Early results announced from continuation trial of PRTX-100 in patients with RA

Protalex Inc. released preliminary data following completion of its phase 1/2 open-label study of patients with rheumatoid arthritis treated during a 6-month period with PRTX-100 and either methotrexate or leflunomide.

PRTX-100, a purified form of Staphylococcal protein A, is in ongoing clinical development for both rheumatoid arthritis (RA) and immune thrombocytopenia, for which it has been granted orphan drug status. According to a company press release, the drug is believed to bind to human B lymphocytes and macrophages.

The trial of patients with RA included 11 patients, eight of whom completed the study protocol of four weekly doses followed by five monthly doses of PRTX-100 during a period of 6 months. Ultrasound joint evaluations, and antibody and biomarker presence were used to assess disease activity at the end of the trial.

According to the release, an acceptable safety profile was observed. Disease activity improved in most patients compared to baseline, with a mean reduction of the DAS28-C-reactive protein score from 5.25 to 2.52. In addition, investigators found disease severity was reduced on ultrasound.

“Our ongoing development program is focused on determining whether PRTX-100 modifies the disease course of RA with an improved safety profile and a dosing regimen comparable to current therapies, such as the Humira, Enbrel and Remicade, all of which can provoke adverse events,” William E. Gannon Jr., MD, Protalex’s chief medical officer, said in the release. “The 105 Study data are consistent with trends we saw in prior RA trials of PRTX-100. Additionally, incorporation of ultrasound joint count technology into small open-label trials may offer enhanced assessment of clinical efficacy.”

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