A phase II clinical trial of polyethylene glycol-conjugated L-asparaginase in patients with advanced ovarian cancer: Early closure for safety.

The anti-angiogenic activity of L-asparaginase (L-ASP) and the sensitivity of ovarian cancer cell lines to L-ASP has been previously demonstrated by preclinical findings. The aim of this clinical trial was to translate those findings and evaluate the activity of polyethylene glycol-conjugated L-asparaginase (PEG-ASP or pegaspargase) in advanced ovarian cancer. Women with recurrent ovarian cancer and good end-organ function were enrolled in an open-label phase II trial of PEG-ASP at a dose of 2,000 IU/m2 by intravenous infusion every 2 weeks. Patients were evaluated for response every 8 weeks and for toxicity on an ongoing basis. Early stopping rules for toxicity and activity were included. Four patients were enrolled and received a total of 7 treatment cycles. The study ended accrual by invoking an early stopping rule, after excessive toxicity was identified in patients. Drug-related toxicities included grade 2 pancreatitis, fatigue, neutropenia, hypoalbuminemia, weight loss, dehydration, decreased fibrinogen and 1 case of grade 3 hypersensitivity reaction during cycle 2. One patient died during the study. No patients were evaluable for response. PEG-ASP was poorly tolerated in this group of advanced-stage ovarian cancer patients and no conclusions regarding activity may be drawn. Further studies of PEG-ASP in ovarian cancer patients are not recommended.