Background and objective: The positive results of high-dose chemotherapy followed by rescue with bone marrow progenitor cell transplantation are generally ascribed to the high dose size (DS) of the drugs given. However, a concomitant marked increase in dose intensity (DI) is always involved. With the aim of comparing the role of DS and DI in non-Hodgkin's lymphomas, a variant of Fisher's ProMACE-CytaBOM regimen was designed in which the projected cumulative drug DIs remained the same as in the original schedule but the DSs were tripled.
Design and methods: Dosages in mg/m(2), route and days of administration were the following: cyclophosphamide 1,950 i.v. on days 1, 64; methotrexate 360 i.v. days 15, 78; vincristine 1.4 iv days 15, 78, 43, 106; etoposide 360 i.v. days 29, 92; epirubicin 120 i.v. days 29, 92; bleomycin 15 i.v. days 43, 106; cytarabine 900 i.v. days 50, 113. Thirty-six outpatients with intermediate- and high-grade non-Hodgkin's lymphomas entered the pilot study; 29 were untreated and 7 had relapse disease. Clinical stage was I in 1 patient, II in 7, III in 5 and IV in 23; 10 had B symptoms; the IPI score was 0-2 in 29 cases and > or =3 in the remaining 7.
Results: Of the 29 previously untreated patients, 16 achieved complete remission, 8 partial remission, 4 developed progressive disease and 1 was withdrawn early from the study because of acute viral hepatitis; subsequently 4 relapsed and 3 died (2 of disease progression, 1 of causes unrelated to the disease). In the pre-treated group 3 patients obtained complete remission, 2 partial remission and in 1 patient the disease progressed; 3 of these pre-treated patients died (1 of progressive disease, 1 of a new relapse, 1 of myocardial infarction during therapy). With a 20-month median follow-up, the 30-month overall and relapse-free survival were 0.58 and 0.70, respectively. G-CSF was administered to all but 2 patients, with median delivery throughout the whole regimen of 8, 400 microg per patient. Actual cumulative DI was 0.82+/-0.11. Grade 3-4 hematologic toxicity consisted of anemia in 3 cases, of leukopenia in 8 and of thrombocytopenia in 2; the same grade of non-hematologic toxicity involved the liver in 2 cases, the heart in 1 (the above mentioned death), the digestive mucosa in 2 and the peripheral nerves in 1 patient.
Interpretation and conclusions: The iso-DI sequential variant of the ProMACE-CytaBOM regimen can be considered feasibile, relatively non-toxic, and can be given on an out-patient basis. Limited use of G-CSF is required (about 3 vials after each drug administration). Thus, a randomized trial with the original ProMACE-CytaBOM regimen can be designed.