Therapy Areas: Inflammatory Diseases
Navidea Biopharmaceuticals to Present Results from its Two Phase 2B Clinical Trials in Rheumatoid Arthritis
16 September 2022 - - Results from US-based precision immunodiagnostic agents and immunotherapeutics developer Navidea Biopharmaceuticals, Inc's (NYSE American: NAVB) completed NAV3-31 Phase 2B clinical study as well as the preliminary results of its ongoing NAV3-32 Phase 2B study have been accepted for presentation as posters at the annual meeting of the American College of Rheumatology, to be held November 10-14, 2022 in Philadelphia, PA, the company said.

In the completed NAV3-31 Phase 2B study (NCT03938636) titled "Evaluation of the Precision and Sensitivity of Tilmanocept Uptake Value on Tc99m Tilmanocept Planar Imaging", 30 rheumatoid arthritis patients with active RA set to start anti-tumor necrosis factor alpha therapy were enrolled and followed for 24 weeks.

Tc99m tilmanocept imaging performed at baseline and week 5 following therapy initiation had high overall accuracy at predicting American College of Rheumatology 50 clinical response at 12 and 24 weeks (27/30 and 24/28 subjects, respectively) after therapy start.

TIL imaging demonstrated high specificity (0.96 at weeks 12 and 24), positive predictive value (0.75 and 0.67, respectively), and negative predictive value (0.92 and 0.88, respectively), and the combination of TIL imaging data with serological and clinical markers in a multivariate model gave an area under the curve of 0.95 for prediction of response at week 24.

These results indicate that marked changes in TIL uptake by week 5 presage clinical efficacy evaluations at week 12 and week 24 of treatment and demonstrate that TIL imaging can provide quantifiable imaging assessment of RA-involved joints that enables an objective, early prediction of clinical response.

In the ongoing NAV3-32 Phase 2B study (NCT04078191) titled, "A Comparison of Tc99m Tilmanocept Quantitative Imaging With Immunohistochemical Analysis of CD206 Expression in Synovial Tissue From Subjects Clinically Diagnosed With Rheumatoid Arthritis " (Abstract #1979), the primary objective is to assess the relationship between joint-specific TIL uptake and the pathobiology of RA-involved joint tissue.

Preliminary results on the first eleven patients indicates that quantitative TIL uptake in the hands and wrists of patients is proportional to the amount of macrophage involvement in an individual RA patient's joint inflammation.

The cellular composition of RA-inflamed joints is known to vary between patients and is frequently separated into one of three pathotypes: fibroid, diffuse myeloid, and lympho-myeloid.

Knowledge of an individual RA patient's pathotype may be clinically important because it may predict to which RA therapy a patient is likely to respond. Imaging with TIL, a high affinity ligand to CD206 expressed on activated macrophages, offers the potential to distinguish between pathotypes without need of invasive biopsy.

In these preliminary results, TIL uptake in RA-inflamed joints was able to discretely differentiate patients with the fibroid pathotype (i.e., low macrophage involvement) from those having either the diffuse myeloid or lympho-myeloid pathotypes of RA (i.e., higher macrophage involvement).

This could have significant implications for decision making onto which therapy a patient is placed.

Overall, data from these two studies supports the hypothesis that TIL imaging has the potential to provide rheumatologists and those suffering with RA a noninvasive, quantifiable, early indicator of whether or not an anti-TNFα treatment is working or likely to work.

This could bring significant benefit to these patients by assisting physicians in putting them on the right course of treatment earlier than is currently possible.

RA is a chronic disease affecting over 1.3 m Americans and as much as 1% of the worldwide population. If the product is successfully developed, Navidea would expect to play a major role in the management of RA patients worldwide.
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