Naomi N. H. Hunder

Phase 1b study of pegylated interferon lambda 1 with or without ribavirin in patients with chronic genotype 1 hepatitis C virus infection.

Interferon lambda 1 (IFN‐λ1) is a type III IFN that produces intracellular responses similar to those of IFN‐α but in fewer cell types because of differences in the receptor distribution pattern, and this could potentially result in an improved safety profile. This was an open‐label three‐part study of patients with chronic hepatitis C virus (HCV) genotype 1 infection. Part 1 evaluated single‐agent pegylated interferon lambda (PEG‐IFN‐λ) at 1.5 or 3.0 μg/kg administered every 2 weeks or weekly for 4 weeks in patients who had relapsed after previous IFN‐α‐based treatment. Part 2 evaluated weekly doses of PEG‐IFN‐λ ranging from 0.5 to 2.25 μg/kg in combination with ribavirin (RBV) for 4 weeks in treatment‐relapse patients. Part 3 evaluated weekly PEG‐IFN‐λ at 1.5 μg/kg in combination with RBV for 4 weeks in treatment‐naive patients. Fifty‐six patients were enrolled: 24 patients in part 1, 25 patients in part 2, and 7 patients in part 3. Antiviral activity was observed at all PEG‐IFN‐λ dose levels (from 0.5 to 3.0 μg/kg). Two of seven treatment‐naive patients (29%) achieved rapid virological response. Treatment was well tolerated with minimal flu‐like symptoms and no significant hematologic changes other than RBV‐associated decreases in hemoglobin. The most common adverse events were fatigue (29%), nausea (12%), and myalgia (11%). Six patients experienced increases in aminotransferases that met protocol‐defined criteria for dose‐limiting toxicity (DLT) or temporarily holding therapy with PEG‐IFN‐λ. Most DLT occurred in patients with high PEG‐IFN‐λ exposure. Conclusion: Weekly PEG‐IFN‐λ with or without daily RBV for 4 weeks is well tolerated with minimal adverse events and hematologic effects and is associated with clear antiviral activity across a broad range of doses in patients with chronic HCV. (HEPATOLOGY 2010;)

Interleukin-21 Has Activity in Patients With Metastatic Melanoma: A Phase II Study

PURPOSE We report a multicenter phase II study of patients with metastatic melanoma (MM), evaluating the efficacy, toxicity, progression-free survival (PFS), immunogenicity, and biomarker profile of interleukin-21 (IL-21). PATIENTS AND METHODS Patients with no prior systemic therapy and with limited-disease MM were treated with IL-21 by using three different dosing regimens. Cohort 1 received 50 μg/kg per day by outpatient intravenous bolus injection for 5 days of each week during weeks 1, 3, and 5 of an 8-week cycle. Cohort 2 received 30 μg/kg per day on the same schedule, and cohort 3 received 50 μg/kg per day for 5 days of each week during weeks 1 and 3 of a 6-week cycle. RESULTS Forty patients were enrolled: three in cohort 1, 30 in cohort 2, and seven in cohort 3. Two patients in cohort 1 and four in cohort 3 had dose-limiting toxicities; all other patients were treated with a dose of 30 μg/kg per day. Common adverse events were fatigue, rash, diarrhea, nausea, and myalgia. Overall response rate (ORR) was 22.5%, with nine confirmed partial responses (median response duration, 5.3 months); 16 had stable disease (median response duration, 5.3 months). ORR did not appear to depended on IL-21 receptor expression or BRAF mutation status. The median PFS was 4.3 months and median overall survival (OS) was 12.4 months (95% CI, 10.09 to 17.81 months). CONCLUSION The ORR to IL-21 is 22.5% for first-line MM and warrants further investigation. The favorable PFS and OS suggest that this is an active agent in comparison to both historical NCIC Clinical Trials Group data and data from meta-analysis of Cooperative Group phase II trials.

A Phase I Dose-Finding Trial of Recombinant Interleukin-21 and Rituximab in Relapsed and Refractory Low Grade B-cell Lymphoproliferative Disorders

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 patients 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. Clin Cancer Res; 18(20); 5752–60. ©2012 AACR.

Interleukin-21 and Cancer Therapy

Interleukin-21 (IL-21) is a pleiotropic cytokine structurally similar to IL-2 and IL-15 but with important distinctions in its biological properties. IL-21 is mainly secreted by activated CD4+ T cells, NKT cells, and follicular T helper (Tfh) cells. The IL-21 receptor is expressed physiologically on lymphoid tissues and peripheral blood mononuclear cells, although expression can be acquired by epithelial, synovial, or transformed cells. The effects of IL-21 signaling include enhancement of adaptive T cell immunity, promotion of antibody production, activation of innate immune responses through NK cells, opposition to immune downmodulation mediated through regulatory T cells, and effects in autoimmunity. IL-21 also has important roles in development of Th17 and Tfh cells. In preclinical models and clinical trials in humans, IL-21 has been shown to mediate anticancer effects either as a single agent or in combination with other strategies such as monoclonal antibodies or tyrosine kinase inhibitors. The biology of IL-21 suggests that it could also be usefully combined with active vaccination, adoptive immunotherapy, or cytotoxic chemotherapy. IL-21 continues to undergo clinical development for a variety of cancer indications.