Rational use of biological response modifiers in hematological malignancies--a review of treatment with interferon, cytotoxic cells and antibodies.

During the last decade the use of various biologic therapeutics/biological response modifiers in hematological malignancies has increased dramatically. Alpha-interferon (alpha-IFN) alone has clearly a substantial antitumoral effect in many hematological diseases. During the coming decade an improved effect will probably be seen by combination of alpha-IFN with cytostatics and other biologic therapeutics as well as by finding the optimal conditions when alpha-IFN should be used. Using unconjugated mouse monoclonal antibodies (MAb) only, an overall response rate of 38% was noted in patients with advanced disease. MAb therapy might be improved by using other Ig molecules, combination with cytokines and by finding an optimal dosage schedule. Only a few patients with hematological malignancies have been treated with IL-2/LAK cells. An overall response rate of 41% was seen in heavily pretreated patients. In all biologic therapeutics, an improved efficacy will be noted if patients with a low tumor burden and an intact immune system are treated. Immunization/vaccination with "tumor antigen" will probably contribute to an improved prognosis, especially in patients with minimal residual disease. There are several good candidates to be used as tumor antigens in hematological malignancies i.e. the idiotypic receptors on T and B cells. Biotherapy in hematological tumors has come to stay. However, due to the complexity of the effector system it will take a long time before an effective treatment concept is developed.