OBJECTIVE: To evaluate the response rate and toxicity of alternating weekly therapy with etoposide-methotrexate-dactinomycin/cyclophosphamide-vincristine for women with high-risk gestational trophoblastic disease. METHODS: Twenty-two women with gestational trophoblastic disease received 126 cycles of the study regimen. Response was evaluated by serial hCG monitoring. Toxicity was assessed using standard criteria. RESULTS: Six women (27%) were treated for primary therapy and 16 (73%) for secondary therapy. The median prognostic index score was 11 (range 7-19). Only 23% of the patients and 11% of the 126 treatment cycles had grade 4 neutropenia, despite the heavily pretreated patient population. Only 2% of the cycles were associated with neutropenic sepsis or required platelet transfusions. Nonhematologic toxicity was modest. Among 16 women who received chemotherapy alone, there were 11 (69%) complete and three (19%) partial responses. When adjuvant therapies are included, the overall complete and partial response rates were 77 and 14%, respectively. Six (35%) of 17 complete responders developed recurrences. Five patients with partial response or relapse were salvaged with additional therapy. Fifteen of the 22 patients (68%) have sustained remissions. CONCLUSION: The regimen of alternating weekly etoposide-methotrexate-dactinomycin/cyclophosphamide-vincristine is effective and well-tolerated chemotherapy for patients with high-risk gestational trophoblastic disease.