Protalex, Inc. Announces Findings From Final Cohort Of U.S. Phase Ib Trial Of PRTX-100 In Active Rheumatoid Arthritis Patients

FLORHAM PARK, N.J.--(BUSINESS WIRE)--Protalex, Inc. (OTCQB:PRTX), a clinical-stage biopharmaceutical company, announced that it has completed analysis from the final cohort (Cohort 5) of its U.S.-based multicenter Phase 1b randomized, multiple-dose, dose-escalation study of PRTX-100 in combination with methotrexate or leflunomide in adults with active rheumatoid arthritis (RA; the 104 Study). PRTX-100, Protalex’s lead drug, is a highly purified form of Staphylococcal Protein A, which is the subject of ongoing clinical development in rheumatoid arthritis RA. Under a separate Investigational New Drug application, the Company will soon commence a clinical trial of PRTX-100 in patients suffering from chronic Immune Thrombocytopenia (ITP), an orphan disease.

The Company previously reported final data from Cohorts 1 through 4 and an interim analysis of pooled data from Cohort 5 of the 104 Study in November 2014. The primary study endpoint of the 104 Study was safety and tolerability with secondary endpoints including immunogenicity, effects on measures of RA disease activity, and evaluating anti-PRTX-100 antibody presence. For patients in all five cohorts of the 104 Study, PRTX-100 was safe and well tolerated in all individuals, including those who develop anti-drug antibodies (ADAs); there were no drug-related Serious Adverse Events (SAEs).

In Cohort 5, the amount of PRTX-100 administered and its dosing frequency were varied from Cohorts 1 through 4 to explore effects on safety, tolerability, and measures of disease activity. Analysis of the Cohort 5 findings suggests that weight-based dosing and monthly maintenance doses were an important aspect of the dosing protocol and should be considered in future trials of PRTX-100.

Additionally, an exploratory analysis of Cohorts 1 through 5 data indicates there may be a relationship between certain biomarkers in a patient’s blood before treatment with PRTX-100 and effects on measures of disease activity. In light of this, the Company intends to re-examine the biomarkers from its prior South African RA trial (the 103 Study). Upon the completion of the combined analysis of the 103 Study and 104 Study biomarkers, the Company will determine any next steps to explore the utility of the biomarker in identifying RA patients most likely to benefit from treatment with PRTX-100.

About Protalex, Inc.

Protalex, Inc. is a clinical-stage biopharmaceutical company focused on the development of a class of drugs for treating autoimmune and inflammatory diseases including Rheumatoid Arthritis (RA) and Immune Thrombocytopenia (ITP). Protalex’s lead product, PRTX-100, is a formulation of a proprietary, highly purified form of Staphylococcal Protein A, which is an immunomodulatory protein produced by bacteria. PRTX-100 has the ability, at very low concentrations, to bind to human B-lymphocytes and macrophages and to modulate immune processes. The safety, tolerability and pharmacokinetics of PRTX-100 have been characterized in five clinical studies. In two Phase 1b clinical trials in adult patients with active RA, PRTX-100 was generally safe and well tolerated at all dose levels, and at certain higher doses, more patients showed improvement in measures of RA disease activity than did patients at the lower dose or placebo cohorts.

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