Genentech Inc.'s tissue plasminogen activator (t-PA) resulted infewer deaths and major complications compared withSmithKline Beecham Corp.'s APSAC (Eminase) or a combinationof the two, according to results of the fourth Thrombolysis inMyocardial Infarction (TIMI-4) study.
Results of the double-blind, 382-patient trial were presentedon Tuesday at the American Heart Association's AnnualScientific Sessions in Atlanta.
Christopher Cannon of Brigham and Women's Hospital in Bostonreported that at one-year follow-up, only 6.8 percent ofpatients receiving front-loaded t-PA had died, compared with19 percent of APSAC-treated patients and 13.3 percent of thosetreated with the combination. Front-loaded t-PA signifies thatthe drug was administered over 90 minutes instead of overthree hours, as indicated in approved labeling. All patientsreceived IV heparin and aspirin.
In addition, the TIMI-4 study found that 42 percent of patientsin the t-PA group experienced an "unsatisfactory outcome"compared with 52 percent in the APSAC group and 57 percentin the combination group (unsatisfactory outcomes includeddeath, intracranial hemorrhage, severe heart failure or shock,ejection fraction<40 percent, reinfarction, major spontaneoushemorrhage, incomplete reperfusion, reocclusion oranaphylaxis).
Cannon said the difference in mortality corresponded withsignificant differences in early patency. In the t-PA group, 78percent of patients had open arteries after only 60 minutescompared with 59 percent in each of the other two groups.Patency was also significantly better in the t-PA group at 90minutes.
Three other major studies have compared t-PA with otherthrombolytic regimens: GISSI-2 (Gruppo Italiano per lo Studiodella Streptochinasi nell'Infarto Miocardico), ISIS-3 (the thirdInternational Study of Infarct Survival) and GUSTO (GlobalUtilization of Streptokinase and T-PA for Occluded CoronaryArteries Trial).
The 12,000-patient GISSI-2 trial compared streptokinase witht-PA, with and without heparin, and the 46,000-patient ISIS-3trial compared three regimens, streptokinase and aspirin withand without heparin, duteplase (a form of t-PA produced byBurroughs Wellcome Co.) and APSAC.
Both studies found no difference in mortality between thethrombolytics, but streptokinase-treated patients hadsignificantly fewer strokes than patients treated with either t-PA or APSAC.
The 41,000-patient GUSTO trial found that t-PA given incombination with heparin statistically saved one more heartattack patient per 100 compared with streptokinase, whichcosts one-tenth as much.
Genentech's stock (NYSE:GNE) closed at $46.75 per share onTuesday, down 25 cents.
-- Brenda Sandburg News Editor
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