Study on the Efficacy and Safety of IGIV3I Grifols (Human Intravenous Immunoglobulin) in Patients Diagnosed with Chronic Immune Thrombocytopenic Purpura.

Intravenous immunoglobulin (IVIG) products are considered a useful treatment in patients with chronic idiopathic/immune thrombocytopenic purpura (ITP) to prevent bleeding or prior to surgery, when platelet counts have to be rapidly increased. IGIV3I Grifols is a highly purified, unmodified human IgG product whose manufacturing process follows the same basic principles of Flebogamma^® (another IVIG manufactured by Grifols in clinical use since 1992). The main differences between both processes are how purification steps are sequentially arranged, and the introduction of two specific steps to inactivate/remove any potential contaminating pathogen (solvent-detergent treatment and sequential nanofiltration through 35 and 20 nm pore size filters), as additional viral elimination steps to pasteurization, already present in Flebogamma^®. An open prospective study was planned to investigate the efficacy and safety of IGIV3I Grifols in 20 adult patients with chronic ITP (at least 6 months after diagnosis). Twenty adult subjects were enrolled and 19 patients with chronic ITP in acute phase (platelet counts <20x10⁹/l) were treated. Patients received 0.4 g/kg body weight for 5 consecutive days. Efficacy endpoints were the proportion of patients who reached a platelet count ≥50x10⁹/l, the time taken for the platelet count to reach the target level and the duration of response. Regression of haemorrhages was documented during the first 14 days of follow-up. Safety parameters including adverse events (AEs), laboratory determinations and vital signs were regularly monitored. The follow-up of patients ended 3 months after first dose of IGIV3I Grifols to determine any change in viral markers for HIV, HCV, HBV and HAV. Results from intention to treat (ITT) population (n=20) and per protocol (PP) population (n=19) are presented. A patient was withdrawn from the study because she did not present an immune idiopathic thrombocytopenic purpura. A total of 14 patients (ITT = 70%; PP = 74%) responded to the study drug. The median time to platelet response was ≥2.5 days and the median number of days in which the platelet count remained ≥50x10⁹/l was ≥7.0 days. For 17 patients (ITT = 85%; PP = 89%) a regression of the bleeding episodes was reported on day 14. Eight out of 20 patients presented 21 AEs potentially related to the study drug (16 mild and 5 moderate). Headache and fever (6 cases each), hypertension (2), decreased blood pressure (2) or hypotension (1), blood pressure fluctuation (1), thrombocythaemia (1), bradycardia (1) and asthenia (1) were AEs potentially related to study drug. No patients experienced clinically significant abnormalities in the laboratory values (haematology and renal and hepatic functions) and no patients changed their virological markers during the follow-up of the study. The results show that IGIV3I Grifols is safe and adequate to achieve a safe platelet count in patients with refractory chronic ITP.