- The patient had an absolute lymphocyte count (ALC) > 30% lower than baseline (defined as baseline prior to any MEDI-507 exposure; or, for patients whose treatment assignments have not been unblinded at the time of entry into this study, drug exposure) at his/her final visit (excluding any long-term follow-up visits) in the most recent Medimmune, Inc. study in which the patient participated; or the patient had an absolute CD4 count of < 250 cells/uL at his/her final visit (including any protocol-specific long-term follow up) in the most recent Medimmune, Inc. study in which the patient participated.