BioWorld International Correspondent

LONDON - Arrow Therapeutics Ltd. spun out a new company, Immunoprime Ltd., which will use Arrow's core technology platform to develop vaccines and monoclonal antibodies against infectious diseases.

Ian Charles, the company's CEO, told BioWorld International, "Immunoprime is an unusual company because it is an early stage spinout from a company that itself is still in the relatively early stages of development."

Arrow's technology, Transposon-Mediated Differential Hybridization (TMDH), is designed for the simultaneous detection of all genes necessary for bacteria to survive, and it can rank each gene in terms of its relative importance for survival. The company is applying TMDH to the development of small-molecule anti-infectives, with the lead compound, for treating respiratory syncytial virus, in Phase II.

Since its formation in 1998, London-based Arrow has raised more than £40 million (US$75.3 million). Charles, a joint founder and former chief scientific officer of Arrow, is looking for funding for Immunoprime and said the spinout allows Arrow to concentrate on small molecules.

"We feel it is important to maintain focus," he said. "Although we will use the same TMDH technology for finding essential genes, we are interested in different ones for immunotherapeutics - we want the stuff that is expressed on the [cell] surface."

Although Arrow is focused on small molecules, it has experience using the TMDH technology in vaccine development through a collaboration with Acambis plc, of Cambridge, UK, agreed to in June 2003. The agreement covers the development of a vaccine, using TDMH to find all the virulence genes that must be deleted or attenuated in an unnamed pathogen to prevent it from causing disease, while still eliciting a protective immune response.

Immunoprime has coined the term "protecteome" to describe the small number of genes that are essential for bacterial survival and are tractable. The London-based company has selected Staphylococcus aureus as its first project, with the goal of developing a monoclonal antibody and an acellular vaccine against the hospital-acquired infection methicillin-resistant S. aureus.

Following whole-genome analysis, targets are selected on the basis of the likely localization of the proteins they encode.

"It is easier to say you have got the best set of genes if you are looking for small-molecule inhibitors," Charles said. "We are not certain yet we have got the right cut of genes for antibody targets."

It is possible that anti-infectives developed against targets in S. aureus might have a broad-spectrum effect. "We are looking for weak spots in S. aureus that might be weak spots that occur in a number of bugs," he said.

Charles also suggested that Immunoprime's technology could be applied to anticipate when bacteria will develop resistance to an antibiotic. "Bugs have great plasticity, but [it would be possible] to keep track of microbial genomes, and to work out what the consequences of changes will be."