Ipilimumab and nivolumab/pembrolizumab in advanced hepatocellular carcinoma refractory to prior immune checkpoint inhibitors.

330 Background: Programmed cell death protein 1 (PD-1) pathway blockade with immune checkpoint inhibitors (ICI) is a standard therapy in advanced hepatocellular carcinoma (HCC) nowadays. No strategies to overcome ICI resistance have been described. We aimed to evaluate the use of ipilimumab and anti-PD-1 ICIs (nivolumab or pembrolizumab) combinations in advanced HCC patients with progression on prior ICIs. Methods: Advanced HCC patients with documented tumour progression on prior ICIs and subsequently received ipilimumab with nivolumab/pembrolizumab were analysed. Objective response rate (ORR), median duration of response (DOR), time-to-progression (TTP), overall survival (OS), and treatment-related adverse events (TRAEs) were assessed. Results: Twenty-five patients were included. The median age was 62 (range 51-83). 68% were of Child-Pugh (CP) grade A and 48% had primary resistance to prior ICI. At median follow-up of 37.7 months, the ORR was 16% with a median DOR of 11.5 months (range 2.76-30.3). Three patients achieved complete response. The median TTP was 2.96 months (95% C.I. 1.61-4.31). Median OS was 10.9 months (95% C.I. 3.99-17.8) and the 1-year, 2-year and 3-year survival rates were 42.4%, 32.3% and 21.6% respectively. The ORR was 16.7% in primary resistance group and 15.4% in acquired resistance group (p=1.00). All responders were of CP A and Albumin-Bilirubin (ALBI) grade 1 or 2. CP and ALBI grades were significantly associated with OS (p=0.006 and p<0.001 respectively). Overall, 52% of patients experienced TRAEs and 12% experienced grade 3 or above TRAEs. Conclusions: Ipilimumab and nivolumab/pembrolizumab can achieve durable antitumour activity and encouraging survival outcomes with acceptable toxicity in patients with advanced HCC who had prior treatment with ICIs.