BioRexis was studying ways to activate glucagon-like peptide 1 (GLP-1), a well-known gastrointestinal hormone that causes insulin to be produced by the islet cells of the pancreas. Pfizer was also developing a GLP-1 activator and will add BioRexis' expertise to the research programme.
In its natural form, GLP-1 would have to be administered continuously to treat diabetes. To combat this, longer lasting versions of GLP-1 have been developed. One example is Byetta (exenatide), which was developed by Eli Lilly and Amylin. However, Byetta still needs to be administered via injection. A small molecule that activates GLP-1 would represent a significant step forward in diabetes therapies because it could be given in a much more convenient oral form.
There are nearly 250 million people worldwide who suffer from diabetes, according to the International Diabetes Federation (IDF). The disease is characterised by a lack of the hormone insulin or insulin resistance.
As well as moderating insulin production, GLP-1 also prevents the pancreas releasing glucagons, a peptide that causes glucose levels in the blood to increase.
Researchers from Pfizer, in collaboration with Novo Nordisk and the University of Copenhagen, recently tested 500,000 small molecules in an attempt to find one that activated GLP-1. However, using a functional assay, they discovered that a specific type of molecule known as a substituted quinoxaline activated the peptide.
By systematically varying the substituted part of the molecule, they created a molecule that increased insulin release in normal mouse islet cells but not in mouse cells lacking the GLP-1 receptor.
Although, the compound was not particularly potent, it may prove a useful starting point for further studies.
As well as acquiring BioRexis' compounds, Pfizer has also gained a protein engineering technology from the company. Based on the human transferrin protein, the technology provides therapeutic molecules that last much longer than synthetic peptides. As well as lowering potential doses, the technique could also lead to increased tolerance in patients.
"Through this acquisition, we are investing in a company with exciting technology and potential new product candidates in diabetes," said Edmund Harrigan, head of worldwide licensing and new business development for Pfizer.
"This is an example of how we are persuing compelling science outside our walls in order to deliver new healthcare solutions to customers and patients."
Pfizer are not the only company expanding its interest in diabetes research. AstraZeneca (AZ) recently announced that it had agreed to co-develop and commercialise two of Bristol-Myers Squibb's (BMS) late stage diabetes compounds in a deal worth up to $1.35bn (€1bn).
The most advanced of the candidates is saxagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, currently in Phase III trials.