A 3-year follow-up study of breast cancer (BC) or melanoma (ME) patients (Pts) who underwent sentinel node biopsy (SLNB) indicates a <2% false negative rate performance with CD206 receptor-targeted 99mTc-tilmanocept (TcTm) as the sole intraoperative lymphatic mapping agent

1553 Objectives Primary:The main endpoint for this study was the regional disease recurrence (RC)-free rate, i.e., the absence of RC of the primary malignancy in the proximal lymphatic basin from which the TcTm-identified SLNs were resected. Secondary: Determine the rates of primary tumor site RC, distal RC, and overall RC. Determine the disease-specific mortality and overall survival. Methods All participating Pts were volunteer BC or ME patients (N=109) who were enrolled in a Phase 3 study (N=179) assessing the performance of TcTm; Pts were TIS-T4, N0, M0 at the time of enrollment on the Phase 3 study. Pts were followed for 36 months for evaluation of the primary and secondary metrics. Results 109 Pts were analyzed (64 BCPts, 45 MEPts). Overall, there were 8 cases of tumor RC, 2BC Pts (1pN+ &1 pN0) and 6 MEPts (3 pN+& 3 pN0). 7 Pts died during the follow-up period. Of these, only 4 were related to the primary malignancy (1pN+ BC, 1 pN0 BC, &2pN+ ME). All had distal RC: 3Pts had only distal RC prior to death (2pN+, 1 pN0), and 1Pt (already pN+ ME) had both regional and distal RC prior to death.Pathology-negative (pN0) Pts had a regional RC-free rate of 98.82% (cumulative), whereas pN+ Pts had a regional RC-free rate of 89.47% (cumulative).The mean overall RC-free time was 956.6 days. Mean RC-free time for ME Pts (879.8 days) as shorter than that for BCPts (1010.6 days). Additionally, mean RC-free time was shorter for pN+ Pts (846.0 days) than for pN0 Pts (983.0 days). Conclusions The NPV for 99mTc-Tilmanocept calculated from Study NEO3-04 was 98.61% (95% confidence interval 92.50-99.96%), which was calculated using the 36-month follow-up data. 99mTc-Tilmanocept provided for reliable SLN discrimination and long-term outcome in BC and ME Pts when evaluated as a single agent for SLNB.