The primary objective is to determine if BPL's GAMMAPLEX raises the platelet count of subjects with chronic ITP to a threshold of 50 x 109/L, similar to that of published response >60%. The secondary objectives are: 1) to determine the safety of GAMMAPLEX at the dosage used in this study. 2) to determine if GAMMAPLEX maintains platelet counts of ³ 50 x 109/L in subjects with chronic ITP for a period of time similar to that of a published data.