotherapy for blood cancers.
(This drug contains antibodies that suppress cancer cell reproduction.)
One study presented at AASLD
found only 58% of patients were screened for HBsAg prior to
chemotherapy and only 20% were screened for both HBsAg and hepatitis B
core antibodies (showing a past, resolved infection) as recommended by
international guidelines. This study found that life-threatening HBV
reactivation occurred in patients whose only indication of past
hepatitis B infection was the presence of core antibodies. (1)
Another impediment to proper
treatment is that doctors don’t know which patients will experience an
HBV reactivation when treated for blood cancers with rituximab
chemotherapy. A Hong Kong study followed 210 patients treated with
rituximab who had previously been infected with hepatitis B. They were
all HBsAg-negative with undetectable HBV DNA.
About 27% of these patients had hepatitis B
reactivation—evidenced by detectable viral load—most within six months
of starting chemotherapy.
As soon as HBV DNA became
detectable, the researchers treated them with the antiviral entecavir
to suppress HBV. During the reactivation, HBsAg levels remained
undetectable. It was an increase in the patient’s HBV DNA that was the
first indication of hepatitis B reactivation. (2)
1. Control ID 1736332. Is isolated anti-HBc positivity a risk for reactivation in rituximab-treated patients? (Abstract #846)
2. Control ID 1736113.
Interim analysis of hepatitis B reactivation in patients with prior HBV
exposure undergoing rituximab-containing chemotherapy: a prospective
study. (Abstract #34)
Labels: chemotherapy, reactivation, screening