Title:Biodistribution and Dosimetry of 177Lu-tetulomab, a New Radioimmunoconjugate for Treatment of Non-Hodgkin Lymphoma
Volume: 6
Issue: 1
Author(s): Ada H. V. Repetto-Llamazares, Roy H. Larsen, Camilla Mollatt, Michael Lassmann and Jostein Dahle
Affiliation:
Keywords:
CD37, Lutetium-177, Non-Hodgkin lymphoma, Radioimmunotherapy
Abstract: The biodistribution of the anti-CD37 radioimmunoconjugate 177Lu-tetraxetan-tetulomab (177Lu-DOTA-HH1)
was evaluated. Biodistribution of 177Lu-tetraxetan-tetulomab was compared with 177Lu-tetraxetan-rituximab and free 177Lu
in nude mice implanted with Daudi lymphoma xenografts. The data showed that 177Lu-tetulomab had a relevant stability
and tumor targeting properties in the human lymphoma model. The half-life of 177Lu allowed significant tumor to normal
tissue ratios to be obtained indicating that 177Lu-tetraxetan-tetulomab could be suitable for clinical testing. The biological
and effective half-life in blood was higher for 177Lu-tetraxetan-tetulomab than for 177Lu-tetraxetan-rituximab. The biodistribution
of 177Lu-tetraxetan-tetulomab did not change significantly when the protein dose was varied from 0.01 to 1
mg/kg. Dosimetry calculations showed that the absorbed radiation doses to normal tissues and tumor in mice were not
significantly different for 177Lu-tetraxetan-tetuloma b and 177Lu-tetraxetan-rituximab. The absorbed radiation doses were
extrapolated to human absorbed radiation doses. These extrapolated absorbed radiation doses to normal tissues for 177Lutetraxetan-
tetulomab at an injection of 40 MBq/kg were significantly lower than the absorbed radiation doses for 15
MBq/kg Zevalin, suggesting that higher tumor radiation dose can be reached with 177Lu-tetraxetan-tetulomab in the clinic.
