Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Peptide containing doai
Reexamination Certificate
2001-02-21
2002-12-17
Carlson, Karen Cochrane (Department: 1653)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Peptide containing doai
C514S012200, C514S014800, C530S300000, C530S326000
Reexamination Certificate
active
06495516
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to peptides derived from or based on bactericidal/permeability-increasing protein and therapeutic uses of such peptides.
Bactericidal/permeability-increasing protein (BPI) is a protein isolated from the granules of mammalian polymorphonuclear neutrophils (PMNs), which are blood cells essential in defending a mammal against invading microorganisms. Human BPI has been isolated from PMNs by acid extraction combined with either ion exchange chromatography (Elsbach, 1979
, J. Biol. Chem
. 254: 11000) or
E. coli
affinity chromatography (Weiss et al., 1987
, Blood
69: 652), and has potent bactericidal activity against a broad spectrum of Gram-negative bacteria. The molecular weight of human BPI is approximately 55,000 daltons (55 kD). The complete amino acid sequence of human BPI, as well as the nucleotide sequence of DNA encoding BPI, have been elucidated by Gray et al., 1989
, J. Biol. Chem
. 264: 9505, incorporated herein by reference (see
FIG. 1
in Gray et al.).
The bactericidal effect of BPI has been shown to be highly specific to sensitive Gram-negative species. The precise mechanism by which BPI kills Gram-negative bacteria is not yet known, but it is known that BPI must first attach to the surface of susceptible Gram-negative bacteria. This initial binding of BPI to the bacteria involves electrostatic interactions between BPI, which is a basic (i.e., positively charged) protein, and negatively charged sites on lipopolysaccharides LPS). LPS is also known as “endotoxin” because of the potent inflammatory response that it stimulates. LPS induces the release of mediators by host inflammatory cells which may ultimately result in irreversible endotoxic shock. BPI binds to Lipid A, the most toxic and most biologically active component of LPS.
BPI is also capable of neutralizing the endotoxic properties of LPS to which it binds. Because of its Gram-negative bactericidal properties and its ability to bind to and neutralize LPS, BPI can be utilized for the treatment of mammals suffering from diseases caused by Gram-negative bacteria, including bacteremia, endotoxemia, and sepsis. These dual properties of BPI make BPI particularly useful and advantageous for such therapeutic administration.
A proteolytic fragment corresponding to the amino-terminal portion of human BPI possesses the LPS binding and neutralizing activities and antibacterial activity of the naturally-derived 55 kD human holoprotein. In contrast to the amino-terminal portion, the carboxyl-terminal region of isolated human BPI displays only slightly detectable antibacterial activity (Ooi et al., 1991
, J. Exp. Med
. 174: 649). One BPI amino-terminal fragment, comprising approximately the first 199 amino acid residues of the human BPI holoprotein and referred to as “rBPI
23
” (see Gazzano-Santoro et al., 1992
, Infect. Immun
. 60: 4754-4761) has been produced by recombinant means as a 23 kD protein. rBPI
23
has been introduced into human clinical trials. Proinflammatory responses to endotoxin were significantly ameliorated when rBPI
23
was co-administered with LPS.
Other endotoxin binding and neutralizing peptides are known in the art. One example is Limulus antilipopolysaccharide factor (LALF) from horseshoe crab amebocytes (Warren et al., 1992
, Infect. Immunol
. 60: 2506-2513). Another example is a cyclic, cationic lipopeptide from
Bacilus polymyxa
, termed Polymyxin B
1
. Polymyxin B
1
is composed of six &agr;,&ggr;-diaminobutyric acid residues, one D-phenylalanine, one leucine, one threonine and a 6-methyloctanoyl moiety (Morrison and Jacobs, 1976
, Immunochem
. 13: 813-818) and is also bactericidal. Polymyxin analogues lacking the fatty acid moiety are also known, which analogues retain LPS binding capacity but are without appreciable bactericidal activity (Danner et al., 1989
, Antimicrob. Agents Chemother
. 33: 1428-1434). Similar properties have also been found with synthetic cyclized polymyxin analogues (Rustici et al., 1993
, Science
259: 361-365).
Known antibacterial peptides include cecropins and magainins. The cecropins are a family of antibacterial peptides found in the hemolymph of lepidopteran insects (Wade et al., 1990
, Proc. Natl. Acad. Sci. USA
87: 4761-4765), and the magainins are a family of antibacterial peptides found in Xenopus skin and gastric mucosa (Zasloff et al., 1988
, Proc. Natl. Acad. Sci. USA
85: 910-913). These peptides are linear and range from about 20 to about 40 amino acids in length. A less active mammalian cecropin has been reported from porcine intestinal mucosa, cecropin P1 (Boman et al., 1993
, Infect. Immun
. 61: 2978-2984). The cecropins are generally reported to be more potent than the magainins in bactericidal activity but appear to have less mammalian cell cytotoxicity. The cecropins and magainins are characterized by a continuous, amphipathic &agr;-helical region which is necessary for bactericidal activity. The most potent of the cecropins identified to date is cecropin A. The sequence of the first ten amino acids of the cecropin A has some homology with the BPI amino acid sequence 90-99. However, the other 27 amino acids of cecropin A are clearly necessary for its bactericidal activity and there is little homology with BPI for those 27 amino acids. The magainins have even less homology with the BPI sequence.
Of interest to the present application are the disclosures in PCT International Application PCT/US91/05758 relating to compositions comprising BPI and an anionic compound, which compositions are said to exhibit (1) no bactericidal activity and (2) endotoxin neutralizing activity. Anionic compounds are preferably a protein such as serum albumin but can also be a polysaccharide such as heparin. In addition, Weiss et al. (1975
, J. Clin. Invest
. 55: 33-42) disclose that heparin sulfate and LPS block expression of the permeability-increasing activity of BPI. However, neither reference discloses that BPI actually neutralizes the biologic activities of heparin. Heparin binding does not necessarily imply heparin neutralization. For example, a family of heparin binding growth factors (HBGF) requires heparin as a cofactor to elicit a biological response. Examples of HBGF's include: fibroblast growth factors (FGF-1, FGF-2) and endothelial cell growth factors (ECGF-1, ECGF-2). Antithrombin III inhibition of clotting cascade proteases is another example of a heparin binding protein that requires heparin for activity and clearly does not neutralize heparin. Heparin binding proteins that do neutralize heparin (e.g., platelet factor IV, protamine, and thrombospondin) are generally inhibitory of the activities induced by heparin binding proteins that use heparin as a cofactor.
BPI (including amino-terminal fragments thereof) has a number of other important biological activities. For example, BPI has been shown to have heparin binding and heparin neutralization activities in copending and co-assigned parent U.S. patent application Ser. No. 08/030,644 filed Mar. 12, 1993 and continuation-in-part U.S. patent application Ser. No. 08/093,202, filed Jul. 15, 1993, the disclosures of which are incorporated by reference herein. These heparin binding and neutralization activities of BPI are significant due to the importance of current clinical uses of heparin. Heparin is commonly administered in doses of up to 400 U/kg during surgical procedures such as cardiopulmonary bypass, cardiac catherization and hemodialysis procedures in order to prevent blood coagulation during such procedures. When heparin is administered for anticoagulant effects during surgery, it is an important aspect of post-surgical therapy that the effects of heparin are promptly neutrazed so that normal coagulation function can be restored. Currently, protamine is used to neutraize heparin. Protamines are a class of simple, arginine-rich, strongly basic, low molecular weight proteins. Administered alone, protamines (usually in the form of protamine sulfate) have anti-coagulant effects. When administered in the presence of heparin, a stable complex is
Carlson Karen Cochrane
McAndrews Held & Malloy Ltd.
Xoma Technology Ltd.
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