Encycle Therapeutics, a Toronto-based drug discovery company that enables the synthesis of a new type of constrained peptide called “nacellins,” has entered a research collaboration with Pfizer. The companies will partner to optimize certain nacellins, which were previously identified by Pfizer during a screening of Encycle’s nacellin library, that act on an undisclosed therapeutic target.
 
Nacellins are a type of peptide macrocycle that can often exhibit higher permeability, solubility, and stability compared to conventional constrained peptides. The synthetic method for preparing nacellins has the ability to cyclize very small peptides that are not normally amenable to constraint at a lower cost and higher yield compared to traditional methods.
 
“We’re very pleased to continue to build our relationship with Pfizer,” said Encycle Therapeutics president and chief executive officer, Dr. Jeffrey Coull. “Unlike small molecules, nacellins can disrupt protein-protein interactions with high affinity, but unlike biologics, they can render this modulation while maintaining drug-like properties, including oral bioavailability. Considering that it is estimated that only a small proportion of the proteome is druggable using conventional therapeutics, we believe that our technology has enormous potential to underpin new therapeutic strategies.”
 
Spiros Liras, vice president of Medicinal Chemistry at Pfizer, said, “Encycle has made progress in demonstrating the potential of nacellins to underpin novel leads for difficult targets, and we look forward to continuing our work together.”