Updated results of ALTER-H006: A phase II study of benmelstobart (PD-L1 inhibitor) plus anlotinib as adjuvant therapy in hepatocellular carcinoma (HCC) with high risk of recurrence after radical resection.

601 Background: Although radical resection offers one of the most favorable prognosis for hepatocellular carcinoma (HCC), the rate of postoperative recurrence remains high, which is the primary cause of mortality in HCC patients. The optimal adjuvant treatment strategy for patients is still under active investigation. Herein we evaluated the efficacy and safety of the anti-angiogenic tyrosine kinase inhibitor, anlotinib, plus benmelstobart, a novel programmed death-ligand 1 (PD-L1) inhibitor as an adjuvant treatment for HCC with high risk of recurrence after radical resection. Methods: This study enrolled patients diagnosed with HCC confirmed through histological or cytological examination, whose age was 18-75, with ECOG 0-1, Child-Pugh class A, 4~8 weeks after R0 resection with any of the following high-risk factors for recurrence: a) tumor nodules ≥4; b) portal vein tumor thrombus (PVTT): vp1 or vp2; c) hepatic vein tumor thrombus (HVTT): vv1 or vv2. Enrolled patients received anlotinib (12 mg, p.o., qd, d1-14, q3w) plus benmelstobart (1200 mg, i.v., d1, q3w) until disease recurrence or unacceptable toxicity or up to 18 cycles (~1 year), whichever occurred first. Tumor assessment was performed at the end of the second cycle and every four cycles thereafter, according to RECIST v1.1. The predefined sample size was 37. The primary endpoint was 1-year recurrence-free survival (RFS) rate. Secondary endpoints included RFS, 1-year overall survival (OS) rate, and safety. Results: As the cutoff date of September 13,2024, a total of 38 patients (pts) were enrolled and 35 pts included in per-protocol set analysis. The majority of the 38 pts were male (94.7%, n = 36), and the median age was 56.5 years (range: 33-75). 18 pts (47.3%) had CNLC Stage IIb and 20 (52.6%) had CNLC Stage IIIa HCC. Among them, 35 pts received at least once tumor assessment. According to RECIST 1.1, of the 35 pts, 18 had no recurrence, 15 experienced relapse, 1 dropped out and 1 discontinued due to serious adverse events. The 1-year RFS rate was 59.97% (95%CI: 39.12-79.68) and the primary median RFS was 16.89m(95%CI: 6.82-26.96). The 1-year OS rate was 91.47% (95%CI: 69.23-97.86). 34 of 38 pts (89.5%) experienced treatment-related adverse events (TRAEs). The most common grade 3 TRAEs occurred in 17 pts (44.7%) including hypertension (32%) and neutropenia(5.3%). No grade 4 or 5 TRAEs were observed. Conclusions: The present study indicated that anlotinib plus benmelstobart as adjuvant treatment for HCC with high risk of recurrence after radical resection exhibited promising efficacy and tolerable safety profile. The conclusion should be validated in more participants included subsequently. Clinical trial information: NCT05111366 .