In vivo stability and metabolism of 99Tcm-labelled anti-CD4 monoclonal antibodies and Fab' fragments

Fully Automated Production and Characterization of 64Cu and Proof‐of‐Principle Small‐Animal PET Imaging Using 64Cu‐Labelled CA XII Targeting 6A10 Fab

“…According to our previous work, this accumulation pattern can be expected, as the metabolism of proteins with molecular weight similar to a Fab fragment (∼55 kDa) is dominated by kidney and liver. The calculated tumor‐to‐contralateral muscle ratio of 12 is notably high for a systemically applied Fab fragment, as Fabs undergo rapid degradation processes and are therefore much more short‐lived in the blood than full‐length antibodies . This encourages further studies regarding the in vivo behavior of this 64 Cu‐labelled compound for diagnostic imaging of CA XII expressing tumors.…”

“…Radionuclides with longer half‐lives such as 89 Zr ( t 1/2 =3.27 days) and 124 I ( t 1/2 =4.18 days), are needed to image molecules with slower biochemical processes and longer blood availability, such as antibodies . Fragment antigen binding (Fab) fragments of antibodies, on the other hand, have shorter bioavailability than full‐length antibodies, but much longer availability than small molecules, such as glucose . Radiolabelling such molecules with an intermediate half‐life PET nuclide such as 64 Cu ( t 1/2 =12.7 h) might therefore be promising.…”

“…[8,9] Fragmenta ntigenb inding (Fab) fragments of antibodies, on the other hand, have shorter bioavailability than full-length antibodies, but much longera vailability than smallm olecules, such as glucose. [10][11][12] Radiolabelling such molecules with an intermediate half-life PETn uclide such as 64 Cu (t 1/2 = 12.7 h) might therefore be promising. Furthermore,i na ddition to b + and electron capture, 64 Cu decay includes as ignificant b À component (probability of 39.0 AE 3%).…”