Protalex, Inc. provided an update on its U.S. Phase 1/2 and European Phase 1b studies of PRTX-100 in adults with persistent, chronic Immune Thrombocytopenia. PRTX-100, Protalex's lead drug candidate, is a highly-purified form of Staphylococcal protein A and is the subject of ongoing clinical development in ITP and rheumatoid arthritis. PRTX-100 has been granted Orphan Drug Designation in the U.S. and in Europe for the treatment of ITP. The 202 Study in U.S. The 202 Study is an open-label, Phase 1/2 dose escalating study in patients who have previously received treatment with a thrombopoietin receptor agonist and at least one additional ITP therapy. This study can enroll up to 36 patients in as many as six cohorts. Each patient receives four weekly intravenous doses of PRTX-100 and is monitored for up to 48 weeks thereafter. The 202 study is enrolling its second cohort of patients at the dose of 3.0 micrograms/kg, three times the 1.0 micrograms/kg dose of the first cohort. The primary study endpoint of the 202 Study is a platelet response to PRTX-100. Secondary endpoints include safety, immunogenicity, and pharmacokinetics. This study can enroll up to 30 patients in as many as five cohorts. Subjects receive four weekly intravenous doses of PRTX-100 and are monitored for up to 48 weeks thereafter. The 203 study is now enrolling patients in the second cohort at a dose of 6.0 micrograms/kg, twice the dose of the first cohort. The primary study endpoint of the 203 Study is safety.