Safety and efficacy of PD-1 blockade-activated multiple antigen specific cellular therapy alone or in combination with apatinib in patients with advanced solid tumors: A pooled analysis of two prospective trials.

e14014 Background: The cancer-cell-killing property of Multiple Antigen Specific Cellular Therapy (MASCT) may be enhanced by blocking PD-1 in vitro and reversing vascular endothelial growth factor (VEGF)/VEGF receptor 2-mediated immunosuppression with apatinib. We analyzed pooled data from our phase Ⅰ/Ⅱ trials to assess the toxicity and efficacy of PD-1 blockade (SHR-1210)-activated MASCT (aMASCT) alone or in combination with apatinib in patients with advanced solid tumors. Methods: Patients with selected types of advanced solid tumors received aMASCT alone (n = 32) or aMASCT plus apatinib (500 mg q.d., n = 38) after standard treatment. The primary endpoint was the safety profile; antitumor response, progression-free survival (PFS), and overall survival (OS) were the secondary endpoints. Circulating regulatory T cells (Tregs) were quantified before and after aMASCT infusion. Results: Treatment-related adverse events (AEs) occurred in 18/32 (56.3%) and 25/38 (65.8%) patients in the aMASCT and aMASCT plus apatinib groups, respectively; fever and chills were the most frequently observed AEs. No serious AEs were reported, and apatinib did not increase immunotherapy-related toxicity. The objective response rate was improved with aMASCT plus apatinib group compared with aMASCT group (34.2% and 18.8%, respectively); PFS was longer (median, 6.0 and 4.5 months, respectively, P < 0.05), but OS was not improved (median, 10.0 and 8.2 months, respectively, P = 0.098). Multivariate analyses indicated that two or more cycles of aMASCT treatment was an independent favorable prognostic factor of PFS and OS. Circulating Tregs decreased in both groups after one cycle of aMASCT treatment (P < 0.05). Conclusions: Treatment with aMASCT plus apatinib was safe and effective in advanced solid tumors. Apatinib plus aMASCT may be beneficial for patients with advanced solid tumors. Clinical trial information: NCT02844881; NCT02858232.