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Immuno-PET Imaging of CD30-Positive Lymphoma Using 89Zr-Desferrioxamine–Labeled CD30-Specific AC-10 Antibody

The CD30-specific antibody–drug conjugate, brentuximab vedotin, is approved for the treatment of relapsed, refractory Hodgkin lymphomas and systemic anaplastic large T-cell lymphomas. Multiple ongoing clinical trials are investigating brentuximab vedotin efficacy in other CD30-positive hematologic malignancies. Because CD30 expression varies among different types of lymphoma and can also change during the course of treatment, companion diagnostic imaging of CD30 could be a valuable tool in optimizing patient-specific brentuximab vedotin treatment regimens. Methods: The mouse antihuman CD30 antibody AC-10 was radiolabeled with the positron-emitting radionuclide 89Zr. The stability and specificity of 89Zr-desferrioxamine (DFO)-labeled CD30-specific AC-10 antibody (89Zr-DFO-AC-10) was evaluated in vitro. The pharmacokinetics of 89Zr-DFO-AC-10 was studied in BALB/c nude mice bearing subcutaneous human Karpas 299 tumors (CD30-positive model) or A-431 tumors (CD30-negative model) using PET/CT imaging, biodistribution studies, and autoradiography. Results: AC-10 was conjugated with a DFO B chelator and radiolabeled with 89Zr to give formulated 89Zr-DFO-AC-10 with a radiochemical yield of 80%, radiochemical purity greater than 99%, and specific activity of 111–148 MBq/mg. 89Zr-DFO-AC-10 was stable in mouse and human sera and preserved the immunoreactivity toward CD30. Biodistribution data showed the highest tissue accumulation of 89Zr-DFO-AC-10 in CD30-positive tumors, with 37.9% ± 8.2% injected activity per gram of tissue at 72 h after injection, whereas uptake in CD30-negative tumors was 11.0% ± 0.4%. The specificity of 89Zr-DFO-AC-10 binding to CD30 in vivo was confirmed by blocking studies. Time–activity curves showed that between 24 and 144 h after injection, tumor-to-muscle ratios increased from 18.9 to 51.8 in the CD30-positive model and from 4.8 to 8.7 in the CD30-negative model. Tumor-to-blood ratios also increased, from 3.2 to 13.6 and from 1 to 2 in the CD30-positive and -negative models, respectively. Conclusion: Our results demonstrate that for measuring CD30 expression, 89Zr-DFO-AC-10 is a sensitive PET agent with high tumor–to–normal-tissue contrast. 89Zr-DFO-AC-10 is a promising CD30-imaging radiotracer for clinical translation in patients with various lymphomas and other diseases.