Constantijn H.J. Muselaers

Indium-111–labeled Girentuximab ImmunoSPECT as a Diagnostic Tool in Clear Cell Renal Cell Carcinoma

BACKGROUND Improved and more frequent radiologic evaluation has resulted in increased identification of renal masses of unknown origin, which frequently pose a diagnostic dilemma for urologists. OBJECTIVE Carbonic anhydrase IX (CAIX) is an antigen ubiquitously expressed in clear cell renal cell carcinoma (ccRCC). The specific and high level of expression in ccRCC makes CAIX an excellent target for imaging ccRCC lesions. We present our experience with immuno-single-photon emission computed tomography (immunoSPECT) imaging with the indium-111 ((111)In)-labeled anti-CAIX antibody girentuximab in patients presenting with either a primary renal tumor or a history of ccRCC and lesions suspect for metastases during follow-up. DESIGN, SETTING, AND PARTICIPANTS Twenty-nine patients received 100-200 MBq (111)In-labeled girentuximab. Whole-body and single photon emission computed tomography (SPECT) images were acquired after 4-7 d. INTERVENTION Injection with (111)In-girentuximab and image acquisition after 4-7 d. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Accuracy of (111)In-girentuximab immunoSPECT. RESULTS AND LIMITATIONS Distinct uptake of (111)In-girentuximab was seen in 16 of 22 patients presenting with a renal mass. All renal masses proven to be ccRCC after resection (n=15) were detected with (111)In-girentuximab. Suspect lesions of six patients showed no uptake of (111)In-girentuximab. In these patients, ccRCC was not found, nor progression occurred. Seven patients with a history of ccRCC and possible metastatic lesions on follow-up computed tomography scans were imaged with (111)In-girentuximab. In four of these patients, the lesions showed preferential uptake of (111)In-girentuximab and local or systemic treatment was initiated. In three other cases, no (111)In-girentuximab targeting was seen. During follow-up of these three patients, one showed progression, for which systemic treatment was started. In the two other patients, no progression occurred, suggesting a benign nature. CONCLUSIONS (111)In-girentuximab immunoSPECT can be used to detect ccRCC lesions in patients with a primary renal mass and to clarify the nature of lesions suspect for metastases in patients with a history of ccRCC.

Tyrosine Kinase Inhibitor Sorafenib Decreases 111In-Girentuximab Uptake in Patients with Clear Cell Renal Cell Carcinoma

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of metastatic clear cell renal cell carcinoma (RCC). Although TKIs have demonstrated good clinical efficacy, the lack of complete responses, the chronic nature of the treatment, and the side effects are clear disadvantages. An interesting new approach in the treatment of clear cell RCC is antibody-mediated therapy with the chimeric anti–carbonic anhydrase IX (CAIX) antibody girentuximab (cG250). As the results of several girentuximab trials become available, the question arises of whether TKI treatment can be combined with girentuximab-based therapy. In this study, we assessed the effect of the widely used TKI sorafenib on the tumor-targeting potential of 111In-labeled girentuximab. Methods: 111In-girentuximab imaging was performed on 15 patients suspected of having a renal malignancy, with surgery being part of their treatment plan. Of these, 10 patients were treated in a neoadjuvant setting with sorafenib (400 mg orally twice daily). Five patients received treatment during 1 wk, and 5 patients received treatment during 4 wk. In both sorafenib-treated groups, baseline and posttreatment tumor targeting of 111In-girentuximab were compared. Surgery was performed 3 d after the last image acquisition. Five additional patients were included as a control group and had only a single 111In-girentuximab injection and scintigraphy without any treatment. Distribution of 111In-girentuximab was determined scintigraphically ex vivo in a 1-cm lamella of the resected tumorous kidney. Expression of CAIX and of the vascular marker CD31 was determined immunohistochemically on specimens of both tumor and normal kidney tissue. Results: Treatment with sorafenib resulted in a marked decrease of 111In-girentuximab uptake in the tumor in clear cell RCC patients, especially in the group treated for 4 wk (mean change in both sorafenib-treated groups, −38.4%; range, +9.1% to −79.4%). Immunohistochemical analysis showed markedly reduced CD31 expression and vessel density in the sorafenib-treated groups but no differences in CAIX expression between the sorafenib-treated groups and the nontreated patients. Conclusion: Treatment with sorafenib resulted in a treatment duration–dependent significantly decreased uptake of 111In-girentumab in clear cell RCC lesions. These results indicate that the efficacy of antibody-mediated treatment or diagnosis modalities is hampered by TKI treatment.

Phase 2 Study of Lutetium 177-Labeled Anti-Carbonic Anhydrase IX Monoclonal Antibody Girentuximab in Patients with Advanced Renal Cell Carcinoma.

UNLABELLED Despite advances in the treatment of metastatic clear cell renal cell carcinoma (ccRCC), there is still an unmet need in the treatment of this disease. A phase 2 radioimmunotherapy (RIT) trial with lutetium 177 ((177)Lu)-girentuximab was initiated to evaluate the efficacy of this approach. In this nonrandomized single-arm trial, patients with progressive metastatic ccRCC who met the inclusion criteria received 2405 MBq/m(2) of (177)Lu-girentuximab intravenously. In the absence of persistent toxicity and progressive disease, patients were eligible for retreatment after 3 mo with 75% of the previous activity dose. A total of 14 patients were included. After the first therapeutic infusion, eight patients (57%) had stable disease (SD) and one (7%) had a partial regression. The treatment was generally well tolerated but resulted in grade 3-4 myelotoxicity in most patients. After the second cycle, continued SD was observed in five of six patients, but none were eligible for retreatment due to prolonged thrombocytopenia. In conclusion, RIT with (177)Lu-girentuximab resulted in disease stabilization in 9 of 14 patients with progressive metastatic ccRCC, but myelotoxicity prevented retreatment in some patients. PATIENT SUMMARY We investigated the efficacy of lutetium 177-girentuximab radioimmunotherapy in patients with metastatic kidney cancer. The treatment resulted in disease stabilization in 9 of 14 patients. The main toxicity was prolonged low blood cell counts. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT02002312 (https://clinicaltrials.gov/ct2/show/NCT02002312).

Optical Imaging of Renal Cell Carcinoma with Anti–Carbonic Anhydrase IX Monoclonal Antibody Girentuximab

Near-infrared dye-tagged antibodies can be used for the sensitive detection of tumor tissue in vivo. Surgery for clear-cell renal cell carcinoma (ccRCC) might benefit from the use of optical imaging to facilitate the intraoperative detection of carbonic anhydrase IX (CAIX)–expressing tumor lesions with chimeric monoclonal antibody (mAb) girentuximab, which has been shown to have excellent imaging capabilities for ccRCC. Here we studied the potential of fluorescence imaging to detect ccRCC tumors in nude mice with RCC xenografts by using mAb girentuximab conjugated with IRDye800CW; SPECT imaging was used as a reference. Methods: Groups of athymic BALB/c mice with subcutaneous CAIX-positive SK-RC-52 ccRCC tumors were injected intravenously with 125I-labeled girentuximab-IRDye800CW or 125I-labeled girentuximab. For determination of the specificity of the accumulation of the anti-CAIX antibody conjugate in ccRCC, separate groups of mice bearing a CAIX-positive tumor (SK-RC-52) and a CAIX-negative tumor (SK-RC-59) received 125I-girentuximab-IRDye800CW or 125I-labeled MOPC21-IRDye800CW (control mAb). Optical images and micro-SPECT images were acquired until 3 d after injection. Mice were euthanized after the last imaging session, and the biodistribution of the radiolabeled antibody preparations was determined. Results: Optical imaging and micro-SPECT imaging at 1 d after the injection of 125I-girentuximab-IRDye800CW showed clear delineation of the CAIX-expressing ccRCC xenografts, and image contrast improved with time. Fluorescence imaging and biodistribution studies showed high and specific uptake of 125I-girentuximab-IRDye800CW in CAIX-positive ccRCC xenografts (SK-RC-52, 31.5 ± 9.6 percentage injected dose per gram [%ID/g] at 72 h after injection). Tumor uptake was specific, as very low uptake of 125I-girentuximab-IRDye800CW was noted in the CAIX-negative SK-RC-59 tumor (4.1 ± 1.5 %ID/g), and no uptake of 125I-MOPC21-IRDye800CW (control mAb) was noted in the CAIX-positive SK-RC-52 tumor (1.2 ± 0.1 %ID/g). Conclusion: Subcutaneous CAIX-expressing ccRCC xenografts were visualized by optical imaging with 125I-girentuximab-IRDye800CW. Optical images showed good concordance with micro-SPECT images. The accumulation of 125I-girentuximab-IRDye800CW in ccRCC tumors was high and specific. Girentuximab-IRDye800CW potentially could be used for the intraoperative detection of CAIX-expressing tumors and the assessment of residual tumor in resection margins or metastatic lesions in patients with ccRCC.

Radionuclide and Fluorescence Imaging of Clear Cell Renal Cell Carcinoma Using Dual Labeled Anti-Carbonic Anhydrase IX Antibody G250

PURPOSE Tumor targeted optical imaging using antibodies labeled with near infrared fluorophores is a sensitive imaging modality that might be used during surgery to assure complete removal of malignant tissue. We evaluated the feasibility of dual modality imaging and image guided surgery with the dual labeled anti-carbonic anhydrase IX antibody preparation (111)In-DTPA-G250-IRDye800CW in mice with intraperitoneal clear cell renal cell carcinoma. MATERIALS AND METHODS BALB/c nu/nu mice with intraperitoneal SK-RC-52 lesions received 10 μg DTPA-G250-IRDye800CW labeled with 15 MBq (111)In or 10 μg of the dual labeled irrelevant control antibody NUH-82 (20 mice each). To evaluate when tumors could be detected, 4 mice per group were imaged weekly during 5 weeks with single photon emission computerized tomography/computerized tomography and the fluorescence imaging followed by ex vivo biodistribution studies. RESULTS As early as 1 week after tumor cell inoculation single photon emission computerized tomography and fluorescence images showed clear delineation of intraperitoneal clear cell renal cell carcinoma with good concordance between single photon emission computerized tomography/computerized tomography and fluorescence images. The high and specific accumulation of the dual labeled antibody conjugate in tumors was confirmed in the biodistribution studies. Maximum tumor uptake was observed 1 week after inoculation (mean ± SD 58.5% ± 18.7% vs 5.6% ± 2.3% injected dose per gm for DTPA-G250-IRDye800CW vs NUH-82, respectively). High tumor uptake was also observed at other time points. CONCLUSIONS This study demonstrates the feasibility of dual modality imaging with dual labeled antibody (111)In-DTPA-G250-IRDye800CW in a clear cell renal cell carcinoma model. Results indicate that preoperative and intraoperative detection of carbonic anhydrase IX expressing tumors, positive resection margins and metastasis might be feasible with this approach.

Optimizing lutetium 177-anti-carbonic anhydrase IX radioimmunotherapy in an intraperitoneal clear cell renal cell carcinoma xenograft model

A new approach in the treatment of clear cell renal carcinoma (ccRCC) is radioimmunotherapy (RIT) using anti-carbonic anhydrase IX (CAIX) antibody G250. To investigate the potential of RIT with lutetium 177 (177Lu)-labeled G250, we conducted a protein dose escalation study and subsequently an RIT study in mice with intraperitoneally growing ccRCC lesions. Mice with intraperitoneal xenografts were injected with 1, 3, 10, 30, or 100 μg of G250 labeled with 10 MBq indium 111 (111In) to determine the optimal protein dose. The optimal protein dose determined with imaging and biodistribution studies was used in a subsequent RIT experiment in three groups of 10 mice with intraperitoneal SK-RC-52 tumors. One group received 13 MBq 177LU-DOTA-G250, a control group received 13 MBq nonspecific 177LU-MOPC21, and the second control group was not treated and received 20 MBq 111In-DOTA-G250. The optimal G250 protein dose to target ccRCC in this model was 10 μg G250. Treatment with 13 MBq 177LU-DOTA-G250 was well tolerated and resulted in significantly prolonged median survival (139 days) compared to controls (49-53 days, p = .015), indicating that RIT has potential in this metastatic ccRCC model.

Tumor-targeted Dual-modality Imaging to Improve Intraoperative Visualization of Clear Cell Renal Cell Carcinoma: A First in Man Study

Intraoperative imaging with antibodies labeled with both a radionuclide for initial guidance and a near-infrared dye for adequate tumor delineation may overcome the main limitation of fluorescence imaging: the limited penetration depth of light in biological tissue. In this study, we demonstrate the feasibility and safety of intraoperative dual-modality imaging with the carbonic anhydrase IX (CAIX)-targeting antibody 111In-DOTA-girentuximab-IRDye800CW in clear cell renal cell carcinoma (ccRCC) patients. Methods: A phase I protein dose escalation study was performed in patients with a primary renal mass who were scheduled for surgery. 111In-DOTA-girentuximab-IRDye800CW (5, 10, 30, or 50 mg, n=3 ccRCC patients per dose level) was administered intravenously and after 4 days SPECT/CT imaging was performed. Seven days after antibody injection, surgery was performed with the use of a gamma probe and near-infrared fluorescence camera. Results: In total, fifteen patients were included (12 ccRCC, 3 CAIX-negative tumors). No study-related serious adverse events were observed. All ccRCC were visualized by SPECT/CT and localized by intraoperative gamma probe detection (mean tumor-to-normal kidney (T:N) ratio 2.5 ± 0.8), while the T:N ratio was 1.0 ± 0.1 in CAIX-negative tumors. ccRCC were hyperfluorescent at all protein doses and fluorescence imaging could be used for intraoperative tumor delineation, assessment of the surgical cavity and detection of (positive) surgical margins. The radiosignal was crucial for tumor localization in case of overlying fat tissue. Conclusion: This first in man study shows that tumor-targeted dual-modality imaging using 111In-DOTA-girentuximab-IRDye800CW is safe and can be used for intraoperative guidance of ccRCC resection.

Indium-111-cG250 immunoSPECT als diagnostisch hulpmiddel bij het management van incidentalomen van de nier

Introductie Tumorcellen van het heldercellig niercelcarcinoom (clear cell renal cell carcinoma: ccRCC) brengen in meer dan 85% van de gevallen het antigeen carbonic anhydrase IX (CAIX) tot expressie. Dit antigeen wordt niet tot expressie gebracht in normale niercellen of niercysten. De hoge en specifieke expressie van dit antigeen maakt het mogelijk om ccRCC-laesies preoperatief in beeld te brengen middels radioactief gelabelde anti-CAIX-antilichamen, wat zeer nuttig kan zijn voor de klinische besluitvorming en chirurgische behandeling van patiënten die zich presenteren met een incidentaloom.