Outcomes of post-immunotherapy durable responders of advanced hepatocellular carcinoma - with emphasis on locoregional therapy for oligoprogression

Introduction The progression patterns, dispositions, and outcomes of patients with advanced hepatocellular carcinoma (HCC) who achieved durable responses with immunotherapy remain poorly characterized. Methods Patients with advanced HCC who received immune checkpoint inhibitor (ICI)-based immunotherapy and achieved durable responses were retrospectively included. A durable response was defined as partial response (PR) or stable disease (SD) per RECIST 1.1 for more than 8 months after initiation of immunotherapy. Oligoprogression and polyprogression were defined as progression at ≤ 3 and > 3 lesions, respectively. Results A total of 91 durable responders (63 PR and 28 SD) were identified. The majority had chronic viral hepatitis (n=69, 75.8%). Forty-seven (51.6%) and 44 (48.4%) patients received the index immunotherapy as first-line and second or beyond-line therapy, respectively. Fifty-four (59.3%) patients subsequently developed progression, with a predominant pattern of oligoprogression (66.7%). The median overall survival (OS) was 46.2 months (95% CI: 34.1–58.3). For patients with subsequent progression, employment of locoregional therapy (LRT) for progression was associated with prolonged OS (univariate analysis: hazard ratio [HR] 0.397, p=0.009; multivariate analysis: HR 0.363, p=0.050). Patients with oligoprogression who received LRT showed longer median OS than those who did not (48.4 vs. 20.5 months, p<0.001). In contrast, the median OS of patients with polyprogression who received LRT was not different from those without LRT (27.7 vs. 25.5 months, p=0.794). Conclusion Approximately 60% of the post-immunotherapy durable responders of HCC subsequently develop progression. Proactive LRT may further rescue patients who develop subsequent oligoprogression. Prospective studies are mandatory to clarify the proper management of durable responders with subsequent progression.