| PATENT ASSIGNEE'S COUNTRY | USA |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 13.06.2000 |
| PATENT TITLE |
Bradykinin antagonist |
| PATENT ABSTRACT |
A bradykinin antagonist of the formula: (BKAn)(X)(Y) where BKAn is a bradykinin antagonist peptide; Y is a pharmacore; and X is a bridging link chemically joining the BKAn and Y components. -------------------------------------------------------------------------------- |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | May 12, 1995 |
| PATENT REFERENCES CITED |
Carr, "The Effect of Anit-Inflammatory Drugs on Increased Vascular Permeability Induced by Chemical Mediators," The Journal of Pathology, vol. 108 (1), (1972) pp. 1-14. Calixto et al, "Nonpeptide Bradykinin Antagonists", (1991), pp. 97-129 The Journal of Pathology, vol. 108 (1), pp. 1-14 (1972). Cheronis et al, "Bradykinin antagonists: Synthesis and in vitro Activity of Bissuccinimidoalkane Peptide Dimers" Recent Progress on Kinins, (1992) pp. 551-558. Whalley et al., `Novel Peptide Heterodimers Withactions At BK2 And Either u Opioid, NK1 Or NK2 Receptors: In Vitro Studies`, British Journal of Pharmacology, vol. 109, Suppl., 19P, Jul. 1993. Vaverk et al., `Suyccinyl Bis-Bradykinins: Potent Agonists with Exceptional Resistance to Enzymatic Degradation`, Peptide: Struc. and Func., Proceedings of the 8th Amer. Pept. Symp., Pierce Chem. Co., Rockford, IL, pp. 381-384 1983. Stewart et al., Bradykinin Chemistry: Agonists and Antagonist, Advances in Experimental Medicine and Biology, Plenum Press, NY, NY pp. 585-589 1983. Calixto et al., `Nonpeptide Bradykinin Antagonist`, Bradykinin Antagonists: Basic and Clinical Research, Ronald Burch (Ed.), Marcel Dekker Inc., NY, NY, pp. 97-129 1991. Kodama et al., `Dimerization of neurokinin A and B COOH- terminal heptapeptide fragments enhanced the selectivity for tachykinin receptor subtypes`, European Journal of Pharmacology, 151, pp. 317-320 1988. |
| PATENT PARENT CASE TEXT | This data is not available for free |
| PATENT CLAIMS |
What is claimed is: 1. A heterodimer of the formula: (BKAn)(X)(Y) where BKAn is a bradykinin antagonist peptide; Y is selected from the group consisting of a neutrophil elastase inhibitor, a cyclooxygenase inhibitor, a NK.sub.1 receptor antagonist, and a NK.sub.2 receptor antagonist; and X is a linking group chemically joining the BKAn and Y components and said linking occurs via the amino acid residue in the 0, 1, 2, 3, 5, or 6 position of said BKAn. 2. A heterodimer according to claim 1, wherein Y is a neutrophil elastase inhibitor. 3. A heterodimer according to claim 1 wherein Y is a cyclooxygenase inhibitor. 4. A heterodimer according to claim 1, wherein Y is an NK.sub.1 receptor antagonist or NK.sub.2 receptor antagonist. 5. A heterodimer according to claim 1, wherein X is hydrolyzable. 6. A heterodimer according to claim 1, wherein X is non-hydrolyzable. 7. A heterodimer according to claim 1, wherein X comprises an amino acid or an amino acid analog incorporated into the BKAn. 8. A heterodimer according to claim 1, wherein X comprises a maleimide/succinimide-based linkage. 9. A heterodimer according to claim 1, wherein X comprises a bissuccinimidoalkane. 10. A heterodimer according to claim 1, wherein the BKAn comprise a cysteine residue in the 6-position; and wherein X forms a linkage through the --S-- atom of the Cys.sup.6 sulfhydryl group of the BKAn. 11. A heterodimer according to claim 1, wherein Y is a neutrophil elastase inhibitor, the BKAn comprise a cysteine residue in the 6-position, and X includes a succinimide group attached to the BKAn through the sulfur atom of the Cys.sup.6 sulfhydryl group of the BKAn. |
| PATENT DESCRIPTION |
The present invention relates to pharmaceutically effective heterodimers comprising a bradykinin antagonist (BKAn) component covalently linked to another different pharmacophore component. In the prior applications mentioned above, there are described bradykinin antagonist dimers of the type: X(BKAn).sub.2 where BKAn represents a bradykinin antagonist peptide and X is a linking group which joins the two BKAn components at points intermediate to their ends. The BKAn substituents may be the same or different. However, also described are certain heterodimers involving the linkage of a BKAn peptide and another peptide of different receptor activity through the linking group X, e.g. an NK.sub.1 or NK.sub.2 antagonist peptide or a mu-opioid receptor agonist peptide. Such heterodimers are particularly useful where there is a close relationship between the activities of concern. Thus, it is known that in a number of pathophysiologically important processes, there is an intimate interaction of inflammatory and neurogenic mediators. This occurs, for example, in both pain secondary to tissue trauma (accidental and post-operative) as well as in asthma. In both situations, there is a complex interplay of tissue and plasma derived mediators (such as kinins acting at BK.sub.2 receptors) and neuronally derived factors such as substance P (NK.sub.1 receptors) and neurokinin A (NK.sub.2 receptors). There are also locally acting neuronal receptors of the mu-opiate class that when stimulated can inhibit the release of the neurogenic peptides regardless of type (substances P, neurokinin A, neurokinin B, cholecystokinin, CGRP, etc.). Given the interaction of these as well as other inflammatory and neurogenic mediators, no one agent is likely to be universally efficacious in ameliorating the symptoms attendant to the pathophysiology. The heterodimers described in the above-noted applications are directed towards addressing these problems with single agents possessing dual selectivity. Other advantages of such heterodimers will also be appreciated by those in the art. BRIEF DESCRIPTION OF THE INVENTION The present invention, in its broadest aspect, is concerned with heterodimers obtained by linking a BKAn peptide to another pharmacophore which is not a bradykinin antagonist, i.e. which may be either a peptide as described in the afore-mentioned applications Ser. No. 07/677,381 and Ser. No. 07/859,582, or a non-peptide, effective against a different, non-bradykinin component responsible, for example, for pain and/or the inflammatory process, or other problems related to or occurring in concert with the activity of the kinins. The resulting compounds are "dual action" compounds that are capable of interacting with two receptor populations or, alternatively, with a receptor and an enzyme. This is not intended to suggest that the single molecule will engage two receptors or a receptor and an enzyme simultaneously; only that the molecule is capable of interacting with either one of two receptor types or with a single class of receptors and/or an enzyme. The overall pharmacological effect of administering such a compound in an appropriate dose, however, is at least the summation of the two types of activities. The compounds can be designed to remain intact or they can be designed to be dissociated into two separate molecules each retaining its own identifiable activity. The heterodimers of the invention can be structurally represented as follows: (Y)(X)(BKAn) where BKAn is a bradykinin antagonist peptide; X is a linking group and Y is a peptide or non-peptide pharmacophore which is not a bradykinin antagonist and demonstrates activity towards a different receptor or enzyme than the BKAn component, preferably one related to pain or the inflammatory process. The present heterodimers offer the possibility of providing a wider spectrum of treatment for pain and inflammation. It is a generally held opinion that in inflammatory states, regardless of severity, the likelihood that a single agent or mediator is completely responsible for all of the clinical manifestations of the syndrome being addressed is extraordinarily small. A corollary to this is that, given the role of bradykinin in inflammatory pathophysiology, any combination therapy used in the treatment of inflammatory disorders should include bradykinin antagonism as part of its overall profile of action. Broad spectrum and potent non-specific therapies (such as the use of steroids in asthma) while perhaps efficacious, carry with them the burdens of undesired and potentially serious side effects and toxicities. In many cases, two discrete mediators are known to act synergistically and to account for an overwhelming proportion of the clinically important manifestations of the disease being treated. Such is the case, for example, with substance-P acting at NK.sub.1 receptors and bradykinin acting at BK.sub.2 receptors in the contexts of asthma and post-traumatic or post-operative pain. Similarly, neutrophil elastase as one of the more important down stream effectors of inflammation and bradykinin as one of the more important initiating and sustaining inflammatory mediators also can be viewed as being synergistic in their actions. The concept of providing homodimers of pharmaceutically active materials to improve such characteristics as metabolic stability, selectivity and receptor binding has previously been described for other systems. This prior work has included the dimerization of peptide agonists and antagonists in order to increase potency and/or duration of action. See, Caporale et al, Proc. 10th American Peptide Symp., Pierce Chemical Co., Rockford, Ill. 449-451 (1988) and Rosenblatt et al, European Patent Application No. EP 293130A2. Thus, dimerization of peptide agonists has been disclosed for enkephalins/endorphins (Shimohigashi, Y., et al, BBRC, 146, 1109-1115, 1987); substance P (Higuchi, Y., et al, E.J.P., 160, 413-416, 1989); bradykinin (Vavrek, R. and Stewart, J., J. Proc. 8th Amer. Pept. Symp., 381-384, 1983); neurokinin A & B, (Kodama, H., et al, E.J.P., 151, 317-320, 1988); insulin (Roth, R. A., et al, FEBS, 170, 360-364, 1984) and atrial natriuretic peptide (Chino, N., et al, BBRC, 141, 665-672, 1986). Dimerization of antagonists has been shown for parathyroid hormone (Caproale, L. H., et al, Proc. 10th Amer. Pept. Symp., 449-451, 1987)). However, the literature has not disclosed heterodimers comprised of a bradykinin antagonist and a different pharmacophore as contemplated herein. BRIEF DESCRIPTION OF DRAWINGS FIGS. 1A and 1B show structural details of some of the compounds or the present invention and some intermediates used in the preparation thereof. FIGS. 2A and 2B show the results obtained with oxymorphone in the mouse formalin test. FIGS. 3A and 3B show the results obtained with compound CP-0127 in the mouse formalin test. FIGS. 4A and 4B show the results obtained with compound CP-0494 in the mouse formalin test. FIGS. 5A and 5B show the results of reverse phase HPLC analysis of metabolites after incubating compound CP-0502 with human plasma, followed by acid precipitation of plasma proteins. DETAILED DESCRIPTION OF THE INVENTION Numerous bradykinin antagonist peptides are known in the art and any of these may be used for present purposes to provide the BKAn substituent of the present dimers. One of the more potent bradykinin antagonists in vitro is the peptide having the formula: D-ARG.sup.0 -Arg.sup.1 -Pro.sup.2 -Hyp.sup.3 -Gly.sup.4 -Phe.sup.5 -Ser.sup.6 -D-Phe.sup.7 -Leu.sup.8 -Arg.sup.9 See Regoli et al, Trends in Pharmacological Science, 11:156-161 (1990). This peptide is referred to herein for convenience as CP-0088. While CP-0088 is a convenient BKAn to use, those in the art will appreciate that other available or known bradykinin antagonist peptides can also be used for present purposes. A wide variety of such bradykinin antagonist peptides have been disclosed in the recent patent literature and any of these can be used for present purposes. See, for example, EP-A-0334244 (Procter and Gamble) which discloses nona- and larger bradykinin antagonist peptides in which certain amino acid residues are modified. EP-A-0370453 (Hoechst) and WO 89/01780 and WO 89/01781 (Stewart et al) also describe bradykinin antagonist peptides. None of these patent publications appears to show dimers as contemplated herein. However, as noted, the peptides of these publications can be used in the practice of the present invention. Any linking group X may be used for present purposes to chemically or covalently link together the BKAn and Y components provided this does not interfere with the activity of the components BKAn and Y. The linking group may be inorganic (e.g. --S--) or organic and may be selected so as to hydrolyze or otherwise dissociate in order to liberate the two active components BKAn and Y in vivo. Alternatively, the linking group may be such that the heterodimer remains intact when used. Conveniently the linking group X can include an --S-- atom derived by reacting a sulfhydryl group on the BKAn peptide chain with the other pharmacophore component. This can be accomplished by reaction involving a cysteine (Cys) sulfhydryl group within the peptide chain, i.e. intermediate the ends of the peptide. This may require initially modifying the starting BKAn peptide so that it includes a Cys group in the appropriate position in the peptide chain. For example, CP-0088 may be modified by replacing the Ser in the 6-position with Cys (such modified CP-0088 being called CP-0126 hereinafter) to provide for convenient linking to the other pharmacophore through the Cys sulfhydryl. CP-0126 can be structurally illustrated as follows: ##STR1## In abbreviated fashion, the formula may be stated as: DR-R-P-J-G-F-C-DF-L-R Using Cys as the position of attachment, the linking group X then includes the --S-- of the cysteine sulfhydryl. This may be the entire linking group X (as in a disulfide based dimer) or only a part thereof. Thus, for example, the linking group may comprise a bissuccinimidoalkane such as bissuccinimidohexane joined at its end to the BKAn and Y components. These and other linking groups are disclosed in the related applications referred to earlier herein and any of these may be used for present purposes. Other linking groups X, some of which do not require or contained an --S-- atom, can be derived from the six families of compounds listed below which can be generically categorized as amino acid analog linkers or maleimide-based linkers. These linkers are included as examples only and are not intended to be totally inclusive of all potential linking moieties: ##STR2## The amino acid analog linkers (Class I) can be directly incorporated into the peptide chain of the BKAn and then used to form esterase stable or labile heterodimers with the geminal pharmacophore (component Y). Alternatively, the maleimide based linker can be reacted with the desired pharmacophore and then conjugated to a sulfhydryl containing peptide. Finally, linkers from any of these families of compounds which contain --CO.sub.2 H as the R.sub.3 moiety can be reacted with another linker from these classes of compounds to form esterase labile (R.sub.3 =--OH containing linkers) or esterase stable (R.sub.3 =--NH.sub.2 containing linkers) which can then be used to form the desired peptide/non-peptide heterodimer. R.sub.1 and R.sub.2 can be varied so as to provide for completely unhindered or significantly hindered access to the carbonyl carbon of an ester based linking element so that the rate of in vivo hydrolysis of said ester can be controlled as desired. Certain of the linker-modified BKAns or pharmacophores used herein to prepare the dimers of the invention are themselves novel and constitute a further aspect of the invention. The component Y of the present heterodimers may be any peptide or non-peptide pharmacophore, other than a bradykinin antagonist, which demonstrates activity towards a different (non-bradykinin) component related to pain and/or the inflammatory process so as to provide dual action compounds that are capable of interacting independently with two different receptor populations or a receptor and an enzyme. Thus, for example, the component Y may be a non-peptide mu-opioid receptor agonist, e.g. morphine or one of its derivatives such as oxycodone or oxymorphone. Indomethacin is a useful choice for the Y component when cyclooxygenase inhibition (COI) is desired. However, any of the other conventional non-steroidal anti-inflammatory agents, such as aspirin, ibuprofen, naproxyn or the like can be used. In this case, the BKAn/COI heterodimer may need to be hydrolyzed in order to obtain in vivo COI activity as cyclooxygenase is generally considered to be an intra-cellular enzyme. Where neutrophil elastase inhibition is required, this may be an active ester, e.g. one of those described in U.S. applications Ser. No. 07/528,967, filed May 22, 1990; Ser. No. 07/692,322, filed May 2, 1991 or Ser. No. 07/841,608, filed Feb. 25, 1992, the contents of which are incorporated herein by reference. The esters described in said applications are 2-phenyl-alkanoate esters. There may also be used a heteroaryl alkanoate esterase inhibitor as described in Ser. No. 07/866,301, filed Apr. 13, 1990 and Ser. No. 07/610,207, filed Nov. 7, 1990, the contents of which are included herein by reference. A preferred neutrophil elastase inhibitor for use herein as component Y is identified below as CE-1218. This is believed to be a new compound and constitutes a further feature of the present invention. Other types of elastase inhibitors which may also be used as component Y, include fluoromethyl ketones, phosphonates, benzoxazoles, beta-lactams, etc. As noted earlier, component Y may comprise a peptide or non-peptide inhibitor having a desired activity other than bradykinin antagonist activity. However, the Y component is preferably selected to provide activity against receptors or enzymes which have a common or close relationship to the activity of bradykinin, e.g. the treatment of pain or inflammation. The rationale for using combinations of a BKAn with a mu-opioid receptor agonist, neutrophil elastase inhibitor, cyclooxygenase inhibitor or NK.sub.1 or NK.sub.2 receptor antagonist in various conditions is discussed below for purposes of illustration. BKAn/mu-opioid Receptor Agonists C-Fiber afferents are known to mediate both the sensation of pain as well as the neurogenic component of inflammation. These afferent neurons release a variety of neuropeptides in response to specific and non-specific stimuli in both the central nervous system (CNS) as well as in the peripherally innervated tissues. Some of these neuropeptides include: substance-P, neurokinin A, neurokinin B, calcitonin gene related peptide (CGRP), cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP), and neuropeptide Y, among other neurotransmitters. To add to this complexity, different C-fibers appear to contain different amounts and/or ratios of these neuropeptides depending on the tissue innervated. All of these peptides have been shown to play contributory roles in the various neurogenic processes that have been implicated in numerous diseases and clinical syndromes. In fact, specific antagonists to these peptides are being developed as potential therapeutics by a variety of pharmaceutical companies and independent research laboratories. One apparently common feature among this otherwise diverse group of neurons is that they all have mu-opioid receptors that modulate the release of these neuropeptides. Both the endogenous enkephalins as well as other exogenously administered small molecular weight compounds such as morphine, oxymorphone, fentanyl and their derivatives will inhibit the release of the neuropeptides from peripheral C-fibers by acting as mu-opioid receptor agonists locally (at terminal mu-opioid receptors in the periphery) and in the CNS. This inhibition is independent of both the constellation of peptides contained in the specific C-fiber as well as the stimulus causing their release. As a result, one important class of compounds considered to have a particularly good profile of activities for the treatment of conditions that are produced by combined humoral and neurogenic processes are BKAn/mu-opioid receptor agonist heterodimers. These compounds would be expected to attenuate or block both the humoral component of the inflammatory process as represented by the kinins as well as the neurogenic aspects of inflammation produced by the release of the neuropeptides. In addition, one of the limiting aspects of the use of existing mu opioid agonists is their propensity to produce sedation, confusion, and a depressed respiratory drive, not to mention their potential for the development of addiction and/or tolerance in the patients being treated with these agents. These undesirable aspects of mu-opioid receptor agonists are due to their ability to easily penetrate the CNS. BKAn/mu-opoid receptor agonist heterodimers, however, should not penetrate the CNS due to the highly cationic nature of the BKAn. Consequently, mu-opoid receptor agonist activity should be limited to the periphery and should result in a substantially reduced side effect/toxicity profile for these types of compounds. BKAn/Neutrophil Elastase Inhibitor (NEI) As previously mentioned the control of both systemic and local inflammatory responses may require interventions in more than one inflammatory pathway. In particular, the ability to block the activity of a primary mediator responsible for the initiation and maintenance of the inflammatory process (such as bradykinin) and a primary final pathway effector responsible for actual tissue degradation and injury (such as neutrophil elastase) may be a key to "single drug therapy" of sepsis or other severe inflammatory conditions requiring parenteral therapy or for the treatment of inflammatory dermatologic or dental/periodontal conditions. Heterodimers containing combined BKAn/NEI activities can be designed to remain intact or to be dissociable as both targets (bradykinin receptors and neutrophil elastase) are extracellular in nature. However, should dissociation of the two active pharmacophores be desired, linking moieties tethering the two active components of the heterodimer can be designed to be hydrolyzed by, for example, plasma hydrolases. These types of dissociable or hydrolyzable heterodimers are discussed herein. BKAn/Cyclooxygenase Inhibitor (COI) A large proportion of the biological activity of bradykinin is interwoven with the generation of prostaglandins. For example, much of the hyperalgesia associated with inflammatory pain appears to be dependent on the generation of certain prostaglandins both by the injured tissues and by the C-fibers themselves. In the latter case, bradykinin and substance-P appear to be the primary stimuli for these "second messengers". The local generation of prostaglandins by the injured tissues is bradykinin independent. This interaction of peptide pro-inflammatory mediators and prostaglandins occurs in other settings as well and can also be considered a target for dual action compounds. Heterodimers containing combined BKAn/COI activities may need to undergo in vivo dissociation of the respective pharmacophores as cyclooxygenase is an intracellular enzyme and functional bradykinin receptors are limited to the external plasma membrane. BKAn/NK.sub.1 -Receptor Antagonist (NKlAn) Bradykinin and substance-P are known to act synergistically in the initiation and maintenance of the inflammatory and neurogenic components of both asthma and a variety of painful conditions. In both of these situations, bradykinin is one of the more potent, if not the most potent, agents capable of stimulating C-fiber sensory afferents that mediate peripheral pain and/or the sensation of cough and dyspnea in asthma. These neurons, regardless of the primary stimulus, will release substance-P which amplifies and augments the activity of bradykinin and other stimuli at the sensory nerve endings where these stimuli are acting. This "one/two punch" of initial stimulus followed by local amplification is well documented and has significant implications for the success or failure of any single intervention. By targeting both components of these processes with a single compound, it is possible to provide a dually-specific agent which is superior than mono-specific agents used alone and both easier and cheaper to use than combination therapies. BKAn/NK.sub.2 Antagonist (NK2An) Bradykinin's ability to produce acute bronchial smooth muscle constriction is at least partially dependent on the release of neurokinin A by the same C-fibers that release substance-P. Neurokinin A exerts its effect via NK.sub.2 receptors on the bronchial smooth muscle. However, more than just bradykinin can release neurokinin A from these neurons and, as a result, a dually-specific antagonist with combined BK.sub.2 /NK.sub.2 antagonist activity should provide better overall amelioration of bronchoconstriction in the asthmatic patient than any other single agent. The heterodimers of the invention may be prepared in generally the same manner as described in the above-mentioned Ser. No. 07/859,582 and Ser. No. 07/677,391. Normally this involves adding the linking group X to the BKAn component at an appropriate position along the peptide chain followed by joining the non-peptide pharmacophore to the BKAn through the linking group. Alternatively, the linking group may be added to the non-peptide pharmacophore and the BKAn thereafter joined to the linker-modified pharmacophore. Representative procedures are described below although it will be recognized that various modifications may be used. The invention is illustrated but not limited by the following examples: |
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