Protease Stable N-Terminally Modified Therapeutic Peptides

PROJECT SUMMARY
Peptide therapeutics combine high potency and selectivity, and engender fewer side effects than traditional
small molecules. This has fueled interest in peptides filling the gap between ‘biologics’ and small molecules,
as peptide-based compounds have key desired properties that are distinct both of the other classes. A major
challenge remains to extend the short half-life of native peptides, which are susceptible to rapid enzyme
catalyzed hydrolytic cleavage and inactivation. The applicants have developed a versatile approach to protect
peptides that are truncated in the blood stream by proteases. By making custom-tailored minor appendages
from a diverse range of suitable chemical moieties to the N-terminus of target peptides, substrate recognition
by frontline proteases is abolished whereas interaction with cognate ligand receptors is not compromised.
The goal of the current proposal is to identify optimal appendages for two promising hormone targets, growth
hormone releasing hormone (GHRH) and peptide tyrosine tyrosine (PYY) that in combination with
complementary peptide modifications could be medically exploited with availability of longer acting analogues.
GHRH acts via a combination of growth hormone-dependent and -independent mechanisms that, among other
potential benefits, have been shown to attenuate lipodystrophia in HIV patients. Furthermore, such
compounds hold promise for the treatment of non-alcoholic steatohepatitis in the general population, a
condition where better treatment options are urgently needed. PYY is an enteroendocrine hormone that,
similar to highly successful incretin-based drugs, provides an opportunity to develop analogues for
simultaneously treating type 2 diabetes and obesity. In addition to their promise as stand-alone drugs, long-
acting PYY mimetics also offer an attractive option to synergize with leading incretin medications and thereby
potentiate metabolic benefits of the latter while minimizing side effects.
In an interdisciplinary collaboration between scientists in academia and biotechnology with expertise in
medicinal chemistry, molecular pharmacology, and early in vivo studies, candidate peptide analogues for future
preclinical development will be identified by pursuing 3 Specific Aims: (1) to identify optimized protease-
resistant analogues of GHRH and PYY that retain full agonist activity, (2) to further protect these molecule from
other proteases by side-chain acylations that are also known to delay clearance from the blood stream by
complementary mechanisms, and (3) to assess serum half life of selected analogues following s.c. injection in
mice, leading to the selection of one candidate and one backup each among tested GHRH and PYY analogues
for future preclinical evaluation. Although beyond the scope of the proposed phase 1 proposal, the objective in
an anticipated phase 2 follow-up will be to investigate safety and efficacy of candidates in animal models of
NASH or diabesity as the basis for IND enabling studies.PUBLIC HEALTH RELEVANCE STATEMENT
Peptides with therapeutic potential often suffer from short half-lives because of
protease catalyzed degradation. We use a molecular design based approach to
judiciously modify structures to achieve protease stability while simultaneously
maintaining biological function. This should result in the retention of
potency/efficacy and significantly increase the duration of effect, making the
designed constructs suitable for clinical use for a number of disease indications.