DRUG SELECTION PERSPECTIVES CLINICAL USE OF BIOLOGIC RESPONSE MODIFIERS INCANCER TREATMENT: AN OVERVIEW PART I. THE INTERFERONS

Thi s article is the first in a two-part series. ABSTRACT: Interferons are proteins with antiviral, antiproliferative, and immune-regulating activity. They are classified as alfa, beta, or gamma on the basis of antigenicity and biologic properties. Alfa interferons as single-agent therapy produce clinical improvement in approximately 90 percent of patients with hairy-cell leukemia, and up to 70 percent of patients with chronic myelogenous leukemia (CML) in early-stage disease. Prolonged suppression or elimination of the leukemic cell clone by interferon may ultimately increase survival of patients with CML. Interferon is not effective single-agent therapy for multiple myeloma, but improves response rate when combined with conventional agents. AIDS-associated Kaposi's sarcoma demonstrates a 40 percent objective response rate to interferon, with less risk of immune system suppression than conventional cytotoxics. Other applications of a1fainterferon include malignant melanoma and renal cell carcinoma. Beta interferon is similar to the alfa subtype and may have utility in treatment of brain tumors. Gamma interferon is an important immune regulator with qualitative and quantitative differences in its efficacy and toxicity when compared with alfa interferon. Dlep Ann Pharmacother 1990;24:761-8. THE HUMAN IMMUNE SYSTEM has long been recognized as a defense against invasion by infectious organisms. It is only in the last few decades, however, that an understanding of the immune system's great value in destroying cancerous cells has begun to unfold. Genetic engineering techniques have permitted large-scale production of immunologic cell products for use in clinical trials. Responses, sometimes dramatic and enduring, have been produced in tumors not responsive to conventional treatments. Although the ulti-mate role of immunotherapy in cancer treatment is still unknown, it is certain that the role will be significant