20 July 2021 - - More than 110 subjects have been enrolled and imaged in US-based precision immunodiagnostic agents and immunotherapeutics developer Navidea Biopharmaceuticals, Inc's (NYSE American: NAVB) NAV3-35 Phase 2b study, "Development of a Normative Database for Rheumatoid Arthritis Imaging with Tc99m Tilmanocept." Expected total enrollment for this two-arm trial will be 135 participants, the company said.

NAV3-35 will establish a database of hand and wrist images taken following Tc99m tilmanocept administration in healthy volunteers age- and sex-matched to the population of RA patients.

Tc99m tilmanocept attaches to mannose receptors (CD206) on macrophages that are frequently involved in RA joint inflammation.

Relatively smaller numbers of CD206 expressing macrophages normally reside in the joints of healthy people without RA.

An integral part of the ability to quantitatively discriminate RA-inflamed joints from those that do not have inflammation using Tc99m tilmanocept imaging is the knowledge of the distribution of Tc99m tilmanocept localization in healthy joints.

The establishment of this normal subject database (i.e., normative database) will enable improved accuracy of discrimination of RA-involved joints from non-RA inflamed joints and should have a positive impact on the ability to predict treatment response early.

This database will also be used in the training of automated image analysis algorithms to further improve the accuracy of the quantification of Tc99m tilmanocept localization in joints as well as the workflow for later commercialization in RA.

The aim is to recruit 135 volunteers in this two-arm study.

The first arm is comprised of 120 healthy subjects who will have planar imaging of their hands and wrists post administration of Tc99m tilmanocept, and arm two is a 15-subject arm comprised of 10 patients with RA and five healthy volunteers with the aim of demonstrating the feasibility of 3-dimensional SPECT/CT imaging for the quantitative assessment of RA-involved inflammation in joints.

To date, over 100 subjects have been imaged for Arm 1, and 10 in Arm 2.

Navidea Biopharmaceuticals, Inc. (NYSE American: NAVB) is a biopharmaceutical company focused on the development of precision immunodiagnostic agents and immunotherapeutics.

Navidea is developing multiple precision-targeted products based on its Manocept platform to enhance patient care by identifying the sites and pathways of disease and enable better diagnostic accuracy, clinical decision-making, and targeted treatment.

Navidea's Manocept platform is predicated on the ability to specifically target the CD206 mannose receptor expressed on activated macrophages.

The Manocept platform serves as the molecular backbone of Tc99m tilmanocept, the first product developed and commercialized by Navidea based on the platform.

Navidea's strategy is to deliver superior growth and shareholder return by bringing to market novel products and advancing the company's pipeline through global partnering and commercialization efforts.