Protalex, Inc. announced that following a planned interim analysis of data from the third dose cohort of its European Phase 1b study of PRTX-100, the Company’s highly purified form of Staphylococcal protein A (SpA,) in adults with persistent/chronic Immune Thrombocytopenia (ITP) (PRTX-100-203 Study), the Company has initiated enrollment in the fourth cohort of this dose-escalating study. The first patient in this penultimate cohort was recently dosed in the United Kingdom at 18.0 µg/kg, the highest dose of PRTX-100 used in any clinical trial to date. PRTX-100 has been granted Orphan Drug Designation in the U.S. and in Europe for the treatment of ITP. The 203 Study is a European open-label, dose escalating study that can enroll up to 30 patients in as many as five cohorts. Patients with chronic, persistent ITP are eligible for the 203 study if they have received one prior ITP treatment and their platelet counts remain low. Each patient will receive four weekly intravenous doses of PRTX-100 and will be monitored for up to 48 weeks thereafter. The primary study endpoint of the 203 Study is to evaluate the safety of PRTX-100. Secondary endpoints include efficacy, immunogenicity, and pharmacokinetics.