Long-term Versus Short-term Sequential Therapy (Intravenous Itraconazole Followed by Oral Solution) of Itraconazole as Primary Prophylaxis in Patients Undergoing Allogeneic Stem Cell Transplantation

* The primary objective of this study is to evaluate the efficacy and safety profile of itraconazole as in primary prophylaxis * The second objective of this study is to find the difference between long-term versus short-term sequential therapy of Itraconazole (intravenous followed by oral itraconazole) as primary prophylaxis of invasive fungal infections (IFI) in patients undergoing allogeneic stem cell transplantation (allo-SCT) * also to explore the relationship between the incidence of IFI with plasma concentrations of itraconazole and hydroxy-itraconazole