Apatinib Combined with Local Irradiation Leads to Systemic Tumor Control via Reversal of Immunosuppressive Tumor Microenvironment in Lung Cancer.

PURPOSE: This study aimed to investigate the potential systemic antitumor effects of stereotactic ablative radiotherapy (SABR) and apatinib (a novel vascular endothelial growth factor receptor 2 inhibitor) via reversing the immunosuppressive tumor microenvironment for lung carcinoma. MATERIALS AND METHODS: Lewis lung cancer cells were injected into C57BL/6 mice in the left hindlimb (primary tumor; irradiated) and in the right flank (secondary tumor; nonirradiated). When both tumors grew to the touchable size, mice were randomly divided into eight treatment groups. These groups received normal saline or three distinct doses of apatinib (50 mg/kg, 150 mg/kg, and 200 mg/kg) daily for 7 days, in combination with a single dose of 15 Gy radiotherapy or not to the primary tumor. The further tumor growth/regression of mice were followed and observed. RESULTS: For the single 15 Gy modality, tumor growth delay could only be observed at the primary tumor. When combining SABR and apatinib 200 mg/kg, significant retardation of both primary and secondary tumor growth could be observed, indicated an abscopal effect was induced. Mechanism analysis suggested that programmed death-ligand 1 expression increased with SABR was counteract by additional apatinib therapy. Furthermore, when apatinib was combined with SABR, the composition of immune cells could be changed. More importantly, this two-pronged approach evoked tumor antigen-specific immune responses and the mice were resistant to another tumor rechallenge, finally, long-term survival was improved. CONCLUSION: Our results suggested that the tumor microenvironment could be managed with apatinib, which was effective in eliciting an abscopal effect induced by SABR.

Apatinib combined with docetaxel as a salvage treatment for metastatic esophageal squamous cancer: a case report.

The first-line treatment for metastatic esophageal squamous cell cancer (ESCC) is a platinum- or fluorouracil-based agent, followed by later treatment with taxanes or irinotecan. However, there is still no standard third-line treatment for patients with metastatic ESCC. We present a 62-year-old man initially diagnosed with locally advanced ESCC. After esophagectomy, the patient was administrated with six cycles of docetaxel and cisplatin combined with radiotherapy. After 8.0 months, computed tomography showed the left cervical lymph node metastasis. However, the metastatic lymph node was not significantly shrunk after locally palliative radiotherapy and the patient was intolerant of irinotecan as second-line systemic therapy. Then, the patient was rechallenged with six cycles of docetaxel combined with apatinib (an oral tyrosine kinase inhibitor to vascular endothelial growth factor receptor 2 [VEGFR2]), followed by single dose of apatinib as maintenance therapy. According to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 standard, partial response was achieved in this case after treating with docetaxel combined with apatinib. Now, the progression-free survival of this patient has been 7.5 months. After administrating with apatinib for 2 weeks, hypertension (grade III) was observed. Thus, the dose of apatinib was decreased from 850 to 500 mg and then the adverse effects were controllable and tolerable. In conclusion, apatinib with concurrent docetaxel provided potential efficacy as a salvage treatment for patients with metastatic ESCC. To our knowledge, this is the first case of ESCC who responded to apatinib combined with docetaxel.