Background: Programmed Cell Death Ligand 1 (PD-L1) inhibitor durvalumab in combination with gemcitabine and cisplatin has been approved as first-line therapy for BTC. However, the efficacy of subsequent standard of care is limited. Tinengotinib is a spectrum-selective multi-kinase inhibitor that targets cell proliferation, angiogenesis, and immune-oncology pathways by inhibiting Aurora kinases A/B, Janus kinases and receptor tyrosine kinases (FGFRs and VEGFRs). Tinengotinib combined with PD-L1 has demonstrated promising antineoplastic activity in preclinical study. Here we present the preliminary data of tinengotinib in combination with atezolizumab (atezo) in pts with advanced BTC from a phase Ib/II trial in China. Methods: In combination therapy, eligible pts with advanced/metastatic BTC were enrolled and treated with tinengotinib plus atezo 1200 mg/20 mL in 21-day cycle. Dose escalation (Phase Ib) and dose expansion (Phase II) were designed. Dose escalation followed a standard 3+3 design. Primary objectives in phase Ib were safety, tolerability, and determination of the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Results: As of 17-Aug-2023, six pts (5 cholangiocarcinoma, 1 gallbladder carcinoma) were enrolled and treated with tinengotinib 8 mg QD plus atezo (n=3) or tinengotinib 10 mg QD plus atezo (n=3). Median age was 62.0 years (range 47-75), 83.3% had ECOG performance status of 1, 83.3% had stage IV disease, 50% had ≥ 3 lines of prior antineoplastic therapies, and 50% had prior immunotherapy. No DLT was observed in these two dose levels. Treatment-related adverse events (TRAEs) were reported in 6 (100%) pts, including Grade (Gr)1-2 for 6 pts, Gr 3 in 2 pts. No Gr 4-5 TRAE. The most common TRAEs (≥ 50%) included hypertension, palmar-plantar erythrodysesthesia syndrome, blood bilirubin increased, proteinuria, hypertriglyceridemia and platelet count decreased. Two pts achieved partial response (PR). One prior immunotherapy naïve pt had a tumor reduction of 48.0% lasting for more than 5 months (tinengotinib 8 mg QD plus atezo). Another pt with prior immunotherapy (sintilimab), target therapy (donafenib) and chemotherapy had a tumor reduction of 39.1% (tinengotinib 10 mg QD plus atezo). Three pts had stable disease (SD). Conclusions: Tinengotinib in combination with atezo was well-tolerated for the treatment of Chinese BTC pts. Preliminary encouraging efficacy of tinengotinib in combination with atezo was observed in pts with heavily pre-treated BTC. The ongoing study is to further evaluate the safety and efficacy of tinengotinib in combination with atezo in pts with BTC who had prior immunotherapy and/or chemotherapy. Clinical trial information: NCT05253053.