Primary and secondary resistance to immune checkpoint inhibitors in hepatocellular carcinoma.

e16209 Background: Immunotherapy have revolutionized the therapeutic landscape of hepatocellular carcinoma (HCC). However, clinical features affecting immune resistance remain largely unknown. This retrospective cohort study aims to investigate the outcomes and characteristics of pts with resistance to immunotherapy in HCC. Methods: Pts with HCC who received immune checkpoint inhibitors (ICIs) of PD-1/PD-L1 antibodies at Eastern Hepatobiliary Surgery Hospital between 2016 and 2021 were retrospectively enrolled and screened for eligibility. Recommended by the Society for Immunotherapy of Cancer (SITC), primary resistance was defined as when pts were exposed to ICIs therapy for at least 6 weeks and with the best overall response (BOR) of PD or SD for less than 6 months. Secondary resistance was defined as pts having disease progression after the initial objective response (CR/PR) or SD for more than 6 months. The durable response group consists of pts with the durable response (CR, PR, or SD) for more than 6 months without progression at data cutoff. Time to progression (TTP), overall survival (OS) and clinicopathological features of HCC pts were compared between groups. Subsequent management after resistance and post-progression survival (PPS) were also analyzed. Results: Of 496 pts included, 229 (46.2%) and 141 (28.4%) pts developed primary resistance and secondary resistance, and 126 (25.4%) pts achieved a durable response. The median follow-up was 22.8 months. For pts with primary resistance, secondary resistance, and durable response, the median TTP was 2.83 2.56-3.09 months, 11.93 10.45-13.40 months, and not reached, respectively. Whereas the median OS was 12.83 10.36-15.30 months, 31.53 28.09-34.97 months and not reached, respectively. Multivariate logistic regression revealed that the Child-Pugh score (Child-Pugh B versus A, OR 3.28 1.51-7.13, p= 0.003), BCLC stage (BCLC B versus A, OR 3.55 1.70-7.43, p= 0.001; BCLC C versus A, OR 2.88 1.47-5.65, p= 0.002), and combinational therapies (ICIs+bevacizumab versus monotherapy, OR 0.14 0.04-0.51, p= 0.003; ICIs plus lenvatinib+monotherapy, OR 0.43 0.26-0.72, p= 0.001) were independently associated with primary resistance, and only the combination of ICIs plus bevacizumab (ICIs+bevacizumab versus monotherapy, OR 0.10 0.01-0.52, p= 0.007) was independently associated with secondary resistance. AFP levels and post-progression therapies were independently associated with PPS in pts with primary resistance, while post-progression therapies were independently associated with PPS in pts with secondary resistance. Conclusions: Risk for resistance was significantly lower among pts who received ICIs plus bevacizumab.High AFP levels independently predict the survival of pts after primary resistance to immunotherapy. ICI-based maintenance therapy after resistance may provide a significant survival advantage for HCC pts.