Pooled analysis of pathological response after neoadjuvant immune checkpoint inhibitors for hepatocellular carcinoma

Neoadjuvant use of immune checkpoint inhibitors (ICIs) before liver resection can result in pathological tumor regression in patients with hepatocellular carcinoma (HCC). Pooled analysis of five phase 1 and 2 trials investigated pathological responses after neoadjuvant ICIs for HCC and the association between the depth of tumor regression and relapse-free survival (RFS). Among 111 included patients,data on pathological response were available for 104 patients. Major pathological response (MPR; at least 70% tumor regression) was seen in 32% and pathological complete response (pCR; 100% tumor regression). MPR and pCR were associated with RFS after liver resection. Among patients with MPR versus no MPR, RFS was not reached versus 28.3 months (HR 0.26; p=0.0024) and among patients with pCR versus no pCR, RFS was not reached versus 32.8 months (0.19; p=0.010). Unbiased recursive partioning of the cohort for the risk of relapse, death, or both identified a threshold of 90% as the optimal cutoff of pathological tumor regression to predict improved RFS. The authors conclude that the extent of tumor regression following neoadjuvant ICI therapy could identify patients with improved RFS following liver resection.