Through conceptual discussion and consideration of a case study, this paper examines how physicians respond to the availability of an innovative treatment of a serious illness. It is argued that the unusual economic environment of the delivery of catastrophic illness care works with the “social contract” in medicine to encourage the use of innovative therapies, even before their efficacy has been demonstrated and often irrespective of their costs, in striking contrast with the conventional innovation adoption process. The primary constraint on catastrophic illness treatment may well be the technology or the state of knowledge. In the case of the management of leukemias in Connecticut, decisions to use drug therapies appear to have been based on a treatment trend rather than on the inherent merits of the therapies. The trend seems to have spread from the treatment of one leukemia, which responded significantly, to the management of three other leukemias. The influence on treatment decisions of a few individual variables differed across the leukemias. For example, treatment decisions in the acute leukemias were unrelated to the patient's economic status, whereas receipt of chemotherapy for one of the chronic leukemias was significantly positively correlated with economic status.