NeXstar Pharmaceuticals entered a potential $30 millioncollaboration with Boehringer Mannheim Therapeutics todevelop NeXstar's lipid conjugates with antiviralcompounds in an effort to boost the drugs' effectivenessand reduce toxic side effects.

Boehringer Mannheim, of Gaithersburg, Md., asubsidiary of Bermuda-based Corange Ltd., intends todevelop two nucleoside-lipid conjugates for AIDS and afoscarnet-lipid conjugate for cytomegalovirus retinitis.The AIDS nucleosides and foscarnet are FDA-approveddrugs.

Joe Alper, NeXstar spokesman, said BoehringerMannheim agreed to pay $2 million for each lipidconjugate that makes it to market for a total of $6 millionand will contribute another $20 million in developmentfunds. Boehringer Mannheim also made a $5 millionequity investment in NeXstar, purchasing nearly 300,000shares. NeXstar has about 24 million shares outstanding.

A lipid is a fat molecule. When attached to an antiviralcompound, the lipid facilitates the drug's ability topenetrate infected cells and kill the virus. By using a lipidconjugate, the antiviral drug presumably would be moreeffective at lower doses and less toxic.

Alper noted foscarnet, a chemical compound, has to beused in large doses because of its poor uptake by cells,but one of the side effects is kidney damage.

NeXstar's main collaboration with Boehringer Mannheimwill focus on the foscarnet-lipid conjugate, which may bedeveloped for oral administration. Boehringer Mannheimwill conduct preclinical development, NeXstar will filethe investigational new drug application with the FDAand the companies will share the cost of clinical trials.

The two companies will co-market the foscarnet productin countries where NeXstar has a sales force and NeXstarwill receive 30 percent of gross profits. Elsewhere,Boehringer Mannheim will sell the drug and pay NeXstarroyalties.

Foscarnet is marketed by Astra AB, of Sodertalje,Sweden.

Boehringer Mannheim will develop the nucleoside-lipidconjugates, focusing first on using AZT, which is sold byGlaxo Wellcome plc, of London.

Alper said NeXstar acquired the lipid conjugatetechnology in 1993 from Vical Inc., of San Diego. n

-- Charles Craig

(c) 1997 American Health Consultants. All rights reserved.