Phase I dose escalation study of recombinant interleukin-21 (rIL-21, BMS-982470) in combination with ipilimumab (Ipi) in patients (pts) with advanced or metastatic melanoma (MM).

Abstract

TPS3109 Background: Ipilimumab is a monoclonal anti-CTLA-4 antibody that promotes T-cell activation and has been approved for the treatment of pts with advanced melanoma. The cytokine rIL-21 is a T-cell and NK-cell growth factor that has also demonstrated antitumor activity in selected solid tumors including MM. We hypothesize that coordinated stimulation of T and/or NK cell function with rIL-21 in conjunction with T-cell checkpoint inhibitor blockade with Ipi will achieve enhanced biologic and clinical activity compared to either agent alone. Here we describe an ongoing phase Ib study to investigate the clinical and biologic effects of combined treatment with rIL-21 and Ipi in pts with MM. Methods: The phase I study includes dose escalation (Part 1) using a 6 + 6 design and cohort expansion (Part 2). In Part 1 (n=48), successive cohorts of pts with melanoma will be treated with rIL-21 in combination with Ipi as follows: Arm A, rIL-21 (10, 30, or 50 μg/kg daily x 5) + Ipi (3 or 10 mg/kg Q3W) in a 3 week cycle; or Arm B, rIL-21 (30, 100, or 150 μg/kg weekly) + Ipi (3 or 10 mg/kg Q3W) in a 3 week cycle. In Part 1, all subjects will receive an initial cycle with rIL-21 monotherapy (lead-in) for biomarker and PK assessment that will be the same as the dose of rIL-21 specified for the cohort. Four cycles of combination treatment will follow the lead-in with restaging evaluation after 4 combination cycles. Subjects with initial benefit are eligible for retreatment at progression. In Part 2, pts (n=25/arm) will be randomly assigned to one of 3 cohorts: Ipi monotherapy at 3 mg/kg Q3W or Ipi + weekly rIL-21 or Ipi + daily rIL-21 at the MTD determined for each schedule in Part 1. The primary objectives of this study are to evaluate the safety of rIL-21 + Ipi and to define the MTD of the respective rIL-21 + Ipi regimens. Secondary objectives include assessment of the preliminary antitumor activity, pharmacokinetics, and immunogenicity. Exploratory objectives include investigation of the immunologic effects of this combination in peripheral blood and paired tumor biopsy specimens, and the association of these effects with clinical outcome. Clinical trial information: NCT01489059.