Comparison of normal tissue pharmacokinetics with 111In/90Y monoclonal antibody m170 for breast and prostate cancer.
OBJECTIVE
Radioactivity deposition in normal tissues limits the dose deliverable by radiopharmaceuticals (RP) in radioimmunotherapy (RIT). This study investigated the absorbed radiation dose in normal tissues for prostate cancer patients in comparison to breast cancer patients for 2 RPs using the monoclonal antibody (MAb) m170.


METHODS
111In-DOTA-glycylglycylglycyl-l-p-isothiocyanatophenylalanine amide (GGGF)-m170 and 111In-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) 2-iminothiolane (2IT)-m170, representing the same MAb and chelate with and without a cleavable linkage, were studied in 13 breast cancer and 26 prostate cancer patients. Dosimetry for 90Y was calculated using 111In MAb pharmacokinetics from the initial imaging study for each patient, using reference man- and patient-specific masses.


RESULTS
The reference man-specific radiation doses (cGy/MBq) were not significantly different for the breast and the prostate cancer patients for both RPs in all but one tissue-RP combination (liver, DOTA-2IT). The patient-specific doses had differences between the groups most of which can be related to weight differences.


CONCLUSIONS
Similar normal tissue doses were calculated for two groups of patients having different cancers and genders. This similarity combined with continued careful analysis of the imaging data might allow the use of higher starting doses in early phase RIT studies.
Lehmann
Joerg
J
Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, CA, USA.
DeNardo
Gerald L
GL
Yuan
Aina
A
Shen
Sui
S
O'Donnell
Robert T
RT
Richman
Carol M
CM
DeNardo
Sally J
SJ
D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics*; D001943:Breast Neoplasms / Q000378:metabolism*; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes / Q000493:pharmacokinetics*; D008297:Male; D008657:Metabolic Clearance Rate; D009928:Organ Specificity; D011471:Prostatic Neoplasms / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution; D015021:Yttrium Radioisotopes / Q000493:pharmacokinetics*
D000911:Antibodies, Monoclonal; D007205:Indium Radioisotopes; D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes