Biomedical subjects

Per-Uno Malmström

Publications and source records attributed to Per-Uno Malmström.

At least 19 recordsLinked to original sources

PubMed2007

[177Lu]pertuzumab: experimental therapy of HER-2-expressing xenografts.

Pertuzumab (Omnitarg) is a novel antibody against HER-2, domain II. HER-2 is a tyrosine kinase receptor that is overexpressed in several carcinomas, especially breast cancer. Pertuzumab, labeled with the low-energy beta emitter (177)Lu, might be a candidate for targeted radiotherapy of disseminated HER-2-positive micrometastases. The radiolabeled antibody [(177)Lu]pertuzumab showed favorable targeting properties in BALB/c (nu/nu) mice with HER-2-overexpressing xenografts. The absorbed dose in tumors was more than five times higher than the absorbed dose in blood and more than seven times the absorbed dose in any other normal organ. Experimental therapy showed that [(177)Lu]pertuzumab delayed tumor progression compared with controls (no treatment, P < 0.0001; nonlabeled pertuzumab antibody, P < 0.0001; and (177)Lu-labeled irrelevant antibody, P < 0.01). No adverse side effects of the treatment could be detected. Thus, the experimental results support the planning of clinical studies applying [(177)Lu]pertuzumab for therapy.

Animals↗

PubMed2007

Human bladder carcinoma is dominated by T-regulatory cells and Th1 inhibitory cytokines.

PURPOSE: Immunotherapy has faced limited success, although many solutions have been proposed. Recently regulatory T cells have made a comeback in the immunological arena and the role of these cells in patients with cancer is in focus. It is under evaluation whether the immunological status of patients with cancer may affect their sensitivity to immunotherapy. We are developing immunostimulating gene therapy for treating bladder cancer. In this study we constructed an immunological profile of patients with bladder carcinoma to understand which obstacles must be circumvented. MATERIALS AND METHODS: Biopsies and blood were used to identify immune cell populations by FACS(R), histochemistry and proliferation assays, and cytokine production by polymerase chain reaction. RESULTS: Results indicate that bladder carcinoma is a Tr1 dominated tumor, as shown by the infiltration of T-regulatory cells expressing FOXP3, and the presence of tumor necrosis factor-beta and interleukin-10 mRNA copies. We further noted that circulating patient T cells were unresponsive to polyclonal T-cell activation compared to healthy donor cells. Moreover, CD4+CD25+ T cells were increased in patient blood and could suppress the expansion of allogeneic T cells from healthy donors. CONCLUSIONS: Patients with bladder carcinoma show an immunosuppressive regulatory profile, including nonresponsive T cells. Clinical protocols able to effectively counteract these mechanisms are warranted.

Humans↗

PubMed2007

Labelling chemistry and characterization of [90Y/177Lu]-DOTA-ZHER2:342-3 Affibody molecule, a candidate agent for locoregional treatment of urinary bladder carcinoma.

The direct instillation of radiolabelled conjugates in the urinary bladder is a promising path for the treatment of bladder carcinoma. The targeting of HER2/neu receptors expressed on the surface of many bladder carcinoma cells shows potential to be developed as a therapeutic strategy, and patients identified with a high risk of progression may benefit from adjuvant targeted radionuclide therapy. A phage-display selected Affibody molecule (Z(HER2:342)) which binds to HER2/neu with picomolar affinity, can be used for targeting HER2/neu-expressing bladder carcinomas. A DOTA-derivative of Z(HER2:342), designated as DOTA-Z(HER2:342)-3, is considered as a suitable targeting agent for therapy. The DOTA chelator provides stable labelling with radiometals, and the low molecular weight (7.2 kDa) of the DOTA-Z(HER2:342)-3 compound is expected to enable efficient tumor penetration. DOTA-Z(HER2:342)-3 was radiolabelled with 90Y and 177Lu in 1 M ammonium acetate buffer, at pH 5.5, and in the presence of ascorbic acid. Nearly quantitative labelling yields were achieved for both nuclides after 15 min of incubation at 60 degrees C. After chelation, the conjugates retained their capacity to specifically bind to HER2/neu-expressing SKOV-3 cells. The radiolabelled affibody conjugate (DOTA-Z(HER2:342)-3) demonstrated high antigen-binding capacity and good cellular retention. Biodistribution in normal mice demonstrated low uptake in all organs and tissues except for kidneys.

Animals↗

PubMed2006

Prediction of recurrence in Ta urothelial cell carcinoma by real-time quantitative PCR analysis: a microarray validation study.

Accurate prediction of tumor recurrence in patients with superficial urothelial cell carcinoma (UCC) might result in a significant reduction of invasive follow-up cystoscopies. A recent study identified a panel of 26 genes from a large cDNA microarray analysis of bladder tumors that discriminated between early- and late-recurring patients with superficial Ta tumors (Dyrskjøt et al., Nat Genet 2003;33:90-6). We aimed to validate this panel of genes in 44 primary Ta UCCs (23 and 21 tumors from patients with short or prolonged recurrence-free periods, respectively), by real-time quantitative PCR. Statistical analysis showed marginal significant different mRNA expression levels between the 2 patient groups. To evaluate a supplementary effect of genes for the identification of patients with short or prolonged recurrence-free intervals, forward logistic regression analysis was applied. This revealed that a combination of the expression profiles of the genes HNRPK, LTB4DH and ANP32B resulted in the best performance, although the combination only marginally increased the predictive value of HNRPK alone. Comparing the receiver-operating-characteristic curves for HNRPK expression among patients with short or prolonged recurrence-free periods, revealed an area under the curve of 0.696 (95% CI, 0.537-0.855). Using the median HNRPK expression level as cut-off, a sensitivity of 69.6% and a specificity of 71.4% were obtained for the identification of patients with short or prolonged recurrence-free periods, respectively. In conclusion, we were not able to confirm the microarray gene expression pattern of the 26 genes shown by Dyrskjøt et al. The discovery of accurate recurrence predictive markers, therefore, remains a challenge.

Gene Expression Profiling↗

PubMed2006

Gene expression analysis for the prediction of recurrence in patients with primary Ta urothelial cell carcinoma.

OBJECTIVES: The individual recurrence-free period after primary surgery of patients with Ta urothelial cell carcinoma (UCC) cannot be predicted accurately. This study aims at discriminating between patients with primary Ta UCC and long or short recurrence-free periods. METHODS: We investigated mRNA expression of 23 genes in 44 primary Ta tumours (23 and 21 tumours were from patients with long [>or=4 yr] or short [<or=2 yr] recurrence-free periods, respectively), using real-time quantitative polymerase chain reaction. The genes were selected from previously published studies and showed a relationship with tumour recurrence in patients with UCC. RESULTS: Differential mRNA expression between the two patient groups indicated statistical significance only for the gene survivin (p=0.0011). Its recurrence predictive value could not be increased by a combination with any of the other genes. Comparison of the receiver operating characteristic curves for survivin expression between patients with long or short recurrence-free intervals revealed an area under the curve of 0.79 (95%CI, 0.65-0.92). Using the median expression (0.84) as cut-off level, survivin identified 71.4% (95%CI, 47.8-88.7) and 69.6% (95%CI, 47.1-86.8) of the patients with long or short recurrence-free periods, respectively. CONCLUSIONS: Our study identifies survivin as the most promising candidate to distinguish between patients with primary Ta UCC and long or short recurrence-free intervals. Therefore, survivin mRNA expression analysis might help the urologist to individualise patient treatment and prevent unnecessary cystoscopies in a subgroup of these patients.

Adult↗

PubMed2006

Positron emission tomography with C11-acetate for tumor detection and localization in patients with prostate-specific antigen relapse after radical prostatectomy.

OBJECTIVES: To evaluate positron emission tomography with C11-acetate as a method for detecting and localizing prostate cancer recurrence. No technique for localizing and detecting prostate cancer recurrence after biochemical relapse available today is sensitive enough to localize recurrence at a stage at which salvage radiotherapy is still curative. METHODS: Twenty patients (age 56 to 77 years) who had undergone radical prostatectomy and had an increasing prostate-specific antigen level measured on two consecutive occasions were included. In addition to the investigations usually performed when prostate cancer recurrence is suspected, they underwent positron emission tomography with C11-acetate as the marker. RESULTS: Pathologic uptake of acetate was seen in 15 (75%) of the 20 patients. In 8 of these patients, a solitary lesion was found (seven in the prostatic fossa and one at the regional lymph nodes). Multiple lesions were found in the remaining 7. False-positive uptake was seen in 3 men (15%). Additional investigations in these men revealed pathologic findings other than prostate cancer. CONCLUSIONS: Positron emission tomography with C11-acetate as marker is a promising method for early detection and localization of prostate cancer recurrence. False-positive uptake does occur.

Acetates↗

PubMed2006

Analysis of clinical characteristics, management and survival of patients with Ta T1 bladder tumours in Sweden between 1997 and 2001.

OBJECTIVE: To analyse the management and outcome of patients with Ta T1 urinary bladder cancer in a population-based national database. MATERIAL AND METHODS: Between 1997 and 2001, 94% of all newly diagnosed cases of urinary bladder cancer were registered in the Swedish National Bladder Cancer Register. Data were analysed regarding gender, healthcare region, stage and grade for patients with Ta T1 tumours. The choice of initial treatment in different regions was reviewed. Survival was analysed by calculating relative survival. RESULTS: Out of 9859 registered patients, there were 4442 Ta tumours and 2139 T1 tumours. The median age at diagnosis was 72 and 73 years for patients with Ta and T1 tumours, respectively. Seventy-six percent of the patients were men. The choice of treatment varied between different healthcare regions. A significant trend towards an increased use of intravesical therapy was seen over time. Significantly fewer older than younger patients received such therapy. There was also a tendency towards more intensive therapy in men. The bladder cancer relative 5-year survival rate was 93% for Ta and 75% for T1 tumours. Survival was similar for men and women. CONCLUSIONS: Our analysis revealed a regional variation in the treatment of bladder cancer. A large group of patients, even those at high risk, were still undertreated. However, the recent publication of guidelines may have contributed to an increased use of intravesical treatment. Urologists tended to treat TaG3 and T1G3 tumours more aggressively than T1G2 tumours. Therapeutic aggressiveness decreased as the age of the patients increased. The survival rate of patients with bladder cancer in Sweden seems to remain at the levels previously reported for the 1980s.

Age Distribution↗

PubMed2005

Radiobromination of humanized anti-HER2 monoclonal antibody trastuzumab using N-succinimidyl 5-bromo-3-pyridinecarboxylate, a potential label for immunoPET.

Combining the specificity of radioimmunoscintigraphy and the high sensitivity of PET in an in vivo detection technique could improve the quality of nuclear diagnostics. Positron-emitting nuclide (76)Br (T(1/2)=16.2 h) might be a possible candidate for labeling monoclonal antibodies (mAbs) and their fragments, provided that the appropriate labeling chemistry has been established. For internalizing antibodies, such as the humanized anti-HER2 monoclonal antibody, trastuzumab, radiobromine label should be residualizing, i.e., ensuring that radiocatabolites are trapped intracellularly after the proteolytic degradation of antibody. This study evaluated the chemistry of indirect radiobromination of trastuzumab using N-succinimidyl 5-(tributylstannyl)-3-pyridinecarboxylate. Literature data indicated that the use of this method provided residualizing properties for iodine and astatine labels on some antibodies. An optimized "one-pot" procedure produced an overall labeling efficiency of 45.5+/-1.2% over 15 min. The bromine label was stable under physiological and denaturing conditions. The labeled trastuzumab retained its capacity to bind specifically to HER2-expressing SKOV-3 ovarian carcinoma cells in vitro (immunoreactivity more than 75%). However, in vitro cell test did not demonstrate that the radiobromination of trastuzumab using N-succinimidyl 5-bromo-3-pyridinecarboxylate improves cellular retention of radioactivity in comparison with the use of N-succinimidyl 4-bromobenzoate.

Antibodies, Monoclonal↗

PubMed2005

Randomized phase II marker lesion study evaluating effect of scheduling on response to intravesical gemcitabine in recurrent Stage Ta urothelial cell carcinoma of the bladder.

OBJECTIVES: To evaluate the response rate for intravesical gemcitabine given in three different schedules to patients with recurrent multiple carcinoma of the urinary bladder Stage Ta, grade 1-2, in whom all but one marker lesion was removed. Furthermore, we sought to define the safety profile. METHODS: This was a multicenter, open-label, randomized, Phase II study in which gemcitabine 2000 mg in 100 mL of unbuffered saline was instilled as a single dose (n = 11), two doses per week for 3 weeks (n = 11), or once weekly for 6 weeks (n = 10). Efficacy was evaluated using cystoscopy after 9 weeks. Toxicity was evaluated by assessing the liver, kidney, bone marrow, and coagulation function at defined intervals and by questionnaire. RESULTS: A total of 32 patients were included, 2 of whom were subsequently excluded because of protocol violations. The overall complete remission rate was 31%. The respective subgroup response rate was 10% in the single-dose group, 44% in the once-weekly group, and 40% in the twice-weekly group. The most common side effect was nausea. One patient withdrew because of nausea and fever, and an additional 2 patients had reversible hematologic toxicity (mild thrombocytopenia causing delayed instillation and mild anemia). The side effects were generally in the multiple-dose groups, with an overrepresentation in women. Ten patients were unable to retain the drug intravesically for the full hour. CONCLUSIONS: The results of our study have shown that gemcitabine has a tumor ablative effect when given intravesically for bladder cancer. A single dose seemed ineffective, and the multiple dosing regimens seemed effective. The side effects were generally mild.

Administration, Intravesical↗

PubMed2005

Low-grade Ta (noninvasive) urothelial carcinoma of the bladder.

This article discusses the development of international guidelines for the diagnosis, treatment, follow-up, and prevention of low-grade Ta urothelial carcinoma of the bladder. The authors, who are experts in this field from 3 continents and 7 countries, reviewed the English language literature through September 2004. The results of the authors' deliberations are presented here as a consensus document. The objective of this study was to determine the optimal diagnostic workup, treatment, follow-up, and prevention of low-grade, Ta urothelial carcinoma of the bladder. A consensus conference convened by the World Health Organization (WHO) and the Société Internationale d'Urologie (SIU) met to critically review the literature on the diagnosis and treatment of low-grade Ta urothelial carcinoma of the bladder. Research was conducted using Medline; this search engine also was used to identify additional works not detected at the initial search. Evidence-based recommendations for diagnosis and management of the disease were made with reference to a 4-point scale. Low-grade Ta urothelial carcinoma of the bladder is a well-studied subject with many level 1 and 2 evidence references that support clinical practice. Findings from 135 reviewed citations are summarized. Many grade A and B recommendations on the diagnostic workup and management of this disease can be given with level 1 and 2 evidence based on prospective randomized clinical trials of sufficient statistical power. This should improve the quality of the treatment of this disease.

Algorithms↗

PubMed2005

Results of second-look resection after primary resection of T1 tumour of the urinary bladder.

OBJECTIVE: To study residual tumours at second-look resection in patients resected 4-8 weeks earlier for T1 tumours of the urinary bladder. MATERIAL AND METHODS: All patients randomized in the ongoing Nordic T1G2-G3 Bladder Sparing Study with monitored data available were included in the study. Data on residual tumours at second-look resection were compared to basic patient and tumour characteristics. RESULTS: There were 72 patients (56%) without and 57 with residual exophytic tumours. In the former group, 20 patients (28%) had carcinoma in situ, compared to 19 (33%) in the latter group. Potentially dangerous tumours (either carcinoma in situ, T1 or Ta grade 3) were observed in 55 patients (43%). Multiple tumours at primary resection were more prone to residual tumour at second-look resection than single tumours. No other tumour or patient characteristics could predict the occurrence of a residual tumour. CONCLUSIONS: Residual tumours are frequently observed at second-look resection 4-8 weeks after primary resection of T1 tumours. The majority of residual tumours detected at this stage are potentially dangerous; therefore, early second-look resection followed by intravesical instillation therapy is mandatory in patients with T1 tumours of the urinary bladder.

Adult↗

PubMed2005

Lymph node staging in prostatic carcinoma revisited.

Despite presumed curative operation almost one-third of patients with prostatic carcinoma relapse. One obvious reason is that the preoperative lymph node staging is not sufficiently effective. Imaging modalities (CT and NMR) have not resolved the problem. Presently lymphadenectomy is not recommended in patients with Gleason score <7 and PSA <20 ng/ml owing to the low frequency of positive nodes. However, these data are based on experience with limited dissection. Results from extended dissection reveal a higher rate of metastases than previously found. The results from extended dissections showed that more than half of the diagnosed lymph node metastases were found outside the generally recommended regions. The drawback is the higher complication rate that follows. Thus the staging can be improved but if this translates into a survival benefit it needs to be addressed in controlled trials. Alternative techniques for lymph node staging have recently been developed. The sentinel lymph node (SLN) method has been tested and proved feasible. The results corroborated those of extended dissection, namely that the obturator region is insufficient to reflect the field of metastases. High-resolution MRI with magnetic nanoparticles can detect small and otherwise undetectable lymph-node metastases. Positron emission tomography (PET), using acetate or choline as tracers, has performed better than fluoro-2-deoyglucose for detection of relapsing prostate cancer after radical prostatectomy. Studies have also started to assess its role for lymph node staging. In summary, lymph node staging has to cover a larger anatomical field than routinely used. Whether surgical dissection can be replaced by the new imaging modalities is presently under investigation.

Humans↗

PubMed2005

EGF-receptor targeted liposomes with boronated acridine: growth inhibition of cultured glioma cells after neutron irradiation.

PURPOSE: To study survival of cultured U-343MGaCl 2:6 glioma cells after incubation with boron-containing liposomes targeting the epidermal growth factor receptor following neutron irradiation. MATERIALS AND METHODS: Epidermal growth factor-tagged liposomes were loaded with water-soluble boronated acridine developed for boron neutron capture therapy, (BNCT). Cellular uptake and distribution were studied. Further, cells were placed at 3 cm depth in a phantom and exposed to an epithermal neutron beam to study clonogenic cell survival. RESULTS: The cellular uptake of boron reached 90 ppm and it was determined by subcellular fractionation that most of the cell-associated boron was located outside of the nucleus. For clonogenic survival, the cells were incubated with epidermal growth factor receptor-targeted liposomes for 4 hours resulting in a cellular concentration of 55 ppm boron (11 ppm 10B). At a fluence of 3 x 10(12) neutrons/cm2 the cell killing effect of the boron-containing epidermal growth factor-liposomes was about ten times higher than for neutrons only. Furthermore, theoretical calculation of the survival by enriched compound (55 ppm 10B), using the parameters from non-enriched compound (11 ppm 10B), shows that the killing effect in this case would be approximately five orders of magnitude higher than for neutrons only. CONCLUSION: The results in this study show that epidermal growth factor-receptor targeted liposomes are suitable as tumor-cell delivery agents of boron for BNCT and support further studies to demonstrate their effectiveness in vivo.

Boron Neutron Capture Therapy↗

PubMed2005

Analysis of HER2 expression in primary urinary bladder carcinoma and corresponding metastases.

OBJECTIVE: To evaluate the expression of HER2 receptors (previously reported to be over-expressed in malignant urothelium) in both primary tumours and metastases of transitional cell cancer, using two different staining methods and two different scoring techniques, considering the potential use of these receptors as targets for planned systemic anti-HER2 nuclide-based treatment. MATERIALS AND METHODS: HER2 expression was evaluated with two different immunohistochemical methods in 90 patients with primary urinary bladder cancer tumours and corresponding metastases. Sections were first stained with the commercially available breast cancer test kit (HercepTest, Dako, Glostrup, Denmark). Parallel sections were then stained with a modified HercepTest procedure. Two different evaluation criteria were compared; the HercepTest score that requires > or = 10% stained tumour cells (as for breast cancer) and a proposed 'Target score' that requires > 67% stained tumour cells. The latter score is assumed to be preferable for HER2-targeted radionuclide therapy. RESULTS: Using the HercepTest kit, the Target score gave lower fractions of positive primary tumours and metastases than the HercepTest score. The modified HercepTest staining procedure and Target score gave high HER2 values in 80% of primary tumours and 62% of metastases, which is considerably more than that obtained with the HercepTest staining and score. There was a significant decrease in HER2 positivity with increasing distance from the primary tumour. In nine sentinel-node metastases assessed, all but one were HER2-positive. Considering all regional metastases, 74% were positive, and of distant metastases, 47%; 72% of the patients with positive primary tumours also expressed HER2 in their metastases. CONCLUSIONS: When combining the modified HercepTest with customised evaluation criteria, more HER2-positive tumours were diagnosed. The degree of HER2 down-regulation was significantly higher in distant than in regional metastases. HER2-targeted therapy may be an alternative or complementary to other methods in the future treatment of metastatic urinary bladder carcinoma.

Adult↗

PubMed2005

An aminoacridine derivative for radionuclide therapy: DNA binding properties studied in a novel cell-free in vitro assay.

Radiolabelled DNA-binding compounds can be used to increase the efficiency of radionuclide cancer therapy of disseminated disease. In this work, the aminoacridine compound N-[3-(acridine-9-ylamino)-propyl]-3-iodobenzamide (A3) labelled with the Auger-emitting nuclide 125I using Chloramine-T was studied. Optimal labelling conditions of 125I-A3 were investigated and the interaction with DNA was studied using a novel cell-free in vitro assay with naked human genomic DNA in agarose plugs. This novel assay showed to be simple and reliable. The results verify that 125I-A3 specifically binds DNA with low dissociation and is potent in causing double-strand breaks, yielding 1.0-1.4 breaks per decay. In conclusion, 125I-A3 is a most suitable DNA-binding compound for future therapeutic studies of Auger-electron emitters like 125I.

Acridines↗

PubMed2004

Neoadjuvant cisplatinum based combination chemotherapy in patients with invasive bladder cancer: a combined analysis of two Nordic studies.

OBJECTIVES: A Nordic collaborative group assessed the effectiveness of cisplatinum based combination chemotherapy prior to cystectomy in two consecutive trials. We analyzed overall survival in all patients and in prespecified subgroups defined by preoperative T-stage, gender and age. METHODS: The studies included in 1985-1997 620 patients with clinically T1G3, T2-T4aNXM0 urothelial bladder cancer and WHO performance </=2. Platinum was combined with adriamycin in the first and with methotrexate in the second trial. In the first of the studies, preoperative radiotherapy was used in both arms. Individual patient data were used. No patients were lost to follow-up. The median follow-up was 4.7 years. A fixed effect model was used to combine the results of the two trials. Subgroup analyses were performed for T-stages, gender and age groups. All analyses were done according to intention to treat. RESULTS: The combined study results showed a hazard ratio of 0.80 (95% confidence interval 0.64-0.99) for overall survival in favor of neoadjuvant treatment. Survival was 56% at five years in the experimental group versus 48% in the control group, thus corresponding to an eight percent absolute risk reduction after neoadjuvant chemotherapy. We could not substantiate any differences in effect by subgroup. CONCLUSIONS: In a combined analysis of two trials within the same study organization and the same clinical and biological domain, neoadjuvant platinum based combination chemotherapy was associated with a 20% reduction in the relative hazard in probability of death.

Adult↗

PubMed2004

A second-look TUR in T1 transitional cell carcinoma: why?

T1 transitional cell cancer of the urinary bladder is associated with a significant risk of tumor progression when transurethral resection (TUR) is the only treatment. Additional intravesical immunotherapy can reduce this risk; however, long-term results of more than 15 years of follow-up indicate that almost half of the patients may lose their bladder or even die due to recurrent tumor. The alternative to TUR is cystectomy at either the initial presentation or time of first recurrence. However, although the results of this treatment strategy are encouraging, an unknown percentage of patients will lose their bladder and go on to experience all possible complications of urinary diversion unnecessarily. The central issue of conservative treatment but also the indication for cystectomy is the quality of TUR. From the present literature, it is evident that a 'textbook TUR' cannot be performed on every patient, i.e. macroscopical clearance of the bladder from tumor, separate thorough resection of the tumor base and separate biopsies of the borders of the resection area. Moreover, even in cases of a so-called 'correct TUR', a significant percentage of residual tumor is left behind and will be the source of local recurrence or progression. In addition, TUR specimens may be difficult to diagnose accurately, especially in respect to grade and stage. Recent publications demonstrate that the routinely performed second TUR detects residual tumors of similar or higher stage in a significant percentage of patients. The clinical implications of these findings can be considerable as the absence or presence of tumor may determine whether patients undergo conservative or aggressive treatment. Moreover, results of retrospective studies support this suggestion. Currently, there is no standard appropriate treatment of T1 tumors. However, we strongly recommend that future studies on the conservative treatment of T1 tumors include a second TUR within 2 to 4 weeks after the first one.

Carcinoma, Transitional Cell↗

PubMed2004

Radiobromination of anti-HER2/neu/ErbB-2 monoclonal antibody using the p-isothiocyanatobenzene derivative of the [76Br]undecahydro-bromo-7,8-dicarba-nido-undecaborate(1-) ion.

The monoclonal humanized anti-HER2 antibody trastuzumab was radiolabeled with the positron emitter (76)Br (T(1/2) =16.2 h). Indirect labeling was performed using the p-isothiocyanatobenzene derivative of the [(76)Br]undecahydro-bromo-7,8-dicarba-nido-undecaborate(1-) ((76)Br-NBI) as a precursor molecule. (76)Br-NBI was prepared by bromination of the 7-(p-isothiocyanato-phenyl)dodecahydro-7,8-dicarba-nido-undecaborate(1-) ion (NBI) with a yield of 93-95% using Chloramine-T (CAT) as an oxidant. Coupling of radiobrominated NBI to antibody was performed without intermediate purification, in an "one pot" reaction. An overall labeling yield of 55.7 +/- 4.8% (mean +/- maximum error) was achieved when 300 microg of antibody was labeled. The label was stable in vitro in physiological and denaturing conditions. In a cell binding test, trastuzumab remained immunoreactive after labeling.

Antibodies, Monoclonal↗