Navidea Announces Clinical Data for Manocept Shows Agent Localizes in Multiple KS Lesions

Navidea Biopharmaceuticals, Inc. NAVB and its subsidiary, Macrophage Therapeutics, Inc., today announced that imaging results from the Manocept™ clinical trial in Kaposi's Sarcoma (KS) and other preclinical studies were presented at the 18th International Workshop on Kaposi's Sarcoma Herpesvirus (KSHV) and Related Agents in Hollywood, Florida. The clinical imaging study, using Tc 99m tilmanocept, a Manocept platform product, in both HIV+ and HIV- patients suggests that KS tumor lesions, both cutaneous and suspected extra-cutaneous sites, can be easily visualized and mapped, demonstrating that this technique may potentially provide a means for routine patient assessment. The results also show that use of Manocept represents a potential therapeutic pathway for targeting tumor associated macrophages (TAMs). Manocept agents are designed to target CD206, which is highly expressed on TAMs and the KS tumor itself. As a potential therapeutic, Manocept could be used as a precision vehicle to deliver payloads to tumor sites throughout the body. "These pre-clinical and clinical studies support using Kaposi's sarcoma as a model tumor system for evaluating therapeutic approaches for the Manocept platform in other forms of solid tumors," commented Michael Tomblyn, M.D., Navidea's Chief Medical Officer. "They provide evidence that Manocept agents can target CD206 and are internalized into tumor associated macrophages and tumor cells. This along with clinical observations that demonstrate tilmanocept can be used to image KS tumors both externally and internally indicates excellent potential for immunotherapeutic utility." "Using a targeted imaging agent like tilmanocept in this group of HHV8+patients represents an elegant approach to potentially detect internal KS lesions that would previously be difficult or impossible to non-invasively locate," commented Toby Maurer, M.D., FAAD, Professor of Dermatology at the University of California, San Francisco (UCSF), and Chief of Dermatology at San Francisco General Hospital and Trauma Center, who co-led the clinical study at UCSF with Michael S. McGrath, M.D., PhD. "Further, the specificity and the ability to quantify tumor burden could enable regular patient evaluations and monitoring of therapeutic effectiveness addressing important unmet patient needs." Five Human Herpes Virus8 positive (HHV8+) patients (4 HIV+, 1HIV-) were enrolled in the NAV03-12 study. Patients received a single subcutaneous injection of Technetium Tc 99m tilmanocept in the region of a cutaneous KS lesion and imaging was performed at 1, 4 and 24-hours post-injection to visualize localization of tilmanocept. Results represented by whole body Single-Photon Emission Computed Tomography (SPECT/CT) imaging scans from study patients were presented. Collectively, the scans show localization of tilmanocept and detected multiple cutaneous lesions in the extremities, face and genitalia, as well as extra-cutaneous localization found in the nasopharynx, lymph nodes and brain. Results also indicate that KS lesions are anatomically linked in chains by and within the lymph ducts. The study concludes that both HIV+ and HIV- patients have pan-tumor expression of CD206, strongly suggests tilmanocept crosses the blood brain barrier and that a Manocept-drug conjugate may have the potential as a therapeutic with high target effect and low off-target concerns. The data from these studies also suggest a novel theory on the genesis of KS in which KS arises from an HHV8 infected macrophage type cell and its interaction with the lymphatic system. This interaction provides the means for access of the KS through CD206 receptor for diagnosis, evaluation, and potential therapy using the Manocept platform. Navidea and Macrophage Therapeutics plan a webcast to provide investors with a complete look at the data being presented at the International Workshop on Kaposi's Sarcoma Herpesvirus (KSHV) and Related Agents conference on July 7, 2015 at 1:00 pm EDT. Webcast details will be available on the Navidea website.