Cytokine therapy for hematological malignancies.

Recently various cytokines have been introduced into the clinic and have played important therapeutic roles in the treatment of hematological malignancies. Among these cytokines, we have focused on interferon (IFN) and granulocyte (G) or granulocyte-macrophage (GM) colony stimulating factor (CSF), which are currently the most useful cytokines in this review. IFN-a is one of most useful and wide-ranging antitumor agents in hematological malignancies. The most striking effects have been studies in chronic phase CML. Cytogenetic responses are seen in 30-40% of the treated patients, and a complete cytogenetic response can be seen in about 10%. Long-term survival can be expected in these patients. Considering the risk of graft-versus-host disease-associated mortality in allogeneic bone marrow transplantation, the most appropriate category of treatment is difficult to determine in IFN-responsive patients. Elucidation of the antitumor mechanism of IFN, as a prototype for other biological response modifiers, may revolutionize cancer treatment. G- and GM-CSF (CSFs) have reduced the duration of neutropenia, incidence of infectious episodes and days of hospitalization following cancer chemotherapy or stem cell transplantation. CSFs have also been used to mobilize peripheral blood stem cells and to increase the dose intensity of chemotherapeutic agents. Leukemic cells from many patients with acute myelogenous leukemia (AML) have surface receptors for CSFs and may proliferate in response to CSFs. However, several randomized studies showed that CSFs can be used safely and effectively in augmenting neutrophil recovery in patients with AML when given after induction chemotherapy. Various trials have been conducted to sensitize leukemic cells by CSFs, making them more susceptible to chemotherapy; but no convincing evidence has been obtained.