Chronically Acting CFTR Inhibitor Discovery for Secretory Diarrhea and ADPKD -
Project Summary Abstract
DiscoveryBioMed, Inc. (DBM) has launched an innovative and automation-friendly drug discovery program to
screen a collection of small molecular compounds on a human epithelial cell platform expressing
physiologically relevant levels of the wild-type Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)
to discover a new class of therapeutic drugs for secretory diseases. CFTR plays a critical role in the regulation
of Cl- transport and fluid secretion such that hyperactivity of the CFTR Cl- channel results in uncontrolled fluid
secretion. Two CFTR-mediated diseases, secretory diarrhea and Autosomal Dominant Polycystic Kidney
Disease (ADPKD), are driven in part by chronically active CFTR. These diseases demand treatment options
that are effective and readily available due to their widespread impact on public health. Diarrheal illnesses are
a leading cause of death worldwide. Despite the accepted practice of oral rehydration therapy, the incidence of
secretory infection remains alarmingly high; and, thus, there is a constant need to develop drugs that alleviate
diarrheal symptoms. The need to find therapeutic options for ADPKD is even more urgent due to a complete
lack of FDA-approved drugs available for the nearly 12.5 million people suffering from this kidney disease.
DBM recognizes the severity of these clinical problems and has focused our drug discovery efforts in
developing an innovative program that would not only provide possible therapeutic options for the
aforementioned diseases, but would also allow for the mechanistic study of CFTR function in the pathogenesis
of CFTR-mediated diseases, which is also currently limited. The novelty in this drug discovery program
depends on the use of a biologically relevant human cell platform that expresses the disease-relevant target,
wild-type CFTR. DBM embodies the philosophy of 'humanized' drug discovery to increase disease relevance
while decreasing risk in advanced stages of de novo drug screening. It is this core principle that reflects DBM's
unique angle, approach, and offering to the drug discovery space. For this SBIR Phase I application, DBM
presents a series of methodical and focused steps that will aid in the successful completion of this proposal
and are outlined by the following Milestones: 1) Develop and implement a novel drug discovery platform with
human CFBE cells expressing wild-type CFTR to detect potent compounds inhibiting CFTR-mediated Cl-
secretion, 2) Perform de novo HTS of 75,000 small molecular compounds for the discovery of novel CFTR
inhibitors, 3) Validate putative hits as delineated by a robust Critical Path, 4) Establish physiological relevance
for validated hits for ADPKD and secretory diarrhea, and 5) Perform chemoinformatics on validated hits for the
identification of hit-to-lead chemical classes for drug candidate selection and deeper chemical profiling. As an
added benefit, DBM has existing internal CF and ADPKD programs which provide a unique infrastructure of
valuable expertise and resources to help accomplish all Milestones and projected goals. A preliminary proof-
of-concept screen of >5% of the total compound library has been completed, where validated hits and
compounds of interest are now being tested in advanced stages within the Critical Path. DBM seeks SBIR
funds to deepen and accelerate this critical CFTR inhibitor drug discovery program.