Background: The anti-angiogenic drug bevacizumab combined with chemotherapy has achieved positive results in previous studies. In particular, the median progression-free survival (PFS) for EGFR-negative patients was increased to 8.3 months in the BEYOND study. Unlike bevacizumab, anlotinib is a novel multitarget tyrosine kinase inhibitor and can be conveniently orally administered. In the phase III trial ALTER 0303, anlotinib significantly improved overall survival (OS) and PFS in advanced NSCLC patients. This exploratory study aims to establish the efficacy and safety of anlotinib in combination with pemetrexed and carboplatin as first-line treatment in advanced non-squamous NSCLC. Methods: This is a multi-center, single-arm clinical trial. Adults with treatment-naive, histologically confirmed stage IIIB-IV non-squamous NSCLC, ECOG 0-1, and without known sensitizing EGFR/ALK alterations are included. Patients received anlotinib (12 mg p.o., QD, d1 to 14, 21 days per cycle) combined with pemetrexed (500 mg/m², iv, d15-21, Q3W) + carboplatin (AUC = 5, iv, d15-21, Q3W) for 4 cycles followed by anlotinib and pemetrexed maintenance until disease progression (PD). The primary endpoint was PFS. Secondary endpoints were OS, objective response rate (ORR), disease control rate (DCR) and safety. Results: Between Mar 2019 and Dec 2020, 40 patients were enrolled in six centers and 31 of them have received at least one tumor assessment. Median age was 62 (33, 75); 66.7% male, 11.1% brain metastasis. At data cutoff (Dec 31, 2020), patients were followed up for a median of 8.26 months. Median PFS was 10.5 months (95% CI: NE, NE); ORR was 67.7% (0 CR, 21 PR), DCR was 96.8% (0 CR, 21 PR, 9 SD) and median OS was NE. The most common Grade ≥ 3 AEs were hypertension 22.2%, neutropenia 19.44%, myelosuppression 11.1%, thrombocytopenia 8.33%, leukopenia 5.56%, hand-foot syndrome 5.56% and there were no Grade 5 toxicities. Conclusions: This study finds that anlotinib plus pemetrexed and carboplatin can significantly improve PFS and ORR compared to standard chemotherapy for treatment-naive non-squamous NSCLC patients. The combination was well tolerated, and the AEs were manageable. The follow-up time is not sufficient, and the OS outcomes need further evaluation. Clinical trial information: NCT03790228