Protalex Inc. announced that it will initiate enrollment for a Phase I/II study of PRTX-100 in adult patients with persistent/chronic immune thrombocytopenia (ITP) at several sites in the United States in the coming weeks. Protalex previously announced U.S. FDA acceptance of an Investigational New Drug application (IND) for this study. PRTX-100, Protalex's drug, is a new generation immuno modulatory therapy that is under investigation for autoimmune diseases such as rheumatoid arthritis (RA) and ITP.

PRTX-100 is a highly purified form of Staphylococcal protein A (SpA), a bacterial protein known to modify aspects of the human immune system. The 202 Study is an open-label, dose escalating study that will enroll up to 36 patients in as many as six cohorts. 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 202 Study is a platelet response to PRTX-100. Secondary endpoints include safety, immunogenicity, and pharmacokinetics. ITP is an autoimmune-mediated condition characterized by bruising and increased bleeding as a result of immune-mediated accelerated destruction of platelets and impaired production of platelets.

The diagnosis of ITP is based upon a low platelet count, usually less than 100,000 per microliter of blood, in the absence of other possible causes of reduced platelet numbers such as an underlying illness or medication. In June 2015, PRTX-100 was granted Orphan Drug Designation (ODD) by the FDA's Office of Orphan Products Development to treat ITP. An application for ODD in Europe for PRTX-100 is pending before the European Medicines Agency.

Orphan drug designation provides certain exclusivity benefits, tax credits for certain research and a waiver of the New Drug Application user fee.