Comparison of key sentinel node biopsy parameters for 99mTc-tilmanocept (TcTM) and 99mTc-sulfur colloid (TcSC) in breast cancer

126 Objectives Intraoperative lymphatic mapping (ILM) for sentinel node biopsy (SLNB) in breast cancer (BC) patients (pts) is conducted with a dye agent and/or a 99mTc-radiotracing agent (RTA). The currently-approved RTAs in the US and Europe for ILM/SLNB are only particulate colloids. TcSC (50-800nm) recently received approval in the US to assist in the localization of lymph nodes draining a primary tumor in pts with BC. TcTM (≤ 7nm) (Lymphoseek; Navidea Biopharmaceuticals, Dublin, OH), a novel, soluble, receptor-targeted (CD206) synthetic molecular ILM RTA has been evaluated in two phase 3 studies for BC. To date, no direct comparative clinical trials have evaluated the efficacy of TcTM and TcSC. Methods A meta-analysis of data from phase 3 TcTM trials vs TcSC published data identified in US regulatory review was conducted with regard to two key ILM/SLNB performance parameters, localization rate (LR) and degree of localization (DL), so as to construct a performance comparison. The functional endpoints were: 1] LR (% of pts w/ a hot node found) and 2] DL (# of hot nodes found/pt). Both metrics define the potential for RTA performance for ILM/SLNB and potentially for evaluation of nodal metastasis. Results The LR for TcSC was 94% (95% CI = 91.4, 96.0; n=9213). The LR for TcTM was 99.9% (95% CI = 99.2, 100.0; n=148); p Conclusions Based on a meta-analysis of clinical trial data, TcTM provided statistically significantly greater performance than TcSC in the key metrics of lymph node localization/pt, and degree of localization (nodes found/pt) in breast cancer. These data suggest that receptor-targeted TcTM may provide improved diagnostic ILM vs the currently employed nonspecific ILM RTA, TcSC.