OBJECTIVE To determine the maximum tolerated dose of granulocyte-macrophage colony-stimulating factor (GM-CSF) that would reduce the severity and duration of neutropenia from combination cytotoxic chemotherapy in the treatment of AIDS-related Kaposi's sarcoma (KS). METHODS Phase I, dose escalation. METHODS Outpatient clinic of a university hospital. METHODS HIV-seropositive patients with advanced KS. METHODS Combination chemotherapy consisting of adriamycin, bleomycin, and vincristine (ABV), with escalating doses of recombinant human GM-CSF (rhGM-CSF). Patients were treated for a median of six cycles (range, between two and seven cycles) of biweekly chemotherapy with GM-CSF administered in divided daily subcutaneous doses on days 2-12. Serum cytokine levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha were measured before, during, and after therapy to correlate with response to therapy. RESULTS A GM-CSF dose of 250 micrograms/m2 was well tolerated, whereas the next dose escalation, of 500 micrograms/m2, was associated with dose-limiting toxicities, including grade 3 fever, fatigue, and diarrhea. GM-CSF produced predictable cyclic increases in granulocytes, allowing for delivery of full-dose chemotherapy on schedule. All patients were HIV-p24-antigen-negative at study entry; no activation of p24 antigenemia was observed after repeat testing. Consistent changes in cytokine levels were not observed. Responses included one complete and three partial responses, and two patients with stable disease parameters. CONCLUSIONS We conclude that GM-CSF can be administered safely to patients with AIDS-related KS receiving myelosuppressive chemotherapy, resulting in granulocytic response, without up-regulation of HIV p24 antigen levels in serum.