Peripheral T-cell lymphomas (PTCL) represent a heterogeneous group of T-cell malignancies including subentities with favourable (large cell anaplastic) or unfavourable (pleomorphic) prognosis. The clinical outcome of PTCL has been controversially discussed, but a worse prognosis than high-grade B-cell Non-Hodgkin's lymphomas (NHL) has been postulated by most authors. In this report we summarize the results of a prospective comparative study investigating the therapy outcome of 27 patients (pts) with PTCL and 55 pts. with high grade B-cell NHL and give an overview of therapy studies in PTCL. The histological subtypes were 14 pleomorphic, 8 large-cell anaplastic (Ki-1+), 2 angioimmunoblastic (AILD) and 3 other PTCL. In three patients the PTCL was associated with non-tropical sprue (11%). Nineteen patients presented with an advanced stage of disease (stage III and IV, 70%), 17 (63%) pts. had B-symptoms. The patients were treated with vincristine 2 mg d1, adriamycin 25 mg/m2 d1-3, cyclophosphamide 800 mg/m2 d1, prednisone 60 mg/m2 d1-7 and etoposide 120 mg/m2 d1-3 (VACPE). In 77% of pts. with PTCL and 84% of patients with high-grade B-cell NHL a complete remission (CR) was achieved. 75% of the complete responders with PTCL and 70% with B-NHL are still in ongoing CR. The subgroup of large-cell anaplastic attained a CR in 88%. The median observation time is 44 months (1(+)-77+). The probability of 1-, 3- and 5-year overall and disease-free survival for the T-cell group were 76%, 54%, 48% and 76%, 62%, 62%, respectively according to Kaplan-Meier. There was no significant difference regarding the remission rate, the overall-, event-free or disease-free survival compared to high-grade B-cell lymphomas. In conclusion, the VACPE regimen is an effective and feasible regimen in the management of PTCL achieving complete remissions in a large proportion of patients.