Prospective , Randomized Trial of 5-Fluorouracil , Leucovorin , Doxorubicin , and Cyclophosphamide Chemotherapy in Combination With the Interleukin-3 / Granulocyte-Macrophage Colony-Stimulating Factor ( GM-CSF ) Fusion Protein ( PIXY 321 ) Versus GM-CSF in Patients With Advanced Breast Cancer
We conducted a prospective randomized trial t o evaluate the ability of the interleukin-3/granulocyte-macrophage colonystimulating factor (GM-CSF) fusion protein, PIXY321, t o ameliorate cumulative thrombocytopenia after multiple cycles of 5-fluorouracil, leucovorin, doxorubicin, cyclophosphamide (FLAC) chemotherapy compared with GM-CSF in patients with advanced breast cancer. Fifty-three patients were randomized t o receive either PIXY321, 375 pg/m2 twice a day subcutaneously, or GM-CSF, 250 pg/m2daily subcutaneously after FLAC chemotherapy. PIXY321 was less well tolerated than GM-CSF, with more patients developing chills and local skin reactions and more patients stopping PIXY321 due to intolerance. While no difference in the neutrophil nadirs was seen with the two cytokines, the duration of the abso-