Feasibility Study Of Adding Bortezomib to R-ICE Chemotherapy To Treat Relapsed/ Refractory Diffuse Large B-Cell Lymphoma

The most commonly used regimen for relapsed/refractory diffuse large B-cell lymphoma (DLBCL) is the R-ICE regime (rituximab, ifosphamide, cisplatin and etoposide). It was previously reported to give an overall response rate (RR) of close to 70%, and a complete response rate of 53%. As most DLBCL patients are now treated in the frontline with R-CHOP regimen, the validity of RRs with R-ICE needs to be reevaluated. Results of the CORAL study, a prospective randomized phase III trial comparing R-DHAP vs R-ICE in relapsed DLBCL were recently presented. It was shown that there was no difference in RR between R-ICE and R-DHAP. However, the RR of patients who had received prior rituximab in the frontline setting was significantly lower at 51%, compared with rituximab-naïve patients at 83%. This suggests that relapses after rituximab exposure are more severe. In addition to the risk of more aggressive subtype of DLBCL (activated B-cell \[ABC\]) that may not be abrogated by rituximab, the presence of rituximab-resistant disease is also strongly implicated. As R-CHOP is currently the frontline standard of care, more has to be done to augment the current available salvage regimens. Incorporation of agents targeting the activated B-cell (ABC)subtype and rituximab-resistance is prudent in the salvage regimen. Bortezomib, a proteosome inhibitor impacts on many cellular processes relevant to the pathogenesis of DLBCL, including inhibition of nuclear factor-kappa B. Preclinical studies have also demonstrated that bortezomib displayed significant antitumor activity against various lymphomas, and in particular the ABC subtype of DLBCL. It is also capable of enhancing the biologic activity of rituximab through upregulation of CD20 in preclinical studies. Demonstration of synergism in these 2 agents, in part due to their dependence on overlapping pathways, suggests that they should be explored as a combination. On this basis, the investigators aim to conduct a pilot study of adding intravenous bortezomib to R-ICE as a salvage regime for adult patients with relapsed/refractory DLBCL.