Abstract 4331
Background
Esophageal adenocarcinoma (EAC) is a lethal disease with poor prognosis due to the limited treatment options. STING is a transmembrane protein that activates transcription of type I IFN genes, resulting in stimulation of APCs and enhanced CD8+ T cell infiltration. Recently, STING agonists have demonstrated not only potent efficacy against the primary tumor but also in the distant metastasis and recurrences. Interestingly, combining the STING agonist with radiotherapy and immune checkpoint inhibitors has demonstrated durable anticancer activity in solid tumors. Hence, the aim of the study was to specifically evaluate the efficacy and immunologic regulatory effects of STING agonist +/- radiation in an established EAC model.
Methods
Esophagojejunostomy was performed on rats to induce gastroduodenojejunal reflux leading to the development EAC. At 32 weeks post operatively, rats received either 50μg STING (ADU-S100) +/- 16Gy radiation or placebo (PBS) +/- 16Gy radiation. Drug or placebo control was delivered intratumorally twice via endoscopy, 3 weeks apart. Drug efficacy was evaluated by pre- and post- treatment MRI, serial biopsies, histology and RT-PCR. Additionally, IHC was performed using CD8 and PD-L1 antibodies.
Results
There was no difference in observed mortality among the groups (p = 0.3). Mean MRI tumor volume decreased by 19.7% and 18.6% in ADU-S100 and ADU-S100 + radiation animals and increased by 34.7% and 90.3% in placebo and placebo + radiation animals, respectively (P = 0.0006). Downstream gene expression, pre- to on- treatment, demonstrated upregulation of IFNγ (p = 0.0003) and TNFα (p = 0.02) in the treatment groups vs. placebo. The most remarkable change was observed in ADU-S100 group (5.5X IFNγ and 10.9X TNFα; p < 0.01). On- or post- treatment, radiation alone, ADU-S100 alone and ADU-S100 + radiation groups demonstrated significantly elevated densities of CD8+ T cells and PD-L1+ tumor and immune stromal cells compared to placebo (p < 0.01).
Conclusions
ADU-S100 exhibits potent antitumor efficacy and a promising immunomodulatory profile in a de novo EAC model providing the rationale for clinical strategies, likely in combination with immune checkpoint inhibitors.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
A.H. Zaidi: Shareholder / Stockholder / Stock options: Array Biopharma; Research grant / Funding (institution): Eli Lilly & Co. All other authors have declared no conflicts of interest.
Resources from the same session
1049 - The Effect Of Multiple Interventions For Women At Risk For Cervical Cancer On Their Health Responsibility, Beliefs Regarding Cervical Cancer, And Having Screening: A Randomized Controlled Experiment
Presenter: Busra Altinel
Session: Poster Display session 2
Resources:
Abstract
1309 - Quantifying the Effects of the Korean National Cancer Screening Program on Cervical Cancer Mortality
Presenter: Nhung Bui
Session: Poster Display session 2
Resources:
Abstract
1346 - Spread of tumor and adverse events after modified radical hysterectomy for FIGO Stage IB1 cervical cancer patients with tumor diameter preoperatively estimated 2 cm or less: Japan Clinical Oncology Group trial (JCOG1101); exploratory analysis before primary analysis.
Presenter: Takahide Arimoto
Session: Poster Display session 2
Resources:
Abstract
5352 - Impact of Combined Interstitial and Intracavitary Brachytherapy in locally advanced Cervical cancer: A Survival and toxicity profile assessment
Presenter: Vibhay Pareek
Session: Poster Display session 2
Resources:
Abstract
2049 - Chemoradiotherapy response prediction model by proteomic expressional profiling in patients with locally advanced cervical cancer
Presenter: Chel Hun Choi
Session: Poster Display session 2
Resources:
Abstract
1923 - Disparities starting adjuvant chemotherapy for locally advanced cervix cancer in the international, academic, randomised, phase 3 OUTBACK trial (ANZGOG 0902, RTOG 1174, NRG 0274)
Presenter: Linda Mileshkin
Session: Poster Display session 2
Resources:
Abstract
3284 - Primary results from CECILIA, a global single-arm phase 2 study evaluating bevacizumab (BEV), carboplatin (C) and paclitaxel (P) for advanced cervical cancer (aCC)
Presenter: Andres Redondo
Session: Poster Display session 2
Resources:
Abstract
843 - Prognostic and clinicopathological significance of PD-L1 in patients with cervical cancer: a meta-analysis
Presenter: Xiaobin Gu
Session: Poster Display session 2
Resources:
Abstract
1020 - Clinical impact of molecular profiling of cervical cancer (CC) patients (pts) in a dedicated Phase I (P1) unit
Presenter: Mariana Scaranti
Session: Poster Display session 2
Resources:
Abstract
872 - Comparative proteomic profiles of cervical cancer and paried paracancerous tissue and the potential effects of DUSP7 over-expression through inhibiting RAS pathway on the biological characteristics of human cervical cancer cell line SIHA
Presenter: Xuan Jiang
Session: Poster Display session 2
Resources:
Abstract