Pretargeted immuno-PET and radioimmunotherapy of prostate cancer with an anti-TROP-2 x anti-HSG bispecific antibody

Purpose

TF12 is a trivalent bispecific antibody that consists of two anti-TROP-2 Fab fragments and one anti-histamine-succinyl-glycine (HSG) Fab fragment. The TROP-2 antigen is found in many epithelial cancers, including prostate cancer (PC), and therefore this bispecific antibody could be suitable for pretargeting in this cancer. In this study, the characteristics and the potential for pretargeted radioimmunoimaging and radioimmunotherapy with TF12 and the radiolabeled di-HSG peptide IMP288 in mice with human PC were investigated.

Methods

The optimal TF12 protein dose, IMP288 peptide dose, and dose interval for PC targeting were assessed in nude mice with s.c. PC3 xenografts. Immuno-positron emission tomography (PET)/CT was performed using TF12/⁶⁸Ga-IMP288 at optimized conditions. The potential of pretargeted radioimmunotherapy (PRIT) using the TF12 pretargeted ¹⁷⁷Lu-IMP288 was determined.

Results

TF12 and ¹¹¹In-IMP288 showed high and fast accumulation in the tumor [20.4?±?0.6 %ID/g at 1 h post-injection (p.i.)] at optimized conditions, despite the internalizing properties of TF12. The potential for PRIT was shown by retention of 50 % of the ¹¹¹In-IMP288 in the tumor at 48 h p.i. One cycle of treatment with TF12 and ¹⁷⁷Lu-IMP288 showed significant improvement of survival compared to treatment with ¹⁷⁷Lu-IMP288 alone (90 vs. 67 days, p?<?0.0001) with no renal or hematological toxicity.

Conclusion

TROP-2-expressing PC can be pretargeted efficiently with TF12, with very rapid uptake of the radiolabeled hapten-peptide, IMP288, sensitive immuno-PET, and effective therapy.     

肾癌的螺旋CT双期扫描及CT分期

目的：探讨肾癌的螺旋CT双期扫描表现及CT分期的价值。方法：对36例手术病理证实的肾癌患者CT双期扫描图像进行分析。结果：CT平扫等密度者17例，低密度者15例，高密度者4例；增强扫描动脉期呈均质强化者7例，不均质强化者29例；高强化者27例，弱强化者9例；实质期肾静脉癌栓者10例(占28％)，下腔静脉癌栓者3例，淋巴结转移者6例。结论：螺旋CT双期扫描可对肾癌做出明确诊断，CT分期对指导治疗方案有较大价值。     

Pretargeting vs. direct targeting of human betalox5 islet cells subcutaneously implanted in mice using an anti-human islet cell antibody

IntroductionWe previously demonstrated MORF/cMORF pretargeting of human islets and betalox 5 cells (a human beta cell line) transplanted subcutaneously in mice with the anti-human islet antibody, HPi1. We now compare pretargeting with direct targeting in the beta cell transplant model to evaluate the degree to which target/non-target (T/NT) ratios may be improved by pretargeting.MethodsSpecific binding of an anti-human islet antibody HPi1 to the beta cells transplanted subcutaneously in mice was examined against a negative control antibody. We then compared pretargeting by MORF-HPi1 plus ¹¹¹In-labeled cMORF to direct targeting by ¹¹¹In-labeled HPi1.ResultsHPi1 binding to betalox5 human cells in the transplant was shown by immunofluorescence. Normal organ ¹¹¹In backgrounds by pretargeting were always lower, although target accumulations were similar. More importantly, the transplant to pancreas and liver ratios was, respectively, 26 and 10 by pretargeting as compared to 9 and 0.6 by direct targeting.ConclusionsPretargeting greatly improves the T/NT ratios, and based on the estimated endocrine to exocrine ratio within a pancreas, pretargeting may be approaching the sensitivity required for successful imaging of human islets within this organ.     

Pretargeting CWR22 prostate tumor in mice with MORF-B72.3 antibody and radiolabeled cMORF

Purpose We have now applied our MORF/cMORF pretargeting technology to the targeting of CWR22 prostate tumor in nude mice. Methods The antiTAG-72 antibody B72.3 was conjugated with an 18 mer MORF while the cMORF was radiolabeled with ^99mTc. The specific binding of the antibody to the CWR22 cells was first confirmed in an assay placing the radiolabeled B72.3 antibody in competition with increasing concentrations of native B72.3. Thereafter, a group of four CWR22 tumored mice intravenously received the MORF-B72.3 and, 3 days later, the ^99mTc-cMORF, and were killed at 3 h postradioactivity injection. The dosage of the labeled cMORF was selected on the basis of previous experience in LS174T tumored mice. As controls, four animals received only the radiolabeled cMORF and another four received only the ¹¹¹In-B72.3. The maximum percent tumor accumulation (MPTA) of the labeled cMORF was subsequently determined by a dosage study of labeled cMORF. Both a multipinhole SPECT image and a planar gamma camera image were obtained of a representative mouse. Results The CWR22 tumor was confirmed to be TAG-72-positive. The MPTA of the labeled cMORF in the CWR22 tumor was 2.22%ID/g compared to only 0.12%ID/g in control mice without pretargeting. Both the planar and tomographic images confirmed the success of the CWR22 pretargeting. Conclusions The MORF/cMORF pretargeting approach has been successfully applied to tumor targeting of the prostate xenograft CWR22. However, the MPTA in this tumor model is lower than that in the LS174T tumor model investigated earlier, possibly due to a lower tumor blood supply. Financial support: CA107360 and CA94994.     

Preferential accumulation of (3)H-tetraphenylphosphonium in non-small cell lung carcinoma in mice: comparison with (99m)Tc-MIBI.

We have previously shown enhanced accumulation of the delocalized lipophilic cation (11)C-triphenylmethylphosphonium in canine brain glioma, suggesting its potential use for tumor staging in humans using PET. Here, we extend our studies of phosphonium cations to nonbrain tumors and characterize the biodistribution and tumor specificity of (3)H-tetraphenylphosphonium ((3)H-TPP) in non-small cell lung carcinoma in mice. METHODS: (3)H-TPP accumulation in isolated malignant lung nodules of the Lewis lung carcinoma (LLC) cell line, in LLC-bearing lung, and in control lung was measured at various intervals after inoculation. Tumor uptake and biodistribution of (3)H-TPP were compared with those of (99m)Tc-methoxyisobutylisonitrile (MIBI). RESULTS: (3)H-TPP accumulation in LLC nodules at 14 d was significantly greater than that in controls, peaked at 21 d, and declined to lower values at 28 d after injection. At 21 d after injection, (3)H-TPP uptake in LLC nodules was greater than that in control lung tissue and in LLC-bearing lung tissue-by 549% and 230%, respectively-whereas (99m)Tc-MIBI nodule uptake was greater by 90% and 30%, respectively. CONCLUSION: The high tumor accumulation and sensitivity to the phase of tumor development suggest the potential use of radiolabeled phosphonium analogs for in vivo tumor staging and as a tool for investigating tumor evolution.     

Two-step targeting and dosimetry for small cell lung cancer xenograft with anti-NCAM/antihistamine bispecific antibody and radioiodinated bivalent hapten.

The "affinity enhancement system," a two-step targeting technique using bispecific antibody and radiolabeled bivalent hapten, has been reported to be useful for carcinoembryonic antigen-expressing tumors. The purpose of this study was to evaluate the efficacy of this method for targeting human small cell lung cancer using an antineural cell adhesion molecule antibody. METHODS: Antineural cell adhesion molecule/antihistamine bispecific antibody NK1NBL1-679 was prepared by coupling an equimolecular quantity of a Fab' fragment of NK1NBL1 to a Fab fragment of antihistamine 679. Athymic mice inoculated with NCI-H69 small cell lung cancer cells expressing neural cell adhesion molecule were administered bispecific antibody and then 48 h later 125I-labeled bivalent histamine hapten. 125I-labeled intact NK1NBL1 was injected into other groups of mice. Biodistributions were examined as a function of time. RESULTS: In mice of the two-step targeting, tumor uptake was 2.5 +/- 0.2, 3.2 +/- 0.4, 6.4 +/- 2.0, 7.2 +/- 2.7, 6.1 +/- 2.1 and 2.2 +/- 0.4 %ID/g at 5, 30 min, 5, 24, 48 and 96 h, and tumor-to-blood, tumor-to-liver and tumor-to-kidney ratios were 1.4 +/- 1.1, 10.8 +/- 13.2 and 4.6 +/- 4.7, respectively, at 5 h, whereas 125I-labeled NK1NBL1 showed a tumor uptake of 5.7 +/- 0.4 %ID/g and tumor-to-blood, tumor-to-liver and tumor-to-kidney ratios of 0.3 +/- 0.1, 1.1 +/- 0.2 and 0.9 +/- 0.1, respectively, at 5 h. These results were confirmed by autoradiographic studies, which demonstrated clear tumor-to-normal tissue contrast. Dosimetry showed that the affinity enhancement system could enhance the therapeutic potential of the antineural cell adhesion molecule antibody NK1NBL1. CONCLUSION: This two-step targeting method seems promising for the diagnosis and therapy of small cell lung cancer.     

Pretargeting of bacterial endocarditis in rats with streptavidin and 111In-labeled biotin.

A radioimaging approach for the detection of endocarditis has been investigated using two-step pretargeting with streptavidin and radiolabeled biotin. METHODS: Hemodynamic alterations within the rat heart were induced by placing an in-dwelling catheter into the left ventricle through the aortic valves. The animals were subsequently infected with Staphylococcus aureus through a tail vein. After an incubation period, rats were first injected with streptavidin and, 2 h later, with 111In-labeled ethylene-diaminetetraacetic acid-biotin. Whole-body gamma camera images were taken 4-5 h postinjection of the radiolabeled biotin. Control animals consisted of catheterized but uninfected, infected but uncatheterized and normal untreated rats. As a further control, the labeled biotin was administered to a study animal without the preadministration of streptavidin. RESULTS: Histology showed typical endocarditic changes in the hearts of study animals with massive deposition of gram-positive cocci. Catheterized but uninfected animals showed alterations corresponding to nonbacterial thrombotic endocarditis. Macroautoradiography showed accumulation of radiolabel in the endocarditic vegetations of study animals. Whole-body gamma camera images showed important cardiac uptake in 7 of 8 catheterized and infected animals and in 3 of 6 catheterized but uninfected animals. Normal rats and those infected but not catheterized showed negative results by histology, autoradiography and imaging. The percent uptake of the injected dose in the heart was 0.20 (SD = 0.13) in catheterized and infected animals, 0.12 (SD = 0.10) in catheterized but uninfected animals, 0.10 (SD = 0.04) in infected but uncatheterized animals and 0.04 (SD = 0.01) in normal control animals. CONCLUSION: The two-step pretargeting approach using streptavidin and 111In-labeled biotin was used successfully to detect S. aureus-induced bacterial endocarditis in rats.     

Imaging experimental atherosclerotic lesions in ApoE knockout mice: enhanced targeting with Z2D3-anti-DTPA bispecific antibody and 99mTc-labeled negatively charged polymers.

In vivo molecular imaging may be improved if specific radioactivity at the target site could be increased while maintaining low background activity. Bispecific antibody complexes and (99m)Tc-labeled negatively charged chelating polymers that react specifically with the capture arm of the bispecific antibody complex were used to demonstrate the feasibility of imaging very small atherosclerotic lesions in ApoE knockout mice. METHODS: Left femoral artery denudation in ApoE(-/-) mice on a hyperlipidemic diet was used to induce accelerated atherosclerotic lesions. Approximately 40 microg of bispecific antibodies were injected intravenously after 2 wk of endothelial denudation. The next day, approximately 15.0 MBq (99m)Tc-DTPA-succinyl-polylysine (2 microg; DTPA is diethylenetriaminepentaacetic acid) were injected intravenously. RESULTS: In vivo gamma-images showed that lesions were observed unequivocally by 2-3 h. Sham-operated right femoral regions showed no radiotracer accumulation. Ex vivo gamma-scintillation counting corrected for sham-operated nonspecific activity and lesion mass showed that the mean lesion activity was 10.10 +/- 6.76 %ID/g (percentage injected dose per gram), whereas nonspecific human IgG bispecific control (NSB control) also corrected similarly was 0.939 +/- 0.877 %ID/g (P < 0.03). Atherosclerotic lesions were confirmed by immunohistochemical staining. Computer planimetry of immunohistograms showed the mean lesion size to be 2.64 +/- 2.46 mg. CONCLUSION: Use of bispecific antibody complexes and (99m)Tc-DTPA-succinyl-polylysine enabled in vivo visualization of very small atherosclerotic lesions in ApoE knockout mice.     

Detection and staging of small cell lung carcinoma with a technetium-labeled monoclonal antibody. A comparison with standard staging methods.

Tumor-associated radiolabeled monoclonal antibodies (MoAb) can detect neoplasms in a variety of settings. The authors conducted a study comparing the ability to detect and stage small cell lung carcinoma by using a Tc-99m labeled monoclonal antibody (NR-LU-10 Fab) (NeoRx Corp, Seattle, WA) with standard staging methods. Standard staging included a physical examination, chest x-ray, a battery of radionuclide scans and/or computerized tomographic studies (head, abdomen, and bone), and bone marrow examination. A total of 22 comparisons were performed in 17 patients (five patients had reevaluations after therapy). Fifty-four (74%) of the 73 lesions defined by standard staging were detected by the radiolabeled MoAb. Seven of eight patients (88%) classified by standard staging as having "limited stage" disease on presentation were concordantly "limited stage" by radioimmunoimaging. One patient deemed "limited stage" by standard staging was correctly upstaged (bone marrow involvement) as a result of the radiolabeled MoAb. Two patients found to have extensive disease at diagnosis were characterized as "limited stage" by the MoAb, for an overall staging accuracy of 0.88. Thirteen of 19 missed lesions were smaller than 2 cm (10 were smaller than 1 cm; 3 measured 1 to 2 cm). This comparative study shows that radioimmunoimaging by Tc-99m labeled NR-LU-10 Fab antibody is capable of complementing standard staging methods used in the evaluation of small cell lung carcinoma.     

螺旋断层放疗联合抗表皮生长因子受体单抗治疗鼻咽癌的初步临床观察

目的 探讨螺旋断层放疗联合抗EGFR单克隆抗体治疗鼻咽癌的近期疗效和不良反应.方法 回顾性分析2008年3月-2009年11月本科34例行根治性螺旋断层放疗鼻咽癌患者临床资料.鼻咽部肿瘤(pGTVnx)及可见的转移淋巴结(pGTVnd)处方剂量70 Gy/33次,高危区(PTV1)60 Gy/33次,低危区(PTV2)...     

Preparation and evaluation of para-[At]astatobenzoyl labeled anti-renal cell carcinoma antibody A6H F(ab′)2. In vivo distribution comparison with para-[I]iodobenzoyl labeled A6H F(ab′)2

A preliminary investigation of an ²¹¹At labeled anti-renal cell carcinoma antibody fragment, A6H F(ab′)₂, was conducted. In the investigation, A6H F(ab′)₂ was labeled by conjugation with N-succinimidyl p-[²¹¹At]astatobenzoate, and the in vivo biodistribution was evaluated in athymic mice bearing TK-82 renal cell carcinoma xenografts. As a control, p-[¹²⁵I]iodobenzoyl labeled A6H F(ab′)₂ was coinjected with the astatinated F(ab′)₂. The data obtained demonstrated that the two radiolabels (²¹¹At and ¹²⁵I) had quite similar distributions, providing evidence that the ²¹¹At remained attached to the A6H F(ab′)₂ in vivo. Further, the astatinated antibody attained a 2:1 tumor-to-blood ratio, and greater than 35:1 tumor-to-muscle ratio, at 4 h post-injection, suggesting that this antibody conjugate could be used to evaluate treatment of metastatic renal cell carcinoma in a mouse model.     

G3m(21) typing by ELISA and dot immunobinding with enzyme-labeled monoclonal anti-G3m(21) antibody

Summary Simple, rapid methods are described for G3m(21) typing with peroxidase-labeled monoclonal anti-G3m(21) antibody. In G3m(21) typing by ELISA, microtiter wells were coated directly with the test antigen, which was detected with the enzyme-labeled monoclonal antibody. To further simplify the procedure, a dot immunobinding method was developed. The antigen in the test serum applied onto a nitrocellulose membrane was successfully detected with the enzyme-labeled monoclonal antibody. These methods, particularly the dot immunobinding, are suitable for forensic casework because they are rapid and simple and require no technical skill.Presented in part at the Annual meeting of The Medico-Legal Society of Japan, April 7–9, Tokyo, Japan. Supported by Grant-in-Aid for Co-operative Research No. 62304039 from The Ministry of Education, Science and Culture     

飞行员小肾癌的航空医学检查与鉴定(附病例报告3例)

目的 分析3例民航飞行员小肾癌病例并进行文献复习,以期加强对该病的认识,提高诊断和鉴定水平. 方法介绍3例民航飞行员小肾癌的临床资料,分析并探讨该病的诊断和医学鉴定方法. 结果 3例患者肿瘤大小均<3 cm,术前明确诊断1例,倾向于恶性和良性各1例,1例行腹腔镜肾脏部分切除术,两例行肾癌根治术,病理检查均诊断为肾透明细胞癌(高分化),肿瘤分期均为T1aN0M0,随访1～6.5年,未见复发.3例明确诊断后即鉴定为飞行不合格,其中1例病程长者于术后第2年特许飞行合格至今,飞行良好. 结论小肾癌诊断较困难,应综合多种影像学检查以明确,确诊仍是病理诊断.小肾癌分期早,分化高,预后好,发生突然失能的可能性低.排除复发或转移,3个月后即可评定为飞行合格,需密切随访.     

Bispecific antibody pretargeting PET (immunoPET) with an 124I-labeled hapten-peptide.

We previously described a highly flexible bispecific antibody (bs-mAb) pretargeting procedure using a multivalent, recombinant anti-CEA (carcinoembryonic antigen) x anti-HSG (histamine-succinyl-glycine) fusion protein with peptides radiolabeled with 111In, 90Y, 177Lu, and 99mTc. The objective of this study was to develop a radioiodination procedure primarily to assess PET imaging with 124I. METHODS: A new peptide, DOTA-D-Tyr-D-Lys(HSG)-D-Glu-D-Lys(HSG)-NH2 (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid), was synthesized and conditions were established for radioiodination with yields of approximately 70% for 131I and 60% for 124I. Pretargeting with the 131I- and 124I-labeled peptide was tested in nude mice bearing LS174T human colonic tumors that were first given the anti-CEA x anti-HSG bs-mAb. Imaging (including small-animal PET) and necropsy data were collected at several intervals over 24 h. Comparisons were made between animals given 124I-anti-CEA Fab', 18F-FDG, the same peptide radiolabeled with 111In and pretargeted with the bs-mAb, and the radioiodinated peptide alone. RESULTS: The radioiodinated peptide alone cleared quickly from the blood with no evidence of tumor targeting, but when pretargeted with the bs-mAb, tumor uptake increased 70-fold, with efficient and rapid clearance from normal tissues, allowing clear visualization of tumor within 1-2 h. Tumor uptake measured at necropsy was 3- to 15-fold higher and tumor-to-blood ratios were 10- to 20-fold higher than those for 124I-Fab' at 1 and 24 h, respectively. Thyroid and stomach uptake was observed with the radioiodinated peptide several hours after injection (animals were not premedicated to reduce uptake in these tissues), but gastric uptake was much more pronounced with 124I-Fab'. Tumor visualization with 18F-FDG at approximately 1.5 h was also good but showed substantially more uptake in several normal tissues, making image interpretation in the pretargeted animals less ambiguous than with 18F-FDG. CONCLUSION: Bispecific antibody pretargeting has a significant advantage for tumor imaging over directly radiolabeled antibodies and could provide additional enhancements for oncologic imaging, particularly for improving targeting specificity as compared with 18F-FDG.     

Contrast MRI in multiple endocrine neoplasia type 1 (MEN) associated with renal cell carcinoma

The radiologic work-up of a patient with multiple endocrine neoplasia type 1 (MEN 1) syndrome and multiple endocrine nodules, with coincidental renal cell carcinoma, is described. Parathyroid adenoma was differentiated from multiple thyroid nodules by gadolinium-enhanced MRI. Adrenal enlargement due to a nonfunctioning adenoma and a renal cell carcinoma next to a simple renal cortical cyst were identified by typical signal intensities on T1- (pre- and post-Gd-DPTA) and T2-weighted images. Insulinoma was visualized only retrospectively.