In 1990, about two-thirds of the 150,000 American patients who received clot-dissolving therapy after a heart attack received a drug called TPA (tissue plasminogen activator). It costs $2,200 a dose and in 1991 had grossed sales of $210 million. Another drug, streptokinase, which two studies show is equally effective in saving lives, costs under $300 (most hospitals get discounts to as low as $76). Had all the patients been given streptokinase, about $200 million would have been saved. Seldom, many doctors say, has the extra benefit of one treatment over another seemed so small and the cost difference so large as in the case of these two drugs. One major difference is the manufacturers of TPA was launched on a huge amount of publicity, which has been maintained; it manufacturers maintain one of the five largest sales and marketing force which calls only on hospitals. There were repeated examples of more positive evaluations of TPA by scientists with relationships with the manufacturer of TPA compared with scientist without such relationships. A new competitor has opted for the high price, heavy marketing strategy.