Clinical Cancer Research Folkman
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Meeting Abstracts Online
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wang, Z.
Right arrow Articles by Tennvall, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wang, Z.
Right arrow Articles by Tennvall, J.
Clinical Cancer Research Vol. 11, 7171s-7177s, October 1, 2005
© 2005 American Association for Cancer Research

Clinical Studies

Blood Pharmacokinetics of Various Monoclonal Antibodies Labeled with a New Trifunctional Chelating Reagent for Simultaneous Conjugation with 1,4,7,10-Tetraazacyclododecane-N,N',N'',N'''-Tetraacetic Acid and Biotin before Radiolabeling

Zhongmin Wang1,5, Linda Mårtensson1, Rune Nilsson4, Pär-Ola Bendahl1, Lars Lindgren4, Tomas Ohlsson2, Hans-Olov Sjögren3, Sven-Erik Strand2 and Jan Tennvall1

Authors' Affiliations: 1 Department of Oncology, Lund University Hospital; Departments of 2 Radiation Physics and 3 Tumor Immunology, Lund University; 4 Mitra Medical AB, Lund, Sweden; and 5 Shanxi Tumor Hospital and Shanxi Tumor Radiotherapy Center, Shanxi, P.R. China

Requests for reprints: Jan Tennvall, Department of Oncology, Lund University Hospital, SE-221 85 Lund, Sweden. Phone: 46-4617-7520; Fax: 46-4617-6080; E-mail: Jan.Tennvall{at}onk.lu.se.


   Abstract
Top
 Abstract
Materials and Methods
 Results
 Discussion
 References
 
Purpose: Knowledge of the blood pharmacokinetics of monoclonal antibodies is crucial in deciding the optimal time for starting the administration of a "clearing agent" or using a "clearing device." The primary purpose was to investigate whether the pharmacokinetics of various antibodies labeled with the same chelator and 111In differed significantly after i.v. injection in immunocompetent rats. A new trifunctional chelator called "1033" containing a biotin and a radiometal chelation moiety is introduced, making it possible to use only one conjugation procedure for the antibody.

Experimental Design: Sixty-five non–tumor-bearing rats were included and divided into four groups (I-IV). The blood pharmacokinetics was investigated for rituximab, BR96, and trastuzumab labeled with 1033 and 111In (I-III). The whole-body activity and activity uptake in muscle, liver, and kidney, which might explain differences in the early pharmacokinetics in blood, were also measured. hMN14 labeled with another chelator [1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)], but with the same radionuclide (111In-biotin-DOTA-hMN14), was studied (IV). The blood pharmacokinetics from another 15 tumor-bearing rats was compared with those of non–tumor-bearing rats (III) by injection of 111In-1033-BR96.

Results: No statistical difference was detected between the groups regarding the blood pharmacokinetics of rituximab, BR96, or trastuzumab. The pharmacokinetics and biodistribution of 111In-biotin-DOTA-hMN14 exhibited a clear difference compared with others. There were no significant differences in the blood pharmacokinetics of 111In-1033-BR96 between tumor-bearing rats and non–tumor-bearing rats.

Conclusions: Different antibodies labeled with the trifunctional chelator 1033 and 111In did not exhibit different blood pharmacokinetics, which means that the pharmacokinetics could be predicted irrespective of the IgG1 antibody chosen. A small tumor burden did not change the pharmacokinetics of the radioimmunoconjugates.

Immunotherapy of solid tumors utilizing unlabeled or radiolabeled monoclonal antibodies (mAb) has not yet been very successful apart from treatment of minimal disease and in adjuvant settings often in combination with other modalities (1). The main obstacle is the low tumor-to-normal tissue ratio, which reflects the expression of target antigen relative normal tissue but also the biokinetics, tumor penetration, and access to the antigens. In an attempt to overcome low tumor-to-normal tissue ratios, various methods can be used to reduce the toxicity in normal radiosensitive organs by improving the clearance of circulating radiolabeled mAbs. By using such strategies, it might be possible to administer higher activities of radiolabeled mAbs without increasing the systemic toxicity. These methods include various types of pretargeting (2) or extracorporeal adsorption (3–9), or administration of secondary anti-idiotypic mAbs (10). There are numerous ongoing studies in animal systems exploring these strategies. It is, however, necessary to know the pharmacokinetics of the first injected antibody to determine the optimal time to use a clearing agent or a clearing device.

The trifunctional chelator used in the present study is a new reagent called "1033" [3-(13'-thioureabenzyl DOTA)trioxadiamine-1-(13''-biotin-Asp-OH)trioxadiamine-5-isothiocyanato-aminoisophtalate; MitraTag; Mitra Medical AB, Lund, Sweden] for simultaneous conjugation with 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA) and biotin to the antibody, removing the need for two separate conjugation procedures and, hence, unnecessary exposure to the antibody (Fig. 1; ref. 11). By combining the biotin moiety and the radiolabeling moiety into a single molecule, every mAb that is radiolabeled will also have biotin bound to it. As a result, the heterogeneity of radiolabeled mAbs is reduced, as the same number of biotin molecules as chelates is always present and a minimum number of conjugation reagents or moieties can be used (11).



View larger version (12K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 1. Schematic of the trifunctional chelator.

 
The primary aim of this study was to investigate whether the pharmacokinetics of various antibodies labeled with 1033 and 111In differed significantly after i.v. injection in immunocompetent rats to ascertain whether the pharmacokinetics of one antibody could be generalized and applied to other antibodies labeled with the same radionuclide and chelator, avoiding time-consuming pharmacokinetic studies for each individual antibody tested. Because most radiolabeled mAbs used for therapy are of IgG1, we have restricted the investigations to this subclass. In addition, the current study also elucidated whether this animal model was sensitive enough to distinguish between different conjugation chemistry that is then shown by exhibition of differing pharmacokinetics when using another antibody with a different chelator (i.e., 111In-DOTA-hMN14) and if the pharmacokinetics was influenced by the tumor burden by injection of 111In-1033-BR96.


   Materials and Methods
Top
 Abstract
 Materials and Methods
Results
 Discussion
 References
 
Preparation of the radioimmunoconjugates
Monoclonal antibodies. The four mAbs investigated in this study were rituximab (Mabthera, Roche, Basle, Switzerland), BR96 (Seattle Genetics, Bothwell, WA), trastuzumab (Herceptin, Roche), and hMN14 (CEA-Cide, Immunomedics, Inc., Morris Plains, NJ). They are all IgG1 immunoglobulins. Both hMN14 and trastuzumab are humanized mAbs, which consist of a human immunoglobulin framework with complementary-determining regions of a murine antibody. The former can recognize the carcinoembryonic antigen overexpressed on the cell surface of human colorectal, pancreatic, lung, breast, and ovarian carcinomas (12, 13). The latter is an antireceptor antibody with a current clinical role in the treatment of breast cancer. It is directed against the extracellular domain of HER2, a type I tyrosine kinase receptor of the HER family, which is overexpressed and/or amplified in 20% to 30% of human breast carcinomas (14–16). Rituximab and BR96 are chimeric murine/human mAbs that have a human immunoglobulin framework with variable regions isolated from a murine mAb. Rituximab binds to the CD20 antigen on the surface of >95% of B-cell non-Hodgkin's lymphomas and normal B cells, but not to hematopoietic stem cells, mature plasma cells, or normal tissues (17). BR96 is directed against the Lewis Y (LeY) glycoprotein, which is expressed on the majority of human epithelial tumors (including breast, gastrointestinal tract, non–small cell lung, cervix, ovary, and some melanomas), but at low levels on normal cells of the gastrointestinal tract in humans, primarily by differentiated cells of the esophagus, stomach, and intestine, as well as acinar cells of the pancreas (18).

The conjugation and radiolabeling of immunoconjugates. In the present study, two different forms of the same chelator were used to link the immunoconjugate and 111In (MDS Nordion, Ottawa, Ontario, Canada). The trifunctional chelator 1033 was used to label the three antibodies—rituximab, BR96, and trastuzumab—with 111In. The preparation of 1033 has previously been described by Wilbur et al. (11). The fourth antibody, hMN14, was conjugated with the chelator DOTA at 4 to 6 DOTA/IgG (this conjugate was obtained from Immunomedics). hMN14-DOTA was biotinylated with sulfo-NHS-biotin (19). The immunoconjugates and 111In were pretempered at 45 ± 2°C for 10 minutes. Thereafter, the immunoconjugates were added to the radionuclide containing vials that were gently stirred and incubated for 15 minutes at the same temperature. The mixture was removed from the heat source and an excess of diethylenetriaminepentaacetic acid was added to quench the reaction. After 5 minutes, the radioimmunoconjugates were purified using size exclusion chromatography (PD10 column; Amersham-Pharmacia Biotech, Buckinghamshire, United Kingdom).

After the mAbs had been conjugated, the number of biotin moieties per molecule of the mAb was measured based on the photometric method of 4'-hydroxyazobenzene-2-benzoic acid displacement by biotin (20).

Quality control of the radioimmunoconjugates
Three parameters were measured for quality control of the radioimmunoconjugates: radiochemical purity, avidin-binding fraction, and antigen binding.

Free radionuclide. The levels of non–protein-bound radionuclide in the immunoconjugate preparations was determined using instant TLC on a 1 x 9 cm silica gel–impregnated fiberglass sheet (Pall Corporation, New York, NY) eluted in 0.1 mol/L EDTA, and high performance liquid chromatography with a 7.8 x 300 mm molecular sieving column, Phenomenex SEC S3000 (Phenomenex, Torrance, CA), eluted in 0.05 mol/L sodium phosphate at 1.0 mL/min. The radioimmunoconjugates were detected by UV absorbance at 280 nm and radioactivity measurements.

Avidin-binding fraction test. An adsorption column packed with ~0.3 mL of Mitra avidin-agarose (Mitra Medical) was used. After the column had been washed four times with PBST (PBS containing 0.05% Tween 20), a 50 µL sample of the radioimmunoconjugate was added to the column and was incubated for 10 minutes at room temperature. The column was washed eight times with 0.5 mL PBST and each batch of washing liquid was collected separately in tubes to measure the radioactive washout. The activity in the column and in each tube was measured with an automatic sample changer NaI (Tl) scintillator well counter. The avidin-binding fraction was expressed as the percentage of radioactivity in the column in relation to the sum of the radioactivity in the tubes and the column.

Antigen-binding test. The antigen-binding properties of the radioimmunoconjugates were investigated by competitive inhibition between radiolabeled immunoconjugate and nonconjugated mAb to the target antigen. First, target antigens were prepared. Various tumor cell lines expressing an epitope for the corresponding antibody were plated on microtest wells (Nunc-Immuno BreakApart, Nunc, Roskilde, Denmark). The wells were coated with 50 µL/well solution with a concentration of 2 x 106 targeted cells/mL PBST and dried at 37°C overnight. Then, the wells were washed with PBST four times; thereafter, the wells were blocked by PBST for 1 hour at room temperature. The concentration of radiolabeled immunoconjugate was determined by measuring the adsorption using an UV/visible spectrophotometer (Pharmacia Biotech Ultrospec 1000) at a wavelength of 280 nm (A280). A constant concentration of radiolabeled immunoconjugate mixed with increasing concentrations of nonconjugated mAbs was applied to each well (four replicates at each concentration) and incubated for 1.5 hours at room temperature. The wells were then washed with PBST and emptied. The activity was measured with the NaI (Tl) scintillation well counter described above, and the competitive inhibition curve was plotted. The concentration of nonconjugated mAbs that inhibited 50% of the radiolabeled immunoconjugate binding to the target antigen (IC50) was calculated utilizing Prism 4 software (GraphPad Software, Inc.).

Animal experiments
Animals. Sixty-five rats were included in this study and they were divided into four groups (Table 1). The rats were provided with standard food pellets and fresh water ad libitum. All studies were conducted in compliance with Swedish legislation on animal rights and protection.


View this table:
[in this window]
[in a new window]

  		Table 1. Experimental groups

 
In addition, another 15 tumor-bearing Brown Norwegian rats were used to investigate whether a small tumor burden affected the pharmacokinetic behavior of the radioimmunoconjugates. The mean tumor mass was 0.96 g with a range of 0.66 to 1.39 (0.4% of the mean body weight) when the pharmacokinetic studies were conducted. The tumor mass was determined by weighing the dissected tumors.

Pharmacokinetics and biodistribution measurements. All immunoconjugates as well as unconjugated antibodies were administered i.v. to the rats. Each rat in group I received a mixture of 200 µg 1033-rituximab labeled with 3 to 5 MBq of 111In and 1.05 mg unconjugated rituximab; in group II, 22 µg 1033-BR96 with 3 to 5 MBq of 111In; in group III, 100 µg 1033-trastuzumab with 3 to 5 MBq of 111In; in group IV, a mixture of 150 µg 111In-hMN14-DOTA (3-5 MBq) and 50 µg of unconjugated hMN14 was administered. Whole-body {gamma}-camera imaging was done using a scintillation camera (SMV DST-Xli, Sopha Medical, Buc, France) equipped with a medium-energy collimator to determine the whole-body activity clearance. A 25% energy window was centered over the 172 keV photopeak and a 20% energy window was centered over the 245 keV photopeak. The rats were anesthetized and placed on the collimator in the prone position. Imaging was done immediately postinjection for all the animals, and at 1, 8, 24, 48, and 96 hours for groups I to III and at 1, 8, 24, 48, 72, and 120 hours for group IV. After background subtraction and decay correction for 111In, the activity in the whole body was expressed as the percentage of injected activity. Blood samples were drawn from the periorbital venous plexus at six to seven points after radioimmunoconjugate administration at times corresponding to the imaging times. Three rats were dissected at the same time as imaging was done (except immediately postinjection) for all groups, and the following organs were removed and weighed: pectoral muscle, kidney, and liver.

The radioactivity in blood samples and in the dissected organs was measured in the NaI (Tl) scintillator well counter. The activity uptake was expressed as a percentage of the injected activity per gram of tissue (%ID/g).

The pharmacokinetic parameters of the radioimmunoconjugates. The pharmacokinetic analysis of the radioimmunoconjugates was based on the curves of the blood activities. The pharmacokinetic parameters were determined according to a two-phase exponential decay model with two rates: the initial rapid decrease, called the distribution phase, mainly representing the equilibration between the intravascular and extravascular components; and the second slower phase, called the elimination phase, due to catabolism. The following parameters were used: {alpha} (distribution rate constant), ß (elimination rate constant), T1/2{alpha} (distribution half-life), and T1/2ß (elimination half-life).

In addition, the data from tumor-bearing and non–tumor-bearing rats were compared to determine whether tumors had any impact on the pharmacokinetics using 111In-1033-BR96.

Statistical analysis. For each rat in the study, activity levels were measured at baseline and at a final observation time. The baseline level was set to 100% and the final measurement was expressed as a percentage of the baseline level. For blood activity data, a two-phase exponential decay model was used to model the percentage of remaining activity (Act) as a function of time postinjection (t):

(A)

This model is a mixture of two exponential functions, with rates of decay K1 and K2, and a plateau. The constants {alpha}, ß, and {gamma} can be interpreted as the contribution of each component to the mixture, and their sums must therefore be 100%, reducing Eq. A to

Nonlinear least-squares fitting was used to estimate the four parameters in the model. The half-lives of the exponential functions are:

An F-test was used to compare the fit of a single two-phase exponential model with that of four two-phase exponential models, one for each immunoconjugate. Data on whole-body activity and uptake in organs were summarized graphically without any statistical modeling or hypothesis testing.

The statistical analysis was carried out with the program Stata (StataCorp 2003, Stata Statistical Software: Release 8.0, Stata Corporation, College Station, TX).


   Results
Top
 Abstract
 Materials and Methods
 Results
Discussion
 References
 
Conjugation and radiolabeling
The ratios of biotin moieties per mAb in this study were 2.3, 2.0, 2.2, and 2.7 for 111In-1033-rituximab (I), 111In 1033-BR96 (II), 111In 1033-trastuzumab (III), and 111In-biotin-DOTA-hMN14 (IV), respectively.

Quality control of the radioimmunoconjugate
Radiochemical purity. Instant TLC showed a radiochemical purity for all four radioimmunoconjugates investigated of at least 95% after gel filtration. No signs of aggregation or fragmentation were observed with high-performance liquid chromatography.

Avidin-binding fraction. The avidin-binding fraction exceeded 93% for all radioimmunoconjugates at the time of injection.

Antigen-binding properties. No significant changes in binding properties of the radioimmunoconjugates were found after conjugation and labeling with 111In.

Pharmacokinetics and biodistribution
Whole-body activity clearance. In Fig. 2, the whole-body activity clearance of the four different 111In-labeled antibodies is given. The whole-body activity clearance of the three 1033-labeled radioimmunoconjugates (I, II, and III) did not differ significantly. Biotin-DOTA-hMN14 immunoconjugate (IV), however, exhibited faster clearance.



View larger version (15K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 2. Whole-body activity clearance of four different mAbs measured with a {gamma}-camera. Points, individual values; mean values are connected by lines.

 
Blood pharmacokinetics. No statistical difference was detected between the groups in terms of blood pharmacokinetics for rituximab, BR96, and trastuzumab (I-III), as shown in Fig. 3A. However, Fig. 3B, as well as Fig. 4, shows that 111In-biotin-DOTA-hMN14 (IV) had significantly faster blood pharmacokinetics than the others. There were no clear differences in the blood pharmacokinetics of 111In-1033-BR96 between tumor-bearing and non–tumor-bearing rats (Fig. 5).



View larger version (15K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 3. Blood activity clearance. The fit of a single two-phase exponential model based on data from groups I to III (rituximab, BR96, and trastuzumab) is shown in (A). Points, individual values. B, fit of four two-phase exponential models, one for each of the groups (rituximab, BR96, trastuzumab, and hMN14).

 


View larger version (20K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 4. Blood activity clearance of each of the radioimmunoconjugates rituximab (I), BR96 (II), trastuzumab (III), and hMN14 (IV). Points, individual values; lines fitted two-phase exponential models.

 


View larger version (14K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 5. Comparison of blood pharmacokinetics between tumor-bearing and non–tumor-bearing rats after injection of 111In-1033-BR96. Points, individual values; lines fitted two-phase exponential models.

 
Activity in organs. Only activity uptake in muscle, liver, and kidney, which might explain differences in the early pharmacokinetics in blood (distribution phase), was investigated in this study. The biodistribution of the three 1033 radioimmunoconjugates was similar in all three organs compared (Fig. 6A-C), apart from a slower initial uptake in the kidneys of 1033-rituximab (Fig. 6A). The DOTA-hMN14-radioimmunoconjugate showed a clearly different biodistribution from the three 1033-radioimmunoconjugates in all three organs (Fig. 6A-C). The liver activity of biotin-DOTA-hMN14 increased more rapidly and remained at a high level. The maximum activity (6.4%/g) occurred at 24 hours postinjection and was ~8- to 12-fold higher than those of the three 1033 radioimmunoconjugates (0.55-0.82%/g).



View larger version (31K):
[in this window]
[in a new window]
[Download PPT slide]
  		Fig. 6. A to C, activity uptake of four different mAbs measured in a NaI (Tl) scintillation well counter. A, kidney uptake; B, liver uptake; C, muscle uptake. Points, individual values; mean values are connected by lines.

 
In addition, the gender and the various strains of rats seemed not to have an impact on the biokinetics in any of the groups.


   Discussion
Top
 Abstract
 Materials and Methods
 Results
 Discussion
References
 
In deciding the optimal time at which to start administration of a clearing agent or using a clearing device, knowledge of blood pharmacokinetics is critical especially in the distribution phase. We hypothesized that data for the pharmacokinetics of blood activity clearance obtained from one radiolabeled antibody in rats could be generalized and applied to other antibodies labeled with the new trifunctional chelator 1033 and the same radionuclide (111In) to remove the need for time-consuming pharmacokinetic studies for each individual antibody tested.

The results of the study confirmed that there was no significant difference in the pharmacokinetics regarding blood activity clearance of three mAbs (rituximab, BR96, and trastuzumab) labeled with the same trifunctional chelator (1033) and radionuclide (111In) in immunocompetent rats after i.v. injection of the radioimmunoconjugate. In addition, this study showed that the activity biodistribution in liver, kidney, and whole body closely reflected, and to a great extent explained, the pharmacokinetics in blood. For example, a higher uptake in liver might explain the more rapid clearance from the blood (hMN14 conjugate). We also studied a third tissue (i.e., the muscle tissue) due to its size, but with a much lower perfusion than those of the other two organs (liver and kidney) investigated. The biodistributions of rituximab, BR96, and trastuzumab in liver, kidney, and muscle tissue were similar.

These findings first confirmed our hypothesis that time-consuming pharmacokinetic studies for each antibody could be omitted before administering a clearing agent or using a clearing device provided that the same chelator and radionuclide are used. However, this is not the case when the same antibody is labeled with different radionuclides using different methods in the same animal model as shown by our previous results (21). In the earlier study, we investigated the biodistribution and pharmacokinetics of 125I/131I pair–labeled biotinylated chimeric BR96 in colon carcinoma isografted rats. Whole-body activity retention differed for the two iodination methods; for example, 131I-chimeric-BR96 (iodogen) had a single half-life of 86.6 hours, whereas 125I-chimeric-BR96 (NSTBB) had a short half-life of 5.9 hours and a long half-life of 72.8 hours, corresponding to 12% and 88% of the administered activity, respectively.

The present study showed that the pharmacokinetics and biodistribution of 111In-biotin-DOTA-hMN14 were clearly different from those of the other radioimmunoconjugates probably reflecting the use of another chelator (DOTA) and the fact that the biotin and that the radioisotope were conjugated using two separate procedures. This result indicates that this animal model was sensitive enough to distinguish between different conjugation chemistry that then is shown by exhibition of differing pharmacokinetics.

In the tumor-bearing rats, the presence of a tumor acts as a sink for the injected mAbs and it can decrease the biological half-life (22). This was also clearly seen in the case of hematologic malignancies. In patients with B-cell lymphomas, the serum level of rituximab is inversely correlated with tumor burden at baseline and also inversely correlated with the number of circulating B-cells at baseline (23–25). The same is true for treatment with alemtuzumab in B-cell chronic leukemia (26). These findings are consistent with the importance of accessible lymphoma in influencing the serum levels of the therapeutic mAb. For solid tumors, we asked if the size of tumors could have an impact on blood pharmacokinetics because small tumors are most likely to be used in studies of radioimmunotherapy (27). In our present study, the mean tumor burden was ~1 g (0.4% of mean body weight) when the pharmacokinetic studies were conducted. The results obtained by comparing tumor-bearing rats and non–tumor-bearing rats injected with 111In-1033-BR96 that showed such small tumor burdens did not affect the blood pharmacokinetics. This might be explained by the fact that the radioactivity in small tumor burdens only accounts for a few percentage of the total administered activity (the mean maximum tumor uptake in the current study was 2.31%/ID), which seems unlikely to change the biological half-life beyond the reference range. This finding is also supported in one of our studies with the same tumor-bearing rat model, demonstrating similar blood clearance when different administered amounts of 1033-BR96 was labeled with a constant activity of 111In (6).

Immunocompetent rats were used instead of immunodeficient rats because immunocompetent rats have normal immune systems (28), which correctly mimic the physiologic conditions in humans (29). This means that the pharmacokinetics and biodistribution of radioimmunoconjugates in this model well reflect the corresponding distributions in humans. We also used rats inoculated with syngeneic tumor cells (rat colon carcinoma) because the expression of the epitopes on tumor and certain normal cells recognized by mAbs is very similar to that of the animal in which the original tumor developed, and possible interference by mAbs would be the same, whereas that in immunodeficient animals would be quite different. As a consequence, the infiltration of the tumor into surrounding normal organs and metastasis at other locations are more similar to the clinical situation than in the xenograft tumor model of immunodeficient rats. These factors were taken into account in this animal model, as it will be used for providing data that could be applied in our future clinical trials. We have recently applied the same technique (extracorporeal adsorption) to patients with refractory B-cell lymphomas but using the 90Y-1033-anti-CD20 mAb (30). Based on the efficacy of clearance of activity from the blood and absence of significant adverse effects, a dose-escalation clinical study will be initiated with this radioimmunoconjugate.

In conclusion, we have shown that different mAbs labeled with the trifunctional conjugate 1033 containing a biotin and a radiometal chelation moiety and 111In exhibited similar pharmacokinetics in blood. This means that the pharmacokinetics could be predicted in advance irrespective of the IgG1-mAb chosen, as could the optimal time for starting extracorporeal adsorption. This animal model was sufficiently sensitive to distinguish between different immunoconjugates. A small tumor burden (in our case, ~0.4% of mean body weight) based on our limited study did not change the pharmacokinetic behavior of the radioimmunoconjugates, but it is probably not valid when some of the metastases are considerably larger than the others.


   Footnotes
 
Grant support: Swedish Cancer Society, Swedish Medical Society, Berta Kamprad Foundation, Gunnar Nilsson Foundation, Lund University Medical Faculty Foundation, and Lund University Hospital Fund.

Presented at the Tenth Conference on Cancer Therapy with Antibodies and Immunoconjugates, October 21-23, 2004, Princeton, New Jersey.


   References
Top
 Abstract
 Materials and Methods
 Results
 Discussion
 References
 

  1. Leyland-Jones B, Gelmon K, Ayoub J-P, et al. Pharmacokinetics, safety, and efficacy of trastuzumab administered every three weeks in combination with paclitaxel. J Clin Oncol 2003;21:3965–71.[Abstract/Free Full Text]
  2. Paganelli G, Chinol M. Radioimmunotherapy: is avidin-biotin pretargeting the preferred choice among pretargeting methods? Eur J Nucl Med Mol Imaging 2003;30:773–6.[Medline]
  3. Strand SE, Zanzonico P, Johnson TK. Pharmacokinetic modelling. Med Phys 1993;20:515–27.[CrossRef][Medline]
  4. Norrgren K, Strand SE, Nilsson R, Lindgren L, Lilliehorn P. A general extracorporeal immunoadsorpation method to increase tumor-normal tissue ratio in radioimmunoimaging and radioimmunotherapy. J Nucl Med 1993;34:448–54.[Abstract/Free Full Text]
  5. Chen J, Strand SE, Tennvall J, Lindgren L, Hindorf C, Sjögren HO. Extracorporeal immunoadsorption compared to avidin chase: enhancement of tumor-to-normal tissue ratio for biotinylated rhenium-188-chimeric BR96. J Nucl Med 1997;38:1934–9.[Abstract/Free Full Text]
  6. Garkavij M, Tennvall J, Strand SE, et al. Extracorporeal whole blood immunoadsorption enhances radioimmunotargeting of 125I-labeled BR-96-biotin monoclonal antibody in syngeneic rat tumor model. J Nucl Med 1997;38:895–901.[Abstract/Free Full Text]
  7. Tennvall J, Garkavij M, Chen J, Sjögren HO, Strand SE. Improving tumor-to-normal-tissue ratios of antibodies by extracorporeal immunoadsorption based on the avidin-biotin concept: development of a new treatment strategy applied to monoclonal antibodies murine L6 and chimeric BR96. Cancer 1997;80:2411–8.[CrossRef][Medline]
  8. Garkavij M, Tennvall J, Ohlsson T, et al. Comparison of 125I- and (111) In-labeled monoclonal antibody BR96 for tumor targeting in combination with extracorporeal immunoadsorption. Clin Cancer Res 1999;5:3059–64s.
  9. Wang ZM, Garkavij M, Tennvall J, Ohlsson T, Strand SE, Sjögren HO. Application of extracorporeal immunoadsorption to reduce circulating blood radioactivity after intraperitoneal administration of In-111-HMFG1-biotin. Cancer 2002;94:1287–92s.[CrossRef][Medline]
  10. Rossi NR, Ullen A, Sandstrom P, et al. Dosimetry of fractionated experimental radioimmunotargeting with idiotypic and anti-idiotypic anticytokeratin antibodies. Cancer 1997;80:2681–8s.[CrossRef][Medline]
  11. Wilbur DS, Chyan MK, Hamlin DK, et al. Trifunctional conjugation reagents. reagents that contain a biotin and a radiometal chelation moiety for application to extracorporeal affinity adsorption of radiolabeled antibodies. Bioconjug Chem 2002;13:1079–92.[CrossRef][Medline]
  12. Juweid M, Sharkey RM, Alavi A, et al. Regression of advanced refractory ovarian cancer treated with I-131-labeled anti-CEA monoclonal antibody. J Nucl Med 1997;38:257–60.[Abstract/Free Full Text]
  13. Sharkey RM, Goldenberg DM, Murthy S, et al. Clinical evaluation of tumor targeting with a high-affinity, anticarcinoembryonic-antigen-specific, murine monoclonal antibody, MN-14. Cancer 1993;71:2082–96.[CrossRef][Medline]
  14. Slamon DJ, Leyland-Jones B, Shak S, et al. Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2. N Engl J Med 2001;344:783–92.[Abstract/Free Full Text]
  15. Thor AD, Liu S, Edgerton S, et al. Activation (tyrosine phosphorylation) of ErbB-2 (HER-2/neu):a study of incidence and correlation with outcome in breast cancer. J Clin Oncol 2000;18:3230–9.[Abstract/Free Full Text]
  16. Cobleigh MA, Vogel CL, Tripathy D, et al. Multinational study of the efficacy and safety of humanized anti-HER2 monoclonal antibody in women who have HER2-overexpressing metastatic breast cancer that has progressed after chemotherapy for metastatic disease. J Clin Oncol 1999;17:2637–48.
  17. Green MC, Murray JL, Hortobagyi GN. Monoclonal antibody therapy for solid tumors. Cancer Treat Rev 2000;26:269–86.[CrossRef][Medline]
  18. Saleh MN, Sugarman S, Murray J, et al. Phase I trial of the anti-Lewis Y drug immunoconjugate BR96-doxorubicin in patients with Lewis Y-expressing epithelial tumors. J Clin Oncol 2000;18:2282–92.[Abstract/Free Full Text]
  19. Wang ZM, Garkavij M, Ohlsson T, Strand SE, Sjögren HO, Tennvall J. Biotinylation, pharmacokinetics and extracorporeal adsorption of humanized MAb 111In-MN14 using an avidin-affinity column in rats. Cancer Biother Radiopharm 2003;18:365–75.[CrossRef][Medline]
  20. Green NM. A spectrophotometric assay for avidin and biotin based on binding dyes by avidin. Biochem J 1965;94:23–5c.
  21. Chen J, Strand SE, Isaksson M, et al. Biodistribution and pharmacokinetics of 125I/131I pair-labeled, biotinylated chimeric BR96 in colon carcinoma isografted rats. Tumor Targeting 1996;2:204–14.
  22. Ghetie V, Ward ES, Witetta ES. Pharmacokinetics of antibodies and immunotoxins in mice and humans. In: Figg WD, Mcleod HL, editors. Handbook of anticancer pharmacokinetics and pharmacodynamics. Totowa (New Jersey): Humana Press Inc.; 2004. p. 475–98.
  23. Berinstein NL, Grillo-Lopez AJ, White CA, et al. Association of serum Rituximab (IDEC-C2B8) concentration and anti-tumor response in the treatment of recurrent low-grade or follicular non-Hodgkin's lymphoma. Ann Oncol 1998;9:995–1001.[Abstract/Free Full Text]
  24. Iacona I, Lazzarino M, Avanzini MA, et al. Rituximab (IDEC-C2B8): validation of a sensitive enzyme-linked immunoassay applied to a clinical pharmacokinetic study. Ther Drug Monit 2000;22:295–301.[CrossRef][Medline]
  25. Scheidhauer K, Wolf I, Baumgartl HJ, et al. Biodistribution and kinetics of (131)I-labelled anti-CD20 MAB IDEC-C2B8 (rituximab) in relapsed non-Hodgkin's lymphoma. Eur J Nucl Med Mol Imaging 2002;29:1276–82.[CrossRef][Medline]
  26. Lundin J, Kimby E, Björkholm M, et al. Phase II trial of subcutaneous anti-CD52 monoclonal antibody alemtuzumab (Campath-1H) as first-line treatment for patients with B-cell chronic lymphocytic leukemia (B-CLL). Blood 2002;100:768–73.[Abstract/Free Full Text]
  27. Garnett MC. Targeted drug conjugates: principle and progress. Adv Drug Deliv Rev 2001;53:171–216.[CrossRef][Medline]
  28. Eccles SA. Models for evaluation of targeted therapies of metastatic disease. In: Teicher BA, editor. Tumor models in cancer research. Totowa (New Jersey): Humana Press Inc.; 2002, pp. 293–319.
  29. Sjögren HO, Isaksson M, Willner D, Hellstrom I, Hellstrom KE, Trail PA. Antitumor activity of carcinoma-reactive BR96-doxorubicin conjugate against human carcinomas in athymic mice and rats and syngeneic rat carcinomas in immunocompetent rats. Cancer Res 1997;57:4530–6.[Abstract/Free Full Text]
  30. Linden O, Kurkus J, Garkavij M, et al. A novel platform for radioimmunotherapy. Extracorporeal depletion of 90Y-anti-CD20-biotin MAb in patients with refractory lymphoma. ASCO 40th Annual Meeting, New Orleans (Los Angeles): 2004 Abstract 6576.



This article has been cited by other articles:


Home page
 JNMHome page
L. Martensson, R. Nilsson, T. Ohlsson, H.-O. Sjogren, S.-E. Strand, and J. Tennvall
Reduced Myelotoxicity with Sustained Tumor Concentration of Radioimmunoconjugates in Rats after Extracorporeal Depletion
J. Nucl. Med., February 1, 2007; 48(2): 269 - 276.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wang, Z.
Right arrow Articles by Tennvall, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wang, Z.
Right arrow Articles by Tennvall, J.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Cancer Research Clinical Cancer Research
Cancer Epidemiology Biomarkers & Prevention Molecular Cancer Therapeutics
Molecular Cancer Research Cancer Prevention Research
Cancer Prevention Journals Portal Cancer Reviews Online
Annual Meeting Education Book Meeting Abstracts Online