BioWorld International Correspondent

Pieris AG entered a research collaboration with Pepscan Therapeutics BV, which provides it with access to the latter firm's CLIPS technology for screening drug candidates that bind G-protein Coupled Receptors (GPCRs).

Pieris, of Freising-Weihenstephan, Germany, is developing anticalins, which are based on a proprietary scaffold derived from a naturally occurring family of ligand-binding proteins called lipocalins. They can bind protein targets with affinities and specificities similar to those of antibodies.

However, they offer several advantages over antibodies, including their small size (20 kiloDaltons), lack of immune effector functions and ease of production in prokaryotic expression systems. They are quickly cleared from the body via the kidney, a feature useful for diagnostic and imaging applications, while their serum half-life can be extended for therapeutic purposes using pegylation.

Terms of the agreement with Pepscan, of Lelystad, the Netherlands, were not disclosed, but the deal encompasses just a single GPCR target. "If it works nicely, I don't see any reason not to continue with other targets," Birgit Zech, senior business development manager at Pieris, told BioWorld International.

The target has been validated clinically, although the partners are not disclosing the indication area at present. "We have a new scaffold technology. We definitely don't want to take the target risk [as well]," Zech said.

GPCRs, ubiquitous membrane-bound transducers of external signals to the interior of cells, rank among the pharmaceutical industry's most heavily exploited drug targets. However, because of their hydrophobicity, they are difficult to work with since they cannot be dissolved in aqueous solution. Pepscan's answer is to present a peptide sequence corresponding to the extracellular domain of a GPCR on a scaffold that conserves the correct conformation. That can be incorporated into screening systems to identify molecules with appropriate binding characteristics.

Pieris was established in 2001 to commercialize the anticalin technology, which was developed by Arne Skerra at the Technical University in Munich. Its lead program concerns an anticalin that binds vascular endothelial growth factor (VEGF), which, Zech said, should enter the clinic in 2009.

It has a collaboration with Fairfield, Conn.-based GE Co.'s GE Health care unit, involving the development of anticalins against two targets for in vivo diagnostic and imaging applications. It regained rights to an asthma program originally partnered with the biopharma unit of Basel, Switzerland-based Syngenta AG, following the latter's decision to exit the drug development arena.

Pieris has raised around €20 million (US$28.84 million) in investment and research funding since its inception. Although it has enough cash to fund operations into 2009, it is seeking further investment due to the high level of interest in the protein scaffold field, Zech said. The company is in parallel discussions with venture capital investors and with potential large pharma strategic partners. It will decide which route it will take early next year, she said, although the company plans to take a selective approach to partnerships. "We really want to restrict them to a number that makes sense to us," Zech said.