Between October, 1984 and October, 1987 a study program was carried out to evaluate the efficacy of MACOP-B in the advanced stages of intermediate/high-grade malignancy non-Hodgkin's lymphomas (NHL). Thirty patients were treated at diagnosis: 14 with D-E-F histology (median age = 56.5 years) and 16 with G-H histology (median age = 46.5). Complete remission (CR) rate was 42.8% for the D-E-F subgroup and 81.2% for the G-H subgroup. Bone marrow involvement was the major adverse factor for CR achievement in patients with intermediate-grade NHL. Overall, disease stage, bulky presentation and the presence of systemic symptoms did not significantly affect response to therapy. Survival curves predict 73% of patients alive at 45 months (median follow-up = 30 mo.). No significant differences were seen between D-E-F (64%; median follow-up = 36 mo.) and the G-H patients (81%; median follow-up = 27 mo.). The disease-free survival curve for all patients in CR reached a plateau phase at 78% (median follow-up = 30 mo). MACOP-B was much less effective when employed in 10 patients at relapse; only 2 out of these 10 reached a durable CR, which persisted 51 and 27 mo. after MACOP-B. The remaining 8 patients had a partial response, followed closely by disease progression: 7 died, whereas 1 patient is still alive after salvage therapy with bone marrow transplant. Thus, MACOP-B proved to be effective in patients at diagnosis with G-H histology.(ABSTRACT TRUNCATED AT 250 WORDS)