Oral LGD-4665 Versus Placebo in Adults With Immune Thrombocytopenic Purpura (ITP) for 6 Weeks Plus Open Treatment Continuation

The purpose of this study is to assess the ability of LGD-4665 given daily by mouth to increase platelet counts in the treatment of patients with ITP (immune thrombocytopenic purpura). LGD-4665 increased platelet counts safely and tolerably compared to placebo in healthy volunteers. This study will examine the safety, tolerability and efficacy of 7.5 mg capsules of LGD-4665 to increase platelets compared to placebo, randomized 2:1, during blinded treatment for 6 weeks. Evaluation of platelet counts, bleeding scores and safety parameters will be done weekly. All patients are eligible to continue on active, open LGD-4665 treatment for an additional 12 weeks with optimal adjustment of dose for each patient.