8. Patients who are HIV positive; patients with active HCV or HBV infection as evidenced by plasma levels of HCV RNA or HBV DNA, respectively. [Note: Tests for viral serology/infection performed prior to transplant and within 6 months of dosing may be used to satisfy this criteria.] 9. HSCT recipients who, other than the qualifying HSCT, received another allogeneic HSCT within the past 2 years. [Note: Patients who received one or more autologous transplants in addition to the qualifying allogeneic HSCT are not excluded from participation.] 10. Patients with renal insufficiency as evidenced by GFR < 30 mL/min. [Note: GFR will be calculated by the central laboratory using the MDRD study formula.] 11. Patients with a current diagnosis of hypotony, uveitis, or retinitis or any intraocular pathology that would predispose the patient to any one of these conditions.