Valganciclovir in Treating Patients With Classic Non-HIV-Associated Kaposi's Sarcoma

RATIONALE: Herpesvirus is found in the lesions of most patients with Kaposi's sarcoma, and may have a role in causing Kaposi's sarcoma. Valganciclovir is an antiviral drug that acts against many types of herpesviruses and may be an effective treatment for Kaposi's sarcoma.

PURPOSE: This clinical trial is studying how well valganciclovir works in treating patients with classic non-HIV-associated Kaposi's sarcoma.

OBJECTIVES:

Primary

* Determine the antitumor activity of valganciclovir in patients with classic non-HIV-associated Kaposi's sarcoma (KS).

Secondary

* Determine the effect of this drug on lytic and latent human herpesvirus-8 gene expression in KS lesions of these patients.
* Determine the effect of this drug on the markers of angiogenesis in KS lesions of these patients.
* Determine the safety and tolerability of this drug in these patients.

OUTLINE: This is a pilot study.

Patients receive oral valganciclovir twice daily for 3 weeks and then once daily for 21 weeks in the absence of disease progression or unacceptable toxicity.

All patients are followed for 1 month after completion of therapy. Patients with responding disease are followed monthly for up to 1 year.

PROJECTED ACCRUAL: A total of 15 patients will be accrued for this study within 1 year.

Eligibility Criteria:
DISEASE CHARACTERISTICS:

* Histologically confirmed classic Kaposi's sarcoma (KS) involving the skin

  * Non-HIV-associated disease

    * HIV negative
* Measurable disease

  * At least 8 KS lesions with ≥ 5 marker lesions measurable in 2 dimensions AND ≥ 3 other lesions measuring ≥ 1 cm in diameter

    * Two 3 mm punch biopsies of a non-marker lesion entirely composed of KS
  * Irradiated cutaneous lesions may not be used as indicator lesions
* No known active visceral KS or symptomatic KS-related edema that would preclude function or require cytotoxic chemotherapy

PATIENT CHARACTERISTICS:

Age

* 18 and over

Performance status

* Karnofsky 70-100%

Life expectancy

* At least 12 months

Hematopoietic

* Hemoglobin ≥ 8 g/dL
* Absolute neutrophil count ≥ 1,500/mm\^3
* Platelet count ≥ 100,000/mm\^3

Hepatic

* Bilirubin ≤ 1.5 times upper limit of normal (ULN)
* AST and ALT ≤ 3 times ULN

Renal

* Creatinine clearance ≥ 50 mL/min

Other

* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective barrier contraception during and for 3 months after study participation
* No hypersensitivity to valganciclovir or ganciclovir
* No other neoplasia requiring cytotoxic therapy

PRIOR CONCURRENT THERAPY:

Biologic therapy

* More than 4 weeks since prior biological therapy for KS
* No concurrent immunotherapy

Chemotherapy

* More than 4 weeks since prior chemotherapy for KS
* No concurrent chemotherapy

Endocrine therapy

* No concurrent corticosteroid treatment except for replacement doses (equivalent to 20 mg of hydrocortisone per day)

Radiotherapy

* See Disease Characteristics
* More than 4 weeks since prior radiotherapy for KS
* No concurrent radiotherapy

Surgery

* Not specified

Other

* More than 14 days since prior acute treatment for infection (other than oral thrush or genital herpes) or other serious medical illness
* More than 60 days since prior local therapy for any KS indicator lesion unless the lesion showed documented progression since treatment
* More than 4 weeks since prior local therapy for KS
* More than 4 weeks since prior investigational agents
* More than 4 weeks since other prior antineoplastic therapy for KS
* No other concurrent antiviral therapy
* No other concurrent investigational agents
* No other concurrent systemic therapy for KS