Idiopathic (immune) thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by platelet destruction and thrombocytopenia (peripheral blood platelet count < 150 x 10^9/L). IVIG therapy is useful in patients in whom the platelet count has to be raised either due to bleeding signs, or where bleeding is predicted (e.g., surgery or parturition). The primary goal of treatment is to maintain the platelet count at a hemostatic level. This study will test the safety and efficacy of IGIV3I Grifols 10% in the treatment of patients with chronic ITP.

Key Inclusion Criteria:

• Diagnosis of chronic ITP
• Platelet count ≤ 20 x 10^9/L
• When administered corticosteroids at any time within 3 weeks before screening visit, the subject must have completed at least 3 weeks (21 days) of therapy at a stable and constant dose and schedule prior to screening visit
• When administered azathioprine (immunosuppressant) at any time within 3 months before screening visit, the subject must have received a stable dose and schedule for at least 3 months prior to screening visit
• When administered vinca alkaloids (eg., vincristine) at any time within 2 weeks before screening visit, the subject must have received a stable dose and schedule for at least 2 weeks prior to screening visit
• When administered attenuated androgens (eg, danazol) at any time within 8 weeks before screening visit, the subject must have received a stable dose and schedule for at least 8 weeks prior to screening visit.
• Females of childbearing potential must test negative for pregnancy

Key Exclusion Criteria:

• History or clinical evidence of medical conditions (other than ITP) felt to be the underlying cause of the thrombocytopenia
• Diagnosis of secondary immune thrombocytopenia
• History of severe (eg, anaphylactic) reactions to blood or any blood- derived product
• History of intolerance to any component of the IP, such as sorbitol
• Suffering serious and/or life-threatening hemorrhage/bleeding defined as:
• Any intracranial or central nervous system bleeding
• Any hemorrhagic event in which the subject is at risk of death at the time of the event
• Females who are pregnant or nursing an infant child
• Known to have immunoglobulin A (IgA) deficiency
• Known to abuse alcohol, opiates, psychotropic agents or other chemicals or drugs, or has done so within 12 months of the screening visit
• Documented diagnosis of thrombotic complications to polyclonal IVIG therapy in the past
• Unstable or uncontrolled disease, or condition, related to, or impacting, cardiac function: unstable angina, congestive heart failure, uncontrolled arterial hypertension
• Is anemic (hemoglobin < 9 g/dL)
• Renal impairment (ie, serum creatinine > 1.5 x upper limit of normal [ULN])
• Aspartate aminotransferase or alanine aminotransferase levels > 2.5 x ULN
• Known to have a positive test for either HCV or HIV (HIV 1/2)
• Splenectomy within the prior 8 weeks to the screening visit
• currently receiving any treatment for ITP except corticosteroids, azathioprine, vinca alkaloids or danazol
• Received an immune serum globulin (ISG) product within the prior 3 weeks (21 days) to the screening visit
• Received any alkylating agent (eg, cyclophosphamide) within 5 weeks prior to the screening visit
• Received rituximab within the prior 3 months to the screening visit
• Was currently receiving, or received, any therapeutic drug or device that was not approved by a Regulatory Authority (US or Canadian) for any indication within the prior 12 weeks to the screening visit