WO2001047512A2

WO2001047512A2 - Method for relieving pain associated with an internal disease site

Info

Publication number: WO2001047512A2
Application number: PCT/US2000/042661
Authority: WO
Inventors: George A. Luiken
Original assignee: Fluoro Probe, Inc.
Priority date: 1999-12-08
Filing date: 2000-12-06
Publication date: 2001-07-05
Also published as: WO2001047512A3; AU4904101A

Abstract

Methods are provided for in vivo administration of a pain-relieving drug, such as a local anesthetic (e.g. lidocaine), to an interior disease site for pain relief at the interior disease site. In the invention pain treatment methods, a subject is administered a targeting construct comprising a biologically compatible pain-relieving agent and a tumor-avid ligand or monoclonal antibody that preponderantly binds to or is taken up by the tissue associated with an interior disease site. Administration is by a method other than topical injection or application, such as parenteral injection. Because the pain-relieving agent is delivered by the ligand to the disease site, intractable pain situated in the interior of the body, such as is caused by various tumors, can be managed using a lower level of the pain-relieving agent then is required when the pain-relieving agent is injected in the free state.

Description

METHOD FOR RELIEVING PAIN ASSOCIATED WITH AN INTERNAL DISEASE SITE

FIELD OF THE INVENTION

The present invention relates to methods for relieving pain associated with an internal disease site. More particularly, the invention relates to methods for relieving chronic pain associated with diseased tissue at an interior body site.

The next best thing to removal of the cause of pain is removal of the sensation of pain. Patients with advanced cancer and patients with tissue injury or tissue necrosis from a variety of sources often experience intense, unrelenting pain as a direct or indirect result of peripheral nerve injury. The pain is often poorly localized and may extend beyond the distribution of the nerve injury that is involved. The pain may also be unpleasant and shock-like (dysesthesia); may be associated with an exaggerated response to a given noxious stimulus (hyperalgesia); and may be associated with a report of pain secondary to a non-painful stimulus i.e., thermal or mechanical (allodynia).

In contrast to most other sensory receptors of the body, the pain receptors and nerves adapt very little and, under some conditions, the excitation of the pain fibers in hyperalgesia becomes progressively greater, stimulating the slow, suffering type of pain. The mechanism of these exaggerated or abnormal sensations, which can be debilitating, is not fully elucidated, but may be due in part to an increase in the density of voltage-sensitive sodium channels in the injured nerve (S.R. Chaplan et al., Anesthesiology £1:775-85, 1995).

Nociceptive pain results from stimulation of primary afferent nociceptors.

A-β afferents respond maximally to light touch and/or moving stimuli and are present primarily in nerves that innervate the skin. Two other classes of primary afferents, the small-diameter myelinated (A-δ) and the unmyelinated (C fiber) axons are present in the nerves of the skin and in deep somatic and visceral structures. In addition, the central nervous system (CNS), including the spinal cord tissues and ganglia, contains opioid receptors, which have been divided into the three major types: mu (μ), kappa (K) and (δ). Opioid analgesics are the most potent pain- relieving drugs current available, and selective agonists and antagonists are known for each of the receptors, but only μ and K agonists are currently available for clinical use. Most of the commercially available opioid analgesics act at the μ receptor, differing mainly in potency, speed of onset, duration of action, and optimal route of administration. Furthermore, of all analgesics, opioids have the broadest range of efficacy, providing the most reliable method for rapidly relieving pain. The most rapid relief with opioids is obtained by systemic IV administration and opioids are widely prescribed for intravenous administration in treatment of deep pain, such as post-operative pain.

However, repeated systemic administration of opioids causes a series of common side effects, ranging from respiratory depression, to less serious effects, such as constipation, nausea, vomiting, and sedation. These effects can be reversed rapidly with the narcotic antagonist naloxone, but reversal causes loss of pain relief as well.

To avoid systemic administration, opioids can be infused through a spinal catheter placed either intrathecally or epidurally. By applying opioids directly to the spinal cord, regional analgesia can be obtained at a relatively low total dose, thus minimizing the risk of side effects. This approach has been used extensively in obstetrical procedures and for lower-body postoperative pain. However, these techniques are not appropriate for treatment of chronic or persistent pain.

Another class of analgesics, the local anesthetics produce a state of local anesthesia by reversibly blocking the nerve conductances that transmit the feeling of pain from a locus to the brain. More particularly, local anesthetics prevent the generation and the conduction of the nerve impulse by decreasing or preventing the large transient increase in the permeability of excitable membranes to sodium ions. It is generally accepted that a local anesthetic blocks nerve conductance by binding to selective site(s) on the sodium channels in the excitable membranes, thereby reducing sodium passage through the pores and thus interfering with the action potentials. In contrast to analgesic compounds, local anesthetics do not interact with the pain receptors or inhibit the release or the biosynthesis of pain mediators.

Most of the clinically useful local anesthetics are tertiary amines with a pK_a value of 7.5 to 9.0. Thus, under physiologic conditions, both protonated forms (onium ions) and unionized, molecular forms are available for binding to proteins in the sodium channel. The exact location of the binding sites(s) in sodium channels and whether all local anesthetics interact with a common site remain a matter of dispute.

Amide-type local anesthetics, such as procainamide and lidocaine, originally developed for local anesthesia by local injection or topical application, are also administered systemically by intravenous injection in treatment of patients with regional hyperalgesia (M.S. Wallace et al., Anesthesiology §&.'• 1262-72, 1997) and have also been shown to increase acute thermal thresholds in the painful areas of patients with peripheral nerve injury. Subanesthetic doses of systemic lidocaine has been shown to produce relevant relief in patients with late stage cancer (M.S. Wallace et al., Pain 6_2:69-77). However, lidocaine can have anticholinergic activity, resulting in side effects to the centred nervous system and symptoms ranging from dry mouth, blurred vision and urinary retention to congestive heart failure in patients with abnormal ventricular function.

Monoclonal antibodies and other ligands specific for tumors have been developed for use in diagnostic procedures and in delivery of therapeutic or toxic agents to tumors, both in tissue samples and in vivo. To avoid host inflammatory response to repeat use of non-human antibodies (e.g., production of host anti-murine antibodies (HAMA)), various types of "humanized" antibodies have been developed, including, most recently, fully human antibodies that are produced in non-human transgenic animal species, such as transgenic mice, or in cell culture. Such fully human antibodies are now commercially available (see for example, Protein Design Labs, Inc (Fremont, CA) and Abgenix, Inc. (Fremont, CA), and can be designed for specificity to virtually any antigen to which antibodies can be raised using techniques known in the art. In addition, certain tumor-avid moieties disproportionately taken up (and optionally metabolized) by tumor cells are used in diagnostic procedures. Two well-known tumor-avid compounds used in diagnostic procedures are deoxyglucose, which plays a telling role in glycolysis in tumor cells, and somatostatin, which binds to and/or is taken up by somatostatin receptors in tumor cells, particularly in endocrine tumors.

For detection of tumors of various types, deoxyglucose is used in diagnostic studies as a radio-tagged moiety, such as fluorodeoxyglucose (¹⁸F-deoxyglucose). It is believed that tumor cells experience such a mismatch between glucose consumption and glucose delivery that anaerobic glycolysis must be relied upon, thereby elevating the concentration of the radioactive tag in tumor tissue. It is also a possibility that the elevated concentration of deoxyglucose in malignant tumors may be caused by the presence of isoenzymes of hexokinase with abnormal affinities for native glucose or its analogs (A. Gjedde, Chapter 6: "Glucose Metabolism," Principles of Nuclear Medicine, 2^nd Ed., W. B. Saunders Company, Philadelphia, PA, pages 54-69). Similarly, due to the concentration of somatostatin in tumor tissue, radio-tagged somatostatin, and fragments or analogs thereof, are used in the art for non-invasive imaging of a variety of tumor types in a procedure known as somatostatin receptor scintigraphy (SRS).

However, there is a need in the art for new and better methods for pain management, especially for management of pain at interior disease sites (such as tumors) characterized by the presence of antigens and other types of marker proteins or polypeptides not normally found in healthy tissues.

SUMMARY OF THE INVENTION

The present invention overcomes many of the problems in the art by providing method(s) for treating pain associated with an interior disease site in a subject in need thereof. The invention pain treatment methods comprise administering to the subject a pain-relieving amount of at least one pain-relieving targeting construct comprising a biologically compatible pain-relieving agent linked to a ligand moiety that preponderantly binds to or is taken up by the tissue associated with a painful interior disease site. The targeting construct is allowed to bind to and/or be taken up selectively by the tissue, thereby delivering local pain relief to the subject.

Although any pain-relieving agent known in the art that can be linked to a ligand moiety to obtain a biologically compatible pain-relieving targeting construct can by used in the invention methods for treatment of pain, the preferred pain-relieving agents for use in the invention methods are of two types: local anesthetics and opioids.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides method(s) for treating pain associated with an interior disease site in a subject in need thereof. The invention pain treatment methods comprise administering to the subject a pain-relieving amount of at least one biologically compatible pain-relieving targeting construct comprising a biologically compatible pain-relieving agent linked to a ligand moiety that preponderantly binds to or is taken up by the tissue associated with a painful interior disease site. The targeting construct is allowed to bind to and/or be taken up selectively by the tissue, thereby delivering pain relief to the subject.

Preferably, the ligand moiety of the invention targeting construct is selected to bind to and/or be taken up specifically by tissue associated with the interior disease site of interest. Many of the tumor-avid moieties disclosed herein and known in the art are taken up by a number of different types of tumors. In many cases it is desirable for the targeting construct to bind to or be taken up by the target tissue selectively or to an antigen associated with the disease site or tumor; however, targeting constructs containing ligand moieties that also bind to or are taken up by healthy tissue or cell structures can be used in the practice of the invention method so long as the concentration of the antigen in the target tissue or the affinity of the targeting construct for the target tissue is sufficiently greater than for healthy tissue that a preponderance of the pain-relieving agent will be delivered to the pain-causing disease site. For example, colon cancer is often characterized by the presence of carcinoembryonic antigen (CEA), yet this antigen is also associated with certain tissues in healthy individuals. However, the concentration of CEA in cancerous colon tissue is often greater than is found in healthy tissue, so an anti-CEA antibody could be used as a ligand moiety in the practice of the invention. In another example, deoxyglucose is taken up and utilized by healthy tissue to varying degrees, yet its metabolism in healthy tissues, except for certain known organs, such as the heart, is substantially lower than in tumor. The known pattern of deoxyglucose consumption in the body can therefore be used to aid in determining the suitability of using deoxyglucose as a tumor-avid agent for delivery of pain relief to a painful interior disease site according to the invention methods.

As used herein the term "tissue associated with the interior disease site" includes various types of tumorous, ischemic and diseased tissues. For example, it is contemplated that the pain-causing target tissue may be characterized by cells that produce either a surface antigen for which a binding ligand is known, or an intracellular marker (i.e. antigen), since many targeting constructs penetrate the cell membrane. Intractable pain located at interior sites and which can be beneficially treated using the invention pain treatment methods is associated with a number of different types of diseased tissues. For example, the tissue associated with the painful interior disease site treated by the invention method may include such various tissues as breast, small-cell and non-small cell lung cancer, Hodgkin's and non-Hodgkin's lymphoma, pancreas, carcinoid, neuroblastoma, or pituitary tumor tissue, and the like, as well as combinations of any two or more thereof.

Each type of tumor can have or be associated with a number of different antigens. As another illustrative example, painful breast cancers are associated with cancerous tissue identified by monoclonal antibodies to carcinoembryonic antigen (CEA), CAl 5-3, human epidermal growth factor receρtor-2 (HER2/neu), CAl 9-9, and human epidermal growth factor receptor-2.

In addition, "tissue associated with the interior disease site" can include tissue infected by bacterial, fungal and viral pathogens, which infections are common sources of pain that is difficult to treat at interior sites. Moreover, various heart conditions are characterized by pain caused by production of necrotic or ischemic tissue or production of artherosclerotic tissue for which specific binding ligands are known. Therefore, as used herein "tissue associated with a disease site" also includes precancerous, necrotic or ischemic tissue, and tissue associated with connective tissue diseases, and auto-immune disorders, and the like, for which specific binding ligands are known.

Moreover, the term "tissue associated with the interior disease site" is intended to encompass tissue containing nerves and/or pain receptors directly or indirectly activated by the tumorous or ischemic tissue. It is known that afferent nociceptors affected by the above various types of diseases have a neuroeffector function. Most nociceptors contain polypeptide mediators that are released from their peripheral terminals when they are activated. For example, substance P, an 11 amino acid peptide, is released from primary afferent nociceptors and has multiple biologic activities. Substance P is a potent vasodilator, degranulates mast cells, is a chemoattractant for leukocytes, and increases the production and release of inflammatory mediators, such as bradykinin, another substance involved in stimulating the slow, suffering type of pain that occurs after tissue injury. Hence, as used herein, the term "tissue associated with the interior disease site" is contemplated to include tissue in the zone of pain that surrounds the disease site to which the targeting construct will deliver relief.

Local anesthetics generally contain a lipophilic portion, an intermediate chain or ester or amide linkage, and a hydrophilic portion. The lipophilic portion of the molecule is essential for local anesthetic activity. Usually, this portion of the molecule consists of either an aromatic group directly attached to a carbonyl function (the amino ester series) or a 2,6-dimethylphenyl group attached to a carbonyl function through an -NH- group (the amino amide series). Both ofthese groups are highly lipophilic and appear to play an important role in the binding of local anesthetics to the sodium channel receptor. Structural modification of this portion of the molecule is known to have a profound effect on its physical and chemical properties, which, in turn, alters its local anesthetic properties. Therefore, in linkage of the local anesthetic to the ligand moiety, it is important to avoid a chemical modification of the local anesthetic that detracts from the lipophilicity of the lipophilic portion of the local anesthetic molecule.

On the other hand, in the amino ester series, an electron-donating substitutent in the ortho or para positions, or both, increases local anesthetic potency. Therefore, an amino, alkylamino or alkoxy group can contribute electron density to the aromatic ring of the molecule both by resonance and inductive effects, thereby enhancing local anesthetic potency over nonsubstituted analogs, such as hexylcaine and meprylcaine.

As is well known in the art, molecular size influences the rate of dissociation of local anesthetics from the receptor sites. Smaller drug molecules can escape from the receptor site more rapidly.

Representative examples of local anesthetics that can be incorporated as the pain-relieving agent in the invention pain-relieving targeting construct(s) include such compounds as bupivacaine, ropivacaine, dibucaine, etidocaine, hexylcaine, lidocaine, mepivacaine, meprylcaine, prilocaihe, procaine, propoxycaine, pyrrocaine, and tetracaine, all of which can be injected parenterally. Biologically compatible salts of these and like compounds, and mixtures of any two or more thereof, can also be used as the pain-relieving agent in the practice of the invention methods. The preferred classes of pain-relieving agents used in the pain-relieving targeting ligands administered in the invention methods are local anesthetics (e.g., sodium channel antagonists), such as lidocaine. Comparison of local anesthetics with respect to structure-function activity, dosage, duration of action, and the like, is well known in the art and is disclosed, for example, in Principles of Medicinal Chemistry. 4^th Ed. Williams & Wilkins, Baltimore, 1995, pages 305-320, which is incorporated herein by reference in its entirety. Lidocaine is the preferred local anesthetic for use in the invention pain treatment methods.

There is a frequency- and voltage-dependence of local anesthetic action. The degree of block produced by a given concentration of local anesthetic depends on how the nerve has been stimulated and on its resting membrane potential. Thus a resting nerve is much less sensitive to a local anesthetic than is one that is repetitively stimulated. Higher frequency of stimulation and more positive membrane potential cause a greater degree of anesthetic block ( Goodman & Gilman's The Pharmacological Basis of Therapeutics. 9^th Edition, McGraw-Hill, 1995, page 333. On the other hand, blockage of sodium channels (and hence of pain), even if temporary, for example for a few hours or days, can have the effect of diminishing hyperalgesia and the secondary release of pain causing pep tides, thus reducing the dose of pain-relieving drug that is required to make a patient comfortable. The term "down regulation of pain" as used herein to refer to the invention treatment methods refers to this effect.

Additional types of sodium channel antagonists that are useful as the pain- relieving agent in the invention methods include anticonvulsants and Class I antiarrhythmic agents, particularly Lamotrigine, which is tolerated systemically at a clinically active dose (J.M. Zakrezewska et al., Pain 22:223-230, 1997), and 4030W92 (Glaxo Wellcome), a new sodium channel antagonist currently in clinical trials for treatment of neuropathic pain. Another class of drugs known as sodium channel blockers are also useful in the practice of the invention methods. The preferred sodium channel blocker is gabapentin, an anticonvulsant. As with systemic local anesthetics, the rationale underlying the use of sodium channel blockers and Class I antiarrhythmics in the practice of the invention methods is their ability to suppress discharges in pathologically altered neurons through their ability to block use-dependent sodium channels.

Inhibitors of chemically mediated pain, such as adenosine kinase inhibitors, prostaglandin receptor antagonists, neurokinin-1 antagonists, glycine antagonists, prosaposins, Cox-2 inhibitors, botulinum toxin, dexmedetomidine, nicotinic receptor agonists, propacetamol, ziconotide, and the like, and combination of any two or more thereof, can also be used in the practice of the invention, either as the pain-relieving agent in the invention construct or in conjunction with administration of such a construct according to the invention methods.

Opioid analgesics are also useful in the practice of the invention methods. The terms "opioid" or "opioid analgesic" as used herein in reference to the invention pain treatment methods means the broad group of opium alkaloids, synthetic derivatives related to the opium alkaloids, and the many naturally occurring and synthetic peptides with morphine-like pharmacologic effect and which bind to opioid receptors. Representative examples of h21opioid analgesics suitable for use in the invention pain-relieving targeting construct(s) and methods of pain treatment using such constructs are hydromorphone, oxycodone, morphine, methadone, meperidine, heroin, dihydrocodeine, dihydromorphine, salts thereof, and the like, and mixtures of any two or more thereof. The typical salts of opioid analgesics are sulfate, hydrochloride, citrate, bitartrate, or lactate salts. The opioid analgesic most preferred for use in the invention pain-relieving methods is morphine.

In one embodiment of the invention method, the ligand moiety of the targeting construct is a protein or polypeptide, such as an antibody, or functional fragment thereof, preferably a monoclonal antibody, that binds with specificity to an antigen associated with tissue at or near a painful interior disease site.

Representative examples of antigens for some common malignancies and the body locations in which they are commonly found are shown in Table I below. Targeting ligands, such as antibodies, for these antigens are known in the art or can be raised using the above procedures and methods.

TABLE I

TUMORS WHERE

ANTIGEN COMMONLY FOUND

CEA (carcinoembryonic antigen) colon, breast, lung

PSA (prostate specific antigen) prostate cancer

PMSA (prostate membrane specific antigen

CA-125 ovarian cancer

CA 15-3 breast cancer

CA 19-9 breast and pancreas cancer

HER2/neu breast cancer α-feto protein testicular cancer, hepatic cancer β-HCG (human chorionic gonadotropin) testicular cancer, choriocarcinoma

MUC-1 breast cancer

Estrogen receptor breast cancer, uterine cancer

Progesterone receptor breast cancer, uterine cancer

EGFr (epidermal growth factor receptor bladder cancer

Thus, illustrative tumor-associated antigens for which antibodies are known and can be used as the ligand moiety in the invention targeting constructs include carcinoembryonic antigen (CEA), mammalian epithelial and mesothelial cancer antigens, tumor specific glycoproteins, mucin-type carbohydrate chain antigens, prostate specific antigen (PSA), CA-125, CA-15-3, CA 19-9, MUC-1, MUC-2 TAG 72, HER2/neu, α-feto protein (AFP), β-human chorionic gonadotropin (β-HCG), estrogen receptor proteins, progesterone receptor proteins, epidermal growth factor (EGFr) receptor, prostate specific membrane antigen, CD5, CD 19, CD20, CD22, CD23, CD45, Ki-1, and the like, or a combination of any two or more thereof. Preferred antibodies for use in the invention pain treatment methods that bind to such tumor-associated antigens include antibodies to CEA, PSA, PMSA, CA-125, CA 15- 3, CA 19-9, HER2/neu, α-feto protein, β-HCG, MUC-1, MUC-2, TAG-72, 5T4, estrogen receptor, progesterone receptor, EGFr, CD5, CD19, CD20, CD22, CD23, CD45, Ki-1 , or a combination of any two or more thereof. Pain caused by colon, breast, and ovarian cancer is a preferred target of the invention pain treatment methods.

The term "antibody" as used in this invention includes intact molecules as well as functional fragments thereof, such as Fab, F(ab')₂, and Fv that are capable of binding the epitopic determinant. The term "monoclonal antibody" is contemplated to include fully human antibodies produced in a non-human transgenic animal species.

Functional antibody fragments retain some ability to selectively bind with their respective antigen or receptor and are defined as follows:

(1) Fab, the fragment which contains a monovalent antigen-binding fragment of an antibody molecule, can be produced by digestion of whole antibody with the enzyme papain to yield an intact light chain and a portion of one heavy chain;

(2) Fab', the fragment of an antibody molecule that can be obtained by treating whole antibody with pepsin, followed by reduction, to yield an intact light chain and a portion of the heavy chain; two Fab' fragments are obtained per antibody molecule;

(3) (Fab')₂, the fragment of the antibody that can be obtained by treating whole antibody with the enzyme pepsin without subsequent reduction; F(ab')₂ is a dimer of two Fab' fragments held together by two disulfide bonds;

(4) Fv, defined as a genetically engineered fragment containing the variable region of the light chain and the variable region of the heavy chain expressed as two chains; and

(5) Single chain antibody ("SCA"), a genetically engineered molecule containing the variable region of the light chain and the variable region of the heavy chain, linked by a suitable polypeptide linker as a genetically fused single chain molecule. Methods of making these fragments are known in the art. (See for example, Harlow & Lane, Antibodies: A Laboratory Manual. Cold Spring Harbor Laboratory, New York, 1988, incorporated herein by reference). As used in this invention, the term "epitope" means any antigenic determinant on an antigen to which the paratope of an antibody binds. Epitopic determinants usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and usually have specific three dimensional structural characteristics, as well as specific charge characteristics.

Antibody fragments of the present invention can be prepared by proteolytic hydrolysis of the antibody or by expression in E. coli of DNA encoding the fragment. Antibody fragments can be obtained by pepsin or papain digestion of whole antibodies by conventional methods. For example, antibody fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a 5S fragment denoted F(ab')₂. This fragment can be further cleaved using a thiol reducing agent, and optionally a blocking group for the sulfhydryl groups resulting from cleavage of disulfide linkages, to produce 3.5S Fab' monovalent fragments. Alternatively, an enzymatic cleavage using pepsin produces two monovalent Fab' fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg, U.S. patents No. 4,036,945 and No. 4,331,647, and references contained therein, which patents are hereby incorporated in their entireties by reference. See also Nisonhoff et al, Arch. Biochem. Biophys. £2:230, 1960; Porter, Biochem. J. 21:119, 1959; Edelman et al., Methods in Enzymology. Vol. 1, page 422 Academic Press, 1967; and Coligan et al. at sections 2.8.1-2.8.10 and 2.10.1-2.10.4. Other methods of cleaving antibodies, such as separation of heavy chains to form monovalent light-heavy chain fragments, further cleavage of fragments, or other enzymatic, chemical, or genetic techniques may also be used, so long as the fragments bind to the antigen that is recognized by the intact antibody.

Fv fragments comprise an association of V_H and V_L chains. This association may be noncovalent, as described in Inbar et al., Proc. Nat 'I Acad. Sci. USA 69:2659. 1972. Alternatively, the variable chains can be linked by an intermolecular disulfide bond or cross-linked by chemicals such as glutaraldehyde. See, e.g., Sandhu, supra. Preferably, the Fv fragments comprise V_H and V_L chains connected by a peptide linker. These single-chain antigen binding proteins (sFv) are prepared by constructing a structural gene comprising DNA sequences encoding the V_H and V_L domains connected by an oligonucleotide. The structural gene is inserted into an expression vector, which is subsequently introduced into a host cell such as E. coli. The recombinant host cells synthesize a single polypeptide chain with a linker peptide bridging the two V domains. Methods for producing sFvs are described, for example, by Whitlow et al, Methods: a Companion to Methods in Εnzvmologv. 2: 97, 1991; Bird et al, Science 242:423-426, 1988; Pack et al, Bio/Technology 11:1271-77,

1993; Sandhu, supra, and Ladner et al, U.S. patent No. 4,946,778, which is hereby incorporated by reference in its entirety.

Another form of an antibody fragment is a peptide coding for a single complementarity-determining region (CDR). CDR peptides ("minimal recognition units") can be obtained by constructing genes encoding the CDR of an antibody of interest. Such genes are prepared, for example, by using the polymerase chain reaction to synthesize the variable region from RNA of antibody-producing cells. See, for example, Larrick et al, Methods: a Companion to Methods in Εnzvmology. 2: 106, 1991.

Antibodies which bind to a tumor cell or other disease-associated antigen can be prepared using an intact polypeptide or biologically functional fragment containing small peptides of interest as the immunizing antigen. The polypeptide or a peptide used to immunize an animal (derived, for example, from translated cDNA or chemical synthesis) can be conjugated to a carrier protein, if desired. Commonly used carriers that are chemically coupled to the peptide include keyhole limpet hemocyanin (KLH), thyroglobulin, bovine serum albumin (BSA), and tetanus toxoid, and the like. The coupled peptide is then used to immunize the animal (e.g., a mouse, a rat, or a rabbit).

The preparation of such monoclonal antibodies is conventional. See, for example, Kohler & Milstein, Nature 256:495_τ 1975; Coligan et al., sections 2.5.1- 2.6.7; and Harlow et al, in: Antibodies: a Laboratory Manual, page 726 (Cold Spring Harbor Pub., 1988), which are hereby incorporated by reference. Briefly, monoclonal antibodies can be obtained by injecting mice with a composition comprising an antigen, verifying the presence of antibody production by removing a serum sample, removing the spleen to obtain B lymphocytes, fusing the B lymphocytes with myeloma cells to produce hybridomas, cloning the hybridomas, selecting positive clones that produce antibodies to the antigen, and isolating the antibodies from the hybridoma cultures. Monoclonal antibodies can be isolated and purified from hybridoma cultures by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein-A Sepharose, size-exclusion chromatography, and ion-exchange chromatography. See, for example, Coligan et al, sections 2.7.1-2.7.12 and sections 2.9.1-2.9.3; Barnes et al, Purification of Immunoglobulin G (IgG), in: Methods in Molecular Biology. Vol. 10, pages 79-104 (Humana Press, 1992).

Antibodies of the present invention may also be derived from subhuman primate antibodies. General techniques for raising therapeutically useful antibodies in baboons can be found, for example, in Goldenberg et al, International Patent Publication WO 91/11465 (1991) and Losman et al, 1990, Int. J. Cancer 46..310, which are hereby incorporated by reference. Alternatively, a therapeutically useful antibody may be derived from a "humanized" monoclonal antibody. Humanized monoclonal antibodies are produced by transferring mouse complementarity determining regions from heavy and light variable chains of the mouse immunoglobulin into a human variable domain, and then substituting human residues in the framework regions of the murine counterparts. The use of antibody components derived from humanized monoclonal antibodies obviates potential problems associated with the immimogenicity of murine constant regions. General techniques for cloning murine immunoglobulin variable domains are described, for example, by Orlandi et al, Proc. Nat'lAcad. Sci. USA £6:3833,1989, which is hereby incorporated in its entirety by reference. Techniques for producing humanized monoclonal antibodies are described, for example, by Jones et al, Nature 121:522, 1986; Riechmann et al, Nature 112:323, 1988; Verhoeyen et al, Science 212:1534, 1988; Carter et al, Proc. Nat'lAcad. Sci. USA £2:4285, 1992; Sandhu, Crit. Rev. Biotech. 12:437, 1992; and Singer et al, J. Immunol. J_5Q:2844, 1993, which are hereby incorporated by reference.

Fully human antibodies produced in a non-human transgenic animal species or cell culture can be obtained commercially by contract production (Protein Design Labs, Inc., Fremont, CA or Abgenix, Inc, Fremont, CA). Methods for producing fully human antibodies are disclosed in U.S. Patents 5,932,448, 5,985,615, 5,882,644, and 5,939,598, the contents of which are incorporated herein by reference, each in its entirety. Such fully human antibod(ies), or functional fragment(s) thereof, are the preferred antibody for use in the invention pain treatment methods to avoid HAMA in the subject treated.

It is also possible to use anti-idiotype technology to produce monoclonal antibodies which mimic an epitope. For example, an anti-idiotypic monoclonal antibody made to a first monoclonal antibody will have a binding domain in the hypervariable region which is the "image" of the epitope bound by the first monoclonal antibody.

In another embodiment of the invention method, the ligand moiety in the pain- relieving targeting construct used in practice of the invention is selected from among the many biologically compatible tumor-avid compounds that bind with specificity to receptors and/or are preferentially taken up by tumor cells. Tumor-avid compounds that are preferentially "taken up" by tumor cells may enter the cells through surface or nuclear receptors (e.g., hormone receptors), pores, hydrophilic "windows" in the cell lipid bilayer, and the like.

Illustrative of this class of tumor-avid compounds are somatostatin, somatostatin receptor-binding peptides, deoxyglucose, methionine, chromogranin-A, and the like. Particularly useful somatostatin receptor-binding peptides are a long- acting, octapeptide analog of somatostatin, known as octreotide (D-phenylalanyl-L- cysteinyl-L-phenylalanyl-D-tryptophyl-L-lysyl-L-threonyl-N-[2-hydroxy-l- (hydroxymethyl)propyl]-L-cysteinamide cyclic (2→7)-disulfide), lanreotide, an oral formulation of octreotide, P829, P587, and the like. Somatostatin-binding peptides are disclosed in U.S. Patent No. 5,871,711, and methods for linking such peptides covalently to a radioisotope through their carboxyl terminal amino acid under reducing conditions are disclosed in U.S. Patent No. 5,843,401, which are both incorporated herein by reference in their entireties. One of skill in the art can readily adapt such teachings for the preparation of the invention pain-relieving constructs when somatostatin or a somatostatin receptor-binding peptide is used as the tumor-avid ligand moiety.

Somatostatin and somatostatin receptor-binding peptides are particularly effective for use as the tumor-avid ligand moiety in the targeting construct administered in the invention pain treatment methods when treating pain associated with a neuroendocrine or endocrine tumor. Examples of neuroendocrine tumors whose pain can be treated or managed using the invention pain treatment methods include adenomas (GH-producing and TSH-producing), islet cell tumors, carcinoids, undifferentiated neuroendocrine carcinomas, small cell and non small cell lung cancer, neuroendocrine and/or intermediate cell carcinomas, neuroendocrine tumors of ovary, cervix, endometrium, breast, kidney, larynx, paranasal sinuses, and salivary glands, meningiomas, well differentiated glia-derived tumors, pheochromocytomas, neuroblastomas, ganglioneuro(blasto)mas, paragangliomas, papillary, follicular and medullary carcinomas in thyroid cells, Merkel cell carcinomas, and melanomas, as well as granulomas, lymphomas, and the like. These tumor cells are known to have somatostatin receptors and can be targeted using somatostatin or somatostatin receptor binding peptides as the tumor-avid ligand in the invention targeting construct.

Vasointestinal peptide (VIP), which is used in VTP receptor scintigraphy (I. Virgolini, EurJ. Clin. Invest. 22Q_Ω):793-800, 1997, is also useful in the invention method for treatment of pain caused by small primary adenocarcinomas, liver metastases, certain endocrine tumors of the gastrointestinal tract, and the like.

Another molecule illustrative of the tumor-avid ligands that are preferentially taken up by pain-causing tumors is deoxyglucose, which is known to be preferentially taken up in a variety of different types of tumors. Illustrative of the types of tumors for which deoxyglucose can be used as the tumor-avid ligand moiety in pain-relieving targeting construct(s) used in invention methods include melanoma, small-cell and non-small cell lung cancer, colon or rectum, pancreas, Hodgkin's disease and non- Hodgkin's lymphoma, myeloma, ovary, head and neck cancer, breast, brain, pituitary, sarcoma, or liver, testicle, thyroid, bladder or uterus tumor tissue, and the like, and combinations of any two or more thereof.

Yet other tumor-avid ligands that are preferentially taken up by tumors and can be used as the ligand moiety in pain-relieving targeting construct(s) used in invention methods are 1-amino-cyclobutane-l-carboxylic acid and L-methionine. L- methionine is an essential amino acid that is necessary for protein synthesis. It is known that malignant cells have altered methionine metabolism and require an external source of methionine.

Additional examples of biologically compatible tumor-avid ligands that bind with specificity to tumor receptors and/or are preferentially taken up by tumor cells include mammalian hormones, particularly sex hormones, neurotransmitters, and the like. In addition, there are compounds expressed by tumor cells to communicate with each other that are preferentially taken up by tumor cells, such as novel secreted protein constructs arising from chromosomal aberrations caused by transfers or inversions within the clone, and the like. Such tumor-produced proteins and polypeptides are referred to herein as "marker proteins and polypeptides" because, like tumor antigens, they are predominantly found only associated with a disease site, and not with not with normal tissue.

The term "hormone" is used herein to refer to compounds that are expressed within a mammal for action at a remote location and includes such compounds as sex hormones, cell growth hormones, cytokines, endocrine hormones, erythropoietin, and the like. As is known in the art, a number of tumor types express receptors for hormones, for example, estrogen, progesterone, androgens, such as testosterone, and the like, in a concentration greatly in excess of that found in healthy tissue. Such hormones are preferentially taken up by tumor cells, for example, via specific receptors. It is also known in the art that the particular type of receptors expressed by a tumor cell may change over time with the same cell or cell mass, for example, expressing estrogen receptors at one point in time, but having the estrogen receptors substantially replaced with androgen receptors at another point in the development of the tumor.

Therefore, it may be desirable or necessary to prescreen the subject to determine what type of tumor cells or other abnormal tissue is present at the site of pain using methods known in the art. For example, in many cases it is beneficial to determine which receptors are currently being expressed by the target cells (i.e., those suspected of causing the pain) if the ligand moiety targets a particular type of receptor. Methods for prescreening a patient to determine the particular receptors or antigens being expressed by a tumor (for example one causing intractable pain) are known in the art and are also disclosed in co-pending U. S. Patent Application Serial No. 09/362,805, filed July 28, 1999, which is incorporated hereby by reference in its entirety.

Methods for obtaining test tumor cells for prescreening to determine the type(s) of tumor-avid compounds that are currently being taken up (e.g., by specific receptors expressed by the tumor cells) are well known in the art. For example, such techniques as fine needle aspirates, scrapings, excisional biopsies, and the like, can in many instances be utilized to obtain test tumor cells relatively non-invasively.

In the practice of the present invention, the pain-relieving agent can be linked to the ligand moiety in the targeting construct by any method presently known in the art for attaching two moieties, so long as the attachment of the linker moiety to the ligand moiety does not substantially impede binding of the targeting construct to the target tissue and/or uptake by the tumor cells and does not substantially reduce the pain-relieving action of the pain-relieving agent. Those of skill in the art will know how to select a linker that meets these requirement. For example, it is important not to use a linker that would substantially reduce the lipophilicity of the lipophilic portion of a local anesthetic. In addition, with regard to octreotide, it has been shown that coupling of a linker to Tyr3 or Phel of octreotide does not prevent the internalization of octreotide after binding to the somatostatin receptor (L.J. Hofland et al, Proc. Assoc. Am. Physicians 1 11 :63-9. 1999). It is also known that 1-amino- cyclobutane-1-carboxylic acid can be tagged at the 3 carbon of the ring.

The length of the optional linker moiety is generally or preferably chosen to optimize the kinetics and specificity of ligand binding, including any conformational changes induced by binding of the ligand moiety to a target, such as an antigen or receptor. The linker moiety should be long enough and flexible enough to allow the ligand moiety and the target to freely interact and not so short as to cause steric hindrance between the proteinaceous ligand moiety and the target.

In a presently preferred embodiment, the linker moiety is a heterobifunctional cleavable cross-linker, such as N-succinimidyl (4-iodoacetyl)-aminobenzoate; sulfosuccinimidyl(4-iodoacetyl)-aminobenzoate; 4-succinimidyl-oxycarbonyl-α-(2- pyridyldithio) toluene ; sulfosuccinimidyl-6-[α-methyl-α-(pyridyldithiol)-toluamido] hexanoate; N-succinimidyl-3-(-2-pyridyldithio)-proprionate; succinimidyl-6-[3(-(-2- pyridyldithio)-proprionamido] hexanoate; sulfosuccinimidyl-6-[3 (-(-2-pyridyldithio)- propionamido] hexanoate; 3-(2-pyridyldithio)-propionyl hydrazide, Ellman's reagent, dichlorotriazinic acid, S-(2-thiopyridyl)-L-cysteine, and the like. Further bifunctional linking compounds are disclosed in U.S. Patent Nos. 5,349,066. 5,618,528, 4,569,789, 4,952,394, and 5,137,877, each of which is incorporated herein by reference in its entirety.

These chemical linkers can be attached to purified ligands using numerous protocols known in the art, such as those described in Pierce Chemicals "Solutions, Cross-linking of Proteins: Basic Concepts and Strategies," Seminar #12, Rockford, IL.

Although not currently preferred, the linker moiety can also be a peptide having from about 2 to about 60 amino acid residues, for example from about 5 to about 40, or from about 10 to about 30 amino acid residues. For example, the linker moiety can be a flexible spacer amino acid sequence, such as those known in single- chain antibody research. Examples of such known linker moieties include GGGGS (SEQ ID NO:l), (GGGGS)„ (SEQ. ID NO:2), GKSSGSGSESKS (SEQ ID NO:3), GSTSGSGKSSEGKG (SEQ. ID NO:4), GSTSGSGKSSEGSGSTKG (SEQ ID NO:5), GSTSGSGKSSEGKG (SEQ ID NO:6), GSTSGSGKPGSGEGSTKG (SEQ ID NO:7), EGKSSGSGSESKEF (SEQ ID NO:8), SRSSG (SEQ. ID NO:9), SGSSC (SEQ ID NO: 10), and the like. A Diphtheria toxin trypsin sensitive linker having the sequence AMGRSGGGCAGNRVGSSLSCGGLNLQAM (SEQ ID NO: 11) is also useful. Alternatively, the peptide linker moiety can be VM or AM, or have the structure described by the formula: AM(G_{2 104}S)_XQAM wherein Q is selected from any amino acid and X is an integer from 1 to 11 (SEQ ID NO: 12). Additional linking moieties are described, for example, in Huston et al, PNAS £.5:5879-5883, 1988; Whitlow, M., et al, Protein Engineering 6:989-995, 1993; Newton et al,

Biochemistry 21:545-553, 1996; A. J. Cumber et al, Bioconj. Chem. 2:397-401, 1992; Ladurner et al, J. Mol Biol. 221:330-337, 1997; and U.S. Patent. No. 4,894,443, the latter of which is incorporated herein by reference in its entirety.

The pain-relieving targeting constructs used in practice of the invention method can be administered by any route known to those of skill in the art, but topical administration (i.e., such as in a cream, gel or ointment) is not preferred. For example, the pain-relieving targeting constructs can be administered intravenously, intracavitarily, intraarticularly, intracisternally, intraocularly, intraventricularly, intrathecally, intramuscularly, intraperitoneally, intradermally, intratracheally, and the like, as well as by any combination of any two or more thereof. The most suitable route for administration will vary depending upon the painful disease site to be treated, or the location of the suspected pain-causing condition or tumor. However, the primary use of the invention methods is in the relief of visceral or bone pain. Therefore, the preferred method of administration is by parenteral (e.g., intravenous) injection, either as a bolus or as an infusion over time.

Upon administration to the subject, the targeting construct is allowed to bind to and/or be taken up selectively in vivo by the target tissue. It should be noted, in this regard, that it is not necessary for the pain-relieving agent in the targeting construct to enter a tumor or other disease structure in order to provide pain relief to tissue associated with the interior disease site. It is expected that the linkage of the pain- relieving agent to the ligand moiety in some portion of the pain-relieving constructs will be broken down (e.g., by enzymes at or in the vicinity of the interior disease site) so that the pain-relieving agent is delivered to and has its pain-relieving effect on nerves or pain receptors in tissue surrounding the actual disease site.

The targeting construct is administered in a "pain-relieving amount." A pain- relieving amount is the quantity of a targeting construct necessary to aid in delivering pain relief to the subject, for example, down regulation of pain receptors in tissue associated with an interior disease site in a subject. A "subject" as the term is used herein is contemplated to include any mammal, such as a domesticated pet, farm animal, or zoo animal, but preferably is a human. Amounts effective for pain relief will, of course, depend on such factors as the pharmacokinetics of the particular pain- relieving agent used, the size and location of the disease site, the affinity of the targeting construct for the target tissue, the type of target tissue, as well as the route of administration. Comparison of local anesthetics with respect to structure-function activity, dosage, duration of action, and the like, is well known in the art and is disclosed, for example, in Principles of Medicinal Chemistry. 4^th Ed. Williams & Wilkins, Baltimore, 1995, pages 305-320. Comparison of opioid analgesics with respect to dosage, duration of action, and the like, is well known in the art and is disclosed, for example in Goodman & Oilman's The Pharmacological Basis of Therapeutics. 9^th Ed., McGraw-Hill, 1995, pages 524- 535, and in Drugs Facts and Comparisons. Wolters Kluwer, 1999, pages 1376-1383, which are each incorporated herein by reference in their entireties.

Individual subjects may present a wide variation in severity of symptoms and each targeting construct has its unique pain-relieving characteristics, including, affinity of the targeting construct for the target, rate of clearance of the targeting construct by bodily processes, the properties of the pain-relieving agent contained therein, and the like. In addition, subjects treated repeatedly with a pain-relieving agent, such as morphine and its cogeners, develop tolerance, so that the safe and effective dosage increases with use. For example, a pain-relieving amount of morphine can be any dosage within the range from about 1 mg/hr to about 400 mg/hr, but no upper limit is known because the pain-relieving dosage depends upon the dose tolerance (i.e., tolerance to the drug) of the particular subject being treated. Therefore, it will be up to the skilled practitioner to weigh the factors and vary the dosages accordingly using the vast information regarding dosages of pain-relieving drugs that is known in the art.

However, because the targeting construct carries the pain-relieving agent to the site of the pain, an effective level of pain relief as measured by the subject's ability to tolerate the pain without the presence of secondary stress response (e.g., increased blood pressure, heart rate, pupil diameter, and plasma cortisol levels, and local muscle contraction) can be accomplished by administration of a lesser amount of the pain-relieving agent in the invention targeting construct than would be needed if the pain-relieving agent were administered (i.e., injected parenterally) in the free (i.e., unattached) state. Thus, the risk of the complications that may accompany systemic administration of the pain-relieving agent are considerably lessened by the practice of the invention pain treatment methods.

The targeting construct used in invention pain-treatment methods can be formulated as a sterile injectable suspension according to known methods using suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example, as a solution in 1-4, butanediol. Local anesthetics as unprotonated amines tend to be only slightly soluble. Therefore, they are generally prepared as water-soluble salts, usually hydrochlorides.

Sterile, fixed oils are also conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed, including synthetic mono- or diglycerides, fatty acids (including oleic acid), naturally occurring vegetable oils like sesame oil, coconut oil, peanut oil, cottonseed oil, etc., or synthetic fatty vehicles like ethyl oleate, or the like. Buffers, preservatives, antioxidants, and the like, can be incorporated as required, or, alternatively, can comprise the formulation. In one aspect of the invention method(s), the targeting construct is administered in a slow release delivery vehicle, for example, encapsulated in a colloidal dispersion system or in polymer stabilized crystals. Useful colloidal dispersion systems include nanocapsules, microspheres, beads, and lipid-based systems, including oil-in-water emulsions, micelles, mixed micelles, and liposomes. The colloidal system presently preferred is a liposome or microsphere. Liposomes are artificial membrane vesicles which are useful as slow release delivery vehicles when injected or implanted. Some examples of lipid-polymer conjugates and liposomes are disclosed in U.S. Patent No., 5,631,018, which is incorporated herein by reference in its entirety. Other examples of slow release delivery vehicles are biodegradable hydrogel matrices (U.S. Patent No. 5,041, 292), dendritic polymer conjugates (U.S. Patent No. 5,714,166), and multivesicular liposomes (Depofoam^®, Depotech, San Diego, CA) (U. S. Patent Nos. 5,723,147 and 5,766,627). One type of microspheres suitable for encapsulating therapeutic agents for local injection (e.g., into subdermal tissue) is poly(D,L)lactide microspheres, as described in D. Fletcher, Anesth. Analg. £4:90-94, 1997.

Those skilled in the art will appreciate that the exact time period over which the targeting construct delivers pain relief (e.g., the time for substantial release of the targeting construct from the time release formulation or the duration of an infusion of the targeting construct), the timing between repetitive administrations of the targeting construct to the subject, and the number of repeat administrations to the subject, will vary depending upon such factors as the nature and location of the painful disease site, the components of the targeting construct, as well as the age, weight, and general health of the subject, and the like. However, in general, these factors are balanced so as to provide the subject with a period of pain relief ranging from about 4 hours to about 20 days at a time, with the course of treatment being repeated as many times as is necessary and is consistent with the overall therapeutic goals of the subject.

The invention pain-relieving targeting constructs can be produced by well known techniques. For example, well known techniques of protein synthesis can be used to obtain proteinaceous components of the targeting construct if the amino acid sequence of the component is known, or the sequence can first be determined by well known methods, if necessary. Some of the ligand genes are now commercially available. An advantage of obtaining commercially available genes is that they have generally been optimized for expression in E. coli. A polynucleotide encoding a protein, peptide or polynuleotide of interest, can be produced using DNA synthesis technology. Methods for obtaining the DNA encoding an unavailable gene and expressing a gene product therefrom are well known and will not be described here in detail.

"Peptide" and/or "polypeptide" means a polymer in which the monomers are amino acid residues which are joined together through amide bonds, alternatively referred to as a polypeptide. When the amino acids are alpha-amino acids, either the L-optical isomer or the D-optical isomer can be used, the L-isomers being preferred. Additionally, unnatural amino acids such as beta-alanine, phenylglycine, and homoarginine are meant to be included. Commonly encountered amino acids that are not gene-encoded can also be used in the present invention, although preferred amino acids are those that are encodable. For a general review, see, for example, Spatola, A.F., in Chemistry and Biochemistry of Amino Acids, Peptides and Proteins, B. Weinstein, ed., Marcel Dekker, New York, p. 267,1983.

It will be apparent to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof, and therefore, the invention encompasses embodiments in addition to those specifically disclosed in the specification, but only as indicated in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for treating pain associated with an interior disease site in a subject in need thereof, said method comprising: administering to the subject a pain-relieving amount of at least one biologically compatible pain-relieving targeting construct comprising a pain-relieving agent linked to a ligand moiety that selectively binds to or is taken up by tissue associated with a painful interior disease site so as to allow the targeting construct to bind to and/or be taken up selectively by the tissue, whereby the targeting construct delivers pain relief to the subject.

2. The method according to claim 1 wherein the pain-relieving agent is a local anesthetic.

3. The method according to claim 2 wherein the local anesthetic is bupivacaine, ropivacaine, dibucaine, etidocaine, tetracaine, lidocaine, xylocaine, procaine, chloroprocaine, prilocaine, mepivacaine, a salt thereof, or a combination of any two or more thereof.

4. The method according to claim 3 wherein the local anesthetic is lidocaine.

5. The method according to claim 1 wherein the pain-relieving agent is an opioid.

6. The method according to claim 5 wherein the opioid is hydromorphone, oxycodone, morphine, methadone, meperidine, heroin, dihydrocodeine, dihydromorphine, buprenorphine, hydrocodone, mixed mu- agonists/antagonists, mu-agonist/antagonist combinations, a salt thereof, or a combination of any two or more thereof.

7. The method according to claim 1 wherein the pain-relieving agent is an anticonvulsant, Class I antiarrhythmic agent, sodium channel blocker, Cox-2 inhibitor, botulinum toxin, dexmedetomidine, nicotinic receptor agonist, propacetamol, ziconotide, or a combination of any two or more thereof.

8. The method according to claim 7 wherein the sodium channel blocker is gabapentin.

9. The method according to claim 1 wherein the tissue is tumor tissue and the ligand moiety is a tumor-avid ligand.

10. The method according to claim 9 wherein the tumor-avid ligand is a hormone, a hormone receptor binding-peptide, deoxyglucose, somatostatin, a somatostatin receptor-binding peptide, or a combination of any two or more thereof.

11. The method according to claim 9 wherein the tumor-avid ligand is somatostatin or a somatostatin receptor-binding peptide.

12. The method according to claim 9 wherein the tumor tissue is a neuroendocrine or endocrine tumor.

13. The method according to claim 12 wherein the tumor tissue is breast, small-cell and non-small cell lung cancer, Hodgkin's and non-Hodgkin's lymphoma, pancreas, carcinoid, neuroblastoma, pituitary tumor tissue, or a combination of two or more thereof.

14. The method according to claim 11 wherein the somatostatin receptor- binding peptide is octreotide, lanreotide, P587 or P829.

15. The method according to claim 9 wherein the tumor-avid ligand is deoxyglucose.

16. The method according to claim 15 wherein the tumor tissue is melanoma, non-Hodgkin's or Hodgkin's lymphoma, small-cell or non-small cell lung cancer, breast, prostate, colon, rectal, ovarian, or pancreas cancer.

17 The method according to claim 15 wherein the tumor tissue is melanoma, myeloma, sarcoma, head, neck, brain, pituitary, liver, testicle, thyroid, bladder, or uterine cancer.

18. The method according to claim 9 wherein the tumor-avid ligand is 1-amino-cyclobutane-l-carboxylic acid, chromogranin-A, or methionine.

19. The method according to claim 1 wherein the ligand moiety is a monoclonal antibody, or a functional fragment thereof, that is specific for an antigen, marker protein, or polypeptide predominantly associated with the interior disease site.

20. The method according to claim 19 wherein the antibody is a fully human antibody produced in a non-human transgenic animal or cell culture.

21. The method according to claim 19 wherein the antigen is selected from the group consisting of cell surface and intracellular antigens.

22. The method according to claim 19 wherein the antigen is carcinoembryonic antigen (CEA), mammalian epithelial and mesothelial cancer antigens, tumor specific glycoproteins, mucin-type carbohydrate chain antigens, prostate specific antigen (PSA), CA-125, CA-15-3, CA 19-9, MUC-1, MUC-2 TAG 72, HER2/neu, α-feto protein (AFP), β-human chorionic gonadotropin (β-HCG), estrogen receptor proteins, progesterone receptor proteins, epidermal growth factor (EGFr) receptor, prostate specific membrane antigen, CD5, CD19, CD20, CD22, CD23, CD45, Ki-1, or a combination of any two or more thereof.

23. The method according to claim 19 wherein the antibody is specific for colon, breast, or ovarian cancer.

24. The method according to claim 19 wherein the antibody is selected from antibodies to CEA, PSA, PMSA, CA-125, CA 15-3, CA 19-9, HER2/neu, α-feto protein, β-HCG, MUC-1, MUC-2, TAG-72, 5T4, estrogen receptor, progesterone receptor, EGFr, CD5, CD19, CD20, CD22, CD23, CD45, Ki-1, or a combination of any two or more thereof.

25. The method according to claim 19 wherein the antibody is specific for an antigen selected from the group consisting of bacterial, fungal, and viral antigens.

26. The method according to claim 19 wherein the target tissue is selected from the group consisting of cardiac, breast, ovarian, uterine, lung, endothelial, vascular, gastro-intestinal, colorectal, prostatic tissue and endocrine tissue.

27. The method according to claim 19 wherein the fragment is selected from the group consisting of Fab, Fab', (Fab')₂, Fv, and single chain antibody fragments.

28. The method according to claim 1 wherein the targeting construct further comprises a linker moiety for attaching the pain-relieving agent to the tumor-avid moiety.

29. The method according to claim 28 wherein the linker moiety is a heterobifunctional crosslinker.

30. The method according to claim 29 wherein the heterobifunctional cross-linker is selected from the group consisting of N-succinimidyl (4-iodoacetyl)- aminobenzoate; sulfosuccinimidyl (4-iodoacetyl)-aminobenzoate; 4-succinimidyl- oxycarbonyl-α-(2-pyridyldithio) toluene ; sulfosuccinimidyl-6-[α-methyl-α- (pyridyldithiol)-toluamido] hexanoate; N-succinimidyl-3-(-2-pyridyldithio)- proprionate; succinimidyl-6-[3 (-(-2-pyridyldithio)-proprionamido] hexanoate; sulfosuccinimidyl-6-[3(-(-2-pyridyldithio)-propionamido] hexanoate; 3-(2- pyridyldithio)-propionyl hydrazide, Ellman's reagent, and dichlorotriazinic acid.

31. The method according to claim 28 wherein the linker moiety is a peptide having from about 2 to about 60 amino acid residues.

32. The method according to claim 31 wherein the peptide contains amino acid residues having a sequence selected from the group consisting of SEQ ID NOS: 1-10.

33. The method of claim 1 wherein the administering is intravenously, intracavitarily, intraarticularly, intracisternally, intraocularly, intraventricularly, intrathecally, intramuscularly, intravascularly, intraperitoneally, intradermally, or by a combination of any two or more thereof.

34. The method according to claim 1 wherein the administering is by intravenous injection.

35. The method according to claim 1 wherein the administering is systemic.