Outpatient therapy with interleukin 21 (IL-21) and Nexavar as a second or third-line therapy for metastatic renal cell cancer was associated with anti-tumor activity, with manageable side effects. Of subjects treated and assessed by independent review, three of 18 patients had a confirmed partial response, for an overall response rate of 17%. In addition, two partial responses have not yet been confirmed.
The overall response rate and disease control rate observed with the combination treatment regimen appears to compare favorably to results obtained in separate studies with single-agent Nexavar.
IL-21 with Nexavar is being tested in the Phase II study in an outpatient setting to evaluate the safety, pharmacokinetics and anti-tumor efficacy of the combination using the maximum tolerated IL-21 dose determined in Phase I (30mcg/kg). Study endpoints were overall response rate and progression-free survival. Subjects had previously received one or two targeted therapies for renal cell cancer but had disease progression.
Anti-tumor activity was observed, with stable disease or partial or complete response at any time on study, in 89% or 16 of 18 patients evaluated by independent and investigator review. Approximately seven (54%) of the 13 patients who completed three treatment courses had stable disease or better. Interim results suggest a potential additive effect of IL-21.
Nicole Onetto, senior vice president and chief medical officer of ZymoGenetics, said: “We continue to see promising anti-tumor effects from the combination of IL-21 and Nexavar in patients with renal cell cancer. We look forward to final results, including progression-free survival data, in the first half of 2009.”