Pharmacokinetics and scintigraphy of indium-111-DTPA-MOC-31 in small-cell lung carcinoma.
Radiolabeled MOC-31 retains its immunoreactivity and shows good in vivo immunolocalization to human SCLC xenografted in nude rats.


METHODS
We evaluated the immunotargeting properties and safety of 111In-labeled monoclonal antibody (MAb) MOC-31 (125 MBq, 5 mg) in six patients with histologically proven small-cell lung cancer (SCLC). Scintigraphy and pharmacokinetics were performed up to 3 days after injection.


RESULTS
No adverse reactions were found after injection of MAb MOC-31. Pharmacokinetics obtained from plasma radioactivity showed plasma disappearance described most properly by a monoexponential model with a mean half-life value of 17.0 +/- 1.4 hr. HPLC analysis documented the monomeric MOC-31 without evidence of immune complexes or radioactive lower molecular weight fractions. Mean 24-hr urinary excretion of radioactivity was 4.3% of the injected dose. Scintigraphy detected primary tumor or metastases in five of six patients. Localization of radioactivity in normal tissue was restricted, but additional experiments need to be performed to elucidate possible cross-reactivity of MOC-31 with normal tissue in vivo.


CONCLUSIONS
Preliminary results justify further studies to reveal the possible usefullness of radiolabeled MOC-31 in the therapeutic and diagnostic management of SCLC.
Department of Pharmacy, University Hospital Groningen, The Netherlands.
J G
JG
Kosterink
M W
MW
de Jonge
E F
EF
Smit
D A
DA
Piers
R A
RA
Kengen
P E
PE
Postmus
D
D
Shochat
H J
HJ
Groen
H T
HT
The
L
L
de Leij
D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics; D018288:Carcinoma, Small Cell / Q000000981:diagnostic imaging* / Q000556:secondary; D006801:Humans; D007205:Indium Radioisotopes / Q000493:pharmacokinetics; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D004369:Pentetic Acid / Q000493:pharmacokinetics; D016719:Radioimmunodetection
D000911:Antibodies, Monoclonal; D007205:Indium Radioisotopes; D004369:Pentetic Acid