Lymphoseek: a molecular imaging agent for melanoma sentinel lymph node mapping.
BACKGROUND
Lymphoseek is a molecular imaging agent specifically designed for sentinel lymph node mapping. We conducted a phase I clinical trial in which Lymphoseek was compared with filtered [(99m)Tc]sulfur colloid (fTcSC) for melanoma sentinel lymph node detection.


METHODS
Twenty-four patients (33-81 years) with melanoma participated in this study. Four groups of six patients received an intradermal administration (.5 mCi) of 1.0, 5.0, or 10.0 nmol of (99m)Tc-labeled Lymphoseek or filtered [(99m)Tc]sulfur colloid. The injection site clearance was monitored by nuclear imaging for 3 hours. Lymph nodes obtained by gamma-guided biopsy (4.0-8.7 hours after injection) were assayed for radioactivity. Clinical chemistry values were monitored (before injection, before surgery, and 4 and 24 hours), and whole-body scans were acquired at 1 and 12 hours after injection.


RESULTS
Lymphoseek exhibited a significantly (P < .001) faster injection site clearance at all dose levels. The mean Lymphoseek clearance half-time was 2.17 +/- .96 hours (n = 18) compared with 14.7 +/- 6.3 hours for fTcSC (n = 6). The mean sentinel lymph node uptakes of Lymphoseek (.73% +/- .94%) and fTcSC (.85% +/- 1.19%) were statistically equivalent (P = .68). Lymphoseek exhibited a lower mean number of sentinel lymph nodes per basin (1.6) than fTcSC (1.9). No adverse events were observed, nor were any clinically significant alterations in laboratory parameters. Radiation absorbed doses were lower than filtered [(99m)Tc]sulfur colloid.


CONCLUSIONS
The molecular imaging agent Lymphoseek demonstrated faster injection site clearance and equivalent primary sentinel node uptake when compared with filtered [(99m)Tc]sulfur colloid.
Wallace
Anne M
AM
Department of Surgery, University of California, San Diego, 200 West Arbor Drive, San Diego, California 92103, USA. amwallace@ucsd.edu
Hoh
Carl K
CK
Ellner
Scott J
SJ
Darrah
Denise D
DD
Schulteis
Gery
G
Vera
David R
DR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D009367:Neoplasm Staging; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D016284:Technetium Tc 99m Pentetate / Q000031:analogs & derivatives; D013671:Technetium Tc 99m Sulfur Colloid
D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid; D016284:Technetium Tc 99m Pentetate