A phase IB study of ipilimumab with peginterferon alfa-2b in patients with unresectable melanoma.
9079 Background: Peginterferon alfa-2b (Sylatron) as adjuvant therapy has been shown to benefit patients with high-risk resected melanoma and some interferon studies have shown that the induction of autoantibodies may correlate with benefit. Ipilimumab (IPI, Yervoy) is a fully human anti-CTLA-4 antibody that induces autoimmune toxicity that in some cases appears to correlate with clinical benefit. This study was performed to assess whether ipilimumab can be safely administered with peginterferon alfa-2b. Methods: This study combined IPI at 3mg/kg every 3 weeks for 4 doses along with concurrent peginterferon alfa-2b at 3 mcg/kg weekly for up to 156 weeks or until disease progression, unacceptable toxicity or patient decision to discontinue. The study was designed to obtain toxicity, tolerability and autoimmune antibody data and to define a well-tolerated dose of the combination. Results: Median age was 61 with 9 female and 8 male subjects. There were 3 patients (pts) with partial responses, 1 stable disease, and 6 with progressive disease in 10 pts evaluable for response thus far. Six pts have not yet completed cycle 1 and therefore are not evaluable for response at the time of this publication but will be presented. One pt withdrew consent prior to finishing cycle 1. Toxicities from peginterferon alfa-2b 3mcg/kg were dose-limiting with 7 pts requiring dose reduction in peginterferon alfa-2b secondary to toxicity. The Grade 3 events leading to dose reductions were nausea and vomiting, leucopenia, dehydration, and hyponatremia. peginterferon alfa-2b was dose reduced to 2 mcg/kg weekly in future pts after these toxicities were noted. No Grade 3 or 4 toxicities attributable to ipilimumab have occurred thus far. No Grade 3 or 4 events have been noted to date in the10 pts initiated at 2 mcg/kg of peginterferon alfa-2b. There was no significant change in the presence autoantibodies (ANA, anti-double stranded DNA, antithyroglobulin, antimicrosomal antibodies, and anticardiolipin antibodies) between responders and non-responders in the evaluable pts. Conclusions: Peginterferon alfa-2b added to IPI results in an excellent response rate in this small population. Peginterferon alpha-2b at 2 mcg/kg weekly with IPI at 3 mg/kg every 3 weeks appears well-tolerated and the combination warrants further exploration. Clinical trial information: NCT01496807.