GelTex Pharmaceuticals Inc., a biopharmaceutical startuplocated in Lexington, Mass., announced Wednesday that it hasraised $6.8 million in its first round of venture capitalfinancing. Investors in the private placement, which closedAugust 27, include Domain Partners, New Enterprise Associates,Norwest Venture Capital, Abbingworth Management, Ltd.,Biotechnology Investments Ltd. and PaineWebber R&DPartners.

GelTex was formed in 1992 to develop and commercializeluminal therapies, which are based on the use of non-absorbable, therapeutic polymers to selectively eliminatesubstances from the gastrointestinal tract. The companyreceived approximately $900,000 in seed financing at the timefrom private investors, including Henri Termeer (chairmanand chief executive officer of Genzyme Corp.), GabrielSchmergel (president and CEO of Genetics Institute) and DavidCastaldi (president and CEO of BioSurface Technology Inc.).

GelTex will use the proceeds from the new venture financing toaccelerate development of its products, with a focus on thosedesigned to absorb excess bile acid in the intestine or to sop upphosphates.

The company's products are designed to act in the lumen of thegastrointestinal tract. They are composed of polymers, and aredesigned to act like molecular sponges, binding selectively andtightly to a target compound while absorbing large amounts ofwater. GelTex's platform technology combines molecularrecognition with advanced polymer science. Because companyresearchers build the polymers from specific monomers, theycan design flexibility into the structures. To make thoseresultant polymers specific to a certain target molecule orcompound, the scientists take into consideration suchparameters as the target's hydrophobicity, size and shape,explained Mark Skaletsky, GelTex's president and chiefexecutive officer. "We want to engineer a polymer to bind astightly as it can to the target," he said.

GelTex's most advanced products are polymers for binding bilesalt in the lumen as a way to reduce serum cholesterol levels(bile salts help emulsify fats). Given orally, these hydrogelsapparently do not cause constipation nor do they exhibit overtsigns of toxicity. They are intended to overcome the limitationsof currently available oral formulations and gels, such as thesequestrant Cholestyramine, said Skatetsky. That product"doesn't bind tightly to bile salts. You need to take 25-30 gramsper day to remove one gram of bile acid. Cholestyramineworks, but a big problem is compliance. People don't like theinconvenience of taking so much on a daily basis," Skaletskytold BioWorld. "We designed our product to bind very tightly tobile acid, which means one can use substantially less material,"he added. GelTex intends to supply its product as a gel capsulefor oral delivery.

The company has already tested the product in animal models,and it could be in the clinic by late 1994.

GelTex's other product in advanced development is forremoving excess phosphate from patients who are undergoingkidney dialysis. High phosphate levels are a significant problemfor many of these patients, who have to be put on fairlyrestrictive diets, explained Skaletsky. And they're also oftendosed with calcium acetate, which works in removingphosphate but may add unacceptably high levels of calcium tothese patients' gastrointestinal tracts -- as well as causeconstipation.

GelTex is also developing hydrogel products for removingpotassium (high levels of potassium in the serum can be life-threatening) and other electrolytes. Longer term, the companyis beginning to look at pathogenic organisms that reside in thegut before being taken up --including H. pylori andCryptosporidia, which affects up to one-third of AIDS patientsand can be fatal, Skaletsky told BioWorld.0909GELTEX

-- Jennifer Van Brunt Senior Editor

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