Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Peptide containing doai
Reexamination Certificate
1999-12-13
2003-10-28
Low, Christopher S. F. (Department: 1653)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Peptide containing doai
C514S002600, C514S021800, C514S008100, C530S350000, C530S300000, C530S303000
Reexamination Certificate
active
06638906
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a novel technology for conjugating amphiphilic oligomers and polymers to peptides in order to modulate their pharmacokinetic profile and thereby improve their clinical utility. The conjugates of the invention have the ability to stabilize and deliver luminal cholecystokinin releasing factor (LCRF) to receptors in the gut, without absorption in the bloodstream.
Endogenous LCRF acts at receptors on the luminal surface of gut epithelial cells, causing them to release cholecystokinin (CCK), a polypeptide hormone that induces satiety and reduces food intake, into the bloodstream. Exogenous LCRF, stabilized and delivered to the gut, will mimic normal physiological activity. The chemical modification of peptides regulating feeding behavior has the potential to treat obesity, a serious and growing public health problem in all industrialized nations, especially the United States.
Obesity is near epidemic proportions in industralized countries, and its prevalence is increasing. The pathogenesis of obesity is complex, involving the interaction of lifestyle, dietary, behavorial and genetic factors. It is an object of the present invention to provide a drug that will induce satiety and will thereby produce weight loss.
The role of neuro- and gastric-peptides in regulation of feeding has been a major focus of obesity research. Convincing evidence exists that CCK inhibits feeding. (Schwartz, G. J., Berkow, G., McHugh, P. R., Moran, T. H., “Gastric Branch Vagotomy Blocks Nutrient and Cholecystokinin-induced Suppression of Gastric Emptying,”
Am. J. Physiol.,
264:R630-7 (1993) (the disclosure of which is incorporated herein in its entirety)). Regulation of CCK expression is achieved in large part by regulation of LCRF, which is constitutively expressed in the duodenum in rats. In humans, it is postulated that stimulation by nutrients is required to stimulate secretion of the putative CCK-releasing factor. (Liddle, R. A. “Cholecystokinin Cells,”
Ann. Rev. Physiol.,
59:221-42 (1997) (the disclosure of which is incorporated herein in its entirety)). After a protein meal, proteins in the food saturate the available trypsin, leaving a greater amount of LCRF unhydrolyzed, which then binds to the CCK cells. This causes them to release CCK, leading to satiety.
In one aspect, the conjugates of the present invention can be used to target the LCRF receptor with LCRF, its natural agonist, in order to initiate CCK release.
It is an object of the invention to provide a means for delivering LCRF to its target receptor. This object is achieved by conjugation of PEG oligomers or polymers modified with alkyl groups to proteins and peptides, to improve their pharmacologic properties. The present invention uses amphiphilic oligomer and polymer conjugation to vary the hydrophobicity and hydrophilicity of drug molecules. This reduces immunogenicity, prevents enzymatic degradation and facilitates oral delivery and partitioning to various tissues.
It is another object of the invention to provide conjugated LCRF which will be able to induce CCK release from CCK-releasing cells, leading to satiety and a reduction in food intake. We propose to deliver LCRF using our proprietary amphiphilic polymer conjugation technology, which will protect LCRF from proteolysis and confine it to the lumen of the gut for an extended period of time, producing satiety. We propose that such a conjugated LCRF would be an effective and safe therapeutic for chronic treatment of obesity.
The invention also provides synthetic methods for attaching an amphiphilic polymer to the N-terminal residues of LCRF, a 35 amino acid fragment that exhibits all the biological activity of full-length LCRF.
The amphiphilic conjugate comprises a polyethylene glycol (PEG) moiety and an alkyl chain. The alkyl chain can integrate into membranes on the epithelium of the intestine, bringing the conjugate in close proximity to LCRF receptors, which are located on the CCK-releasing cell surface. Stability of the peptide will be prolonged to maintain bioactivity. Moreover, where greater stability and a reduced tendency to penetrate the intestinal epithelium is required, peptides can be provided with conjugates at the N-terminus, at K19 and the C-terminus.
The operability of the LCRF conjugate molecules can be validated in a cell-based assay, using freshly prepared CCK-releasing cells obtained from rat intestine. A radioimmunoassay (RIA) can be used to detect CCK release.
LCRF is secreted in the duodenum and is physiologically regulated by proteolysis, particularly by trypsin. By protecting LCRF from proteolytic digestion, it will retain activity, bind to, and activate, LCRF receptors on CCK cells.
An amphiphilic polymer can be covalently attached to the &egr; amino group of K19
1
, adjacent to the only trypsin cleavage site in LCRF (1-41), thus protecting LCRF from trypsin proteolysis by steric hindrance. It is preferable that modifications made to LCRF must not obstruct key residues involved in receptor binding. Since it is known that K19 is within the region crucial for receptor binding, it is preferable to attach the K19 conjugate with a linker that is slowly hydrolyzed under conditions found in the duodenum. As the K19 conjugate is released, the peptide then regains full activity. Slow hydrolysis may also extend action of the delivered LCRF, to minimize dosing.
About 55% of the US population is overweight or obese, with serious public health consequences. (The National Heart Lung and Blood Institute in cooperation with The National Institutes of Diabetes and Digestive and Kidney Diseases, “Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults,” NIH Publication no. 998-4083 (1998) (the disclosure of which is incorporated herein in its entirety)). Three of the most serious sequelae of obesity are heart disease, hypertension, and diabetes. Dieting and exercise have been largely unsuccessful long-term strategies for most overweight pepole (Wadden, T. A. “Treatment of Obesity by Moderate and Severe Caloric Restriction, Results of Clinical Research Trials,”
Ann. Intern. Med.,
119:688-693 (1993) (the disclosure of which is incorporated herein in its entirety)); thus there is a need for pharmaceuticals that suppress appetite. One approach to appetite suppression is to induce release of CCK, a peptide hormone that produces satiety and reduces feeding.
CCK is one component of the hormonal system that tightly regulates hunger and satiety, digestion, and disposal of nutrients. CCK has several activities: it induces satiety and reduces food intake; stimulates gallbladder contraction; increases pancreatic enzyme secretion; and delays gastric emptying. When food, especially fat and protein, enters the small intestine, CCK is released into the blood where it binds to receptors in the peripheral nerves, pancreas, gall bladder, and stomach. (Mutt, V. “Secretin and Cholecystokinin,” in “Gastrointestinal Hormones,” 251-320 (ed. V. Mutt, San Diego, Academic Press, 1998) (the disclosure of which is incorporated herein in its entirety)).
CCK release in the intestine is under negative feedback regulation. (Green, G. M. & Lyman, R. L. “Feedback Regulation of Pancreatic Enzyme Secretion as a Mechanism for Trypsin Inhibitor-induced Hypersecretion in Rats,”
Proc. Soc. Exp. Biol. Med.,
140:6-12 (1972) (the disclosure of which is incorporated herein in its entirety)). LCRF is a constitutively produced, trypsin-sensitive intestinal CCK-releasing peptide responsible, in part, for this negative feedback phenomenon. (Lu, L., Louje, D., & Owyang, C. “A Cholecystokinin Releasing Peptide Mediates Feedback Regulation of Pancreatic Secretion,”
Am. J. Physiol.,
256:G430-G435 (1989); Miyasaka, K., Guan, D., Liddle, R. A. & Green, G. M. “Feedback Regulation by Trypsin: Evidence for Intraluminal CCK-releasing Peptide,
Am. J. Physiol.,
257:G175-G181 (1989) (the disclosure of which is incorporated herein in its entirety)).
FIG. 1
(adapted from Miyasaka K & Funakoshi A (1998) P
Barrett, Esq. William A.
Low Christopher S. F.
Myers Bigel Sibley & Sajovec P.A.
Nobex Corporation
Robinson Hope A.
LandOfFree
Amphiphilic polymers and polypeptide conjugates comprising same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Amphiphilic polymers and polypeptide conjugates comprising same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Amphiphilic polymers and polypeptide conjugates comprising same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3143783