Protalex, Inc. announced that following a planned interim analysis of data from the second dose cohort of its European Phase 1b study of PRTX-100 in adults with persistent/chronic Immune Thrombocytopenia (ITP) (PRTX-100-203 Study), the company has initiated enrollment in the third cohort of this dose-escalating study. The first patient in the third cohort was recently dosed at 12.0 µg/kg, double that of the second dose cohort of 6.0 µg/kg. 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 only needed to have received one prior ITP treatment to potentially be eligible for the 203 study. 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. As previously noted, Protalex has opened seven new clinical trial sites in the U.K. for the 203 Study to accelerate recruitment. Nicola Cooper, M.D., Hammersmith Hospital, London, is the National Coordinating Investigator for the trial in the U.K. Dr. Cooper enrolled the final patient into the second cohort of the 203 study, which marked the first patient enrolled in the U.K.