Genentech Inc.'s market share for its tissue plasminogenactivator (t-PA), Activase, has climbed steadily since results ofthe GUSTO trial were announced in April and is now up to itsprevious peak of 66 percent, the company announced Friday.

Results from the GUSTO trial were published in the NewEngland Journal of Medicine last week.

Introduced in 1987, Activase obtained a 66 percent overallmarket share in 1990, with sales of $210 million.

But data from the ISIS-3 trial, which were announced in March1991, found no advantage between t-PA, priced at $2,200, andstreptokinase, which costs $200, on mortality rate among heartattack patients. Since then, t-PA's market share began to slip,falling to 56 percent by December 1991 and leveling off at 52percent in 1992, where it remained until last April. Despite thedrop in sales to $182 million, t-PA still accounted for more thanone-third of Genentech's (NYSE:GNE) total 1992 revenues of$554 million.

The results of the GUSTO (Global Utilization of Streptokinaseand t-PA for Occluded Coronary Arteries) study were firstannounced in April at a clinical research meeting inWashington, D.C. The two-year trial -- the largest thrombolyticstudy ever conducted -- included 41,021 heart attack patientsin 1,081 sites in 15 countries. It concluded that t-PA givenconcurrently with heparin statistically saved one more heartattack patient per 100 than streptokinase.

Peter Drake, an analyst with Vector Securities InternationalInc., said the firm's monthly survey of drug distribution foundthat U.S. sales of t-PA grew from $21 million in June to $23million in July. Vector is targeting U.S. Activase sales at $57million for the current quarter and $215 million for the entireyear.

In contrast, sales of SmithKline Beecham's thrombolytic,Eminase, fell 20 percent, from $1.9 million in June to $1.6million in July. Eminase, a modified form of a naturallyoccurring blood protein, had sales of about $14 million in 1992,a fraction of SmithKline's approximate total sales of $9 billion.

Astra Pharmaceuticals, however, reported record sales of itsStreptase (streptokinase). "We've never sold more Streptasethan we are right now," said Stefan Sovell, Astra's vicepresident of finance and administration. The company does notdisclose its sales figures.

Nonetheless, David Stone, an analyst with Cowen & Co., believesthat Genentech of South San Francisco, Calif., will retain two-thirds of the market and maybe a little more. "What pushed itto 50-50" was the inability of physicians to justify the greatercost of t-PA, he said. Now, "armed with data from GUSTO, anyphysician who wants to use it can."

He said that physicians are comfortable using what theylearned in residency, and that factor to some extent hasdetermined the choice of t-PA over streptokinase.

Despite the drug's expense, Stone said t-PA is competitive withother drugs in terms of the money spent per year of life saved."If we touted up the cost of heart medication taken over 10 or20 years" to reduce acute risk, it would be more than the extracost of t-PA, which has an immediate life-saving effect.

The cost of t-PA may still be a significant factor in the clot-buster war. Health management organizations (HMOs), forexample, have taken cost into account when deciding the mostappropriate therapeutic regimen.

In a New England Journal editorial appearing with the GUSTOresults, Valentin Fuster, a physician at Massachusetts GeneralHospital, said, "A critical question about GUSTO needs to beanswered. What is the cost effectiveness of the widespread useof t-PA, given that its apparent survival advantage overstreptokinase (which is considerably less expensive), althoughstatistically significant ... was rather small (an absolutereduction of only 1 percent)? The answer to this question mustawait the further analysis of data from GUSTO and other trialsbefore the accelerated- t-PA strategy can be confidentlyrecommended for general use."

-- Brenda Sandburg News Editor

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