Simultaneous Imaging and Therapy Using Epitope-Specific Anti-Epidermal Growth Factor Receptor (EGFR) Antibody Conjugates

Abstract

Matuzumab and nimotuzumab are anti-EGFR monoclonal antibodies that bind to different epitopes of domain III of EGFR. We developed 89Zr-matuzumab as a PET probe for diagnosis/monitoring of response to treatment of a noncompeting anti-EGFR nimotuzumab antibody drug conjugate (ADC) using mouse colorectal cancer (CRC) xenografts. We developed 89Zr-matuzumab and performed quality control in EGFR-positive DLD-1 cells. The KD of matuzumab, DFO-matuzumab and 89Zr-matuzumab in DLD-1 cells was 5.9, 6.2 and 3 nM, respectively. A competitive radioligand binding assay showed that 89Zr-matuzumab and nimotuzumab bound to noncompeting epitopes of EGFR. MicroPET/CT imaging and biodistribution of 89Zr-matuzumab in mice bearing EGFR-positive xenografts (HT29, DLD-1 and MDA-MB-231) showed high uptake that was blocked with pre-dosing with matuzumab but not with the noncompeting binder nimotuzumab. We evaluated nimotuzumab-PEG6-DM1 ADC in CRC cells. IC50 of nimotuzumab-PEG6-DM1 in SNU-C2B, DLD-1 and SW620 cells was dependent on EGFR density and was up to five-fold lower than that of naked nimotuzumab. Mice bearing the SNU-C2B xenograft were treated using three 15 mg/kg doses of nimotuzumab-PEG6-DM1, and 89Zr-matuzumab microPET/CT was used to monitor the response to treatment. Treatment resulted in complete remission of the SNU-C2B tumor in 2/3 mice. Matuzumab and nimotuzumab are noncompeting and can be used simultaneously.

[225Ac]Ac/[89Zr]Zr-labeled N4MU01 radioimmunoconjugates as theranostics against nectin-4 positive triple negative breast cancer

“…The in vitro cytotoxicity (IC 50 values) of [ 225 Ac]Ac-Macropa-N4MU01, control immunoconjugates anti-CD20 [ 225 Ac] Ac-Macropa-rituximab, and unlabeled N4MU01 in nectin-4 positive MDA-MB-468, MCF-7, and nectin-4 negative MDA-MB-231 was determined using IncuCyte Cytotox Red reagent in an IncuCyte S3 live-cell imager (Essen BioScience, AnnArbor, MI) as previously reported [24]. The detailed methods are in the supplementary materials.…”

“…The binding of [ 89 Zr]Zr-DFO-N4MU01 to nectin-4 positive MCF-7 cells and [ 225 Ac]Ac-Macropa -N4MU01 to nectin-4 positive MDA-MB-468 was determined using a saturation radioligand binding assay as described previously [24]. The detailed method is described in the supplementary method section.…”

Radiopharmaceuticals for Cancer Imaging and Therapy

“…Fonge et al, from the university of Saskatchewan, have successfully developed and evaluated [ 89 Zr]Zr-matuzumab as a PET probe for the diagnosis/monitoring of response to the treatment of a noncompeting anti-EGFR nimotuzumab antibody drug conjugate (ADC) using mouse colorectal cancer (CRC) xenografts [ 2 ]. MicroPET/CT imaging and the biodistribution of [ 89 Zr]Zr-matuzumab in mice bearing EGFR-positive xenografts showed a high uptake that could be blocked with the pre-dosing of matuzumab but not with the noncompeting binder nimotuzumab.…”