Background: PD-1/PD-L1 blockade monotherapy delivered positive outcomes in early-phase trials in advanced triple-negative breast cancer (TNBC). However, the highest objective response rate (ORR) is 18.5%. IMPassion130 trial has demonstrated that only PD-L1⁺ TNBC had overall survival benefit from anti-PD-L1 antibody combined with chemotherapy. Preclinical studies found that antiangiogenic therapy could sensitize anti-PD-1 treatment via inducing PD-L1 expression and increasing CTLs infiltration in tumor microenvironment. Thus, we designed a phase II, open-label trial (NCT03394287) of SHR-1210 (anti-PD-1 antibody) in combination with apatinib (VEGFR2 inhibitor) in patients with advanced TNBC. Methods:20-58 advanced TNBC patients whose systemic therapy lines in the metastatic setting was less than 3, will be randomly (1:1) enrolled from Sun Yat-sen Memorial Hospital to receive either SHR-1210 200mg Q2W plus apatinib 250mg, continuous dosing (d1-d14), or SHR-1210 200mg Q2W plus apatinib 250mg, intermittent dosing (d1-d7), until progression or unacceptable toxicities. Primary endpoint was ORR. Secondary end points included PFS, DCR, TTR, DoR, CBR, one year-OS and toxicity. Results: Until Jan 30, 2019, 34 patients were enrolled, 10 in the intermittent dosing arm, and 24 in the continuous dosing arm. 26 (76.5%) patients had prior systemic therapy in the metastatic setting. At the cutoff date (Jan 30, 2019), 28 patients were evaluable for ORR as per RECIST. The ORR was 47.4% (9 of 19) in the continuous dosing cohort, and no confirmed objective response was found in the intermittent dosing arm. The DCR was 68.4% in the continuous dosing arm, whereas it was 44.4% in the other arm. The median PFS was 2 months in the intermittent dosing cohort, while it was not reached in the continuous dosing cohort. The most common adverse events (AEs) was fatigue (65.0%), hand-foot syndrome (63.3%), and elevated aspartate aminotransferase and/or alanine aminotransferase (73.3%). There were no treatment-related deaths. Another 5 patients will be enrolled into the continuous dosing arm because of its favorable response. Conclusions: Anti-PD-1 antibody SHR-1210 combined with apatinib demonstrates favorable clinical activity and a manageable safety profile in patients with advanced TNBC. Clinical trial information: NCT03394287