LBA21 Radioembolization with chemotherapy for colorectal liver metastases: A randomized, open-label, international, multicenter, phase III trial (EPOCH study)

Safety and efficacy of trans-arterial Yttrium-90 radioembolization (TARE) in combination with systemic chemotherapy in the second-line setting for colorectal liver metastases is unknown. In this phase 3 trial, patients with colorectal liver metastases who progressed on first-line therapy were randomized 1:1 to receive second-line chemotherapy with or without glass microsphere TARE. The two primary endpoints were progression-free survival (PFS) and hepatic PFS (hPFS), assessed by blinded-independent central review. Randomization was stratified by unilobar/bilobar disease, oxaliplatin/irinotecan-based first-line chemotherapy, and KRAS mutation status. 428 patients from 94 centers were randomized to chemotherapy +/- TARE. The hazard ratio (HR) for PFS was 0.69 (95% confidence interval [CI], 0.54-0.88; 1-sided p=0.0013), with a median PFS of 8.0 (CI, 7.2-9.2) and 7.2 (CI, 5.7-7.6) months, respectively. The HR for hPFS was 0.59 (CI, 0.46-0.77; 1-sided p<0.0001), with a median hPFS of 9.1 (CI, 7.8-9.7) and 7.2 (CI, 5.7-7.6) months, respectively. Objective response rates were 34.0% (CI, 28.0-40.5%) and 21.1% (CI, 16.2-27.1%; 1-sided p=0.0019) for TARE and chemotherapy groups, respectively. Median overall survival was 14.0 (CI, 11.8-15.5) and 14.4 months (CI, 12.8-16.4; 1-sided p=0.7229) with a HR of 1.07 (CI, 0.86-1.32) for TARE and chemotherapy groups, respectively. Grade 3 adverse events were reported more frequently in the TARE group (68.4 vs 49.3%). The PFS benefit of TARE was observed for tumors with KRAS mutation (HR 0.57, CI: 0.40-0.80), left-side primary tumor (HR 0.65, CI: 0.48-0.88), hepatic tumor burden 10-25% (HR 0.43, CI: 0.26-0.72), ≤3 lesions (HR 0.33, CI: 0.14-0.76), addition of a biologic agent (HR 0.58, CI: 0.40-0.84), and resected primary (HR 0.63, CI: 0.46-0.85). EPOCH study met both primary endpoints, demonstrating the addition of TARE to systemic therapy for second-line colorectal liver metastases leads to significantly longer PFS and hPFS. Further subset analyses will better define the ideal patient population benefitting from TARE.