Young Joo Min

Background: With the development of immunology, immune checkpoint inhibitors (ICIs) have been widely used in various cancer treatments. Although some patients can benefit from ICIs, other patients have no response to ICIs or suffer from hyperprogression. There has been no biomarker for predicting the efficacy of ICIs. Thus, the objective of this study was to find biomarkers for predicting the efficacy of ICIs using peripheral blood. Methods: Adults patients planned to be treated with ICIs were enrolled in this study. Blood sampling was carried out before and after administration of ICIs. Changes of immune cell fraction were analyzed for each patient. Results: Among 182 patients enrolled, immune cell analysis was performed for 90 patients. The objective response rate was 14.4% (n = 13/90). The median progression-free survival (PFS) was 6.0 months (95% CI: 3.1–8.9 months), and the median overall survival (OS) was 13.9 months (95% CI: 5.6–22.2 months). Significant benefits in ORR and OS were shown for patients with increased NKp46-/CD56+ NK cells (p = 0.033 and p = 0.013, respectively). The PFS tended to be longer in these patients, although the difference was not statistically significant (p = 0.050). Conclusion: Changes of immune cell fraction before and after administration of ICIs could be a novel biomarker for predicting the efficacy of immunotherapy.

4051 Background: Afatinib, an irreversible pan-ErbB kinase inhibitor showed anti-tumor activity against esophageal cancer in phase I trial. In this multicenter, open-label, single arm phase II study, we aimed to evaluate the activity and safety of afatinib in R/M ESCC. Methods: Patients (pts) who had ECOG PS 0-2 and had progressed on platinum-based chemotherapy for R/M ESCC were enrolled. Pts were treated with afatinib 40mg/day until disease progression, unacceptable toxicity, or patient’s refusal. Primary endpoint was objective response rate (ORR) per RECIST 1.1. The estimated sample size was 49, using a two-stage minimax design to evaluate incremental response rate from 5 to 15%. Secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and safety profile. Additionally, we try to identify biomarker to predict efficacy of afatinib with target capture sequencing and gene expression profile as exploratory endpoints. Results: In a total of 49 enrolled pts (median age 60; range 44 -84), ORR and DCR were 14.3 % and 73.3%, respectively. With a median follow-up of 6.6 months, median PFS and OS was 3.4 months (95% CI 2.2-4.6) and 6.6 months (95% CI 5.2-8.0). Median treatment duration and duration of response were 2.8 months (range, 0.4-15.3) and 7.1 months (range, 2.5-13.9), respectively. Dose reduction and interruption occurred in 19 (38.8%) and 15 (30.6 %) pts. Treatment-related adverse events (TRAE) occurred in 33 pts (67.3%) with most common TRAEs being diarrhea (n=22, 44.9%) and acneiform rash (n=12, 24.5%). G3-4 TRAEs were rare, occurring in 7 pts (14.3 %). Conclusions: Afatinib demonstrated modest efficacy with manageable toxicity in platinum-resistant R/M ESCC patients. Given the modest response rate, identification of predictive biomarkers is essential for further clinical investigation of afatinib in R/M ESCC. Those biomarkers are being analyzed and will be presented in the conference (NCT02353936). Clinical trial information: NCT02353936. [Table: see text]

Summary Purpose CKD-516 is a benzophenone analog in which the B ring is modified by replacement with a carbonyl group. The study assessed CKD-516 as a vascular disrupting agent or anti-cancer drug. Methods To assess the effect of S516 on vascularization, we analyzed the effect on human umbilical vein endothelial cells (HUVECs). To determine the inhibition of cell proliferation of S516, we used H460 lung carcinoma cells. The alteration of microtubules was analyzed using immunoblot, RT-PCR and confocal imaging. To evaluate the anti-tumor effects of gemcitabine and/or CKD-516, H460 xenograft mice were treated with CKD-516 (2.5 mg/kg) and/or gemcitabine (40 mg/kg), and tumor growth was compared with vehicle-treated control. For histologic analysis, liver, spleen and tumor tissues from H460 xenograft mice were obtained 12 and 24 h after CKD-516 injection. Results Cytoskeletal changes of HUVECs treated with 10 nM S516 were assessed by immunoblot and confocal imaging. S516 disrupted tubulin assembly and resulted in microtubule dysfunction, which induced cell cycle arrest (G2/M). S516 markedly enhanced the depolymerization of microtubules, perhaps due to the vascular disrupting properties of S516. Interestingly, S516 decreased the amount of total tubulin protein in HUVECs. Especially, S516 decreased mRNA expression α-tubulin (HUVECs only) and β-tubulin (HUVECs and H460 cells) at an early time point (4 h). Immunocytochemical analysis showed that S516 changed the cellular microtubule network and inhibited the formation of polymerized microtubules. Extensive central necrosis of tumors was evident by 12 h after treatment with CKD-516 (2.5 mg/kg, i.p.). In H460 xenografts, CKD-516 combined with gemcitabine significantly delayed tumor growth up to 57 % and 36 % as compared to control and gemcitabine alone, respectively. Conclusion CKD-516 is a novel agent with vascular disrupting properties and enhances anti-tumor activity in combination with chemotherapy.