CA1339340C - Method for tumor detection and treatment - Google Patents

Abstract

The invention relates to a method of detecting an Fc receptor-expressing tumor site in an individual by administering to the individual a diagnostically effective amount of detectably-labeled non-specific immunoglobulin or Fc or Fc' fragment thereof, wherein the immunoprotein substantially accumulates at the site when the site bears such a tumor. By using a therapeutically-labeled specific or non-specific immunoglobulin or Fc or Fc' fragment thereof, the tumor may be treated therapeutically.

Description

TITLE OF T~E lN Vh~ llON

~OD FOR T~HOR DETECTION AND TR~M~T

BACRGROUND OF THE lN V~ llON

Field of the Invention This invention is directed to a method of diagnosing a tumor site in an individual by a non-invasive technique, and treating such tumor by a similar non-invasive technique.

DescriPtion of the Bach~L~-~ Art Currently available non-invasive diagnostic methods of tumor localization include isotope scans (e.g. liver scan, gallium scan), radiology (e.g. plain X-ray, barium meal, computerized tomography), and ultrasonography.
Such methods vary in their sensitivity, depending upon the size, site, and histological type of cancer, but all of them are nonspecific. Zalcberg, J.R., Am. J. Clin.
Oncol. 8:481-9 (1985).
Antibodies have long been recognized as potential target-specific imaging agents. Pressman et al. tJ.
Immunol. 59:141-6 (1948)) were the first to demonstrate conclusively the localization of radiolabeled antibodies ~.' in specific target organs in vivo. Since then, antibodies have been used for detection and visualiza-tion of various malignant tissues in experimental animals. (For a review, see Zalcberg, supra, and Carrasquillo, J.A., et al., Cancer Treatment Reports 68:317-28 (1984).) Early studies used the immunoglobulin fractions of tumor-specific antisera for detection of tumors, or non-specific markers such as anti-fibrinogen, usually detectably labeled with radioactive 131I. More recent-ly, antibodies to oncofetal proteins, also labeled with 131I, were used as immunologic tumor imaging agents;
however, the amount of radiolabeled antibody localized in the tumor was low compared with that localized in the blood and other organs, particularly the liver, thus limiting the clinical utility of such methods.
Advances in the production of tumor-specific or tumor-associated antibodies led to the advent of mono-clonal antibody technology to provide a source of large quantities of a specific antibody directed against a single epitope. Kohler, G., et al., Nature 256:495-7 (1975); Mach, J.R., et al., Immunol. Today 2:239-49 (1981).
Improvements in radiolabeling now permit the forma-tion of stable, pharmacologically inert complexes of antibody with isotopes such as t~chn i tium-99m or indium-111. These radiolabels, which have desirably short half-lives, allow high quality images to be recorded by scintigraphy with low radiation burden to the patient.
Khaw, B.A., et al., J. Nucl. Med. 25:592-603 (1984).
Radiolabels have generally been attached to antibody proteins by two general techniques: oxidation methods, and coupling with cross-linkers. Oxidation y ~'~

methods include chloramine-T, lactoperoxidase, and chloramide iodogen (see, for example: Zalutzsky, M., et al., Int. J. Nucl. Med. Biol. 12:227-33 (1985);
Sternthal, E., et al., New Engl. J. Med. 303:1083-8 (1980); and Marchalonis, J.J., et al., Biochem. J.
113:299-20S (1969)). Coupling of radiolabels to antibody proteins using cross-linkers such as diethylenetriaminepentacetic acid cyclic anhydride in the presence of SnC12 and citrate in the presence of SnC12 are the current methods of choice. (See, for example, Krejcarek, G.E., et al., Biochem. Biophys. Res.
Commun. 77:581-5 (1977); Khaw, B.A., et al., Science 2-09:205-7 (1980); Khaw, B.A., et al., J. Nucl. Med.
23:1011-19 (1982); Wong, D.W., U.S. Pat. No. 4,636,380;
and Gansow, O.A., et al., U.S. Pat. No. 4,472,509.) Generally such labeling procedures produce a labeled immunoprotein which retains its physicobiological pro-perties, is pharmacologically inert, and is suitable for imaging tumors.
Wong, U.S. patent supra, has disclosed the use of indium-111-labeled, tumor-specific autologous polyclonal antibodies for tumor imaging by scintigraphy. 111In-labeled human fibrinogen was also disclosed by this patent for neoplasm imaging.
Detectably labeled monoclonal antibodies directed to specific tumor antigens have achieved prominence in imaging specific tumors in vivo by scintigraphy (see, for example, Carrasquillo, supra; Khaw, supra; Zalcberg, supra; Nelp, W.B., et al., J. Nucl. Med. 28:34-41 (1987); Hayes, D.F., et al., Cancer Res. 46:3157-63 (1986); Murray, J.L., et al., J. Nucl. Med. 28:28-33 (1987); Larson, S.M., J. Nucl. Med. 26:538-45 (1985);
Hwang, K.M., et al., J. Natl. Canc. Inst. 76:849-55 _4- 1 339 3~ o (1986); Goldenberg, M.D., U.S. Pat. No. 4,624,846; and Wong, D.W., U.S. Pat., supra).
Anti-tumor monoclonal antibodies (TMoAb) are directed against antigenic determinants that are selec-tively expressed on the surfaces of tumor cells. How-ever, before such monoclonal antibodies can be used for imaging purposes, two essential criteria must be ful-filled. Hwang, supra. The first criterion is the target antigen specificity of the individual tumor monoclonal antibody. This is established by preliminary experiments on both tissue sections and cultured cells using a variety of techniques to establish both surface and intracellular antigen expression. A second criterion, which also requires examination in a systematic manner, is the pharmacokinetics of the puta-tive TMoAb; this involves a comparison of the uptake by tumor relative to that by normal tissue, determination of the extent of degradation of the antibody to inert species by the host's enzymes, and excretion of the antibody or fragments thereof by the kidney.
The preparation of a specific TMoAb that meets all necessary criteria for tumor imaging is a difficult, laborious and expensive process. Larson, supra. The overall procedure entails: (1) isolation and identification of the specific tumor antigen; (2) immunizing a mouse against this antigen; (3) preparing spleen cells from such an immunized mouse and fusing these cells with an immortal human cell line (e.g.
myeloma cells); (4) establishing hybridoma colonies; (5) identifying hybridomas that secrete the antibody of interect, particularly those that produce large quantities; (6) cloning the hybridomas of interest; (7) isolating and purifying all of the different monoclonal ~, antibodies; and (8) determining whether single or multiple TMoAb's are required for tumor imaging, as each monoclonal antibody is directed to a specific epitope on the tumor antigen.
Another complication in the use of TMoAb arises from its frequently inadequate concentration at tumor sites, and from its tendency to form immune complexes that are poorly excreted by the kidney. This, in turn, has created a need to use fragments derived from the monoclonal antibody for tumor imaging. It has been reported that antibody fragments such as F(ab')2 or Fab, perhaps because of their relatively small size, diffuse m;ore easily into tumors and are excreted more rapidly by the kidney. Thus, the tumor to blood ratio might be increased as a result of these two concurrent events.
Zalcberg, supra at 484; Mach et al., supra; Larson et al., supra; Khaw et al., supra; Carrasquillo et al., supra. The F(ab')2 and Fab fragments of the immuno-globulin IgG represent the specific, variable N-terminal heavy and light chain domains of the immunoglobulin.
These fragments must be prepared from the parent protein by proteolysis with specific proteinases, followed by isolation and rigorous purification.
Immunoglobulin molecules can bind to the surfaces of tumor cells by two mechAni~ms. The first requires the presence of a specific antigenic determinant on the cell surface, which interacts with an immunological site found in the variable region of the antibody. This region contains the tumor-specific F(ab)2 and Fab frag-ments previously used in tumor imaging (see supra). The second mechAnism requires a cell-surface receptor that binds to a non-specific constant (Fc) region of homolo-gous and heterologous immunoglobulins. Such receptors ' ~'~

are termed the Fc receptors. Various cells of the reticuloendothelial and lymphatic tissues (monocytes, macrophages, T and B lymphocytes), as well as malignan-cies from these cells (such as lymphoma, sarcomas, and leukemias), as well as certain types of breast and lung cancer, possess Fc receptors on their surfaces. The amino acid sequence of the heavy chain C-terminal domain of the immunoglobulin (FC) fragment remains relatively stable, regardless of the antigenic stimulus.
Thus, there is a distinct difference between the preparation of an antibody that is capable of reacting specifically via its Fab region with a particular tumor-specific epitope, and a non-specific immunoglobulin that interacts with the Fc receptor on cells at the tumor site. A tumor imaging approach that can employ the latter mP~h~n;sm would be highly desirable because of its simplicity and inexpensive nature.

SUMMARY OF THE lNvhNllON

The present invention relates to a substantially non-invasive method of diagnosing sites of certain tumors in patients and of treating such tumors.
The present inventors have discovered that, when an intact human immunoglobulin is allowed to contact both a normal and a tumor site expressing Fc receptors in an individual, the intact immunoglobulin tends to accumu-late at the tumor site.
Further, it was surprisingly discovered that the accumulation of immunoglobulin at the site of the Fc receptor-bearing tumor is not dependent upon the epitopic specificity of the immunoglobulins, and that non-specific immunoglobulins and the Fc, but not .

F(ab' )2~ portions of the immunoglobulin will accumulate at the site of the tumor.
This effect, the concentration of polyclonal immunoglobulin and the Fc fragment derived therefrom at tumor sites expressing Fc receptors, but no concentration of the F(ab' )2 fragment derived therefrom, and the use of this property in non-invasive diagnostic imaging and therapeutic treatment of such tumors, has not been previ-ously recognized. In other words, non-specific immuno-globulins or mixtures thereof, or non-specific Fc or Fc' fragments derived therefrom, can be used for imaging of Fc receptor-expressing tumors.
The present invention thus relates to an in vivo method of detecting an Fc receptor-expressing tumor site in an individual, this method comprising administering to the individual a detectably labeled non-specific immunoglobulin or an Fc or Fc' fragment thereof; allowing the contact of the immunoglobulin or Fc or Fc' fragment thereof with Fc receptors at the tumor site; and detecting the detectably labeled immunoglobulin or Fc or Fc' fragment thereof.
The present invention also relates to the use of a diagnostically effective amount of a detectably labeled non-specific immunoglobulin or Fc or Fc' fragment thereof in conjunction with a therapeutically effective amount of an anti-tumor agent bound to an immunoglobulin or fragment thereof in the treatment of an Fc receptor-expressing tumor site in an individual.
In one embodiment, the invention relates to an immunoglobulin comprising pooled, human, polyclonal IgG
conjugated to a diagnostically detectable label, wherein the immunoglobulin is not IgG conjugated to EDTA and labeled with 111In and the immunoglobulin is not IgG labeled with ~mTc. The immunoglobulin accumulates at a site of inflammation but has substantially no epitopic specificity for the site of inflammation.

_,.

-7a- 1 3 3 9 3 1 0 In another embodiment, the invention relates to an immunoglobulin fragment comprising an Fc fragment of one or more monoclonal antibodies, wherein the Fc fragment is conjugated to a diagnostically detectable label, and the Fc fragment is not an Fc fragment labeled with l25I, and wherein the Fc fragment accumulates at a site of inflammation.
In yet another embodiment, the invention relates to an immunoglobulin comprising Fc fragments of IgG conjugated to a diagnostically detectable label, wherein the Fc fragments of IgG are not Fc fragments labeled with l25I, and wherein the Fc fragments accumulate at a site of inflammation.
In a further alternative embodiment, the invention relates to an immunoglobulin comprising pooled, human, polyclonal IgG conjugated to DTPA and labeled with a radioisotope label, wherein the immunoglobulin accumulates at a site of inflammation and the immunoglobulin has substantially no epitopic specificity for the site of inflammation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention relates to a method of detecting a tumor site in vivo in an individual which comprises administering to such an individual a diagnostically effective amount of a detectably labeled immunoglobulin or an Fc fragment thereof, wherein such immunoprotein f~

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-8- 1 3393~0 substantially accumulates at such a tumor site when the site is an Fc receptor-bearing tumor. The invention also relates to an antibody-based method of treating such Fc receptor-bearing tumors.
By the term "individual" is meant to include both animals and humans.
By the term "tumor" is intenAPA abnormal growth of cells that may result in the invasion of normal tissue sites or in the spread through distant organs. Tumors may be malignant or benign. By the term "malignant" is intended those abnormal cells that exhibit the propen-sity for invasion and distant spread. By "benign" is intended those abnormal cell growths that are not invasive in character.
By the term "Fc receptor-expressing tumor" is intended those tumors, particularly of hematopoietic or reticuloendothelial cell origin, that produce and insert into their cell surfaces special proteins termed "Fc receptors," that recognize and bind with high affinity to the non-specific, constant heavy chain portion of circulating immunoglobulins, termed "Fc region" or "Fc fragment." Examples of cell types that express large numbers of Fc receptors include monoclonal phagocytes, granulocytes, lymphocytes, basophils, and mast cells.
Examples of tumors of such cell types include melanomas, lymphomas, sarcomas, leukemias, as well as certain types of breast and lung cancer.
By the term "non-specific immunoglobulin or Fc or Fc' fragment thereof" is intended any intact non-speci-fic immunoglobulin or Fc or Fc' fragment thereof, whether monoclonally or polyclonally derived, that has no epitopic specificity for the tumor site and that can be directed against any antigen, including tumor bind-. .

-9- 13393~0 ing sites necessary to effect binding of said non-speci-fic immunoglobulin or Fc or Fc' fragment thereof to tumors and to accumulate at the site thereof.
Polyclonal immunoglobulin preparations can be derived directly from the blood of the desired animal species. Thus, in the case of humans, polyclonal immunoglobulin preparations can be prepared from out-dated units of blood utilizing protocols known or readily ascertA~n~hle to those of ordinary skill in the art. Such products are commercially available (Sandoz Limited; Cutter Laboratories; Hyland Laboratories) and are conventionally used in the treatment of immunodefi-ciency states, but not in diagnosis.
In addition, if desired, polyclonal immunoglobulin preparations may be prepared from the blood of immunized individuals of the desired species following immuniza-tion with any of a variety of antigens, followed by harvesting of the blood and processing it according to defined techniques. A distinctive advantage of non-specific, immunoglobulin preparations is that by prepar-ing immunoglobulin from the same species into which it will be injected, immune reactions across species bar-riers are prevented and repeated injections of the same product are less likely to cause side-effects. It should be emphasized that cross-species injections can be done. However, their use might increase the in-cidence of untoward reactions such as anaphylactic reac-tions, febrile reactions, and/or the generation of an immune response to the foreign immunoglobulin protein that will block its effective use, as well as endanger the health of the patient. The avoidance of such reac-tions adds greatly to the appeal of using an im-~' -lO- 1339340 munoglobulin preparation which is from the same species as that being diagnosed.
Monoclonal immunoglobulins which can be used according to the method of the invention can be prepared using hybridoma fusion techniques (Kohler et al., European Journal of Immunoloqy 6:292, 1976) or can be derived from known secreting myeloma cell lines such as those available from depositories such as the American Type Culture Collection. As with the polyclonal immunoglobulin preparation, no antigenic or epitopic specificity is needed for the monoclonal immunoglobulin preparation to function effectively in this method. As a consequence, monoclonal antibodies of any specificity can be used.
In detecting an in vivo Fc receptor-expressing tumor site in an individual, the detectably labeled immunoglobulin is advantageously given in a dose which is diagnostically effective. The term "diagnostically effective" means that the amount of detectably labeled immunoglobulin administered is sufficient to enable detection of the tumor site when compared to the back-ground signal. It is preferred that the non-specific immunoglobulin exhibit no non-tumor binding. However, to the extent that non-tumor binding of the im-munoglobulin does occur, one with ordinary skill will be able to differentiate over tumor-bound immunoglobulin based on location, intensity of the image, and the like.
Generally, the dosage of detectably labeled immunoglobulin for diagnosis will vary depending on considerations such as age, condition, sex, and extent of disease in the patient, counterindications, if any, and other variables, to be adjusted by the individual ,. .
~1 physician. Dosage can vary from 0.0003 mg/kg to 0.3 mg/kg.
The term "Fc fragment or part thereof" as used in this invention is meant to include intact Fc fragments as well as portions of the Fc fragment capable of accum-ulating at the site of the tumor. Fc fragments, which contain the CHl, CH2 and CH3 domains of the IgG mole-cule, are produced by proteolytic methods (i.e., use of the proteinase papain) well known to those of ordinary skill in the art. A fragment of the Fc domain, termed "Fc'," consists of the separated C-terminal CH3 domain of the IgG molecule. By the term "Fc' fragment" as used ;herein is intended a detectably-labeled CH3 fragment of the IgG molecule that is capable of substantially ac-cumulating at a tumor site. Fc' fragments are prepared by a combination of proteinases, employed sequentially, namely, papain, pepsin and subtilisin.
The term "detectably labeled" means that the im-munoglobulin has attached to it a diagnostically detec-table label.
There are many different labels and methods of labeling known to those of ordinary skill in the art.
Examples of the types of labels which can be used in the present invention include radioactive isotopes and paramagnetic isotopes. Those of ordinary skill in the art will know of other suitable labels for binding to the immunoglobulins used in the invention, or will be able to ascertain such, using routine experimentation.
Furthermore, the binding of these labels to the immunoglobulin can be done using st~n~rd t~chn;ques common to those of ordinary skill in the art.
For diagnostic in vivo imaging, the type of detec-tion instrument available is a major factor in selecting a given radionuclide. The radionuclide chosen must have a type of decay which is detectable for a given type of instrument. In general, any conventional method for visualizing diagnostic imaging can be utilized in accordance with this invention.
Another important factor in selecting a radio-nuclide for in vivo diagnosis is that the half-life of a radionuclide be long enough so that it is still detec-table at the time of maximum uptake by the target, but short enough so that deleterious radiation upon the host is minimized. Ideally, a radionuclide used for in vivo imaging will lack a particulate emission, but produce a large number of photons in a 140-200 keV range, which may be readily detected by conventional gamma cameras.
For in vivo diagnosis, radionuclides may be bound to immunoglobulin either directly or indirectly by using an intermediary functional group. Intermediary func-tional groups which are often used to bind radioisotopes which exist as metallic ions to immunoglobulins are diethylenetriaminepentaacetic acid (DTPA) and ethylene-diaminetetracetic acid (EDTA). Typical examples of metallic ions which can be bound to immunoglobulins are Tc, I, 111In 131I, 97Ru 67CU 67Ga 125I 68 72AS 89zr, and 20iTl.
The immunoglobulins used in the method of the invention can also be labeled with paramagnetic isotopes for purposes of in vivo diagnosis. Elements which are particularly useful (as in Magnetic Resonance Imaging (MRI) techni~ues) in this manner include 157Gd, 55Mn, 162Dy 52cr, and 56Fe.
Alternatively, the method of the in~ention can be used to monitor the course of tumor invasiveness or metastasis in an individual. Thus, by measuring the increase or decrease in the size or number of tumor sites by serial imaging it would be possible to deter-mine whether a particular therapeutic regimen aimed at ameliorating the cause of the tumorigenic process, or the tumor itself, is effective.
Another embodiment of the invention includes a method for tumor therapy wherein the non-specific im-munoglobulin or Fc fragment therefrom of the invention is modified, prior to administration to an individual, by coupling to it covalently a cytotoxic material such as the lectin ricin which has a cell-destructive capa-bility. Thus, the ricin, delivered by the immunopro-;teins of the invention, will destroy the tumor cells,when delivered in therapeutically effective concentra-tions.
The invention also embodies another method for tumor therapy. In this method, an individual suspected of having an Fc receptor-bearing tumor site is first a~inictered a diagnostically effective amount of non-specific immunoglobulin or Fc fragment thereof, as previously described. This detectably labeled immuno-protein may be of the same or different species as the individual to whom it is being administered. The indi-vidual suspected of having a tumor site is then imaged to determine the presence of such a site. If the indi-vidual is found to have a tumor site, the individual is then given an antibody preparation(s) specific for the tumor which is suspected. This specific antibody can be from an individual of the same, or a different, species to that of the individual having the tumor site. After determining the specific tumor type it is then possible to administer a therapeutic agent, such as therapeuti-cally conjugated antibody specific for the tumor or tumorigenic tissue at the tumor site. By "treating" is intended the administration to an individual of an agent that has an ameliorative, curative or prophylactic effect upon the tumor or tumorigenesis.
The term "therapeutically conjugated" means that a non-specific or specific immunoglobulin or fragment thereof used in the just-described preferred method of the invention is conjugated to a therapeutic agent. The therapeutic agents used in this conjugate act directly upon the tumor or upon the underlying cause of the tumor site. Examples of therapeutic agents that can be coupled to the specific antibodies used according to the method of the invention are anti-tumor drugs, DNA alkyl-ating agents, analogs of nucleotides and nucleosides, DNA intercalcating drugs, antimetabolites, radioiso-topes, lectins, toxins, and antibiotics. Many anti-tumor chemicals are known in the art. A requirement of the present invention is that the therapeutic means should not be conjugated to the Fc portion of the im-munoglobulin so as not to block binding of the thera-peutic immunoprotein to the Fc receptor-bearing tumor.
By the term "lectins" is intended a glycoprotein, usually isolated from plant material, which bind to specific sugar moieties. Many lectins are also able to agglutinate cells and stimulate lymphocytes. Certain lectins are extremely toxic to animal cells. For ex-ample, ricin is a toxic lectin which has been used immunotherapeutically. This is accomplished by binding the alpha-peptide chain of ricin, which is responsible for toxicity, to the antibody molecule to enable site-specific delivery of the toxic effect.
Toxins are poisonous substances produced by plants, animals, or microorganisms that, in sufficient dose, are . _ yi -15- 133 93~0 often lethal. One such toxin is diphtheria toxin, a protein produced by Corynebacterium diphtheriae that inhibits protein synthesis in various cell types. This toxin consists of an alpha and beta subunit which, under proper conditions, can be separated. The toxic compo-nent can be bound to antibody and used for site-specific delivery to the primary or metastisizing tumor sites.
Examples of radioisotopes which can be bound to specific antibody for therapeutic purposes, used accord-ing to the method of the invention, are 125I, 131I, 90Y, Cu, Bi, At, 212pb, 47Sc, 109Pd, and 184Re-Antibiotics are substances which inhibit suchinfectious microorganisms as bacteria, viruses, fungi, and parasites. These antibiotics can be any of those known to those of ordinary skill in the art.
Other therapeutic agents which can be coupled to immunoproteins used according to the method of the invention are known, or can be easily ascertained, by those of ordinary skill in the art.
Preparations of the imaging immunoglobulins for parenteral administration include sterile aqueous or non-aqueous solutions, suspensions, and emulsions.
Examples of non-aqueous solvents are propylene glycol, polyethylene glycol, vegetable oil such as olive oil, and injectable organic esters such as ethyl oleate.
Aqueous carriers include water, alcoholic/aqueous solu-tions, emulsions or suspensions, including saline and buffered media, parenteral vehicles including sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's, or fixed oils.
Intravenous vehicles include fluid and nutrient repleni-shers, electrolyte replenishers, such as those based on Ringer's dextrose, and the like. Preservatives and ~, . ~
~,, other additives may also be present, such as, for ex-ample, antimicrobials, anti-oxidants, chelating agents, and inert gases and the like. See, generally, Reminq-ton's Pharmaceutical Science, 16th ed., A. Osol, ed., Mack, 1980.
The above disclosure generally describes the present invention. A more complete underst~n~;ng can be obtained by reference to the following specific example which is provided herein for purposes of illustration only, and is not intended to be limiting unless other-wise specified.

; EXAMPL~ 1 Murine ovarian reticulum cell sarcoma of monocytic origin (M5076), an Fc receptor-bearing tumor, was im-planted intramuscularly in the right thigh of syngeneic C57BL/6 in-bred mice. Five days post-implantation of a 10 mg tumor, each mouse was injected with 40-50 ug (60-80 uCi) of one of the following lllIn-labeled types of antibodies: intact polyclonal human IgG, or its puri-fied Fc or F(ab')2 fragment. lllInCl was coupled to immunoproteins by the mixed and cyclic anhydride-DTPA
methods, as described, for example, by B. Khaw et al., Science 209:295 (1980) and Hnatowich et al., Jour. of Appl. Radiat. Isot. 33:327 (1982). At least 6 mice per group were used. Scintigraphic imaging was performed on a gamma camera with pinhole collimation immediately post-injection of the radiolabeled material, and again at 24 and 48 hours thereafter. The animals were imaged for ten minutes each. Whole body, organ, and tumor uptake of the radiopharmaceuticals was calculated according to the following formula: (organ counts-.~. , .~-r~ , background counts/standard counts) * (standard dose/
injected dose). Biodistribution of radiolabel in tis-sues (Table 1 infra) was done at 48 hours. At the time of sacrifice, tumor size was about 20 mg.
In order to compare tumor uptake of Fc to that of Fab, l11In-labeled antibody modified by cyclic DTPA was used, and one group of mice received radiolabeled Fc fragments and the second group radiolabeled Fab frag-ments.
In order to compare tumor localization with 125I-labeled antibody to that of lllIn-labeled antibody, six animals were injected with doubly-labeled intact poly-;clonal IgG, and both l11In and 25I peaks were visualizedby posterior pinhole imagery.
As seen by the data of Table 1, tumor localization was seen with 111In-labeled intact polyclonal IgG and its Fc fragment, but not with the F(ab')2 fragment. The bio-distribution data revealed that about 32~ of the injec-ted dose of l11In-labeled Fc was retained per gram of tumor at 48 hours post-injection, which can be explained by the considerably higher blood activity in the IgG
group (Table 1). The tumor-to-background ratio was 12:1 in the IgG group and 10:1 in the Fc group.
The results of imaging experiments with 111In-labeled Fab(A) and Fc(B) modified by cyclic anhydride-DTPA are shown in Figure 1. In these experiments, tumor was detected with Fc fragments only.
It can be concluded that it is possible to detect Fc receptor-bearing tumors with non-specific polyclonal IgG in both its intact and Fc forms, but not in its F(ab)2 form. As tumor detection appears to depend on the presence of intact Fc fragments, it is likely to be mediated by the Fc receptor. In comparison with the biodistribution of F(ab')2 at 48 hours post-injection, there was no evidence that Fc fragment was significantly retained in tissues of the reticuloendothelial septem.
These data indicate that employment of Fc receptor imaging provides a new approach to early non-specific tumor detection.

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Claims (51)

1. A method of detecting an Fc receptor-expressing tumor site in vivo in an individual which comprises:
administering to said individual a diagnostically effective amount of a non-specific detectably-labeled immunoglobulin or an Fc or Fc' fragment thereof;
allowing the contact of said immunoglobulin or Fc or Fc' fragment thereof with Fc receptors at said tumor site; and detecting said detectably-labeled immunoglobulin or Fc or Fc' fragment thereof.

2. The method of claim 1, wherein said immunoglobulin is monoclonally derived.

3. The method of claim 1, wherein said immunoglobulin is polyclonally derived.

4. The method of claim 1, wherein said fragment is the Fc portion of said immunoglobulin.

5. The method of claim 1, wherein said fragment is the Fc' portion of said immunoglobulin.

6. The method as in any one of claims 1-5, wherein said detectable label is a radioactive isotope.

7. The method of claim 6, wherein said isotope is selected from the group consisting of 99m Tc, 123I, 131I, 111In, 97Ru, 67Cu, 67Ga, 69Ga, 72As, 89Zr, 201Tl or other positron emitter.

8. The method as in any one of claims 1-5, wherein said detectable label is a paramagnetic isotope.

9. The method of claim 8, wherein said paramagnetic isotope is selected from the group consisting of 157Gd, 55Mn, 162Dy 52Cr, and 56Fe.

10. The method of claim 8, wherein said detecting is by magnetic resonance imaging or positron emission tomography.

11. The method of claim 1, wherein said administration is parenteral by bolus or infusion.

12. The method of claim 11, wherein said parenteral administration is by intradermal, subcutaneous, intramuscular, intraperitoneal, or intravenous injection.

13. The use of a diagnostically effective amount of a detectably labelled non-specific immunoglobulin or Fc or Fc' fragment thereof in conjunction with a therapeutically effective amount of an anti-tumor agent bound to an immunoglobulin or fragment thereof in the treatment of an Fc receptor-expressing tumor site in an individual.

14. The use of claim 13, wherein said anti-tumor agent is bound to a tumor-specific immunoglobulin.

15. The use of claim 13, wherein said anti-tumor agent is bound to the F(ab) 2 portion of a tumor-specific immunoglobulin.

16. The use of claim 13, wherein said anti-tumor agent is bound to a non-specific immunoglobulin.

17. The use of claim 13, wherein said anti-tumor agent is bound to an Fc or Fc' fragment of a non-specific immunoglobulin.

18. The use of claim 13, wherein said immunoglobulin antibody is monoclonally derived.

19. The use of claim 13, wherein said immunoglobulin is polyclonally derived.

20. The use as in any one of claims 13 to 17, wherein said agent is a drug.

21. The us as in any one of claims 13 to 17, wherein said agent is a lectin.

22. The use of claim 21, wherein said lectin is the alpha-chain of ricin.

23. The use as in any one of claims 13 to 17, wherein said agent is a toxin.

24. The use of claim 23, wherein said toxin, is diphtheria toxin.

25. The use as in any one of claims 13 to 17, wherein said agent is a radioactive isotope.

26. The use of claim 25, wherein said radioactive isotope is selected from the group consisting of 125I, 131I, 90Y, 67Cu, 217Bi, 211At, 212Pb, 47Sc, 109Pd or 184Re.

27. The use as in any one of claims 13 to 17, wherein said agent is an antibiotic.

28. The use of claim 27, wherein said antibiotic is selected from the group consisting of an anti-bacterial, an anti-fungal, an anti-viral, and an anti-parasitic agent.

29. The use as in any one of claims 13 to 17, wherein said agent is a DNA alkylating agent.

30. The use as in any one of claims 13 to 17, wherein said agent is a DNA intercalcating agent.

31. The use as in any one if claims 13 to 17, wherein said agent is an antimetabolite.

32. The us as in any one of claims 13 to 17, wherein said agent is an analog of nucleotides or nucleosides.

33. An immunoglobulin comprising pooled, human, polyclonal IgG conjugated to a diagnostically detectable label, wherein said immunoglobulin is not IgG conjugated to EDTA and labeled with 111In and said immunoglobulin is not IgG labeled with 99mTc, and wherein said immunoglobulin accumulates at a site of inflammation and said immunoglobulin has substantially no epitopic specificity for said site of inflammation.

34. The immunoglobulin of claim 33, wherein said detectable label is a radioactive isotope or a paramagnetic label.

35. The immunoglobulin of claim 33, wherein said radioactive isotope is selected from the group consisting of 123I, 131I, 111In, 97Ru, 67Cu, 67Ga, 68Ga, 72As, 89Cr, and 201Tl.

36. The immunoglobulin of claim 33, wherein said paramagnetic label is selected from the group consisting of 157Gd, 55Mn, 162Dy, 52Cr, and 56Fe.

37. The immunoglobulin of claim 33, wherein said radioisotope label is bound to IgG indirectly via DTPA.

38. An immunoglobulin comprising one or more monoclonal antibodies conjugated to a diagnostically detectable label, wherein said antibody or antibodies are not monoclonal IgG1 labeled with 125I, and wherein said antibody or antibodies accumulate at a site of inflammation and said antibody or antibodies have substantially no epitopic specificity for said site of inflammation.

39. An immunoglobulin fragment comprising an Fc fragment of one or more monoclonal antibodies, wherein said Fc fragment is conjugated to a diagnostically detectable label, and said Fc fragment is not an Fc fragment labeled with 125I, and wherein said Fc fragment accumulates at a site of inflammation.

40. The method of claim 1 or 13, wherein said individual is a human.

41. The immunoglobulin of any one of claims 38 or 39, wherein said monoclonal antibody is non-antigenic.

42. The immunoglobulin of any one of claims 38 or 39, wherein said detectable label is a radioactive isotope or a paragmagnetic label.

43. The immunoglobulin of claim 42, wherein said radioactive isotope is selected from the group consisting of 99mTc, 123I, 131I, 111In, 97Ru, 67Cu, 67Ga, 68Ga, 72As, 89Zr, and 201Tl.

44. The immunoglobulin of claim 42, wherein said paramagnetic label is selected from the group consisting of 157Gd, 55Mn, 162Dy, 52Cr, and 56Fe.

45. An immunoglobulin comprising Fc fragments of IgG
conjugated to a diagnostically detectable label, wherein said Fc fragments of IgG are not Fc fragments labeled with 125I, and wherein said Fc fragments accumulate at a site of inflammation.

46. The immunoglobulin of claim 45, wherein said IgG
comprises pooled, human, polyclonal IgG.

47. The immunoglobulin of any one of claims 45 or 46, wherein said detectable label is a radioactive isotope or a paramagnetic label.

48. The immunoglobulin of claim 47, wherein said radioactive isotope is selected from the group consisting of 99mTc, 123I, 131I, 111In, 97Ru, 67Cu, 67Ga, 68Ga, 72As, 89Zr, and 201Tl.

49. The immunoglobulin of claim 47, wherein said paramagnetic label is selected from the group consisting of 157Gd, 55Mn, 162Dy, 52Cr, and 56Fe.

50. An immunoglobulin comprising pooled, human, polyclonal IgG conjugated to DTPA and labeled with a radioisotope label, wherein said immunoglobulin accumulates at a site of inflammation and said immunoglobulin has substantially no epitopic specificity for said site of inflammation.

51. The immunoglobulin of claim 50, wherein said radioisotope label is selected from the group consisting of 99mTc, 123I, 131I, 111In, 97Ru, 67Cu, 67Ga, 68Ga, 72As, 89Zr, and 201Tl.