Antiviral treatment in chronic infection with hepatitis B virus

Comparative study of three doses of interferon-alpha 2a in chronic active hepatitis B. The International Hepatitis Trial Group

To determine the efficacy of interferon-alpha 2a in chronic active hepatitis B, 238 patients were randomly divided, into four groups: three groups received either 2.5 MIU m-2, 5.0 MIU m-2 or 10.0 MIU m-2, three times weekly by intramuscular injection for 12-24 weeks; and a control group received no treatment. Patients were followed for up to 12 months after treatment was discontinued. There was a statistically significant difference in response [clearance of hepatitis B e antigen (HBeAg) and hepatitis B viral DNA (HBV-DNA)] between treated and untreated patients (37 vs 13%) but no statistically significant difference was seen between treatment groups (33%, 34% and 43% for the 2.5, 5.0 and 10.0 MIU m-2 groups, respectively). A transient rise in transaminases (seroconversion hepatitis) was seen in responders, but levels returned to within the normal range after response to treatment. In patients responding to interferon therapy there was a significant reduction in the severity of the hepatitis. Interferon-alpha 2a was generally well tolerated with respect to vital signs and laboratory parameters.

THF gamma 2 stimulates cytokine release by peripheral blood mononuclear cells of patients with chronic hepatitis B virus infection

A recent study indicated that thymic hormones have antiviral effects in human hepatitis B virus infection and woodchuck hepatitis virus infection. These hormones are known to exert immunomodulatory effects on lymphocyte maturation and function; because these are abnormal in patients with chronic hepatitis B virus infection, we have examined the effects of a thymic hormone (THF gamma 2) on peripheral blood mononuclear cells from patients with chronic hepatitis B virus infection. THF gamma 2 (50 or 150 ng/ml) alone was without effect; in the presence of low doses of the mitogen phytohaemagglutinin, it had a broad effect in patients and controls. The effect on interleukin-2 production was greater in patients than controls with a significant increase in production at 150 ng/ml for patients alone (p = 0.037). Tumour necrosis factor alpha production was enhanced in all patients and controls, with a greater effect seen at 150 ng/ml THF gamma 2 than 50 ng/ml. There was no effect on interferon gamma production or on the expression of membrane markers of T-cell activation. THF gamma 2 has substantial immunomodulatory activity in chronic hepatitis B virus carriers and in vivo assessment of THF gamma 2 in chronic hepatitis B virus is indicated.

Therapy of chronic hepatitis B with recombinant human alpha and gamma interferon

Eight patients with chronic hepatitis B entered a pilot study of gamma interferon and alpha interferon in combination. Gamma interferon alone had minimal inhibitory effects on serum levels of hepatitis B virus as monitored by serum HBV DNA and DNA-polymerase activity. The drug also gave troublesome side effects. In contrast, alpha interferon had more potent inhibitory effects on serum HBV levels and fewer side effects. When combined, the two interferons showed no additive or synergistic effects in inhibiting serum levels of HBV DNA or DNA polymerase. These findings indicate that the addition of gamma interferon to alpha interferon provides no additional antiviral effects but contributes significantly to side effects.

A controlled trial of human lymphoblastoid interferon in chronic hepatitis B in Italy

Sixty-four heterosexual Italian carriers of HBsAg with chronic HBeAg and hepatitis B virus DNA-positive hepatitis were assigned randomly either to receive human lymphoblastoid interferon (injections of 5 million units per m2 three times per week for 6 months) or to serve as untreated controls. After 18 months of follow-up evaluation, 26 of the 33 treated patients (79%) had cleared hepatitis B virus DNA, 23 (70%) had lost HBeAg and 20 (61%) had seroconverted to anti-HBe. Fifteen of the 31 controls (48%) had cleared hepatitis B virus DNA (p = 0.01), 12 (39%) had lost HBeAg and nine (29%) had seroconverted to anti-HBe (p = 0.002). Eight treated patients but only one control had lost HBsAg and seroconverted to anti-HBs (24% vs. 3%, p = 0.01). Treated patients cleared hepatitis B virus markers after a mean interval of 4 months, compared with 8 months in the controls. All responders to interferon cleared intrahepatic HBcAg, and 50% showed histological improvement. The baseline hepatitis B virus DNA levels and the original histology were not predictive of a response to therapy; women appeared to respond better than men. Lymphoblastoid interferon provides an effective therapy in the heterosexual Italian patient with chronic hepatitis B.

Failure of interferon to prevent recurrent hepatitis B infection in hepatic allograft

Chronic liver disease associated with hepatitis B virus infection is both common and serious; no satisfactory treatment currently exists. Orthotopic liver transplantation is an option for patients with end-stage liver disease associated with hepatitis B virus infection despite the risk of allograft reinfection. Passive immunoprophylaxis has been attempted perioperatively to prevent graft infection but has not been beneficial. Some patients with chronic type B hepatitis have benefited clinically from antiviral therapy and, in particular, interferon, but its use has not previously been reported as an approach to prevent allograft infection. We administered recombinant leukocyte A interferon perioperatively to a patient who underwent liver transplantation for type B chronic active hepatitis and cirrhosis. Circulating hepatitis B virus DNA was found postoperatively while the patient was receiving interferon, and stainable viral antigen subsequently reappeared in the transplanted liver. Thus, the drug failed to prevent viral replication and allograft infection. Thus far, no evidence of progression of the chronic hepatitis has been noted.

Treatment of acute and chronic viral hepatitis

Over the 12 years since the first introduction of interferon for the treatment of chronic hepatitis B, progress has apparently been slow. Nevertheless, it now appears that at least one third of chronic hepatitis virus carriers, particularly those with more severe disease, and a similar, perhaps greater, proportion of those with chronic parenteral non-A, non-B hepatitis, can be successfully treated with alpha-interferon. In the not too distant future, controlled trials of alpha-interferons in these situations will be complete and they will be a yardstick by which other future therapies can be judged. Already a number of trials are in progress to determine which agents might, in addition to interferon, augment the response rates. The situation clinically is analogous to that for tuberculosis in the 1950s and for cancer chemotherapy only a decade or so ago. The prospects of prevention of the progression to cirrhosis, and perhaps in the long term reduction in the incidence of hepatocellular carcinoma, are exciting, and with the introduction of a number of new cytokines available through recombinant technology, each with novel antiviral activities, the future prospects are exciting indeed.

Randomized, controlled trial of recombinant human alpha-interferon in patients with chronic hepatitis B

Forty-five patients with chronic hepatitis B were entered into a randomized controlled trial of recombinant human alpha-interferon therapy. All patients had hepatitis B surface antigen in serum for at least 1 yr and had stable serum levels of both hepatitis B virus deoxyribonucleic acid and hepatitis B e antigen. During the 4-mo period of therapy, 10 of 31 (32%) treated patients and only 1 of 14 (7%) control patients became negative for serum hepatitis B virus deoxyribonucleic acid and deoxyribonucleic acid polymerase. All 10 patients who became negative for serum hepatitis B virus deoxyribonucleic acid subsequently had a marked improvement in serum aminotransferase activities and lost hepatitis B e antigen from serum, and 9 of them had improvement in liver histology. Comparison of responders to nonresponders indicated that female sex and a high initial level of serum aspartate aminotransferase correlated best with response to interferon therapy. These findings indicate that a 4-mo course of recombinant alpha-interferon can induce a remission in disease in approximately one-third of patients with chronic hepatitis B.

Clearance of pre-S2 antigen: a marker of successful interferon therapy in hepatitis B virus infection

The relation between viral replication, the presence of HBsAg and pre-S2 in serum and eventual clinical outcome has been investigated in fourteen patients undergoing treatment with lymphoblastoid interferon for chronic hepatitis B virus (HBV) infection. In four patients permanent loss of pre-S2 was accompanied by loss of serum HBV-DNA in association with a marked elevation of serum aspartate aminotransferase activity and in each of these cases HBsAg was subsequently cleared from serum. In contrast there was no significant fluctuation in the concentration of either pre-S2 or HBsAg in four cases not responding to therapy although substantial or complete inhibition of viral replication had been observed during treatment. In the third group, permanent loss of HBV-DNA was observed but in these cases pre-S2 and HBsAg persisted in serum, albeit at lower concentrations, while in this group loss of HBV-DNA from serum was not accompanied by a flare in disease activity. These results suggest first, that assay of pre-S2 is a further measure of the response to interferon and second that in some cases interferon enhances immune recognition of both the pre-S2 and HBsAg polypeptides.

Inhibition of hepatitis B virus DNA polymerase by 3'-azido-3'-deoxythymidine triphosphate but not by its threo analog

An inhibitory effect of 3'-azido-3'-deoxythymidine triphosphate on hepatitis B virus DNA polymerase was found. No effect was seen by its threo analog. The effect was detected at and above a concentration of 0.05 microM. The inhibition of DNA polymerase activity was the same in ten different strains of HBV. The mechanism was shown to be competitive, with an inhibition constant (Ki) of approximately 0.04 microM, and the Km value for dTTP was 0.1 microM.