Results Of A Phase I Trial Of Lenalidomide, Rituximab (R-2) And Ixazomib For Frontline Treatment Of High Risk Follicular And Indolent Non-Hodgkin Lymphoma

INTRODUCTION: Lenalidomide and Rituximab (R2) is an effective frontline treatment regimen for patients (pts) with indolent B-cell lymphoma including follicular lymphoma (FL). Recent phase III data from the RELEVANCE trial comparing R2 to traditional chemoimmunotherapy showed that this regimen is generally well-tolerated and has favorable clinical efficacy [61% overall response, 53% CR rate, 77% 3-year progression free survival (PFS) (Morschhauser, et al)]. Proteasome inhibitors such as bortezomib disrupt NF-KB signaling and have shown clinical activity in indolent NHL. Although randomized trials have failed to demonstrate clinical benefit of adding bortezomib to standard chemoimmunotherapy regimen bendamustine + rituximab (BR) for frontline treatment of FL, the addition of proteasome inhibitors to lenalidomide is a mainstay of treatment for plasma cell neoplasms due to synergistic antitumor effect. The oral proteasome inhibitor ixazomib has less potential for dose-limiting neuropathy than bortezomib, making it an attractive option to incorporate into the R2 regimen. We sought to investigate the safety and efficacy of the addition of ixazomib to R2 for FL and indolent B-cell NHL through a phase I clinical trial of this combination for patients with high risk disease.