- Use of biological response modifiers, such as granulocyte-colony stimulating factor (G-CSF), within 3 weeks prior to the first dose of study drug. Granulocyte-colony stimulating factor (G-CSF) and other hematopoietic growth factors may be used in the management of acute toxicity such as febrile neutropenia when clinically indicated or at the discretion of the investigator, however, they may not be substituted for a required dose reduction