Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Recombinant dna technique included in method of making a...
Reexamination Certificate
2001-05-02
2004-01-13
Carlson, Karen Cochrane (Department: 1653)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Recombinant dna technique included in method of making a...
Reexamination Certificate
active
06677136
ABSTRACT:
BACKGROUND OF THE INVENTION
A need exists for recombinant or modified therapeutic agents having glucagon antagonist activity.
Recombinant and modified proteins are an emerging class of therapeutic agents. Useful modifications of protein therapeutic agents include combination with the “Fc” domain of an antibody and linkage to polymers such as polyethylene glycol (PEG) and dextran. Such modifications are discussed in detail in a patent application entitled, “Modified Peptides as Therapeutic Agents,” U.S. Ser. No. 09/428,082, PCT appl. No. WO 99/25044, which is hereby incorporated by reference in its entirety.
A much different approach to development of therapeutic agents is peptide library screening. The interaction of a protein ligand with its receptor often takes place at a relatively large interface. However, as demonstrated for human growth hormone and its receptor, only a few key residues at the interface contribute to most of the binding energy. Clackson et al. (1995),
Science
267: 383-6. The bulk of the protein ligand merely displays the binding epitopes in the right topology or serves functions unrelated to binding. Thus, molecules of only “peptide” length (2 to 40 amino acids) can bind to the receptor protein of a given large protein ligand. Such peptides may mimic the bioactivity of the large protein ligand (“peptide agonists”) or, through competitive binding, inhibit the bioactivity of the large protein ligand (“peptide antagonists”).
Phage display peptide libraries have emerged as a powerful method in identifying such peptide agonists and antagonists. See, for example, Scott et al. (1990),
Science
249: 386; Devlin et al. (1990),
Science
249: 404; U.S. Pat. No. 5,223,409, issued Jun. 29, 1993; U.S. Pat. No. 5,733,731, issued Mar. 31, 1998; U.S. Pat. No. 5,498,530, issued Mar. 12, 1996; U.S. Pat. No. 5,432,018, issued Jul. 11, 1995; U.S. Pat. No. 5,338,665, issued Aug. 16, 1994; U.S. Pat. No. 5,922,545, issued Jul. 13, 1999; WO 96/40987, published Dec. 19, 1996; and WO 98/15833, published Apr. 16, 1998 (each of which is incorporated by reference in its entirety). In such libraries, random peptide sequences are displayed by fusion with coat proteins of filamentous phage. Typically, the displayed peptides are affinity-eluted against an antibody-immobilized extracellular domain of a receptor. The retained phages may be enriched by successive rounds of affinity purification and repropagation. The best binding peptides may be sequenced to identify key residues within one or more structurally related families of peptides. See, e.g., Cwirla et al. (1997),
Science
276: 1696-9, in which two distinct families were identified. The peptide sequences may also suggest which residues may be safely replaced by alanine scanning or by mutagenesis at the DNA level. Mutagenesis libraries may be created and screened to further optimize the sequence of the best binders. Lowman (1997),
Ann. Rev. Biophys. Biomol. Struct.
26: 401-24.
Another biological approach to screening soluble peptide mixtures uses yeast for expression and secretion (Smith et al. (1993),
Mol. Pharmacol.
43: 741-8) to search for peptides with favorable therapeutic properties. Hereinafter, this and related methods are referred to as “yeast-based screening.”
Still other methods compete with phage display in peptide research. A peptide library can be fused to the carboxyl terminus of the lac repressor and expressed in
E. coli
. Another
E. coli
-based method allows display on the cell's outer membrane by fusion with a peptidoglycan-associated lipoprotein (PAL). Hereinafter, these and related methods are collectively referred to as “
E. coli
display.” In another method, translation of random RNA is halted prior to ribosome release, resulting in a library of polypeptides with their associated RNA still attached. Hereinafter, this and related methods are collectively referred to as “ribosome display.” Other methods employ peptides linked to RNA; for example, PROfusion technology, Phylos, Inc. See, for example, Roberts & Szostak (1997),
Proc. Natl. Acad. Sci. USA,
94: 12297-303. Hereinafter, this and related methods are collectively referred to as “RNA-peptide screening.” Chemically derived peptide libraries have been developed in which peptides are immobilized on stable, non-biological materials, such as polyethylene rods or solvent-permeable resins. Another chemically derived peptide library uses photolithography to scan peptides immobilized on glass slides. Hereinafter, these and related methods are collectively referred to as “chemical-peptide screening.” Chemical-peptide screening may be advantageous in that it allows use of D-amino acids and other unnatural analogues, as well as non-peptide elements. Both biological and chemical methods are reviewed in Wells & Lowman (1992),
Curr. Opin. Biotechnol.
3: 355-62.
In the case of known bioactive peptides, rational design of peptide ligands with favorable therapeutic properties can be completed. In such an approach, one makes stepwise changes to a peptide sequence and determines the effect of the substitution upon bioactivity or a predictive biophysical property of the peptide (e.g., solution structure). Hereinafter, these techniques are collectively referred to as “rational design.” In one such technique, one makes a series of peptides in which one replaces a single residue at a time with alanine. This technique is commonly referred to as an “alanine walk” or an “alanine scan.” When two residues (contiguous or spaced apart) are replaced, it is referred to as a “double alanine walk.” The resultant amino acid substitutions can be used alone or in combination to result in a new peptide entity with favorable therapeutic properties.
Structural analysis of protein—protein interaction may also be used to suggest peptides that mimic the binding activity of large protein ligands. In such an analysis, the crystal structure may suggest the identity and relative orientation of critical residues of the large protein ligand, from which a peptide may be designed. See, e.g., Takasaki et al. (1997),
Nature Biotech.
15: 1266-70. Hereinafter, these and related methods are referred to as “protein structural analysis.” These analytical methods may also be used to investigate the interaction between a receptor protein and peptides selected by phage display, which may suggest further modification of the peptides to increase binding affinity.
Conceptually, one may discover peptide mimetics or antagonists of any protein using phage display, RNA-peptide screening, yeast-based screening, rational design, and the other methods mentioned above.
SUMMARY OF THE INVENTION
The present invention concerns therapeutic agents that have glucagon antagonist activity with advantageous pharmaceutical characteristics (e.g., half-life). In accordance with the present invention, such compounds comprise:
a) a glucagon antagonist domain, preferably having very little or no glucagon agonist activity, or sequences derived therefrom by rational design, yeast-based screening phage display, RNA-peptide screening, or the other techniques mentioned above; and
b) a vehicle, such as a polymer (e.g., PEG or dextran) or an Fc domain, which is preferred;
wherein the vehicle is covalently attached to the glucagon antagonist domain. The vehicle and the glucagon antagonist domain may be linked through the N- or C-terminus of the glucagon antagonist domain, as described further below. The preferred vehicle is an Fc domain, and the preferred Fc domain is an IgG Fc domain. Preferred glucagon antagonist domains comprise the amino acid sequences described hereinafter in Table 1. Glucagon antagonist domains can be generated by rational design, yeast secretion screening, rational design, protein structural analysis, phage display, RNA-peptide screening and the other techniques mentioned herein.
Further in accordance with the present invention is a process for making therapeutic agents having glucagon antagonist activity, which comprises:
a. selecting at least one peptide having glucagon antagonist activity; and
b. covale
Marshall William S.
Stark Kevin Lee
Amgen Inc.
Carlson Karen Cochrane
Gaul Timothy J.
Levy Ron K.
Odre Steven M.
LandOfFree
Glucagon antagonists does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Glucagon antagonists, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Glucagon antagonists will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3222657