Phase II study of paclitaxel in patients with previously treated osteosarcoma and its variants

Patients with osteosarcoma and its variants who did not respond to standard chemotherapy including doxorubicin, ifosfamide, cisplatin, and high dose methotrexate were treated with paclitaxel so that its therapeutic activity in these patients could be determined.

We conducted a Phase II study of paclitaxel in patients with conventional osteosarcoma (10), malignant fibrous histiocytoma of the bone (3) and dedifferentiated chondrosarcoma (2) whose disease had progressed after prior standard chemotherapy including doxorubicin, cisplatin, ifosfamide, and high dose methotrexate. Paclitaxel was administered at a starting dose of 175 mg/m2 as a 24-hour infusion with standard premedication every 21 days or upon hematologic recovery (absolute granulocyte count [AGC] > 1500/microliters, platelets > 100,000/microliters). Neupogen was not used routinely. The study was conducted based on a two-stage design. A total of 17 patients were entered into the protocol. Two were ineligible since they had Ewing's sarcoma. Responses were assessed radiographically and pathologically when feasible, using standard criteria.

Fifteen eligible patients were treated in the first stage of the study. Median age of the patients was 31 years (range, 19-61 yrs). There were 8 females and 7 males with a Zubrod performance status of 0 or 1. One patient achieved a mixed response and 14 developed progressive disease. Median AGC nadir was 0.3, on Day 13, lasting 5 days. Median platelet nadir was 134, on Day 8. There were no Grade III or IV nonhematologic toxicities and no deaths related to treatment.

Paclitaxel, at this dose and schedule, is well tolerated but inactive in this patient population.