Phase Ib study of anlotinib combined with TQB2450 in pretreated advanced biliary tract cancer and biomarker analysis

Background and aims: We evaluated the efficacy and safety of the antiangiogenic tyrosine kinase inhibitor anlotinib plus TQB2450, a programmed death-ligand 1 inhibitor in pretreated advanced biliary tract cancers (BTCs).

Approach and results: In this pooled analysis of two single-center, phase Ib clinical trials (TQB2450-Ib-05 and TQB2450-Ib-08 trials), 66 patients with advanced BTCs who had progressed or declined or were ineligible for first-line chemotherapy were included. With the treatment of anlotinib plus TQB2450, two patients achieved complete response, and 12 had a partial response assessed by Response Evaluation Criteria in Solid Tumors 1.1, yielding an objective response rate of 21.21%, a disease control rate (DCR) of 72.73%, and a clinical benefit rate (CBR) of 42.42%. With a median follow-up of 19.68 months, median progression-free survival (PFS) and overall survival (OS) were 6.24 (95% confidence interval [CI], 4.11-8.25) and 15.77 (95% CI, 10.74-19.71) months, respectively. Adverse events (AEs) were reported in 64 (96.97%) patients, and the most common grade 3 or worse treatment-related AEs included elevated levels of aspartate aminotransferase (7.58%), alanine aminotransferase (6.06%), and hypertension (6.06%). Patients with high tumor mutational burden (TMB; ≥5 mutations/Mbp) had a better CBR (70.8% vs. 22.2%), longer OS (14.32 vs. 9.64 months), and a trend toward longer PFS (7.03 vs. 4.06 months). Patients with kirsten rat sarcoma viral oncogene homolog ( KRAS ) mutations showed a lower CBR (12.5% vs. 58.8%) and shorter PFS (2.02 vs. 6.80 months) and OS (10.53 vs. 13.13 months).

Conclusions: Anlotinib combined with TQB2450 showed promising efficacy and was well tolerated in advanced BTCs. KRAS mutation and high TMB might serve as predictors of treatment efficacy.