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A BW Reporter System for Studying Receptor-Ligand Interactions
Published on: January 7, 2019
A phase I dose-finding trial of recombinant interleukin-21 and rituximab in relapsed and refractory low grade B-cell
John M Timmerman1, John C Byrd, David J Andorsky
1Division of Hematology & Oncology, University of California Los Angeles Medical Center, Los Angeles, California 90095-1678, USA. jtimmerman@mednet.ucla.edu
Purpose:
We conducted a phase I study to determine the safety, maximum-tolerated dose (MTD), and efficacy of weekly bolus recombinant human interleukin-21 (rIL-21) plus rituximab in patients with indolent B-cell malignancies.
Experimental Design:
One week after a lead-in rituximab dose, cohorts of three patients were treated with 30, 100, or 150 μg/kg rIL-21 weekly for four weeks, concurrent with four weekly doses of rituximab. Patients with stable disease or better were eligible for a second course of therapy.
Results:
Twenty-one patients with relapsed small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL, n = 11), follicular lymphoma (n = 9), or marginal zone lymphoma (n = 1) were enrolled, with 19 completing at least one course of therapy. The MTD for rIL-21 was 100 μg/kg, based on observed toxicities including nausea, vomiting, diarrhea, hypotension, edema, and hypophosphatemia. Clinical responses were seen in 8 of 19 evaluable patients (42%; 3 CR/CRu, 5 PR), with 4 of longer duration than the patient's previous response to rituximab-based treatment (median 9 months vs. 3 months).
Conclusions:
Outpatient therapy of indolent B-cell malignancies with rituximab and weekly rIL-21 was well tolerated and clinically active, with durable complete remissions in a small subset of patients. Additional studies of rIL-21 and anti-CD20 antibodies in lymphoma and SLL/CLL are warranted.
