Phase II trial of weekly or bi-weekly tocilizumab with ipilimumab and nivolumab in advanced melanoma: Clinical outcomes and biomarker analysis.

Abstract

9553 Background: Combination immune-checkpoint inhibitors (ICIs) improved outcomes in a plethora of cancer subtypes. However, up to 60% of patients (pts) receiving ipilimumab (ipi) plus nivolumab (nivo) experience grade 3/4 (G 3/4) immune-related adverse events (irAEs), often leading to treatment discontinuation. We evaluated two therapeutic strategies targeting interleukin-6 receptor (IL-6R) to reduce irAEs while enhancing ICls efficacy. Methods: Phase Il trial (NCT04940299) investigating safety/efficacy of frontline tocilizumab (toci; IL-6R inhibitor) combined with ipi 3mg/kg + nivo 1mg/kg Q3 weeks (wks) for 12 wks in advanced melanoma. Initially, toci was given as 162 mg subcutaneously (SQ) bi-weekly for 6 doses (regular dosing regimen; RD). Then, we escalated to a dose dense (DD) regimen (162 mg SQ weekly for 6 wks then bi-weekly for 6 wks; 9 doses total). Primary objective was rate of G 3/4 irAEs. Secondary objectives were objective response rates (ORR) and disease control rate (DCR) per RECIST 1.1. Exploratory objectives involved immune analysis (gene expression, CyTOF, cytokine analysis) on longitudinal blood and tissue samples to identify drivers of auto- vs antitumor immunity. Results: As of Feb 2024, 35 pts were enrolled (25 pts to RD regimen; 10 pts to DD regimen). In RD group, median follow-up is 18 months (6 - 25 months). By 12 wks, 44% of pts developed G 3/4 irAEs including colitis (20%), hepatitis (16%), pancreatitis (12%), type I diabetes and serum sickness (4% each) and 20% of pts required hospitalization due to irAEs. Median time to G 3/4 irAEs onset was 7.4 wks. 16% of pts discontinued ICIs due to irAEs. ORR was 56% at 12 wks including 40% in pts with high LDH and DCR was 80%. Gene expression analysis showed a trend towards higher expression of IL-17 pathway genes in pts who developed G 3/4 irAEs, suggesting IL-6/Th17 pathway was not sufficiently inhibited. Thus, we enrolled 10 pts into the DD regimen aiming to achieve better inhibition of the IL-6/Th17 pathway. In DD group, median follow-up is 7 months (3 - 13 months). By 12 wks, 40% of pts developed G 3/4 irAEs, including colitis (10%), hepatitis (20%), and uveitis (10%) and 30% of pts required hospitalization due to irAEs. Median time to G 3/4 irAEs onset was 4.9 wks. 30% of pts discontinued ICIs due to irAEs. ORR was 70% at 12 wks including 75% in pts with high LDH and DCR was 80%. Conclusions: To our knowledge, this is the first study to investigate toci in combination with high dose ipi3/nivo1. Although our cohort is small, preliminary data suggests IL-6R blockade using the DD regimen could decrease the rate of G 3/4 irAEs while maintaining antitumor responses of ipi3/nivo1. A randomized phase ll trial investigating this strategy is underway. Ongoing immune analysis comparing treatment regimens aims to identify distinct pathways involved in auto- vs antitumor immunity and IL-6/Th17 independent pathways of toxicity. Clinical trial information: NCT04940299 .