Washington Editor

Medarex Inc. and diaDexus Inc. are expanding an existing collaboration for the research and development of fully human antibody therapeutics against novel cancer targets provided by diaDexus.

Separately, diaDexus granted Medarex, of Princeton, N.J., exclusive right to develop and commercialize therapeutic antibodies to a target for use in ovarian cancer. DiaDexus expects to receive an up-front payment for that right, plus potential milestones and royalties on future sales of products developed and commercialized by Medarex. Patrick Plewman, president and CEO of South San Francisco-based diaDexus, told BioWorld Today specific financial information related to the deal has not been disclosed.

Meanwhile, under the expanded deal (originally signed in January 2003), the partners said they will develop antibodies against three cancer targets outside of lung cancer, the focus of the earlier deal. Medarex plans to use its UltiMAb Human Antibody Development System to generate antibodies to the targets provided by diaDexus.

DiaDexus, a privately held firm, focuses much of its work on developing diagnostic tools like its PLAC test, for quantitative determination of lipoprotein-associated phospholipase A2 in blood to be used as a predictor of risk for coronary heart disease.

In setting up diaDexus as a company in 1997, its founders believed that a subset of its diagnostic test discoveries would be amenable to develop as potential therapeutic antibodies, thus the deal with Medarex, Plewman said.

"So we are providing Medarex with new targets that they can put through their clinical development system," Plewman said. "We have assembled a discovery and early development capability, but we don't have the downstream capabilities, so we look to partner these targets with companies who can progress them into the clinic and ultimately into the commercial field."

Indeed, while officials at Medarex could not be reached Thursday, the firm's president and CEO said in a prepared statement: "We are impressed with diaDexus' ability to identify potential important new targets, as well as their ability to move products into development. We look forward to continuing our collaboration with diaDexus and moving these potential products forward."

As part of the lung cancer deal signed in early 2003, diaDexus was given access to Medarex's UltiMAb technology to generate antibodies to other therapeutic targets outside the collaboration. DiaDexus was founded by SmithKline Beecham (now London-based GlaxoSmithKline plc) and what is today Incyte Corp., of Wilmington, Del. The company is developing several diagnostic products, including one to detect colon cancer.

Medarex's stock (NASDAQ:MEDX) Thursday was up 17 cents to close at $6.75.