pirarubicin and 4-hydroxycyclophosphamide

We analysed the in vitro sensitivity of 50 fresh gynecologic cancer specimens to the new anthracycline-analogue pirarubicin (Pira). Nine endometrial and cervical tumors were excluded from the evaluation in this study. The in vitro sensitivities of 41 ovarian cancer specimens to Pira were evaluated with the adenosine triphosphate chemosensitivity assay (ATP-CSA). The results were compared to the sensitivity of drugs used in gynecologic oncology: Adriamycin, cisplatin, and the metabolite of cyclophosphamide, 4-hydroxycyclophosphamide (4-HC). Sensitivity (S) is defined as > or = 70%, partial sensitivity as 50-69% ATP decrease compared to controls at 20% of the peak plasma concentration. In vitro response is defined as S + PS. Twenty-two primary ovarian tumors were assayed, with 77% response to Pira, 12% to Adriamycin, 29% to cisplatin, and 38% to 4-HC. In 19 recurrent ovarian tumors, Pira showed 53% response; Adriamycin, 25%; cisplatin, 8%; and 4-HC, 67%. The in vitro data are partly consistent with reported data from the literature. Pira reveals a significantly higher degree of cytotoxicity compared to the three drugs listed above. The IC50 of Pira is less than 20% of the peak plasma concentration achievable in patients and is significantly lower compared with the IC50s of other drugs. We conclude from our in vitro data that Pira is more active than Adriamycin, cisplatin, and 4-HC.

Topics: Adenosine Triphosphate; Antineoplastic Agents; Cisplatin; Cyclophosphamide; Doxorubicin; Drug Screening Assays, Antitumor; Female; Humans; In Vitro Techniques; Ovarian Neoplasms; Recurrence