SAN FRANCISCO _ Cadus Pharmaceutical Corp., a four-year-oldprivately held company, has staked out broad claims to a unique drugdiscovery technology with a U.S. patent award for yeast-based assaysto identify compounds that regulate the signals human cells use tocontrol physiological functions.
"This patent is for a fundamental technology of Cadus," said JeremyLevin, president and CEO of the Tarrytown, N.Y.-based company.
Using Cadus' technology, yeast cells are modified with human genesto create a specific human signal transduction pathway triggered by aknown receptor, which is expressed by the yeast cell.
"God made yeast cells similar to human cells," Levin said. Thehybrid human-yeast cells evaluate potential drug candidates not onlyfor binding capability but also for how they biologically affect thereceptor, that is whether they trigger its signal.
"The yeast cells are genetically engineered so their growth dependson activation of the signaling pathway," he explained.
The assays, Levin said, can be used to screen libraries of potentialtherapeutic compounds generated by combinatorial chemistry, naturalproducts and standard chemical methods.
Cadus has two corporate collaborations based on the yeast assays.Bristol-Myers Squibb Co., of New York, and Solvay Group, ofBrussels, have agreed to pay up to a combined $100 million for useof Cadus' technology.
"There are one or two pharmaceutical companies that have attemptedto replicate our methods," Levin said, "and we will be talking tothem. There has been a lot of interest from companies in thistechnology."
Two other methods of screening drug candidates are binding assays,which test whether a compound attaches to a receptor but not if ittriggers biological activity, and mammalian cell assays, which canassess biological function but are expensive.
"In the middle of those two are yeast assays," Levin said."Mammalian cell assays are effective second-tier assays."
With yeast cells, he said, a single signal transduction pathway can beisolated and taken out of the complex milieu of the mammalian cell.
Levin announced the issuance of U.S. patent No. 5,482,835 hereMonday at the 14th Annual Health Care Conference of Hambrecht &Quist Inc., of San Francisco.
Cadus' research has focused on three different receptor systemsresponsible for transferring external signals into cells to regulate theirbehavior. The patent covers yeast-based assays with known receptors,such a G protein-coupled receptors.
However, Levin said Cadus' technology also enables scientists toengineer yeast with orphan receptors, whose functions are not known,and determine how they are affected by potential therapeuticcompounds. Although about 200 G protein-coupled receptors areknown, thousands more are classified as orphan receptors becausetheir biological responsibilities are unknown.
Cadus, Levin said, was founded in 1991 with one patent and now has47 other patent applications filed. Three, including the yeast-basedassay composition and method patent, have been issued.
"We have $30 million in the bank," he added, "and a burn rate of $3million a year." n
-- Charles Craig
(c) 1997 American Health Consultants. All rights reserved.