Radioimmunodetection of non-small cell lung cancer using technetium-99m-anticarcinoembryonic antigen IMMU-4 Fab' fragment. Preliminary results.
BACKGROUND
Although computed tomography and magnetic resonance imaging have improved the staging and evaluation of non-small cell lung cancer (NSCLC), mediastinal staging lacks adequate specificity and sensitivity. Radioimmunodetection may augment computed tomography and magnetic resonance imaging. The authors evaluated the ability of the technetium 99m-anticarcinoembryonic antigen IMMU-4 Fab' fragment to localize NSCLC in vivo, measured its pharmacokinetics, and estimated its radiation dose.


METHODS
Seventeen patients with carcinoembryonic antigen-positive NSCLC received 16-30 mCi of technetium 99m IMMU-4 Fab'. Planar imaging was performed at 1-7 hours and 20-24 hours. Single-photon emission computed tomography (SPECT) was performed within 8 hours after injection. In 10 patients, blood sampling, urine collection, and quantitative imaging were performed to determine blood and urine pharmacokinetics and radiation dose estimates. Human anti-mouse antibody response was measured for as long as 3 months after administration.


RESULTS
Planar and/or SPECT imaging detected 72% of 32 known lesions. SPECT was more sensitive than planar imaging. T1/2 alpha averaged 0.18 +/- 0.33 hours; T1/2 beta averaged 8.02 +/- 5.53 hours. The mean concentration versus time value was 1.11 +/- 0.56 mg.h. The average whole body dose estimated for administration of 30 mCi was 0.45 +/- 0.08 rads. No human anti-mouse antibody responses were detected.


CONCLUSIONS
The tumor detection rate was high, but the persistent blood pool at < 8 hours complicated image interpretation. An intermediate imaging time point (12-16 hours) might be preferable. SPECT is an important adjunct to imaging with this radioimmunoconjugate. The acceptable dosimetry estimated for 30 mCi Technetium 99m IMMU-4 Fab' and the lack of human anti-mouse antibody responses suggest this is a promising localizing tool for NSCLC:
Kramer
E L
EL
Division of Nuclear Medicine, New York University Medical Center, NY 10016.
Noz
M E
ME
Liebes
L
L
Murthy
S
S
Tiu
S
S
Goldenberg
D M
DM
D000911:Antibodies, Monoclonal / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging*; D007140:Immunoglobulin Fab Fragments; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D016719:Radioimmunodetection; D013667:Technetium / Q000493:pharmacokinetics; D014055:Tomography, Emission-Computed
D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D013667:Technetium; C081678:arcitumomab