Hepatic failure and lactic acidosis due to fialuridine (FIAU), an investigational nucleoside analogue for chronic hepatitis B.

BACKGROUND: We describe severe and unexpected multisystem toxicity that occurred during a study of the antiviral nucleoside analogue fialuridine (1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-iodouracil, or FIAU) as therapy for chronic hepatitis B virus infection. METHODS: Fifteen patients with chronic hepatitis B were randomly assigned to receive fialuridine at a dose of either 0.10 or 0.25 mg per kilogram of body weight per day for 24 weeks and were monitored every 1 to 2 weeks by means of a physical examination, blood tests, and testing for hepatitis B virus markers. RESULTS: During the 13th week lactic acidosis and liver failure suddenly developed in one patient. The study was terminated on an emergency basis, and all treatment with fialuridine was discontinued. Seven patients were found to have severe hepatotoxicity, with progressive lactic acidosis, worsening jaundice, and deteriorating hepatic synthetic function despite the discontinuation of fialuridine. Three other patients had mild hepatotoxicity. Several patients also had pancreatitis, neuropathy, or myopathy. Of the seven patients with severe hepatotoxicity, five died and two survived after liver transplantation. Histologic analysis of liver tissue revealed marked accumulation of microvesicular and macrovesicular fat, with minimal necrosis of hepatocytes or architectural changes. Electron microscopy showed abnormal mitochondria and the accumulation of fat in hepatocytes. CONCLUSIONS: In patients with chronic hepatitis B, treatment with fialuridine induced a severe toxic reaction characterized by hepatic failure, lactic acidosis, pancreatitis, neuropathy, and myopathy. This toxic reaction was probably caused by widespread mitochondrial damage and may occur infrequently with other nucleoside analogues.

A controlled seroprevalence survey of primate handlers for evidence of asymptomatic herpes B virus infection.

Herpes B virus (BV) is a common cause of recurring mucocutaneous infections in monkeys of the genus Macaca. Like its human counterpart, herpes simplex virus (HSV), BV establishes lifelong latency and can be reactivated from infected monkeys symptomatically or asymptomatically. Incidental infection of humans handling BV-shedding monkeys can result in fatal meningoencephalitis. To determine whether humans exposed to infected monkeys can acquire asymptomatic BV infections, 480 subjects were evaluated in a controlled seroprevalence study. Sera from 321 primate handlers, including many with repeated injuries inflicted by Macaca monkeys, and 159 people never exposed to monkeys were tested in blinded fashion by both competition ELISA and Western blot to determine the prevalence of BV and HSV seropositivity. Although 293 persons proved positive for HSV antibodies, no primate handlers or control subjects showed BV-specific antibody responses. There is no serologic evidence that BV causes asymptomatic infections in humans.

Placebo-controlled trial of vaccination with recombinant glycoprotein D of herpes simplex virus type 2 for immunotherapy of genital herpes.

Immunotherapy of chronic viral diseases with vaccines is an important but unproven concept. We investigated the effect of a vaccine containing recombinant glycoprotein D (gD2) of herpes simplex virus type 2 (HSV-2) on the frequency of symptomatic outbreaks in patients with genital herpes. 98 patients with documented genital herpes who reported 4-14 recurrences per year were enrolled in a double-blind, placebo-controlled trial. Subjects received injections of either 100 micrograms gD2 in alum or alum alone (placebo) at 0 and 2 months, and recurrences were documented for 1 year. The vaccine was well tolerated. gD2 recipients reported fewer recurrences per month than placebo recipients (mean 0.42 [SE 0.05] vs 0.55 [0.05]; p = 0.055), had fewer virologically confirmed recurrences per month (0.18 [0.03] vs 0.28 [0.03]; p = 0.019), and had a lower median number of recurrences for the study year (4 [range 0-17] vs 6 [0-15]; p = 0.039). Neither genital recurrence nor the placebo vaccine had any discernible effect on HSV-2-specific antibody responses, but gD2 vaccine boosted neutralising antibodies to HSV-2 fourfold and gD2-specific titres sevenfold over baseline levels. These results inspire optimism about the potential use of vaccine for the treatment of chronic, recurring viral diseases.

Induction and enhancement of immune responses to herpes simplex virus type 2 in humans by use of a recombinant glycoprotein D vaccine.

A vaccine for a chronic or recurrent viral infection should induce immune responses that protect against primary disease or that augment preexisting defenses sufficiently to diminish the likelihood of disease recurrence or progression. Such a vaccine was sought for genital herpes, a sexually transmitted infection of epidemic proportion. Vaccine containing recombinant herpes simplex virus type 2 glycoprotein D expressed in CHO cells was given repeatedly and safely to 24 human volunteers. In previously uninfected subjects, the vaccine induced primary antigen-specific and neutralizing antibody responses nearing or exceeding those seen at entry in subjects with genital herpes. Primary cellular immune responses were also evoked. Vaccination of previously seropositive subjects boosted antibody titers to levels that remained, for > or = 1 year, severalfold above those attained in recurrent genital herpes. Either the quantity or mode of presentation of antigen permitted this vaccine to exhibit previously unachieved immunogenicity, which may prove adequate for antiviral immunoprophylaxis or treatment of genital herpes.