Background: Chiauranib (CS2164) selectively inhibits multiple kinase targets, including Aurora B, vascular endothelial growth factor receptors, platelet-derived growth factor receptor, c-Kit and colony stimulating factor 1 receptor. Phase 1 studies showed that chiauranib 50mg once daily was well tolerated. Here we report results from an exploratory phase 2 study of chiauranib monotherapy for small cell lung cancer (SCLC) conducted in China (NCT03216343). Methods: This single arm phase 2 study involved SCLC patients with progression after platinum-based regimen and at least one other chemotherapy therapy. Patients received chiauranib 50 mg once daily orally until disease progression or unacceptable toxicity. Tumor assessments were conducted at baseline, 4 weeks for the first time and every 8 weeks thereafter. The primary endpoint of this study was objective response rate (ORR) by investigator assessment per the Response Evaluation Criteria in Solid Tumors, version 1.1. Disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), overall survival (OS) and safety were evaluated as secondary endpoints. Results: Between November 21, 2017 and March 21, 2019, 28 patients were enrolled in six study sites in China. The median age was 55.5 (range 32-71) years and 21 (75%) patients were male. Eastern Cooperative Oncology Group performance status was 0 in 8 (28.6%) patients and 1 in 20 (71.4%) patients. 12 (42.9%) patients were treated with two prior systemic treatment regimens, 16 (57.1%) patients were treated with three or more. At the cut-off date of Nov 15, 2020, the median follow-up duration was 25.6 (Range, 19.5-not evaluable) months. Two patients were still receiving treatment. Patients received a median of 3.5 cycles treatment. Twenty-seven patients had at least one tumor assessment and one patient died before the first assessment. The ORR and DCR were 17.9% (95% confidence interval [CI]: 6.06%-36.89%) and 64.3% (95% CI: 44.07%-81.36%), respectively. The median PFS, DOR and OS were 3.6, 8.2 and 8.4 months, respectively. The ≥ 10% adverse events (AEs) were mainly grade 1-2, and grade 3-4 AEs were hypertension (25%), hyponatremia (14.3%), fatigue (7.1%), diarrhea (3.6%), hypertriglyceridemia (3.6%), cough (3.6%) and limb pain (3.6%). No treatment related death was reported in the study. Two patients discontinued treatment due to grade 3 fatigue. Conclusions: Chiauranib exhibited impressing antitumor activity in patients with recurrent or metastatic SCLC who had undergone two or more previous lines of chemotherapy, and was well tolerated. Further clinical studies are in plan to verify the findings from the current report.

Citation Format: Yuankai Shi, Jian Fang, Xingya Li, Yutao Liu, Zhendong Chen, Zhiyong Ma, Tao Sun. An exploratory phase 2 study of chiauranib monotherapy for small cell lung cancer after two or more lines of previous therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT157.