The rationale for conducting this study lies in the premise that if indeed the reason for a limited response of Kaposi's sarcoma lesions and other advanced malignancies to chemotherapy is attributable to a high expression of P-glycoprotein, then, by inhibiting this pump, tumor kill would be enhanced and response rates as well as duration of responses would also increase. Doxil is chosen since recent studies have shown that it is superior to combination chemotherapy with ABV or BV. Doxil is also known to be active in other malignancies such as breast and ovarian cancer (34,35). PSC 833 is chosen since it has been found to reverse P-gp in vitro and in vivo, is non-immunosuppressive, and has been shown in recent Phase 1 studies to be well tolerated. There are yet no human studies reported on Doxil pharmacokinetics when combined with MDR modulators. Preclinical data shows that pharmacokinetics of Doxil, unlike free doxorubicin, is minimally affected by the addition of PSC 833 (36). Enhanced tumor toxicity was observed when PSC 833 was combined with Doxil. Since doxorubicin, the active agent in Doxil, is metabolized by the same cytochrome P450, interactions between these 2 agents may have very significant clinical implications. The purpose of this study is to assess the toxicity and determine the maximum tolerated dose of Doxil when combined with PSC 833 in the treatment of AIDS-KS and other advanced malignancies.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Enrollment
14
Washington University School of Medicine
St Louis, Missouri, United States
Safety profile and tolerability of Doxil in combination with PSC 833
Each cycle is 2 weeks long and can continue until disease progression, toxicity, or patient decision
Maximum tolerated dose of Doxil in combination with PSC 833
Dose limiting toxicity of Doxil in combination with PSC 833
Effects of PSC 833 on Doxil pharmacokinetics
Confirm the MDR expression with immunohistochemistry and functionally, with 99MTc-sestamibi
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