N-(phosphonacetyl)-L-aspartate (PALA) in advanced soft tissue sarcoma: a phase II trial of the EORTC soft tissue sarcoma group.

Thirty-six patients with measurable or evaluable advanced soft tissue sarcoma were entered in a phase II trial with PALA. Among the 27 evaluable patients, 15 were men, the median age was 55 yr (16-69) and the median performance status (Karnofsky) was 80 (50-100). Most patients had leiomyosarcoma (8), liposarcoma (3), neurofibrosarcoma (3), synovial cell sarcoma (3), or undifferentiated sarcoma (3). Indicator lesions consisted essentially of lung metastases (21) and/or soft tissue lesions (14). All patients had received prior chemotherapy with 1-5 regimens and 6 had achieved objective response with these previous treatments. PALA was given as a 60-min i.v. infusion at a daily dose of 2.5 g/m2 for two consecutive days. Courses were repeated every two weeks. A median number of 3 courses (2-17) were administered. Partial remission (greater than 50%) was obtained in one patient with a liposarcoma who had also responded to prior combination chemotherapy. This single response to PALA lasted 6 weeks from initiation of therapy. Four patients had unchanged disease after 6+ courses of PALA and 22 had progressive disease. Toxic effects were generally mild to moderate and included cutaneous toxicity (17), diarrhea (14), stomatitis (13), ocular manifestations, consisting of conjunctivitis, corneal ulceration and/or photophobia (11), nausea and vomiting (6) and, possibly, seizures (2). There was no evidence of drug-related myelosuppression. It is concluded that PALA given at the dose schedule selected for this trial has no significant antitumor activity in advanced soft tissue sarcoma previously treated with chemotherapy.