Comparison of Foscarnet Versus Vidarabine in the Treatment of Herpes Infection in Patients With AIDS Who Have Not Had Success With Acyclovir

Inclusion Criteria Concurrent Medication: Allowed for phase B: Aerosolized pentamidine prophylaxis for Pneumocystis carinii pneumonia (PCP). Prior Medication: Allowed for phase A: Ganciclovir. Patients receiving this drug at the time of study enrollment must discontinue the drug at the time of enrollment and for the duration of the study period. Exclusion Criteria Co-existing Condition: For phase A, patients with pre-existing severe neurologic impairment such as seizure disorder or marked or incapacitating ataxia are excluded. Concurrent Medication: Excluded upon entry into phase B: Ganciclovir. Immunomodulators. Probenecid. Ciprofloxacin. Allopurinol. Zidovudine (AZT). Antiretrovirals. Other investigational agents. Acyclovir for another labeled indication. Potentially nephrotoxic agents. Patients will be excluded from the study for the following reasons: Phase A: Previous hypersensitivity reaction to foscarnet or vidarabine. Patients who have a documented history of vidarabine intolerance may be eligible for the foscarnet on the non-randomized arm of the study. Phase B: Clinical response to therapy with acyclovir in phase A described as "healed" or "good." Prior Medication: Excluded within 14 days of study entry: Immunomodulators or biologic response modifiers. Phase A: Excluded within 30 days of study entry: Foscarnet. Phase B: Excluded within 7 days of study entry into phase B: Any potentially nephrotoxic agent, except acyclovir. Prior Treatment: Excluded for phase A within 14 days of study entry: Lymphocyte replacement therapy. Patients must demonstrate the following clinical and laboratory findings: Phase A: HIV positive by federally licensed ELISA test confirmed by Western blot, p24 serum antigen, or a positive HIV culture; or a prior diagnosis of AIDS as defined by Centers for Disease Control criteria. Mucocutaneous herpes simplex virus (HSV) infection confirmed by viral culture persisting for a minimum of 2 weeks which is clinically resistant to therapy with acyclovir in the opinion of the patient's physician. Phase B: Persistent shedding of HSV at the completion of or within 1 week after completion of phase A acyclovir therapy as confirmed by viral culture. Documented in vitro resistance of the virus to acyclovir. All strains must be referred to the Diagnostic Virology Laboratories at either San Francisco General Hospital or Beth Israel Hospital, Boston, for susceptibility testing. Two serum acyclovir levels drawn during phase A. Results may be pending at time of entry into phase B. All eligibility evaluations must be performed within 7 days prior to study entry for phase A or B.