<qa>  What is the duration of the study?Subjects participation in the study will last approximately 19 months, including screening and baseline procedures, treatment with study drug and a follow-up visit 1 12 months after finishing treatment, plus a visit for blood tests 6 months after the last infusion in the study. This research study requires that the patient have another person, such as a spouse, child, other relative, close friend, aide or other professional caregiver, who will accompany the patient to each clinic visit. 