Repligen Corp. announced Friday that it has filed aninvestigational new drug (IND) application to begin testingrecombinant platelet factor-4 (rPF4) in a Phase I clinical trialwith patients undergoing cardiac catheterization.

Fermented in e. coli extracts of the naturally occurring proteinhave been extensively tested in small animals, Ramesh Ratan,chief financial officer, told BioWorld.

The human safety trial with rPF4, trade-named Replistatin, isthe first in a series of clinical studies planned in cardiovascularprocedures where heparin neutralization is required.

Heparin is used to temporarily block coagulation in somevascular imaging procedures and in the majority ofcardiopulmonary bypass operations. Once the procedures arecompleted, a patient's normal coagulation is generally restoredby neutralizing the heparin.

A collaboration with Massachusetts General Hospital helpedRepligen determine the dose range required for clinical use in arecent study on heparinized human blood removed duringsurgery. The study, reported at the annual meeting of TheAmerican Society of Anesthesiologists in October, also showedReplistatin matched the ability of protamine, the currentneutralizing agent, to restore coagulation.

Preclinical comparative studies published in last March's issueof Circulation demonstrated that Replistatin is as effective asprotamine, but without protamine's adverse effects, and can beadministered more rapidly to hasten its effect and shorten timein surgery.

"This clinical study is an important first step in ourdevelopment of Replistatin for multiple cardiovascularindications," said Sandford D. Smith, president and chiefexecutive officer of the Cambridge, Mass., biopharmaceuticalcompany.

"Also, it was the third IND application Repligen has filed sinceJune 1992, and brings us close to achieving our goal ofinitiating five clinical trials by our 1993 fiscal year close onMarch 31."

Repligen recently received notice of a U.S. patent allowancecovering its use of Replistatin in heparin neutralization.

Repligen's stock (NASDAQ:RGEN) was down 38 cents a share onFriday to $$8.75.

-- Nancy Garcia Associate Editor

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