Biopharmaceutical company Navidea Biopharmaceuticals Inc (NYSE American:NAVB) reported on Thursday positive results from its ongoing Phase 2B study in rheumatoid arthritis (RA).

According to Navidea, the analysis of subjects who have completed Arm 3 of its NAV3-31 Phase 2B trial further corroborates the company's hypotheses that Tc99m tilmanocept imaging can provide robust, quantitative imaging in patients with active RA and that this imaging can provide an early indicator of treatment efficacy.

There are three arms of the study: Arm 1 consists of healthy subjects, Arm 2 is comprised of patients with active, moderate-to-severe RA who are on stable therapy, and Arm 3 is a pilot arm of the upcoming Phase 3 trial assessing the ability of Tc99m tilmanocept to provide an early indicator of efficacy of anti-tumor necrosis factor (TNF) alpha treatment in RA patients.

This third arm was designed to evaluate the magnitude of change of Tc99m tilmanocept signal localized to RA-involved joints in patients before and after treatment with an anti-TNF alpha therapy as well as to examine whether the localization or change in localization can serve as an early, quantifiable predictor of treatment efficacy as determined by clinical assessments at 12 and 24 weeks.

Results of the preliminary analysis demonstrate that Tc99m tilmanocept imaging from baseline to week 5 was predictive of clinical outcome at 24 weeks in 13 out of 16 patients (81.3%).

Early results also support the hypothesis that, in a subset of RA patients, the baseline scan alone can be a reliable predictor of non-responsiveness to anti-TNF alpha therapy.