Glaxo Wellcome Inc. Tuesday ended its five-yearcollaboration with CytRx Corp. on development of thelatter's heart attack drug, RheothRx, sending the Atlantacompany's stock down 57 percent.

The loss of support from Glaxo Wellcome, of ResearchTriangle Park, N.C., was coupled with release of Phase IIItrial results confirming earlier evaluations that the drug'sclinical benefit occurs only at high doses judged too toxicfor patients.

CytRx's stock (NASDAQ:CYTR) closed Tuesday at$1.19, down $1.56.

RheothRx was being tested in combination withthrombolytics to improve blood flow in heart attackpatients, inhibit clot formation and enable damagedtissues to heal. The major adverse side effect waspotential for kidney failure.

The dosage problems were discovered in September 1994and the Phase III trials were completed at lower doselevels. Data released Tuesday showed that in using lowerdoses where toxicity was not a problem RheothRxdemonstrated no clinical benefit.

Jim Yahres, CytRx chief financial officer, said GlaxoWellcome, a subsidiary of London-based Glaxo Holdingsplc, has returned all rights to RheothRx as well as the trialdata.

CytRx began collaborating on RheothRx's developmentin 1990 with Burroughs Wellcome Co., of ResearchTriangle Park, N.C. Burroughs Wellcome, a subsidiary ofthe London-based Wellcome Foundation Ltd., wasacquired by Glaxo Holdings in 1995 in a $15 billion deal.

Yahres said Wellcome has spent $70 million ondevelopment of RheothRx in addition to $9 million itpaid to CytRx for rights to the drug. He said the end ofthe collaboration will not result in loss of researchfunding for CytRx and no changes are planned in thecompany.

CytRx, which has three subsidiaries, is expected to endthe year with $24 million in cash, Yahres said. Heprojected a 1996 burn rate for all four companies ofbetween $4 million and $5 million.

Yahres said the RheothRx trial data will be evaluated byCytRx before any decisions are made on continuingdevelopment. The drug was targeted for indications otherthan heart attacks.

A Phase II trial tested RheothRx for symptoms associatedwith acute sickle cell crisis. Yahres said some patients inthe study experienced a decrease in complications.

Another Phase I trial evaluated RheothRx's use withchemotherapeutic drugs to improve blood flow of thecancer-killing agents to tumors. One patient, Yahresobserved, is still taking RheothRx.

CytRx's three subsidiaries are Vaxcel Inc., whichdevelops vaccine delivery systems; Vetlife Inc., whichtargets the animal health field; and Proceutics Inc., whichprovides preclinical drug development services. n

-- Charles Craig

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