Biomedical subjects

D M Goldenberg

Publications and source records attributed to D M Goldenberg.

At least 37 records · Page 2Linked to original sources

PubMed2000

Degranulating eosinophils in human endometriosis.

Degranulating eosinophils have been described in most endometrial cancers. We hypothesized that endometriosis (ectopic, nonneoplastic endometrial tissue) would be an appropriate model system for determining whether eosinophil degranulation is part of a specific immune response to endometrial cancer or if it is related to the more general phenomenon of tissue remodeling (wound healing) that is common to both disorders. To test this hypothesis, we performed immunohistochemistry and Western blotting to evaluate the presence of eosinophil peroxidase (a marker of eosinophil degranulation) in normal endometrium (n = 20) and endometriosis samples (n = 24) and to define the coexpression of three eosinophil chemoattractants: interleukin-5 (IL-5), eotaxin, and regulated on activator-normal T cell expressed and secreted (RANTES). There was focally intense deposition of eosinophil peroxidase in the fibrotic connective tissue and blood vessels of 21 of 24 human endometriosis specimens; two samples showed weak staining, and only one tissue was negative for eosinophil degranulation. None of the 10 normal proliferative endometrial specimens had evidence of eosinophil degranulation, and four of 10 secretory tissues stained only weakly for eosinophil peroxidase. The presence of degranulating eosinophils was also associated with the presence of eotaxin and IL-5 in some samples and with RANTES in others. We conclude that the abundant presence of degranulating eosinophils in the fibrous regions of endometriosis supports the interpretation that eosinophils are involved in general tissue remodeling and wound healing rather than a tissue-directed immune response.

Blotting, Western↗

PubMed2000

Regulation of tumour drug delivery by blood flow chronobiology.

The chronobiology of various physiological phenomena that impact tumour drug delivery has not been established. Since the delivery of therapeutic agents is directly influenced in part by tumour vascular volume (VV), vascular permeability (VP) and local blood flow (BF), we have performed a series of studies to assess the natural rhythms of these functions in tumour and normal tissues. Preliminary results by Hori et al. Cancer Res 1992, 52, 912-916, have demonstrated fluctuations in tumour blood flow in subcutaneous (s.c.) rat tumours with a higher rate at 15-21 h after light onset (HALO) compared with 3-9 HALO. We used the GW-39 and LS174T human colon carcinoma xenografts grown s.c. in nude mice for these studies. VV, VP and BF were determined at 3, 7, 10, 13, 17, 20 and 23 HALO. In separate studies, dosing with a small therapeutic agent ([3H]-5-fluorouracil (5-FU)) or a macromolecule ([131I]-131-MN-14-anti carcinoembryonic antigen (CEA) immunoglobulin G (IgG)) was done at 10 and 17 HALO and 3, 10 and 17 HALO, respectively, and tissue and tumour uptake was determined in each group. Well-defined peaks and nadirs were observed for all three vascular functions. The peaks for VV and VP were similar in tumour and normal tissue whereas BF rate had a unique rhythm in tumour. Using cosinor analysis of the BF rate, we have found that the acrophase (peak) for tumour BF occurs at approximately 17 HALO in both tumour xenografts, while maximal liver, lung and kidney BF occurred at 10-13 HALO. Tumour BF rate ranged from the lowest value of 1.34+/-0.54 microliter/g/min at 20 HALO to the highest value of 2.79+/-0.57 microliter/g/min at 17 HALO. Liver BF rate ranged from 4.1+/-1.1 microliter/g/min at 3 HALO to 10.22+/-1.31 microliter/g/min at 10 HALO, and was 5.83+/-1.37 microliter/g/min at 17 HALO. Thus, the rhythm of tumour and normal tissue BF are different, creating a window of opportunity when tumours can be targeted with a therapeutic agent. At 3 h postinjection, the %ID/g of 5-FU in tumour at 10 HALO was 0.14+/-0.09 and at 17 HALO was 0.32+/-0.12 (P<0.02). In liver at 10 HALO, uptake was 0.13+/-0.06 and at 17 HALO was 0. 07+/-0.03 (P<0.05). At 24 h postinjection, the %ID/g of [131I]-MN-14 IgG in tumour at 10 HALO was 11.50+/-1.58 and at 17 HALO was 1. 5-fold higher at 16.96+/-2.35 (P<0.001). In liver at 10 HALO, uptake was 6.47+/-0.49 and at 17 HALO was 30% lower at 4.48+/-0.81 (P<0.01). These results suggest that small shifts in the chronobiology of BF in tumour and in normal tissue can have a sizeable impact on the distribution of chemotherapeutics and antibody-based drugs.

Animals↗

PubMed2000

Can postoperative surveillance with serial CEA immunoscintigraphy detect resectable rectal cancer recurrence and potentially improve tumor-free survival?

BACKGROUND: This study was performed to determine if postoperative serial monitoring of rectal cancer patients can be performed with an immunoscintigraphic imaging test for carcinoembryonic antigen (CEA). It was also of interest to assess whether this test, in combination with standard monitoring procedures used in an intensive surveillance plan, can result in the identification of surgically salvageable patients. STUDY DESIGN: Forty consecutive resected Dukes' B and C rectal cancer patients underwent a prospective, single-institution, surveillance trial of physical examination (including digital rectal examination), endoscopy, CT of the abdomen and pelvis, liver ultrasound, chest x-ray, blood CEA, and CEA immunoscintigraphy with arcitumomab (CEA-Scan, Immunomedics, Morris Plains, NJ) every 6 months for the first 2 years and every 12 months for the next 3 years after initial operation. Outcomes were compared with those from a similar group of 69 patients treated previously at the same institution but without CEA imaging. RESULTS: A total of 219 CEA imaging studies were performed without any significant adverse effects or immune responses, and resulted in lesion sensitivity, specificity, accuracy, and positive and negative predictive values of 94.1%, 97.5%, 97.3%, 76.2%, and 99.5%, respectively. Of the 40 patients, 16 developed 22 surgically confirmed local or distant recurrences, and CEA imaging correctly disclosed 82% of these lesions pre-operatively. All of the patients found to have recurrences had at least one tumor site by CEA imaging; only 6 of 16 had elevated blood CEA titers. On a patient-basis, there was a sensitivity of 100%, a specificity of 79.2%, an accuracy of 87.5%, and positive and negative predictive values of 76.2% and 100%, respectively. The potential therapeutic benefit of serial arcitumomab imaging is suggested by the fact that 6 of 16 patients (37.5%) with recurrence underwent potentially curative second-look operations, compared with 6 of 69 (8.7%) of a comparable population studied at this institution during an earlier 6-year period, using all of the same tests except CEA imaging. None of the patients in this historic control group survived more than 21 months, although the mean survival of the six patients resected for cure in the study population was 35 months (range 11 to 69 months). During 6 years of followup, three of the six re-resected patients eventually died of cancer recurrence, two died from other causes (and were confirmed by necropsy to be tumor-free), and one patient is still free of disease in the sixth year. CEA scanning appeared to be more predictive of recurrence than blood CEA testing or other diagnostic modalities. CONCLUSIONS: Arcitumomab inclusion in intensive surveillance of patients with resected rectal cancer can disclose tumor recurrence at a stage that allowed surgical salvage therapy in 37.5% of the 16 patients with recurrence who had second-look surgery, and in 19% the patients were free of disease during longterm followup. This pilot study suggests that a randomized prospective trial comparing standard surveillance procedures to the use of CEA imaging added thereto should be undertaken.

Adenocarcinoma↗

PubMed2000

Progressive intermediate-grade non-Hodgkin's lymphoma after high-dose therapy and autologous peripheral stem-cell transplantation: changing the natural history with monoclonal antibody therapy.

The prognosis of patients with progressive intermediate-grade non-Hodgkin's lymphoma (NHL) after high-dose chemotherapy and autologous peripheral stem-cell transplantation (PSCT) is poor, with survival measured in months. The advent of monoclonal antibody therapy for NHL has created new options for effective therapy with relatively mild side effects. We report on two patients with progressive intermediate-grade NHL after PSCT who were treated with monoclonal antibody therapy. Both patients initially received rituximab (unlabeled anti-CD20 monoclonal antibody) and were subsequently treated with (90)Y-epratuzumab (yttrium-90-labeled humanized anti-CD22 monoclonal antibody) at relapse. One patient received (90)Y-epratuzumab alone while the other was treated with higher doses in combination with autologous peripheral stem-cell infusion. Both patients achieved a rapid response to the radiolabeled antibody with minimal toxicity. Monoclonal antibody therapy may be an effective and tolerable treatment for progressive NHL after PSCT.

Antibodies, Monoclonal↗

PubMed2000

Initial experience with high-dose radioimmunotherapy of metastatic medullary thyroid cancer using 131I-MN-14 F(ab)2 anti-carcinoembryonic antigen MAb and AHSCR.

UNLABELLED: This phase I study was initiated to determine the toxicity and therapeutic potential of high-dose 131I-MN-14 F(ab)2 anti-carcinoembryonic antigen monoclonal antibody (MAb) combined with autologous hematopoietic stem cell rescue (AHSCR) in patients with rapidly progressing metastatic medullary thyroid cancer. METHODS: Twelve patients were entered into the study. Dose escalation was based on prescribed radiation doses to critical organs (i.e., kidney, lung, and liver). Starting doses were 900 cGy to the kidney and no more than 1200 cGy to the lung and liver, with dose increments of 300 cGy until the maximum tolerable dose is determined. Tumor targeting was assessed by external scintigraphy, toxicity was assessed according to the common toxicity criteria of the National Cancer Institute, and therapy responses were assessed by CT, serum carcinoembryonic antigen, and calcitonin. RESULTS: One patient received 9.95 GBq 131I-MN-14 F(ab)2, for an initial dose of 656 cGy to critical organs, 8 received 900 cGy (8.69-17.98 GBq), and 3 received 1200 cGy (15.17-17.69 GBq). The MAb scans of all patients showed positive findings. Autologous hematopoietic stem cells were given to all patients 1-2 wk after therapy, when the total body radiation exposure was less than 5.2 x 10(-7) C/kg/h. Dose-limiting toxicity, defined as grade 3 or 4 nonhematologic toxicity, was not seen in the patient who received the 656-cGy dose, and only 1 of the 8 patients treated at the 900-cGy dose level had grade 3 toxicity, which was gastrointestinal and reversible. No dose-limiting toxicity was seen in the 3 patients treated at the 1200-cGy dose level. Except for the instance of grade 3 gastrointestinal toxicity, nonhematologic toxicity was relatively mild, with only grade 1 or 2 toxicity observed in 9 patients. No renal toxicity was seen. Of the 12 patients, 1 had partial remission for 1 y, another had a minor response for 3 mo, and 10 had stabilization of disease lasting between 1 and 16 months. CONCLUSION: The results show the safety of administering high myeloablative doses of 131I-MN-14 F(ab)2 with AHSCR in patients with metastatic medullary thyroid cancer. The antitumor responses in patients with aggressive, rapidly progressing disease are encouraging and warrant further research to optimize the effectiveness of this new treatment.

Adult↗

PubMed2000

Safety and efficacy of arcitumomab imaging in colorectal cancer after repeated administration.

UNLABELLED: In pivotal phase III clinical trials for detecting recurrent or metastatic colorectal cancer, most patients received a single arcitumomab injection. However, the early detection of postsurgical recurrence or metastases with arcitumomab will necessitate serial studies for surveillance. We present immunogenicity, safety, and imaging data supporting the use of multiple administrations of arcitumomab. METHODS: Human antimouse antibody (HAMA) response, adverse events, clinical laboratory values, and diagnostic imaging results were evaluated in 44 patients (24 men, 20 women; age range, 2878 y) after repeated arcitumomab administration (44 second and 3 third injections). Most patients initially had Dukes' class B or C colorectal cancer and had known or occult disease recurrence and elevated serum carcinoembryonic antigen levels at the time of the repeated injection. RESULTS: At the repeated injection, in no patient did elevated HAMA titers develop, hematology and serum chemistry changes were clinically insignificant, and only 1 adverse event (eosinophilia) was judged at least possibly related to arcitumomab. Arcitumomab imaging results at the second injection were comparable with those obtained in phase III trials after a single injection of arcitumomab, having a 78% per-lesion concordance with CT in the abdomen and pelvis and a 73% sensitivity and 94% specificity based on 9 patients with cancer confirmed surgically at 11 anatomic sites and excluded at 16 sites. CONCLUSION: These data indicate that at least 2 injections of arcitumomab can be given safely to patients with colorectal cancer, without increased immunogenicity and with imaging efficacy equivalent to the first administration.

Adenocarcinoma↗

PubMed2000

Radionuclides linked to a CD74 antibody as therapeutic agents for B-cell lymphoma: comparison of Auger electron emitters with beta-particle emitters.

UNLABELLED: We demonstrated previously that human B-cell lymphomas were effectively and specifically killed in vitro by an antibody to CD74 (LL1) linked to (111)In or other Auger electron emitters. This study was intended to more accurately compare the potency and specificity of 3Auger electron emitters, (111)In, 67Ga, and 125I, and to evaluate beta-particle emitters, 131I and 90Y. The unique property of LL1 is its high level of intracellular uptake. METHODS: Raji B-lymphoma cells were incubated with serial dilutions of the radiolabeled Abs for 2 d and then monitored for cell growth by 2 assays: a cell counting assay and a clonogenic assay. The uptake of radioactivity per cell was monitored at various time points, and the radiation dose was calculated using published S values for radioactivity located in the cytoplasm. Both specific and nonspecific toxicity were evaluated. RESULTS: The beta-particle emitters had considerably higher levels of nonspecific toxicity than the Auger electron emitters, but both 131I and 90Y, and particularly 131I, still had high levels of specificity. Both of these results were consistent with dosimetry calculations. Relative to the delivered disintegrations per cell, 131I and 67Ga were the most potent of the radionuclides tested, with 125I and (111)In being significantly weaker and 90Y being intermediate. The high potency of 67Ga, together with its low nonspecific toxicity, caused this radionuclide to have the highest specificity index. CONCLUSION: When delivered by Ab LL1, both Auger electron and beta-particle emitters can produce specific and effective toxicity. The choice of the optimal radionuclide for therapy may depend on the ease and efficiency of labeling, the specific activity obtained, the nature of the tumor being targeted, and other factors, but the high specificity indices of the Auger electron emitters may be an advantage.

Antibodies↗

PubMed2000

Cure of metastatic human colonic cancer in mice with radiolabeled monoclonal antibody fragments.

There is currently no method to cure patients with disseminated colorectal cancer, which is the third leading cancer killer in the Western World. This report shows that the GW-39 intrapulmonary micrometastatic human colonic cancer model in nude mice can be cured with radiolabeled antibodies against carcinoembryonic antigen, and that this approach of radioimmunotherapy is superior to conventional chemotherapy with 5-fluorouracil and leucovorin (5-FU/LV). Monovalent Fab fragments labeled with 131I are superior to intact IgG when survival was evaluated 3, 7, and 14 days after implantation, leading to cures in up to 90% of the mice. Histological results provide support for the differences in therapeutic efficacy observed. Microautoradiography was used to evaluate the intratumoral distribution of each form of antibody. The enhanced tumor control by Fab compared with IgG could be explained in part by the homogeneity of radioantibody distribution of Fab. Biodistribution analysis and initial dose rate calculations for all three forms of antibody also help explain the ability of 131I-labeled Fab to provide better tumor growth control than seen with 131I-labeled IgG. Thus, radioimmunotherapy may be a new modality to treat metastatic disease, particularly when using small antibody fragments.

Animals↗

PubMed1999

Cytotoxicity with Auger electron-emitting radionuclides delivered by antibodies.

We investigated the in vitro cytotoxic potential of Auger electron-emitting radionuclides delivered to the cytoplasm or, more specifically, to lysosomes, via antibodies. The antibody (Ab) used was LL1, which is specific for CD74, an epitope of the major histocompatibility complex (MHC) class II antigen invariant chain, Ii, present on the cell surface. It is taken up in large amounts, approximately 10(7) Ab molecules per cell per day, and delivered to lysosomes. The radioisotopes tested included (111)In, 99mTc and 125I. With sufficient specific activity, approximately 10 mCi/mg Ab, all of these isotopes were potent cytotoxic agents. 125I was active only if a "residualizing" form was used, meaning a form that is trapped within cells after catabolism of the Ab to which it was conjugated (conventional oxidative iodination produces a non-residualizing label). The conjugates of (111)In and 99mTc used are known to be residualizing. One hundred percent cell kill in vitro was obtained with (111)In and 125I, under conditions in which a non-reactive control Ab, conjugated in the same way, produced no significant toxicity. 99mTc was also potent and specific, but appeared somewhat less active than the other isotopes under the conditions evaluated. Although few Abs are accreted by cells at the same rate as LL1, it may be possible to use other Abs to deliver similar amounts of radioactivity, if Abs with higher specific activity can be produced. Such conjugated radioisotopes may be useful for attacking tumor cells in vivo, particularly for single cells or micrometastases.

Antibodies↗

PubMed1999

High-linear energy transfer (LET) alpha versus low-LET beta emitters in radioimmunotherapy of solid tumors: therapeutic efficacy and dose-limiting toxicity of 213Bi- versus 90Y-labeled CO17-1A Fab' fragments in a human colonic cancer model.

Recent studies suggest that radioimmunotherapy (RIT) with high-linear energy transfer (LET) radiation may have therapeutic advantages over conventional low-LET (e.g., beta-) emissions. Furthermore, fragments may be more effective in controlling tumor growth than complete IgG. However, to the best of our knowledge, no investigators have attempted a direct comparison of the therapeutic efficacy and toxicity of a systemic targeted therapeutic strategy, using high-LET alpha versus low-LET beta emitters in vivo. The aim of this study was, therefore, to assess the toxicity and antitumor efficacy of RIT with the alpha emitter 213Bi/213Po, as compared to the beta emitter 90Y, linked to a monovalent Fab' fragment in a human colonic cancer xenograft model in nude mice. Biodistribution studies of 213Bi- or 88Y-labeled benzyl-diethylene-triamine-pentaacetate-conjugated Fab' fragments of the murine monoclonal antibody CO17-1A were performed in nude mice bearing s.c. human colon cancer xenografts. 213Bi was readily obtained from an "in-house" 225Ac/213Bi generator. It decays by beta- and 440-keV gamma emission, with a t(1/2) of 45.6 min, as compared to the ultra-short-lived alpha emitter, 213Po (t(1/2) = 4.2 micros). For therapy, the mice were injected either with 213Bi- or 90Y-labeled CO17-1A Fab', whereas control groups were left untreated or were given a radiolabeled irrelevant control antibody. The maximum tolerated dose (MTD) of each agent was determined. The mice were treated with or without inhibition of the renal accretion of antibody fragments by D-lysine (T. M. Behr et al., Cancer Res., 55: 3825-3834, 1995), bone marrow transplantation, or combinations thereof. Myelotoxicity and potential second-organ toxicities, as well as tumor growth, were monitored at weekly intervals. Additionally, the therapeutic efficacy of both 213Bi- and 90Y-labeled CO17-1A Fab' was compared in a GW-39 model metastatic to the liver of nude mice. In accordance with kidney uptake values of as high as > or = 80% of the injected dose per gram, the kidney was the first dose-limiting organ using both 90Y- and 213Bi-labeled Fab' fragments. Application of D-lysine decreased the renal dose by >3-fold. Accordingly, myelotoxicity became dose limiting with both conjugates. By using lysine protection, the MTD of 90Y-Fab' was 250 microCi and the MTD of 213Bi-Fab' was 700 microCi, corresponding to blood doses of 5-8 Gy. Additional bone marrow transplantation allowed for an increase of the MTD of 90Y-Fab' to 400 microCi and for 213Bi-Fab' to 1100 microCi, respectively. At these very dose levels, no biochemical or histological evidence of renal damage was observed (kidney doses of <35 Gy). At equitoxic dosing, 213Bi-labeled Fab' fragments were significantly more effective than the respective 90Y-labeled conjugates. In the metastatic model, all untreated controls died from rapidly progressing hepatic metastases at 6-8 weeks after tumor inoculation, whereas a histologically confirmed cure was observed in 95% of those animals treated with 700 microCi of 213Bi-Fab' 10 days after model induction, which is in contrast to an only 20% cure rate in mice treated with 250 microCi of 90Y-Fab'. These data show that RIT with alpha emitters may be therapeutically more effective than conventional beta emitters. Surprisingly, maximum tolerated blood doses were, at 5-8 Gy, very similar between high-LET alpha and low-LET beta emitters. Due to its short physical half-life, 213Bi appears to be especially suitable for use in conjunction with fast-clearing fragments.

Animals↗

PubMed1999

Phase I/II trial of (131)I-MN-14F(ab)2 anti-carcinoembryonic antigen monoclonal antibody in the treatment of patients with metastatic medullary thyroid carcinoma.

BACKGROUND: Monoclonal antibodies (MAbs) against carcinoembryonic antigen (CEA) have been recognized as targeting agents for medullary thyroid carcinoma (MTC). This Phase I/II study was initiated to determine the safety, maximum tolerated dose (MTD), and therapeutic potential of (131)I-MN-14 F(ab)2 anti-CEA MAb for patients with metastatic MTC. METHODS: Fifteen patients were enrolled in this study. Dose escalation was based on estimates of radiation dose to the bone marrow, and the radioactive dose given was determined by a pretherapy diagnostic study in which 8 mCi (0.6-20 mg) of (131)I-MN-14 F(ab)2 was administered 1 week prior to therapy. RESULTS: Three patients received an initial dose of 140 centigray (cGy) to bone marrow, 11 received 180 cGy, and 1 received 220 cGy. Myelosuppression was the only significant treatment-related dose-limiting toxicity (DLT), and the MTD appeared to be 180 cGy to the bone marrow. Human antimouse antibodies (HAMA) developed in 8 patients 2-6 weeks after therapy. Seven patients had a median of 55% reduction of tumor markers. One patient showed a dramatic improvement in the mass effect on the airways caused by 3 tumor lesions in the neck, with a 45% reduction of overall tumor burden. The disease has continued to be radiologically stable in 11 of 12 assessable patients for periods ranging from 3+ to 26+ months. CONCLUSIONS: Therapy with (131)I-MN-14 F(ab)2 is well tolerated and shows evidence of biochemical and radiologic antitumor activity. HAMA development suggests that humanized MAbs will be required in trials with repeated dose schedules. Further dose escalation, alone or in combination with other therapy modalities, is indicated for future trials, preferably with humanized anti-CEA MAbs.

Adult↗

PubMed1999

Breast cancer imaging with radiolabeled antibodies.

Over the past 2 decades, numerous anticancer antibodies against different molecular targets and labeled with different gamma-emitting radionuclides have been studied in human tumor xenografts and in clinical trials. In breast cancer, these molecular targets have included principally tumor-associated antigens, such as carcinoembryonic antigen (CEA) and the polymorphic epithelial mucin antigen, MUC1, and more recently the growth factor receptors, EGF-R and HER-2/neu. No antibody-based agent has yet been approved for clinical use in the diagnosis of mammary carcinoma, because few trials have addressed the issue of clinical use of these imaging agents in the management of breast cancer patients. Recently, the CEA antibody Fab' fragment approved for colorectal cancer detection, Arcitumomab (CEA-Scan, [Immunomedics, Morris Plains, NJ]), has been found to image both palpable and nonpalpable breast lesions that were suspicious on screening mammograms. Results to date indicate that Arcitumomab can complement mammography by providing a high specificity and positive predictive value, thus indicating when a patient with an abnormal mammogram may proceed directly to definitive surgery without an intermediate diagnostic biopsy. Breast cancer immunoscintigraphy holds promise for advancing toward immunoPET, which should combine the specificity of antibodies with the high sensitivity and resolution of PET. It is also the foundation of breast cancer radioimmunotherapy with humanized antibodies against CEA and MUC1, as well as other immunotherapy strategies.

Antibodies, Monoclonal↗

PubMed1999

Chronotolerance of experimental radioimmunotherapy: clearance, toxicity, and maximal tolerated dose of 131I-anti-carcinoembryonic antigen (CEA) IgG as a function of time of day of dosing in a murine model.

The temporal variation in bone marrow proliferation has been used to help define the optimal time of day to dose with approximately 30 chemotherapeutic agents, so that treatment efficacy is maximised and toxicity is minimised. Since myelosuppression is also the dose-limiting toxicity for most forms of radioimmunotherapy, we hypothesised that time of day of administration might also influence tolerance for radioantibody therapy. Bone marrow proliferative activity in BALB/c mice was determined using cell cycle analysis of propidium iodide-stained bone marrow samples collected at 3 h intervals. Myelosuppression was determined at weekly intervals after a therapeutic dose of 131I-NP-4 anti-CEA (carcinoembryonic antigen) intact IgG at either 0900 h (2 h after light onset [HALO]), 1300 h (6 HALO) or 1600 h (9 HALO). The highest bone marrow proliferative activity was noted between 20 HALO (0300 h) and 4 HALO (1100 h), and the lowest activity could be measured at 10-13 HALO (1700-2000 h). Seven days after a maximal tolerated dose (MTD) of radioantibody, granulocyte reduction was 50% at both 2 and 6 HALO and only 32% at 9 HALO (P < 0.003). Fourteen days after radioantibody therapy, an 87% granulocyte suppression was observed in mice treated at 2 HALO and only a 64% granulocyte loss was noted in the 9 HALO treated group (P < 0.001). The 2 HALO group recovered earlier than the 9 HALO group (P < 0.013; 22% loss from the 2 HALO dose and 40% loss from the 9 HALO dose) on day 28 post-radioimmunotherapy. The difference in magnitude of neutropenia, rather than duration, was critical for establishing the MTD. A 30% increase in the MTD was possible if mice were dosed at 9 HALO (320 microCi) versus 2 HALO (240 microCi). These studies suggest that principles of chronobiology may govern the magnitude of toxicity and the highest dose tolerated in radioantibody therapy in the same way that it does for cytotoxic drug therapy.

Animals↗

PubMed1999

Cell surface expression and metabolism of major histocompatibility complex class II invariant chain (CD74) by diverse cell lines.

We previously described the processing of antibodies to CD74 (the major histocompatibility complex class II-associated invariant chain, Ii), by B-cell lymphoma cell lines. These cells expressed relatively low levels of Ii on the surface, but the molecules were rapidly internalized and replaced by new molecules, so that approximately 8 x 10(6) antibody molecules per cell were taken up per day. We herein report the results of similar studies with other cell types, namely a melanoma, a colon carcinoma, a T-cell lymphoma and B-lymphoblastoid cell lines. The melanoma and the carcinoma were treated with interferon-gamma to induce high levels of the antigen. The T-cell lymphoma, HUT 78, was selected specifically because it was previously reported to lack cell surface Ii, while expressing the molecule intracellularly. However, HUT 78 displayed Ii on the cell surface, as did the other cell lines tested, and catabolism of the antibody was very fast on all of the cell lines. The capacity of four of the cell lines for cumulative antibody uptake was evaluated, using 'residualizing' radiolabels, which are trapped within the cell after catabolism of the antibody to which they were conjugated. A high level of uptake was observed in all cases, although there was significant variation between the cell lines. With melanoma SK-MEL-37, the total LL1 uptake in 24 hr was nearly 10(7) molecules per cell and the average turnover time for Ii on the cell surface was 4 min; with carcinoma HT-29, the total LL1 uptake in 24 hr was approximately 10(6) molecules per cell, and the average turnover time for Ii on the cell surface was 27 min. Based on the cell content of mature class II antigens (alphabeta), these data suggest that a large fraction, or all, of immature class II molecules (alphabetaIi) reach the cell surface before entering the peptide-loading compartment, independent of the particular cell type.

Antigen-Antibody Reactions↗

PubMed1999

Carcinoembryonic antigen as a target for radioimmunotherapy of human medullary thyroid carcinoma: antibody processing, targeting, and experimental therapy with 131I and 90Y labeled MAbs.

The poor prognosis of patients with advanced medullary thyroid carcinoma (MTC) has prompted a search for new treatment modalities. In this report we explore the characteristics of carcinoembyronic antigen (CEA) as a target for radioimmunotherapy (RAIT) of MTC, with respect to antibody processing, targeting, and experimental therapy. In vitro studies showed a high level of CEA expression on the cell surface of the MTC cell line TT. MAbs bound to the cell were predominantly retained for several days, although there was also a significant level of internalization and catabolism. Immunohistology of frozen sections of tumor xenografts demonstrated that approximately half of the cells were darkly stained, however, some cells expressed little or no CEA. In biodistribution studies in nude mice bearing TT tumors, the mean percent injected dose per gram of tumor observed at three days post injection (time of maximum uptake) of 125I-MN-14 was 19.7%. When the MAb was labeled with 88Y, a residualizing label, a much higher accretion, 50.5%, was observed at the time of maximum uptake (7 days). Significant anti-tumor effects were seen at the maximum tolerated doses of 131I- and 90Y-MN-14, compared with relatively rapid tumor growth in untreated animals or those treated with the same dose of control MAbs. Importantly, it was observed that 90Y-MN-14 yielded significantly improved therapeutic efficacy in comparison to 131I-MN-14, which may have important implications for design and conduct of future clinical trials for the treatment of MTC.

Animals↗

PubMed1999

Co-secretion of two distinct kappa light chains by the mu-9 hybridoma.

Mu-9 is a monoclonal antibody (MAb) specific for the CSAp antigen (Ag) expressed by colorectal cancers. By using variable (V)-region-specific primers, the respective VH and VL sequences of Mu-9 were polymerase chain reaction (PCR)-amplified. However, chimeric Ab (cMu-9-1) constructed from these PCR-amplified V sequences failed to bind the CSAp Ag. Although the light chain of murine Mu-9 was not glycosylated, that of cMu-9-1 was found to be O-glycosylated, as confirmed by reducing SDS-PAGE analyses, glycoprotein blotting and O-linked specific deglycosylation studies. Removal of O-linked oligosaccharides either by enzymatic digestion or by blocking O-glycosylation with a specific inhibitor did not restore the immunoreactivity of cMu-9-1, indicating that light chain O-glycosylation was not the cause for lack of immunoreactivity. We reported earlier that screening of a Mu-9 cDNA library uncovered the presence of an additional light chain sequence that was later proven to be the authentic light chain of Mu-9. Analyses of the cDNA sequence encoding the nonimmunoreactive light chain, however, revealed no defects that would preclude the sequence from being translated and secreted by the murine hybridoma. By adapting the Mu-9 hybridoma culture to serum-free conditions, we confirmed the secretion of low levels of O-glycosylated light chain. The biological significance of the O-glycosylation as well as the cosecretion of both light chains with respect to allelic exclusion are discussed.

Amino Acid Sequence↗

PubMed1999

In vivo stability and metabolism of 99Tcm-labelled anti-CD4 monoclonal antibodies and Fab' fragments.

In a comparative study, the in vivo metabolic profile of 99Tcm-anti-CD4 monoclonal antibodies (MAb) and Fab' fragments (direct thiol-reduction method) was investigated in rats with adjuvant arthritis. Plasma samples were obtained 1, 4 and 15 h following intravenous injection and urine was collected over 15 h. The composition of the radiolabelled molecules was analysed by gel filtration chromatography. The profile of the complete MAb was as follows. (1) Serum: a predominant peak of 150 kDa (complete MAb; approximately 80%); three minor peaks of 125, 100 and 50 kDa (presumably H2L1, H2 and H1 chains; 14%); and two small peaks of approximately 1500 and 300 Da (presumably 99Tcm-glutathione and Cys-99Tcm-Cys; 5%). (2) Urine: minor peaks of 125, 100 and 50 kDa (15%), major peaks of 1500 and 300 Da (50%), and an additional 25-kDa peak (30%). The profile of the Fab' was as follows. (1) Serum: three minor peaks of 150 kDa [conceivably F(ab')2 plus soluble-CD4], 110 kDa [F(ab')2] and 95 kDa (Fab' plus soluble-CD4; together 30%); a predominant peak of 55 kDa (Fab'; 61%); and two minor peaks of 1500 and 300 Da (8%). (2) Urine: predominantly a 55 kDa (16%) and 1500 and 300 Da peaks (74%). Also, the anti-CD4 Fab' showed higher urine excretion and lower plasma levels than the complete anti-CD4 MAb, but still more favourable tissue-to-blood ratios following scintigraphy of the arthritic joints. Thus, the complex metabolic profile of the anti-CD4 Fab' does not appear to interfere with specific targeting of the inflamed synovial membrane.

Animals↗

PubMed1999

Rapid diagnostic imaging of acute, nonclassic appendicitis by leukoscintigraphy with sulesomab, a technetium 99m-labeled antigranulocyte antibody Fab' fragment. LeukoScan Appendicitis Clinical Trial Group.

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of a technetium 99m-labeled antigranulocyte antibody Fab' fragment (sulesomab) as a diagnostic imaging agent in patients with suspected acute, nonclassic appendicitis. METHODS: This prospective multicenter trial involved 141 children and adults with suspected acute, nonclassic appendicitis. The investigators interpreted planar images acquired 15 to 30 minutes and 1, 2, and 4 hours after injection and also by single-photon emission computed tomography (SPECT). The imaging results were confirmed surgically, whereas nonsurgical patients were considered as not having appendicitis (intent to treat). RESULTS: Sulesomab had a sensitivity of 91% (29/32 patients) and a negative predictive rate of 97% for acute appendicitis. It detected additional abnormalities in 7 of 9 patients with other inflammatory abdominal disease and had a specificity of 92% (91/99 patients) and a positive predictive value of 80% for surgically confirmed right-lower-quadrant disease. In positive studies, 26% were identified by planar imaging at 15 to 30 minutes, 46% by 1 hour, 63% by 2 hours, and 71% by 4 hours; 29% required SPECT to detect the abnormality. Scanning time was 5 to 10 minutes per planar image and about 45 minutes for a SPECT study. Investigators found that sulesomab would have changed clinical management or reduced additional diagnostic studies in 64% of the patients. Adverse events were infrequent, minor, and self-limiting (9/141 patients, 6%). No human antimurine antibody response occurred in 48 evaluable patients. CONCLUSIONS: Sulesomab is safe, well-tolerated, and with no apparent immunogenicity. Focal inflammation or infection in the setting of suspected atypical appendicitis is rapidly and accurately detected. Management decisions incorporating sulesomab imaging potentially provide clear patient benefits, especially by correctly predicting surgery to be unnecessary in 97% of patients without acute appendicitis.

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