Canadian cancer trials group LY.17: A randomized phase II study evaluating novel salvage therapy pre-autologous stem cell transplant in relapsed/refractory diffuse large B-cell lymphoma-outcome of rituximab-dose-intensive cyclophosphamide, etoposide, cisplatin (R-DICEP) versus R-GDP.

ABSTRACT

The Canadian Cancer Trials Group (CCTG) LY.17 is an ongoing multi-arm randomized phase II trial evaluating novel salvage therapies compared with R-GDP (rituximab, gemcitabine, dexamethasone and cisplatin) in autologous stem cell transplantation (ASCT)-eligible patients with relapsed/refractory diffuse large B-cell lymphoma (RR-DLBCL). This component of the LY.17 trial evaluated a dose-intensive chemotherapy approach using a single cycle of inpatient R-DICEP (rituximab, dose-intensive cyclophosphamide, etoposide and cisplatin) to achieve both lymphoma response and stem cell mobilization, shortening time to ASCT. This report is the result of the protocol-specified second interim analysis of the 67 patients who were randomized to either 1 cycle of R-DICEP or to 3 cycles of R-GDP. The overall response rate (ORR) was 65.6% for R-DICEP and 48.6% for R-GDP. The ASCT rate was 71.9% versus 54.3%, and 1-year progression-free survival rate was 42% versus 32%, respectively, for R-DICEP versus R-GDP. Although the improvement in ORR for R-DICEP versus R-GDP exceeded the pre-specified 10% threshold to proceed to full accrual of 64 patients/arm, higher rates of grade 3-5 toxicities, and the need for hospitalization led to the decision to stop this arm of the study. CCTG LY.17 will continue to evaluate different salvage regimens that incorporate novel agents.