Efficacy, safety, and immune activation with pegylated human IL-10 (AM0010) plus FOLFOX in metastatic pancreatic adenocarcinoma (PDAC).

Abstract

4111 Background: Oxaliplatin or nal-irinotecan plus 5-FU are used as 2nd-line PDAC therapy (mOS 5-6 months (m)). PDAC also has been largely refractory to immune therapies which may depend on the expansion of activated, intratumoral, tumor specific cytotoxic CD8+ T cells that are low in most PDACs. AM0010 stimulates survival, expansion and cytotoxicity of intratumoral CD8+ T cells. Immune activation, durable stable disease and a 1yr survival of 22.5% was seen in salvage PDAC patients (pts) receiving AM0010 alone. Platins or 5-FU may activate immune responses to cancer and AM0010 has shown synergistic anti-tumor results with FOLFOX in preclinical models. In this phase 1b clinical study, the safety and efficacy of AM0010 +FOLFOX was studied in PDAC pts. Methods: PDAC pts progressing on a median of 1 prior therapy (range 1-3) were treated with AM0010 (5ug/kg SQ, qd) + FOLFOX (n = 21), an additional 4 pts with prior oxaliplatin and 5-FU were included in the safety population (n = 25). Tumor responses were assessed using irRC. Serum cytokines, activation of blood derived T cells and peripheral T cell clonality were analyzed. Pretreatment archival tissue samples were evaluated by IHC for tumor infiltration by CD8+ T cells. Results: On AM0010 + FOLFOX, G3/4 TrAEs included thrombocytopenia (52%), anemia (36%) and neutropenia (36%). A modified AM0010 dose schedule (5 days on 2 days off) avoided G3/4 thrombocytopenia. As of 01/31/2017, 2 patients remained on treatment for > 1 year. 19 pts had objective tumor response assessment; 2 had irCR, 1 irPR, 11 irSD. ORR is 15.8%, DCR is 73.7%. With median follow-up of 11.0 m (range 5.8-16.3), mPFS was 3.5 m and mOS 10.0 m. Pts with more intra-tumoral CD8+ T cells had longer OS. AM0010 + FOLFOX increased serum Th1 cytokines and reduced mediators of chronic inflammation and TGFb. AM0010 induced de-novo oligoclonal expansion of T cell clones in patients with prolonged survival. Conclusions: AM0010 plus FOLFOX is well tolerated in patients with PDAC. The observed immune activation including clonal T cell expansion and prolonged objective tumor responses are encouraging in this advanced PDAC population. This regimen is currently being studied in a phase 3 trial. Clinical trial information: NCT02009449.