99mTc-tilmanocept (Lymphoseek) use in phase 3 sentinel node mapping study in squamous cell carcinoma (SCC) of the head & neck

Objectives The primary endpoint of the phase 3 study is the false negative rate (FNR) associated with 99mTc-tilmanocept-identified sentinel lymph nodes (SLNs) relative to the pathology status of nonSLNs in elective neck dissection (END). The secondary objectives are sensitivity, negative predictive value, and overall accuracy of 99mTc-tilmanocept-detected SLNs relative to the pathology status of LNs in the END. The safety objective will be accomplished by evaluation of AEs, clinical laboratory tests, physical exams, etc.

Methods All patients receive a single dose of 50 µg of Tc99m tilmanocept, radiolabeled with either 0.5 mCi Tc99m for same day surgery or 2.0 mCi Tc99m for injections on next day surgery. Patients undergo intraoperative mapping for SLN resection followed by complete END. Excised lymph nodes (SLN and non-SLN) undergo pathology evaluation for presence/absence of metastatic disease. Patients are contacted 30d post-surgery for follow-up assessment.

Results There have been 40 patients enrolled in the study and injected with the study drug. Due to the statistical design of this study, no efficacy outcomes can be analyzed prior to the database lock at study completion. To date, no patients have been discontinued from the study because of AEs. There have been three serious adverse events (SAEs) recorded which include: hematoma-neck, wound infection, and atelectasis, none is related to the study drug. There have been no deaths. Initial case reviews indicates that 99mTc-tilmanocept provides excellent intraoperative illumination of multiple SLNs and it is well tolerated.

Conclusions The safety data do not indicate any effect of 99mTc-tilmanocept on adverse event rates or clinical laboratory parameters. Tilmanocept provides exceptional bio-targeting of SLNs with illumination of SLNs not typically discovered with region-directed head and neck dissection.

Research Support This study is supported as a phase 3 clinical trial by the Neoprobe Coporation of Dublin, OH 43217