PHASE II PROTOCOL WITH LABORATORY CORRELATES OF 1-[(S)-3-HYDROXY-2-(PHOSPHOMETHOXY)PROPYL]CYTOSINE DIHYDRATE(CIDOFOVIR) IN PATIENTS WITH KAPOSI'S SARCOMA (KS)

Inclusion Criteria

DISEASE CHARACTERISTICS: Biopsy-proven Kaposi's sarcoma (KS) HIV infection (measured by
ELISA and Western blot) allowed NCI pathology review required At least 5 measurable
lesions required No prior local therapy to indicator lesions Lesions evaluable by
noninvasive methods No actively bleeding or critically located KS of immediate risk to
patient or at the discretion of the Principal Investigator and/or Study Chairperson No
pulmonary or other potentially acutely life-threatening KS lesions

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 70-100% Life
expectancy: More than 3 months Hematopoietic: Absolute neutrophil count at least 750/mm3
Platelet count at least 75,000/mm3 Hemoglobin at least 11 g/dL (10 g/dL in women) CD4
count greater than 50 cells per cubic millimeter Hepatic: Bilirubin no greater than 1.5
times normal (unless due to Gilbert's disease) Patients on protease inhibitors may have
bilirubin no greater than 3.5 mg/dL (direct bilirubin no greater than 0.2 mg/dL) AST/ALT
no greater than 75 IU/mL Alkaline phosphatase no greater than 2.5 times normal Renal:
Creatinine less than 1.5 mg/dL Creatinine clearance (calculated) greater than 55 mL/min
Proteinuria less than 2+ Cardiovascular: No significant EKG abnormality Other: No actively
life-threatening infection At least 14 days since treatment for serious infection No known
clinically significant allergy to probenecid or sulfa No grade 3 or worse clinical or
laboratory toxicity other than lymphopenia No medical condition that precludes protocol
treatment or informed consent No second malignancy within 1 year except basal cell skin
cancer No pregnant or nursing women Negative pregnancy test required of fertile women
within 1 week prior to entry, every 4 weeks while on study, and 4 weeks after last
treatment Effective contraception required of fertile women

PRIOR CONCURRENT THERAPY: At least 1 week since treatment with any of the following:
Diuretics Vidarabine Amphotericin B Aminoglycoside antibiotics Intravenous pentamidine
Other known or potentially nephrotoxic agents Other investigational agents with
anti-herpesvirus activity At least 4 weeks since systemic or local anti-herpesvirus
therapy other than mucocutaneous acyclovir cream At least 4 weeks since systemic therapy
for KS or other systemic or cutaneous malignancy At least 1 month since discontinuation of
antiretroviral therapy Concurrent antiretroviral therapy allowed provided doses of the
following, either alone or in combination, stable for at least 1 month prior to entry: AZT
ddC 3TC ddI d4T protease inhibitor