The development of successful immunotherapeutic protocols requires new therapeutic strategies as well as the development of clinically predictive tumor models and protocols. A bell-shaped response curve is observed with many biological response modifiers (BRMs), not only for immunomodulation, but also for therapeutic activity. Although most BRMs, including poly(I,C)-LC, are toxic at high doses, the administration of nontoxic doses by an optimal protocol and route of injection results in significant therapeutic benefit and increased immunomodulation in tumor-bearing animals compared to the administration of a maximum tolerated dose (MTD). We suggest that Phase II clinical trials using an optimal immunomodulatory protocol may result in increased therapeutic activity compared to protocols based on the MTD.