Biological response modifiers (BRM) are a new approach of cancer treatment The guidelines for their evaluation are comparable to those used for evaluating conventional anticancer treatments However it is more difficult to assess their efficacy and toxicity because of their own properties and of the characteristics of underlying diseases. The objectives of studying BRM efficacy are the following: 1- to confirm the pharmacodynamic effect observed in experimental models 2- to assess the benefit for the patient Phase IT studies can occasionally be performed in healthy volunteers. Efficacy criteria are objective response rate, progression free survival overall survival or, for hematopoietic growth factors, more specific criteria. In randomized phase III studies patients in the control arm can be observed without treatment or receive a placebo or a standard treatment. Rr regards toxicity, side effects specifically related to the use of BRM are the synthesis of cytokines, the stimulation of immune system, the stimulation of tumor growth, the synthesis of anti-mouse of anti-BRM antobodies.