Lymphoseek: a molecular radiopharmaceutical for sentinel node detection.
BACKGROUND
Lymphoseek is a new radiopharmaceutical that accumulates in lymphatic tissue by binding to a receptor that resides on the surface of macrophage cells. We conducted a phase I clinical trial in which Lymphoseek was compared with filtered [(99m)Tc]sulfur colloid (fTcSC) for sentinel node detection in patients with breast cancer.


METHODS
Twelve women (42-71 years) with breast cancer were randomly assigned to a 3-hour imaging protocol with peritumoral/subdermal injections (.5 mCi) of either Lymphoseek (1 nmol; molecular weight, 28 kDa; diameter,.007 micro m) or.2 micro m of fTcSC. Serial images were acquired for 180 minutes. Sentinel nodes, excised within 4.2 to 7.3 hours of administration, were assayed in a dose calibrator.


RESULTS
The receptor-binding agent, Lymphoseek, exhibited a significantly (P =.0025) faster injection site clearance (rate,.255 +/-.147/hour; fTcSC rate,.014 +/-.018/hour); the mean Lymphoseek clearance half-time was 2.72 +/- 1.57 hours compared with 49.5 +/- 38.5 hours for fTcSC. The primary sentinel node uptake of Lymphoseek (range,.02%-1.12%; mean,.55% +/-.43%) and fTcSC (range,.00%-1.93%; mean,.65% +/-.63%) did not differ (P =.75). Lymphoseek exhibited a lower mean number of sentinel nodes per study (n = 1.3) than fTcSC (n = 1.7) and a higher concordance with Lymphazurin.


CONCLUSIONS
The molecular receptor-binding agent Lymphoseek demonstrated faster injection site clearance and equivalent primary sentinel node uptake when compared with fTcSC.
Wallace
Anne M
AM
Department of Surgery, University of California, San Diego Comprehensive Cancer Center, USA. amwallace@ucsd.edu
Hoh
Carl K
CK
Vera
David R
DR
Darrah
Denise D
DD
Schulteis
Gery
G
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology*; D003911:Dextrans; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008264:Macrophages; D008351:Mannans; D008875:Middle Aged; D015609:Organotechnetium Compounds; D004369:Pentetic Acid; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D016284:Technetium Tc 99m Pentetate / Q000031:analogs & derivatives; D013671:Technetium Tc 99m Sulfur Colloid
D003911:Dextrans; D008351:Mannans; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C431884:technetium-diethylenetriaminepentaacetic acid-mannosyl-dextran; D013671:Technetium Tc 99m Sulfur Colloid; D004369:Pentetic Acid; D016284:Technetium Tc 99m Pentetate