Preliminary Results Of A Phase Ii Study Of Neoadjuvant Immune Checkpoint Inhibitor Imc-001 (Anti-Pd-L1 Monoclonal Antibody) In Patients With Resectable Gastrointestinal Cancers (Neochance Study).

e16542 Background: Immune checkpoint inhibitors have shown survival benefits in unresectable/metastatic gastric cancer (GC), esophageal cancer (EC), and hepatocellular carcinoma (HCC). Based on scientific rationale for neoadjuvant immunotherapy, including enhanced immune recognition, we initiated a phase II study of IMC-001, a novel PD-L1 targeting fully human monoclonal Ab in the neoadjuvant setting for resectable GC, EC, and HCC. Methods: This is a prospective, open-label, phase II study of neoadjuvant IMC-001 (20 mg/kg iv every 2 weeks for 2 cycles) across three cohorts of resectable gastrointestinal cancers (GC, EC, HCC). The primary endpoint is major pathologic response rate ( < 10% of viable tumor cells) and secondary endpoints include safety, feasibility, R0 resection rate, clinical tumor response rate/disease control rate (DCR), progression-free survival, relapse-free survival, and overall survival. Exploratory endpoints include immune monitoring and biomarker analysis in tumor tissues, blood, and stool. Results: From Sep. 2019 to Feb. 2020, 14 eligible patients (pts) (6 HCC; 5 GC; 3 EC) were enrolled; male (79%), median age = 63 yrs (range, 40-72), clinical stage (AJCC 8th) I (57%)/II (21%)/III (21%). 12 pts completed 2 cycles of neoadjuvant IMC-001 and one pt stopped after one cycle due to G3 autoimmune hepatitis, which was only G3 adverse event (AE) and resolved with steroid. Other AE included G2 hyperthyroidism (n = 1), G1 pruritus (n = 2), G1 rash (n = 1), G1 myalgia (n = 1), G1 arthralgia (n = 1), G1 diarrhea (n = 1), G1 cough (n = 1), G1 palate discomfort (n = 1), and G1 chest discomfort (n = 1). So far, 10 clinical response-evaluable pts showed a 100% DCR and underwent surgery, which was all R0 resection. Post-treatment surgery specimens showed various degrees of lymphocyte infiltration in intratumoral or peritumoral areas ranging from 10% to 90%, which was increased compared to pre-treatment biopsies. In HCC pts, adjacent hepatic parenchyma showed mild to moderate, diffuse portal inflammation regardless of Hepatitis B virus status and minimal and moderate fatty change. IHC for PD-L1 using 22C3, SP263 and SP142 clones showed similar results among three Abs with relatively low expression regardless of tumor types (range, 0-20%). Conclusions: Neoadjuvant IMC-001 seems to be well tolerated and have preliminary immune modulating activity in resectable GC, EC, and HCC pts. The study is ongoing and the updated clinical and immunologic results will be presented. Clinical trial information: NCT04196465 .