A phase II study of rituximab combined with pirarubicin-cyclophosphamide, vincristine and prednisolone regimen as first-line therapy for patients with indolent B-cell lymphoma.

The anthracycline drug pirarubicin (tetrahydropyranyl-adriamycin [THP]) apparently has been reported to show fewer cardiotoxic effects than doxorubicin. We have previously described the effectiveness of the R-THP-COP regimen comprising rituximab, cyclophosphamide, pirarubicin, vincristine and prednisolone in patients with diffuse large B-cell lymphoma. We conducted a phase II study to determine the effectiveness of a regimen incorporating rituximab (R-THP-COP) for patients with previously untreated advanced-stage indolent CD20-positive B-cell lymphoma according to the Working Formulation and World Health Organization classification. Four to six courses of the regimen were administered every 3 weeks in 50 patients. The complete remission rate was 57%, while the 3-year overall survival rate was 92%. Regimen-related death was not observed. The R-THP-COP regimen appears very effective for patients with previously untreated advanced-stage indolent CD20-positive B-cell lymphoma. The present results indicate the need for randomized trials of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone) and R-THP-COP among patients with CD20-positive indolent lymphoma.