LONDON - Ribotargets Ltd. has agreed to a research collaboration with Molecular Simulations Inc. (MSI) to develop and adapt MSI's protein modeling software for modeling RNA and designing RNA-targeted drugs.

Terms were not disclosed, but Simon Sturge, CEO of Ribotargets, which is based in Cambridge, U.K., told BioWorld International, “We are paying MSI a notional fee for access to their software, which would have cost £1 million to license, and will together adapt it for the RNA environment.“

Sturge said the agreement was open on whether the RNA software would subsequently be commercialized by MSI, of San Diego, or if it would be exclusive to Ribotargets. Pharmacopeia Inc., of Princeton, N.J., disclosed in February a proposal to acquire MSI.

The collaboration, he observed, “is critical to the development of Ribotargets. Our whole strategy is based on doing rational drug design around RNA NMR [nuclear magnetic resonance] data.“

The fact that the software works in proteins is a start, but adapting it for RNA means “moving into virgin territory,“ Sturge said.

Ribotargets was set up in July 1997 around research carried out by the U.K. government-funded Medical Research Council. It raised £7 million in its first round - the largest initial fund raising for a U.K. company, and enough to last until 2000.

The initial oral drug candidates, in HIV, hepatitis C and a broad-spectrum antibiotic, block critical RNA-protein interactions necessary for the replication of bacteria and viruses.

Two U.S. patents have been granted defining RNA targets for use in the treatment of HIV. These targets are focussed on the pool of slowly replicating integrated virus, which is resistant to current treatments.

The company claims to be a world leader in the use of NMR to determine the three-dimensional structure of RNA and develop a detailed picture of how drugs bind to RNA in solution. It also has designed proprietary combinatorial chemistry libraries of small molecules that bind specifically to RNA.

Sturge said the company is currently “recruiting like crazy.“ It is looking for 15 postdoctoral students and has been “overwhelmed by 700 top quality candidates from all over the world.“

He believes that as the first company to specialize in RNA, Ribotargets “has struck a cord.“ Among recruits already on board are Cathy Prescott, formerly head of London-based SmithKline Beecham plc's RNA program. *