Randomized, blinded, placebo-controlled phase I trial of pegylated recombinant human megakaryocyte growth and development factor with filgrastim after dose-intensive chemotherapy in patients with advanced cancer.

Thrombocytopenia caused by chemotherapy is an important cause of morbidity and mortality in the treatment of malignant disease. Recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) is a potent stimulator of megakaryocytopoiesis and prevents chemotherapy-induced thrombocytopenia in preclinical studies. We administered PEG-rHuMGDF with filgrastim after dose-intensive chemotherapy to 41 patients with advanced cancers to determine its safety and effects on hematologic recovery. Carboplatin 600 mg/m2 and cyclophosphamide 1,200 mg/m2 were administered to patients with advanced cancer. Patients were randomly assigned to receive blinded study drug, either PEG-rHuMGDF or placebo (3-to-1 ratio), commencing the day after chemotherapy. PEG-rHuMGDF was given at doses of 0.03, 0.1, 0.3, 1.0, 3.0, and 5.0 microg per kilogram body weight by daily subcutaneous injection for between 7 and 20 days. All patients received concurrent filgrastim 5 microg per kilogram body weight per day until neutrophil recovery. Fifteen patients had received PEG-rHuMGDF alone in a previous phase I study. Platelet function and peripheral blood progenitor cells (PBPC) were assessed. PEG-rHuMGDF enhanced platelet recovery in a dose-related manner when compared with placebo. The platelet nadir occurred earlier in patients given PEG-rHuMGDF (P = .002) but there was no difference in the depth of the nadir. Recovery to baseline platelet count was achieved significantly earlier following PEG-rHuMGDF administration compared with placebo (median, 17 days for PEG-rHuMGDF 0.3 to 5.0 microg/kg versus 22 days for placebo, P = .014). In addition, platelet recovery was faster in patients who had previously received PEG-rHuMGDF, suggesting that pretreatment might be beneficial. Platelet function did not change during or after administration of PEG-rHuMGDF. Levels of PBPC on day 15 after chemotherapy were significantly greater in patients administered PEG-rHuMGDF 0.3 to 5.0 microg/kg and filgrastim compared with those given placebo plus filgrastim. PEG-rHuMGDF was well tolerated at all doses. Two patients given PEG-rHuMGDF had a thrombotic episode. PEG-rHuMGDF accelerates platelet recovery after moderately dose-intensive carboplatin and cyclophosphamide, and is likely to be clinically useful in treatment of chemotherapy-induced thrombocytopenia. Because it enhances mobilization of PBPC by filgrastim, PEG-rHuMGDF might also allow more efficient collection of stem cells for autologous or allogeneic transplantation.