A study reported Saturday in the British Medical Journal (BMJ)showed that thrombolytic therapy with SmithKline Beecham'sanistreplase was most effective when the heart attack patientsreceived therapy within two hours of the onset of symptoms.

The study corroborated reports presented in April at anAmerican College of Cardiology meeting in Dallas involvingSmithKline Beecham's clot-dissolving agent anistraplase, tradename Eminase, and Genentech Inc.'s clot-buster, Activase.

The two companies' thrombolytics came under fire earlier thisyear when results from an ISIS-3 study showed that new-generation thrombolytics were no more effective than aninexpensive, 30-year-old drug, streptokinase. Unlike thethromboyltics, streptokinase must be given via infusion ratherthan injection.

Saturday's BMJ reported a 37-month, placebo-controlledScottish study aimed at determining the "feasibility, safety andefficacy of domiciliary thromoblysis by general practitioners."

Of 163 acute myocardial infarction patients who receivedanestraplase at home prior to transportation to the hospital, 11died within three months. Of the 148 patients who got theirclot-busting treatment in a hospital, 20 died.

"The median times of injection of active anistreplase at homeand in hospital were 101 and 240 minutes, respectively,"according to the study.

The study reported in Dallas found that mortality amongpatient administered a thrombolytic prior to hospitalizationwas 17 percent lower than among those treated in a hospital.

James F. Buchanan, Genentech's medical informationcoordinator, told BioWorld that in the same study, if treatmentbegan within 70 minutes of the attack's onset, mortality wasonly 1 percent. If delayed between 70 and 180 minutes, 10percent. Among 360 patients in this study, overall deathsamong those treated before reaching the hospital were 7percent compared with 10 percent when treatment wasinitiated in the hospital.

In the Dallas study, the thrombolytic was administered byparamedics in ambulances, while doctors administered thedrug in Scotland to patients at home.

-- David N. Leff Science Editor

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