23 May 2013 - 23 May 2013 - US developer of autoimmune inflammatory disease drugs Protalex Inc (OTCMKTS:PRTX) said Wednesday it would continue patient enrolment and dose increase in a Phase Ib trial of its product PRTX-100 in adults with active rheumatoid arthritis (RA) after a planned interim safety review by its Data Safety Monitoring Committee.

PRTX-100 is formulated with a proprietary highly purified form of Staphylococcal Protein A.

The randomised, multiple-dose, dose-escalation trial aims to determine, as a primary endpoint, the safety and tolerability profile of weekly intravenous PRTX-100 over a period of five weeks in patients with active RA on methotrexate or leflunomide therapy. Secondary goals are the effects of PRTX-100 on measures of disease activity, as well as evaluation of the immunogenicity and pharmacokinetic (PK) parameters after repeated doses, and determining possible relationships between the immunogenicity of PRTX-100 and safety, PK and efficacy parameters.

The study is currently assessing PRTX-100 in a dose of 12.0 micrograms/kg, or eight times higher than the initial starting dose of 1.5 micrograms/kg.

The sequential dose-escalation phase will recruit up to 40 patients in five cohorts ranging from 1.5 micrograms/kg to 18.0 micrograms/kg of PRTX-100, or placebo. This phase may be followed by up to 12 additional participants for cohort expansion at a selected dose.