Abstract 939P
Background
Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and is responsible for more than 500,000 deaths annually. Bavi, a monoclonal antibody designed to inhibit the immunosuppressive effects of phosphatidylserine through interaction with TIM and TAM receptor family members in the tumor microenvironment (TME), is being evaluated in combination with pembro, a monoclonal antibody designed to inhibit Programmed cell death protein 1 (PD-1), in patients with advanced HCC.
Methods
This phase II, open-label, multi-site trial included patients with histologically confirmed locally advanced or metastatic HCC who have not received prior systemic therapy. Patients were treated with pembro (200 mg Q3W) in combination with bavi (3 mg/kg QW) until disease progression. The primary endpoint of the trial is confirmed ORR by RECIST 1.1. A minimax two-stage method to analyze ORR after 15 patients and enroll an additional 13 patient if 3 or more responses observed in first 15 patients.
Results
Three of out 15 patients responded during Stage 1, allowing for enrollment to continue with a planned 13 additional patients in Stage 2; 18 out of a planned 28 total patients are currently enrolled. Of 18 patients evaluable for safety, 4 patients developed grade 3 AEs, and 1 patient developed grade 4 AEs. Grade 5 AEs developed in 3 patients, but none were determined to be related to study medications. The overall response rate (ORR) based upon data from 16 patients evaluable for response was 31.3% (5 confirmed, partial responses). The disease control rate was 56.3% (5 partial responses, 4 stable disease).
Conclusions
The combination of bavi and pembro appears to be well tolerated in this patient population and has a toxicity profile comparable to monotherapy immune checkpoint inhibitor. Preliminary analyses suggest that bavi and pembro may have promising anti-tumor activity in advanced HCC. Updated data from the study, including correlations with tumor biomarkers, will be presented.
Clinical trial identification
NCT03519997.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Merck, OncXerna.
Disclosure
All authors have declared no conflicts of interest.