Rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone in patients with newly diagnosed diffuse large B-cell non-Hodgkin lymphoma: a phase 3 comparison of dose intensification with 14-day versus 21-day cycles

Background Dose intensification with a combination of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) every 2 weeks improves outcomes in patients older than 60 years with diffuse large B-cell lymphoma compared with CHOP every 3 weeks. We investigated whether this survival benefit from dose intensification persists in the presence of rituximab (R-CHOP) in all age groups. Methods Patients (aged >= 18 years) with previously untreated bulky stage IA to stage IV diffuse large B-cell lymphoma in 119 centres in the UK were randomly assigned centrally in a one-to-one ratio, using minimisation, to receive six cycles of R-CHOP every 14 days plus two cycles of rituximab (R-CHOP-14) or eight cycles of R-CHOP every 21 days (R-CHOP-21). R-CHOP-21 was intravenous cyclophosphamide 750 mg/m(2), doxorubicin 50 mg/m(2), vincristine 1.4 mg/m(2) (maximum dose 2 mg), and rituximab 375 mg/m(2) on day 1, and oral prednisolone 40 mg/m(2) on days 1-5, administered every 21 days for a total of eight cycles. R-CHOP-14 was intravenous cyclophosphamide 750 mg/m(2), doxorubicin 50 mg/m(2), vincristine 2 mg, rituximab 375 mg/m(2) on day 1, and oral prednisolone 100 mg on days 1-5, administered every 14 days for six cycles, followed by two further infusions of rituximab 375 mg/m(2) on day 1 every 14 days. The trial was not masked. The primary outcome was overall survival (OS). This study is registered, number ISCRTN 16017947. Findings 1080 patients were assigned to R-CHOP-21 (n=540) and R-CHOP-14 (n=540). With a median follow-up of 46 months (IQR 35-57), 2-year OS was 82.7% (79.5-85.9) in the R-CHOP-14 group and 80.8% (77.5-84.2) in the R-CHOP-21 (standard) group (hazard ratio 0.90, 95% CI 0.70-1.15; p=0.3763). No significant improvement was noted in 2-year progression-free survival (R-CHOP-14 75.4%, 71.8-79.1, and R-CHOP-21 74.8%, 71.0-78.4; 0.94, 0.76-1.17; p=0.5907). High international prognostic index, poor-prognosis molecular characteristics, and cell of origin were not predictive for benefit from either schedule. Grade 3 or 4 neutropenia was higher in the R-CHOP-21 group (318 [60%] of 534 vs 167 [31%] of 534), with no prophylactic use of recombinant human granulocyte-colony stimulating factor mandated in this group, whereas grade 3 or 4 thrombo cytopenia was higher with R-CHOP-14 (50 [9%] vs 28 [5%]); other frequent grade 3 or 4 adverse events were febrile neutropenia (58 [11%] vs 28 [5%]) and infection (125 [23%] vs 96 [18%]). Frequencies of non-haematological adverse events were similar in the R-CHOP-21 and R-CHOP-14 groups. Interpretation R-CHOP-14 is not superior to R-CHOP-21 chemotherapy for previously untreated diffuse large B-cell lymphoma; therefore, R-CHOP-21 remains the standard first-line treatment in patients with this haematological malignancy. No molecular or clinical subgroup benefited from dose intensification in this study.