Phase II Trial of Weekly Bortezomib in Combination with Rituximab in Relapsed or Relapsed/Refractory Waldenstrom's Macroglobulinemia.
Authors: Ghobrial Irene M. , Hong Fangxin , Padmanabhan Swaminathan , Badros Ashraf Z. , Rourke Meghan , Leduc Renee , Chuma Stacey , Kunsman Janet , Warren Diane , Harris Brianna , Sam Amy , Anderson Kenneth C. , Richardson, M.D. Paul , Treon Steven , Weller Edie , Matous Jeffrey 
Published: October 2019

Abstract
Abstract 2727
Poster Board II-703

INTRODUCTION:
This study aimed to determine activity and safety of weekly bortezomib and rituximab in patients with relapsed/refractory Waldenstrom's Macroglobulinemia (WM).

METHODS:
Patients who had at least one previous therapy were eligible. All patients received bortezomib IV weekly at 1.6 mg/m2 on days 1, 8, 15, q 28 days x 6 cycles, and rituximab 375 mg/m2 weekly on cycles 1 and 4. Primary endpoint was the percent of patients with at least a minor response.

RESULTS:
Thirty-seven patients were treated. Majority of patients (78%) completed treatment per protocol. At least minimal response (MR) or better was observed in 81% (95% CI: [65,92]) with 2 patients (5%) in complete remission (CR)/near CR, 17 (46%) in partial response (PR), and 11(30%) in MR. The median time to progression was 16.4 months (95% CI, 11.4–21.1). Death occurred in 1 patient due to viral pneumonia. The most common grade 3 and 4 therapy related adverse events included reversible neutropenia in 16%, anemia in 11%, and thrombocytopenia in 14%. Grade-3 peripheral neuropathy occurred in only 2 patients (5%). The median event-free survival (EFS) is 12 months (95% CI, 11–20) with estimated 12 month and 18 month EFS of 49% (95% CI: [31, 67%]) and 38% (95% CI: [20, 56%]). The median overall survival has not been reached.

CONCLUSIONS:
The combination of weekly bortezomib and rituximab showed significant activity and minimal neurological toxicity in patients with relapsed WM.

Disclosures:
Ghobrial: Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau. Anderson:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Richardson:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keryx: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Treon:Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Genentech: Honoraria, Research Funding, Speakers Bureau. Matous:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Cephalon: Membership on an entity's Board of Directors or advisory committees.