Protalex announces results from PRTX-100 Phase 1b trial on active rheumatoid arthritis

Protalex, Inc. (OTCBB: PRTX), a clinical stage biopharmaceutical company focused on the development of a class of drugs designed to treat autoimmune and inflammatory diseases including rheumatoid arthritis (RA), today announced results from its recently completed Phase 1b randomized, multiple-dose, dose-escalation study. The study conducted in South Africa of PRTX-100 in adult patients with active RA demonstrated that the drug was generally safe and well-tolerated at all dose levels and at the higher doses, more patients showed improvement in their CDAI (Clinical Disease Activity Index for RA) than did patients at the lower dose or placebo cohorts.

A total of 37 patients who had active RA on methotrexate were enrolled in four dose-escalating cohorts ranging from 0.15 μg/kg to 1.50 μg/kg PRTX-100 or placebo, administered weekly for four weeks. Safety and disease activity were evaluated over sixteen weeks following the first dose. The primary disease activity response endpoint was the number of patients with a DAS28-CRP < 3.2 at week six.

The results showed that the PRTX-100 patients as a group had more responders than placebo at all times, that responders increased over time during the sixteen week study evaluation period, and that the maximum tolerated dose was not reached at the highest dose level.

Additionally, in this study PRTX-100 did not decrease CRP (C-Reactive Protein) levels, even in those patients whose swollen and tender joint count and global VAS (Visual Analogue Scale) scores had decreased to low levels after treatment. Because CRP is a statistically important component of the DAS28-CRP score, we performed a post-hoc analysis using CDAI scores, which do not include CRP. In the placebo, 0.15 µg/kg, and 0.45 µg/kg dose groups, one of eight patients in each group attained low disease activity (CDAI ≤10) on two or more consecutive visits. In the 0.90 µg/kg and 1.50 µg/kg dose groups, two of eight and two of five patients, respectively, attained this same endpoint, and maintained a CDAI < 10 through the week sixteen final visit. Of the four apparent responders in the 1.50 µg/kg group, two attained a CDAI ≤6 (remission), one attained a CDAI ≤10 (low activity), and one achieved a CDAI of 10.1 at one or more visits. The mean time to peak response in this group occurred six weeks after their last dose.

"As previously noted, the initial disease activity results demonstrated an acceptable safety profile and at the higher dose levels, more patients showed improvement as scored by the CDAI. These results warrant further study of PRTX-100 at doses of 1.50 µg/kg and higher, and the next trial which will have study centers in both the U.S. and South Africa, should provide a better understanding of safety and treatment effect on RA disease activity measurements. The new trial should also help us define the optimal dose", stated William E. Gannon, Jr., M.D., Chief Medical Officer of Protalex.

Patient enrollment in the first cohort of the new study is expected to commence later in the 4^th quarter of 2012.