Sequential cyclophosphamide-prednisone and vincristine-bleomycin (CPOB). An effective, schedule-dependent treatment for advanced diffuse histiocytic lymphoma.

In an Eastern Cooperative Oncology Group non-Hodgkin's lymphoma clinical trial, 90 patients with Stage III or IV diffuse histiocytic lymphoma (DHL) were treated with one of four chemotherapy regimens. All patients were previously untreated with chemotherapy, and careful restaging was required to document responses. Each treatment included cyclophosphamide, vincristine and prednisone (COP) plus Adriamycin (COPA), BCNU (BCVP) or bleomycin (COPB and CPOB). The two bleomycin-containing regimens differed only in the schedule of drug administration. CPOB-treated patients received cyclophosphamide on day 1, prednisone on days 1 to 5 and vincristine and bleomycin on day 15 of each 21-day cycle. COPB-treated patients received the same four drugs in the same dosage; however, the schedule was changed so that vincristine and bleomycin were given on day 1. Treatment of responders was continued for 8 cycles. Those with a complete response (CR) were randomized to maintenance therapy with BCVP or no treatment. Treatment with CPOB yielded a CR rate of 55% compared to 25% for COPB (P = 0.07). In contrast to COPB, treatment with CPOB was associated with a significantly longer median duration of CR (26.5 versus 5.7 months; P less than 0.05) and median survival (27.7 versus 11.2 months; P less than 0.02). The CR rate was 31% for BCVP and 45% for COPA, and the median survivals were 10.7 months and 14.4 months, respectively. One half of the CPOB-treated patients who achieved CR remained alive in continuous CR after 30 to 72 months. No advantage for maintenance therapy was observed. Myelotoxicity was greater with CPOB than COPB, but comparable to COPA. This trial demonstrated that the results of treatment of DHL with COP plus bleomycin were strikingly dependent upon the schedule of administration of bleomycin and vincristine. Bleomycin effectively combined with COP, as in CPOB, yielded results comparable to those obtained when Adriamycin was added to COP. CPOB appears to be an effective treatment for DHL that should be considered as an alternative to other regimens, particularly for patients who cannot receive Adriamycin.