title: Tumor-Absorbed Dose for Non-Hodgkin Lymphoma Patients Treated with the Anti-CD37 Antibody Radionuclide Conjugate 177Lu-Lilotomab Satetraxetan.
abstract: 177Lu-lilotomab satetraxetan is a novel antibody radionuclide conjugate currently tested in a phase 1/2a first-in-human dosage escalation trial for patients with relapsed CD37+ indolent non-Hodgkin lymphoma. The aim of this work was to develop dosimetric methods and calculate tumor-absorbed radiation doses for patients treated with177Lu-lilotomab satetraxetan.
  
  
  METHODS
  Patients were treated at escalating injected activities (10, 15 and 20 MBq/kg) of177Lu-lilotomab satetraxetan and with different predosing, with or without 40 mg of unlabeled lilotomab. Eight patients were included for the tumor dosimetry study. Tumor radioactivity concentrations were calculated from SPECT acquisitions at multiple time points, and tumor masses were delineated from corresponding CT scans. Tumor-absorbed doses were then calculated using the OLINDA sphere model. To perform voxel dosimetry, the SPECT/CT data and an in-house-developed MATLAB program were combined to investigate the dose rate homogeneity.
  
  
  RESULTS
  Twenty-six tumors in 8 patients were ascribed a mean tumor-absorbed dose. Absorbed doses ranged from 75 to 794 cGy, with a median of 264 cGy across different dosage levels and different predosing. A significant correlation between the dosage level and tumor-absorbed dose was found. Twenty-one tumors were included for voxel dosimetry and parameters describing dose-volume coverage calculated. The investigation of intratumor voxel doses indicates that mean tumor dose is correlated to these parameters.
  
  
  CONCLUSIONS
  Tumor-absorbed doses for patients treated with177Lu-lilotomab satetraxetan are comparable to doses reported for other radioimmunotherapy compounds. Although the intertumor variability was considerable, a correlation between tumor dose and patient dosage level was found. Our results indicate that mean dose may be used as the sole dosimetric parameter on the lesion level.
authors: Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.
authors: Johan
authors: J
authors: Blakkisrud
authors: Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Ayca
authors: A
authors: Løndalen
authors: Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.|The Department of Physics, University of Oslo, Oslo, Norway.
authors: Anne C T
authors: AC
authors: Martinsen
authors: Nordic Nanovector ASA, Oslo, Norway.
authors: Jostein
authors: J
authors: Dahle
authors: Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.
authors: Jon E
authors: JE
authors: Holtedahl
authors: Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
authors: Tore
authors: T
authors: Bach-Gansmo
authors: Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway; and.
authors: Harald
authors: H
authors: Holte
authors: Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway; and.
authors: Arne
authors: A
authors: Kolstad
authors: Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway carsto@ous-hf.no.|Department of Life Science and Health, Oslo and Akershus University College of Applied Sciences, Oslo, Norway.
authors: Caroline
authors: C
authors: Stokke
mesh_terms: D065638:Absorption, Radiation; D000328:Adult; D000911:Antibodies, Monoclonal / Q000008:administration & dosage*; D000951:Antigens, Neoplasm; D005260:Female; D006801:Humans; D008187:Lutetium / Q000008:administration & dosage*; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011868:Radioisotopes / Q000008:administration & dosage*; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059470:Tetraspanins / Q000037:antagonists & inhibitors*; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; C059071:CD37 protein, human; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D059470:Tetraspanins; D008187:Lutetium
keywords: antibody radionuclide conjugate; dose-volume-histogram; non-Hodgkin’s lymphoma; tumor absorbed dose