PT  - JOURNAL ARTICLE
AU  - Gerhard Glatting
AU  - Marguerite Müller
AU  - Bernd Koop
AU  - Kathrin Hohl
AU  - Claudia Friesen
AU  - Bernd Neumaier
AU  - Eleanor Berrie
AU  - Pru Bird
AU  - Geoffrey Hale
AU  - Norbert M. Blumstein
AU  - Herman Waldmann
AU  - Donald Bunjes
AU  - Sven N. Reske
TI  - Anti-CD45 Monoclonal Antibody YAML568: A Promising Radioimmunoconjugate for Targeted Therapy of Acute Leukemia
DP  - 2006 Aug 01
TA  - Journal of Nuclear Medicine
PG  - 1335--1341
VI  - 47
IP  - 8
4099  - http://jnm.snmjournals.org/content/47/8/1335.short
4100  - http://jnm.snmjournals.org/content/47/8/1335.full
SO  - J Nucl Med2006 Aug 01; 47
AB  - The outcome of hematopoietic cell transplantation for hematologic malignancies may be improved by delivering targeted radiation to hematopoietic organs while relatively sparing nontarget organs. We evaluated the biodistribution of 111In-labeled anti-CD45 antibody in humans using the rat IgG2a monoclonal antibody YAML568 that recognizes a common CD45 epitope present on all human leukocytes. Methods: Eight patients undergoing bone marrow transplantation received YAML568 labeled with 122 ± 16 MBq of 111In intravenously followed by serial blood sampling, urine collection, and conjugated view planar γ-camera imaging up to 144 h after injection. Time–activity curves were obtained using region-of-interest analysis in the accumulating organs and residence times were calculated. An estimate for the radiation-absorbed doses for each organ per unit of administered activity of 90Y was calculated using software for internal dose assessment. The first patient received no unlabeled antibody preloading. The second 2 patients received a preloading dose of 10 mg (0.15 mg/kg). The last 5 patients received a preloading dose of 30−47 mg (0.5 mg/kg). Results: No significant administration-related side effects were seen. The 3 patients receiving no antibody or low antibody preloading had an unfavorable biodistribution with a high initial accumulation of activity in the liver (37%) and the spleen (34%). For the patients receiving 0.5-mg/kg antibody preloading, the estimated radiation-absorbed doses for red bone marrow, spleen, liver, kidney, and total body were 6.4 ± 1.2, 19 ± 5, 3.9 ± 1.4, 1.1 ± 0.4, and 0.6 ± 0.1 mGy/MBq, respectively, demonstrating preferential red marrow targeting. A linear regression model showed that the amount of unlabeled antibody preloading per body weight has a strong influence on the estimated red marrow absorbed dose (P = 0.003, R2 = 0.80). Conclusion: This study shows that the anti-CD45 monoclonal antibody YAML568 is suitable for delivering selectively radiation to hematopoietic tissues when labeled with 90Y provided that a preloading dose of about 0.5 mg/kg unlabeled antibody is given.