Atezolizumab/Bevacizumab vs. Lenvatinib as First-Line Therapy for Unresectable Hepatocellular Carcinoma: A Real-World, Multi-Center Study

Lenvatinib (LENV) and atezolizumab/bevacizumab (ATE/BEV) have been approved as first-line regimens for the treatment of unresectable hepatocellular carcinoma (HCC). We aimed to compare their clinical efficacy and safety. Patients receiving ATE/BEV (n = 86) or LENV (n = 146) as first-line treatment were recruited from three academic hospitals in Korea. Overall survival (OS), progression-free survival (PFS), and radiological response were assessed according to the Response Evaluation Criteria in Solid Tumors. Clinical features of the two groups were balanced through propensity score (PS) matching with a 1:1 ratio and inverse probability of treatment weighting (IPTW) analyses. The median age was 62 years, with male predominance (83.6%). There was no significant difference in the objective response rate between the ATE/BEV and LENV groups (32.6% vs. 31.5%; p = 0.868). Neither median OS (not reached vs. 12.8 months; p = 0.357) nor PFS (5.7 vs. 6.0 months; p = 0.738) was different between ATE/BEV and LENV groups. PS-matched and IPTW analyses yielded comparable results in terms of OS and PFS (all p > 0.05). Grade ≥ 3 adverse events occurred in 42.8% and 21.9% of patients in the ATE/BEV and LENV groups, respectively (p = 0.141). The two first-line therapy regimens for unresectable HCC had comparable clinical efficacy and safety in real-world practice settings. Further studies with a larger sample size and longer follow-up are needed to validate these results.

New management unit for conservation of the Endangered green turtle Chelonia mydas at the Xisha (Paracel) Islands, South China Sea

The Qilianyu cluster of the Xisha (Paracel) Islands has one of the few remaining green turtle Chelonia mydas rookeries in the China region. Genetic samples were obtained from dead green turtle embryos and hatchlings salvaged from post-hatched nests at Middle Island (n = 3), North Island (n = 9) and South Sand (n = 1) of the Qilianyu cluster in 2017-2019. The ~800 bp mitochondrial DNA control region was sequenced from the samples, and 5 haplotypes were identified belonging to 2 documented clades (clades III and VIII), including 2 new haplotypes (CmP243.1 and CmP244.1) and 3 previously reported haplotypes (CmP18.1, CmP19.1, CmP20.1). These results were combined with previously published mtDNA data for the Qilianyu cluster and nearby (~93 km) Yongle Islands indicating a lack of differentiation based on truncated 384 bp control region sequences (exact test, p = 0.0997; FST = 0.015, p = 0.2760), to represent a single Xisha Islands rookery. The rookery at the Xisha Islands was significantly differentiated (p < 0.01) from all 19 management units (MUs) documented in the Indo-Pacific and Japan regions, supporting recognition of the Xisha Islands rookery as a new independent MU. The results will help inform national and international conservation action plans by China and the countries around the South China Sea to protect green turtles in the West Pacific Ocean.

Phase II study of sitravatinib in combination with tislelizumab in patients with advanced biliary tract cancer who have failed to at least 1 prior systemic treatment: Trial in progress

TPS490

Background: In biliary tract cancer (BTC), there was a positive association of overall survival (OS) with high levels of tumor-infiltrating CD4+, CD8+, and Foxp3+ T lymphocytes, whereas increases in PD-1+/CD8+ tumor-infiltrating lymphocytes had a negative association with OS (Tariq NU et al. 2018). Therefore, immune-modulating treatment can be promising option to overcome a dismal prognosis in BTC patients. However, immune checkpoint inhibitor (ICI) monotherapy, including tislelizumab (anti-PD-1 monoclonal antibody), has a modest effect in advanced BTC (Desai J et al. 2020). Thus, several combination strategies to improve the anti-tumor effect of ICI are being conducted. Anti-angiogenic agent in combination with ICI is one of the promising strategies in which anti-angiogenic agent induced improved anti-tumor immune responses by increasing tumor antigen presentation and promoting lymphocyte infiltration and migration (Song Y et al. 2020). However, this combination have not been widely tested in BTC patients. Sitravatinib is a potent inhibitor of multiple receptor tyrosine kinases including Axl, MER, MET, KIT, FLT3, RET, VEGFR1-3, PDGFRα, which targets are expressed in a number of immune cell types and promote an immunosuppressive tumor microenvironment. This study aim to evaluate the efficacy of the combination strategy of sitravatinib with tislelizumab in advanced BTC and to reveal the immune-modulation through the combination of ICI and antiangiogenic agents. Methods: This study is an open-label, phase 2 study to evaluate the efficacy of sitravatinib and tislelizumab combination treatment in advanced BTC patients who have failed to first-line chemotherapy. Eligible patients have histologically proven BTC (including intrahepatic cholangiocarcinoma, extrahepatic bile duct cancer, gallbladder cancer, and ampulla of Vater cancer) and have failed one prior systemic chemotherapy. Patients who have previously received ICI can be enrolled. However, patients who have experienced unacceptable toxicity during prior ICI treatment are excluded. All patients will receive sitravatinib 120mg orally once daily in combination with tislelizumab 200mg intravenously once every 3 weeks until disease progression, unacceptable toxicity, or withdrawal of consent. The primary endpoint is disease control rate, with key secondary endpoints including overall response rate, progression-free survival, overall survival, and safety. For evaluating metabolic response, 18F-FDG PET-CT scan will be performed before treatment and at the first response evaluation. Tissue biopsies will be conducted three times in total: screening, the first response evaluation, and disease progression. Blood samples are being collected every cycles for translational biomarker studies. Clinical trial information: NCT04727996.

Regorafenib plus nivolumab as first-line therapy for unresectable hepatocellular carcinoma (uHCC): Multicenter phase 2 trial (RENOBATE)

415

Background: The immunomodulatory effect of regorafenib may enhance the anti-tumor activity of nivolumab in patients with uHCC. We report results from a phase 2 study of regorafenib plus nivolumab as first-line therapy in patients with uHCC. Methods: In this open-label, multi-center, single-arm study, patients with >19 years, ECOG PS 0 or 1, BCLC stage B or C, and no prior systemic therapy were eligible. Patients received intravenous nivolumab 480 mg, every 4 weeks, and oral regorafenib 80 mg daily, 3 weeks on/1 week off, every 4 weeks. Tumor response was evaluated per RECIST v1.1, every 8 weeks (fixed schedule). Primary endpoint was overall response rates (ORR) per RECIST v1.1. Secondary endpoints were progression-free survival (PFS), overall survival (OS), ORR per mRECIST, and safety profile per NCI-CTCAE v5. Results: A total of 42 patients were enrolled between JUL-2020 and JAN-2021. Median age was 61 years (range, 40-79), and 31 patients (73.8%) were male. Most patients had BCLC C stage (n=38, 90.5%) and hepatitis B virus infection (n=30, 71.4%). Extrahepatic metastasis was noted in 36 patients (85.7%) and baseline serum AFP levels were >400 ng/mL in 17 patients (40.5%). With median follow-up duration of 9.2 months (95% CI, 8.5-9.9 months), 21 patients were ongoing in this study. ORR per RECIST v1.1 was 31.0% (CR 1 [2.4%] and PR 12 [28.6%]), and ORR per mRECIST was 35.7% (CR 4 [9.5%] and PR 11 [26.2%]). Median PFS was 5.5 months (95% CI, 1.8-9.1 months) and median OS was not reached. The 6-months PFS and OS were 49.9% and 90.4%. Most common adverse events were hand-foot skin reaction (n=14, 33.3%), skin rash (12, 28.5%), and alopecia (10, 23.8%). Conclusions: Regorafenib plus nivolumab shows promising efficacy outcomes in uHCC. There was no unexpected safety signals and most of toxicities were manageable. Clinical trial information: NCT04310709.

Clinical feasibility of curative surgery after nab-paclitaxel plus gemcitabine-cisplatin chemotherapy in patients with locally advanced cholangiocarcinoma

387

Background: In a recent phase II trial, nab-paclitaxel plus gemcitabine-cisplatin (Gem/Cis/nab-P) demonstrated prolonged survival and unprecedentedly high response rate in patients with advanced cholangiocarcinoma following treatment. We aimed to evaluate the clinical feasibility of this triplet chemotherapy as induction chemotherapy in patients with locally advanced cholangiocarcinoma. Methods: We retrospectively reviewed patients with locally advanced cholangiocarcinoma who were treated with Gem/Cis/nab-P between October 2019 to December 2020. Resectability after induction chemotherapy was evaluated by a multidisciplinary team. Treatment response and surgical pathology were reviewed. Results: Of the 85 patients were included in this study. 46 (54.1%) had measurable lesions. The objective response rate (ORR) and disease control rate in patients with measurable disease were 51.1% and 85.1%, respectively. Fifty-two (61.2%) patients were determined as resectable. Four patients that were judged to be resectable did not undergo surgery due to patient refusal or poor performance status after chemotherapy. Finally, 48 out of 85 patients (56.5%) underwent subsequent curative surgery after induction chemotherapy. There were six complete remission cases (12.5%) in the final pathology, which all reported patients with extrahepatic cholangiocarcinoma. R0 resection was achieved in 46 out of the 48 patients (95.8%). Despite the initial locally advanced cholangiocarcinoma, a pathologic T stage of less than T2 was reported in 44 (95.7%) patients. Lymph node metastasis was confirmed in 13 (27.1%) patients. The overall survival rates in patients who had chemotherapy followed by surgery was better than in those treated with chemotherapy alone ( P = 0.009). Conclusions: Gem/Cis/nab-P as induction chemotherapy showed promising efficacy and clinical feasibility before curative surgery in patients with locally advanced cholangiocarcinoma. This study showed that triplet chemotherapy using Gem/Cis/nab-P has a clear down-staging effect through a high response rate in patients with cholangiocarcinoma

Deep learning model enables the discovery of a novel immunotherapeutic agent regulating the kynurenine pathway

Kynurenine (Kyn) is a key inducer of an immunosuppressive tumor microenvironment (TME). Although indoleamine 2,3-dioxygenase (IDO)-selective inhibitors have been developed to suppress the Kyn pathway, the results were not satisfactory due to the presence of various opposing mechanisms. Here, we employed an orally administered novel Kyn pathway regulator to overcome the limitation of anti-tumor immune response. We identified a novel core structure that inhibited both IDO and TDO. An orally available lead compound, STB-C017 (designated hereafter as STB), effectively inhibited the enzymatic and cellular activity of IDO and TDO in vitro. Moreover, it potently suppressed Kyn levels in both the plasma and tumor in vivo. STB monotherapy increased the infiltration of CD8⁺ T cells into TME. In addition, STB reprogrammed the TME with widespread changes in immune-mediated gene signatures. Notably, STB-based combination immunotherapy elicited the most potent anti-tumor efficacy through concurrent treatment with immune checkpoint inhibitors, leading to complete tumor regression and long-term overall survival. Our study demonstrated that a novel Kyn pathway regulator derived using deep learning technology can activate T cell immunity and potentiate immune checkpoint blockade by overcoming an immunosuppressive TME.

Development of a One-item Screening Question to Assess Spiritual Well-Being for Advanced Cancer Inpatients in Korea

CONTEXT

Spiritual well-being (SWB) is significant for patients with life-limiting illnesses. Thus, shortened versions of questions would be helpful in approaching SWB.

OBJECTIVES

Our goal was to develop a one-item screening question to assess the SWB of advanced cancer inpatients.

METHODS

This was a cross-sectional, multicenter study involving adult advanced cancer inpatients from seven palliative care units in South Korea. The candidate one-item questions were three questions scored using numeric rating scales from 0 to 10: feeling at peace (Are you at peace?), self-rated spirituality (Do you think of yourself as a spiritual person?), and self-rated religiosity (Do you think of yourself as a religious person?). The Functional Assessment of Chronic Illness Therapy-Spirituality 12 (FACIT-Sp-12) comprised of two subscales Meaning/Peace and Faith was used to assess SWB. Pearson's correlation test was conducted to determine the relationship between the three questions, the total FACIT-Sp-12 score, and its subscales.

RESULTS

A total of 202 patients were enrolled. A strong correlation was observed between self-rated spirituality (r = 0.732 and 0.790; P < 0.001 and < 0.001 respectively) and religiosity (r = 0.708 and 0.758; P < 0.001 and < 0.001 respectively) with the total FACIT-Sp-12 scores and faith subscale scores. Feeling at peace showed a moderate correlation with the total of FACIT-Sp-12 scores (r = 0.505, P < 0.01). All three questions had a moderate correlation with the meaning/peace subscale.

CONCLUSION

Self-rated spirituality and religiosity showed better convergence validity than feeling at peace. Therefore, we recommend self-rated spirituality or religiosity as a one-item question for screening SWB in inpatients with advanced cancer.

High endothelial venule is a surrogate biomarker for T-cell inflamed tumor microenvironment and prognosis in gastric cancer

Background

High endothelial venule (HEV) is a specialized vasculature for lymphocyte trafficking. While HEVs are frequently observed within gastric cancer (GC), the vascular–immune interaction between HEV and tumor-infiltrating lymphocytes (TILs) has not been well elucidated. In this study, we aimed to unveil the potential value of HEVs as a surrogate marker for T-cell inflamed immune microenvironment in GC using a large number of prospectively collected surgical specimens of GC.

Methods

We included 460 patients with GC who underwent surgical resection. Nanostring PanCancer immune profiling was performed to evaluate the immunological phenotype of GCs. HEV density and three distinct patterns of TILs (Crohn-like lymphoid reaction, peritumoral lymphoid reaction, and intratumoral lymphoid reaction) were analyzed for their relationship and evaluated as prognostic factors for relapse-free survival (RFS) and overall survival (OS).

Results

HEV-high GC revealed increased infiltration by immune cell subsets, including dendritic cells, CD8⁺ cytotoxic T cells, and CD4⁺ helper T cells. In addition, HEV-high GC demonstrated increased immune-modulating chemokines, type I or II interferon pathway, and immune checkpoints, all of which indicate the inflamed tumor microenvironment (TME). All three distinct patterns of TILs were associated with HEV density. In survival analysis, patients with HEV-high GC displayed significantly longer RFS and OS than those with HEV-low GC (p<0.001 for RFS, p<0.001 for OS). Multivariate analysis demonstrated that HEV was the most significant immunological prognostic factor for RFS (patients with high HEV compared with those with low HEV; HR 0.412, 95% CI 0.241 to 0.705, p=0.001) and OS (HR 0.547, 95% CI 0.329 to 0.909, p=0.02) after adjustment for age, stage, and TIL.

Conclusion

HEV is the most significant immunological prognosticator for RFS and OS in resected GC, indicating inflamed TME.

Molecular Characterization of Biliary Tract Cancer Predicts Chemotherapy and Programmed Death 1/Programmed Death-Ligand 1 Blockade Responses

BACKGROUND AND AIMS

Biliary tract cancer (BTC) exhibits diverse molecular characteristics. However, reliable biomarkers that predict therapeutic responses are yet to be discovered. We aimed to identify the molecular features of treatment responses to chemotherapy and immunotherapy in BTCs.

APPROACH AND RESULTS

We enrolled 121 advanced BTC patients (68 cholangiocarcinomas [33 intrahepatic, 35 extrahepatic], 41 gallbladder cancers, and 12 Ampulla of Vater cancers) whose specimens were analyzed by clinical sequencing platforms. All patients received first-line palliative chemotherapy; 48 patients underwent programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) blockade therapy after failed chemotherapy. Molecular and histopathological characterization was performed using targeted sequencing and immunohistochemical staining to investigate treatment response-associated biomarkers. Genomic analysis revealed a broad spectrum of mutational profiles according to anatomical location. Favorable responses to chemotherapy were observed in the small-duct type compared with the large-duct type intrahepatic cholangiocarcinoma, with frequent mutations in BRCA1-associated protein-1/isocitrate dehydrogenase 1/2 and KRAS proto-oncogene, GTPase/SMAD family member 4 genes, respectively. The molecular features were further analyzed in BTCs, and transforming growth factor beta and DNA damage response pathway-altered tumors exhibited poor and favorable chemotherapy responses, respectively. In PD-1/PD-L1 blockade-treated patients, KRAS alteration and chromosomal instability tumors were associated with resistance to immunotherapy. The majority of patients (95.0%) with these resistance factors show no clinical benefit to PD-1/PD-L1 blockade and low tumor mutational burdens. Low tumor-infiltrating lymphocyte (TIL) density in tumors with these resistance factors indicated immune-suppressive tumor microenvironments, whereas high intratumoral TIL density was associated with a favorable immunotherapy response.

CONCLUSIONS

This study proposes predictive molecular features of chemotherapy and immunotherapy responses in advanced BTCs using clinical sequencing platforms. Our result provides an intuitive framework to guide the treatment of advanced BTCs benefiting from therapeutic agents based on the tumors' molecular features.

Oncolytic vaccinia virus reinvigorates peritoneal immunity and cooperates with immune checkpoint inhibitor to suppress peritoneal carcinomatosis in colon cancer

Background

Peritoneal carcinomatosis (PC) is a common and devastating manifestation of colon cancer and refractory to conventional anticancer therapeutics. During the peritoneal dissemination of colon cancer, peritoneal immunity is nullified by various mechanisms of immune evasion. Here, we employed the armed oncolytic vaccinia virus mJX-594 (JX) to rejuvenate the peritoneal antitumor immune responses in the treatment of PC.

Methods

PC model of MC38 colon cancer was generated and intraperitoneally treated with JX and/or anti-programmed cell death protein 1 (PD-1) antibody. The peritoneal tumor burden, vascular leakage, and malignant ascites formation were then assessed. Tumors and peritoneal lavage cells were analyzed by flow cytometry, multiplex tissue imaging, and a NanoString assay.

Results

JX treatment effectively suppressed peritoneal cancer progression and malignant ascites formation. It also restored the peritoneal anticancer immunity by activating peritoneal dendritic cells (DCs) and CD8⁺ T cells. Moreover, JX selectively infected and killed peritoneal colon cancer cells and promoted the intratumoral infiltration of DCs and CD8⁺ T cells into peritoneal tumor nodules. JX reinvigorates anticancer immunity by reprogramming immune-related transcriptional signatures within the tumor microenvironment. Notably, JX cooperates with immune checkpoint inhibitors (ICIs), anti-programmed death-1, anti-programmed death-ligand 1, and anti-lymphocyte-activation gene-3 to elicit a stronger anticancer immunity that eliminates peritoneal metastases and malignant ascites of colon cancer compared with JX or ICI alone.

Conclusions

Intraperitoneal immunotherapy with JX restores peritoneal anticancer immunity and potentiates immune checkpoint blockade to suppress PC and malignant ascites in colon cancer.

Effect of supplementing hydroxy selenomethionine on meat quality of yellow feather broiler

This study was conducted to evaluate the effect of supplementing hydroxy selenomethionine (OH-SeMet) on performance, selenium (Se) deposition in the breast muscle, quality and oxidative stability, and expression of selenoprotein encoding genes of breast meat of the native slow-growing yellow-feathered broiler birds. A total of 375 one-day-old local yellow male birds were randomly assigned into 5 dietary treatments, supplemented with Se 0.0, 0.2, 0.4, 0.6, and 0.8 mg/kg in the form of OH-SeMet. Each treatment consisted of 5 replicates and each replicate had 15 birds, the birds were fed on basal diet containing corn and soybean meal, and the experiment lasted for 63 d. The results showed that dietary Se supplementation linearly increased (P < 0.001) Se contents in both serum and muscle, no significant changes (P > 0.05) were observed on growth performance, yield of breast, meat color, and intramuscular fat deposition of the breast muscle. Dietary Se addition improved water-holding capacity, the pH_24h value, and tenderness of breast muscle, evidenced by a linear decreases of shear force (P < 0.05), accompanied by lower thiobarbituric acid reactive substances and higher glutathione reductase activity. The mRNA abundance of selenoprotein encoding genes also responded to dietary Se levels. It is concluded that, dietary supplementation with OH-SeMet improved muscular Se deposition and meat quality of the native yellow birds, with enhanced antioxidant capability and regulation in selenogenome.

Real-world efficacy and safety of nab-paclitaxel plus gemcitabine-cisplatin in patients with advanced biliary tract cancers: a multicenter retrospective analysis

Background

A recent phase II trial reported prolonged survival in patients with advanced biliary tract cancer (BTC) following treatment with nab-paclitaxel plus gemcitabine-cisplatin (Gem/Cis/nab-P). We aimed to evaluate the clinical outcomes of Gem/Cis/nab-P in Asian patients with advanced BTC in a real-world setting.

Methods

We reviewed the data of patients who received Gem/Cis/nab-P for the management of advanced BTC between September 2019 and April 2021 at four institutes in Korea. Patients were classified into the Gem/Cis/nab-P and nab-P addition groups depending on the starting point of nab-P administration.

Results

A total of 178 patients treated with Gem/Cis/nab-P were included in the study. Of these, 43.8% had intrahepatic cholangiocarcinoma (CCA), 34.8% had extrahepatic CCA, and 21.3% had gall bladder cancer. A total of 117 (65.7%) patients received Gem/Cis/nab-P as the first-line treatment, while 61 (34.3%) were treated with gemcitabine-cisplatin-based chemotherapy followed by nab-P addition. The objective response rate (ORR) and disease control rate in all patients were 42.1% and 84.8%, respectively. The ORR in the Gem/Cis/nab-P group was 47.9%, while that in the nab-P addition group was 31.1%. The median progression-free survival and overall survival were 8.5 months [95% confidence interval (CI), 6.9-10.1] and 14.6 months (95% CI, 10.2-19.0), respectively. In patients who received Gem/Cis/nab-P as initial treatment, the median PFS was 9.4 months (95% CI, 7.9-10.9) and the median OS was not-reached (95% CI, not available). Anemia (n = 42, 23.6%), neutropenia (n = 40, 22.5%), and thrombocytopenia (n = 16, 9.0%) were the most common grade 3-4 toxicities. A total of 20 patients (11.2%) had conversions from unresectable to resectable disease and underwent surgery with curative intent.

Conclusion

Gem/Cis/nab-P showed favorable real-life efficacy and safety outcomes in Korean patients with advanced BTC, which was consistent with the phase II trial outcomes.

A Prognostic Model to Facilitate Palliative Care Referral in Oncology Outpatients

Purpose

We aimed to develop a prognostic model to assist palliative care referral at least 3 months before death in advanced cancer patients treated at an outpatient medical oncology clinic.

Materials and Methods

In this prospective cohort study, a total of 200 patients were enrolled at a tertiary cancer center in South Korea. The major eligibility criterion was an expected survival of less than a year as estimated by their oncologists. We analyzed the influences of known prognostic factors along with chemotherapy status, mid-arm circumference, and triceps skinfold thickness on survival time.

Results

The mean age of the patients was 64.5 years, 36% were female, and the median survival time was 7.6 months. In the multivariate analysis, we found six significant factors related to poor survival: a poor Eastern Cooperative Oncology Group (ECOG) performance status (≥ 2), not undergoing chemotherapy, anorexia, a low lymphocyte level (< 12%), a high lactate dehydrogenase (LDH) level (≥ 300 IU/L), and a low mid-arm circumference (< 23 cm). We developed a prognostic model (score, 0–8.0) to predict 3-month survival based on the multivariate analysis. Patients who scored ≥ 4.0 points had a short survival of less than 3 months (p < 0.001). The discriminating ability of the prognostic model using the area under the receiver operating characteristic curve was 0.88.

Conclusion

The prognostic model using ECOG performance status, chemotherapy status, anorexia, lymphocytes, LDH, and mid-arm circumference can predict 3-month survival in medical oncology outpatients. It can alert oncologists to refer patients to palliative care specialists before it is too late.

Abstract 1914: Orally available oncolytic reovirus, RC402, effectively promotes anti-cancer immunity and synergizes with immune checkpoint blockade in colon cancer

Introduction: Reoviruses are replication-competent and selectively infect and destroy cancer cells. Although the most common route of oncolytic virotherapy is intratumoral or intravenous administration, these routes are often not clinically feasible because of tumor inaccessibility, tumor multiplicity, and systemic toxicities. Here, we developed an orally available oncolytic reovirus, RC402, to elicit potent anti-tumor immune responses without the above mentioned limitations and thereby maximize the efficacy of PD-1 immune checkpoint blockade in colon cancer.

Method: MC38 or CT26 colon cancer-bearing immunocompetent mice were treated with RC402 and/or anti-PD-1 antibody. Tumor growth was monitored after treatment and comprehensively analyzed by flow cytometry and/or multiplex tissue imaging.

Results: RC402 treatment effectively delayed tumor growth regardless of the route of administration (per os as well as intratumorally). In particular, orally administered RC402 was well tolerated without gross toxicity and interacted with intestinal immune cells, eliciting adaptive T cell responses within intestinal lymphoid organs such as Peyer's patch. Most of the RC402 was cleared in the gastrointestinal tract within 10 days of the first treatment, and it was not detectable in the blood stream or major organs after oral administration. However, RC402 selectively induced strong and durable anti-tumor immunity in distant tumor tissues. Oral RC402 monotherapy markedly increased CD8+ cytotoxic T cells and decreased CD4+CD25+Foxp3+ regulatory T cells in distant colon cancers, while there were no significant changes in tumor-associated myeloid cells. Finally, oral RC402 treatment cooperated with anti-PD-1 blockade to further suppress colon cancer growth and augment anti-tumor immunity within the tumor microenvironment, leading to complete regression of tumors and survival benefit of tumor-bearing mice.

Conclusion: Our study demonstrates that orally available oncolytic reovirus, RC402, could induce potent anti-cancer immune responses and effectively suppress colon cancer progression in combination with anti-PD-1 blockade.

Citation Format: Chan Kim, Hong Jae Chon, Hye Jin Lee, Won Suk Lee, Hannah Yang, Jeong Hun Kim, So Jung Kong, Yu Seong Lee, Seung Joon Lee, Enkhtaivan Gansukh, Ki-Hoon Song, Yeon-Sook Lee, Beodeul Kang. Orally available oncolytic reovirus, RC402, effectively promotes anti-cancer immunity and synergizes with immune checkpoint blockade in colon cancer [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 1914.

STING activation normalizes the intraperitoneal vascular-immune microenvironment and suppresses peritoneal carcinomatosis of colon cancer

Background

Peritoneal carcinomatosis is a fatal clinical presentation of colon cancer, characterized by unresponsiveness to conventional anticancer therapies, including immune checkpoint inhibitors. Here, we elucidated the immune-evasion mechanisms during the peritoneal carcinomatosis of colon cancer and developed a novel immunotherapy by activating the stimulator of interferon genes (STING) pathway.

Methods

We generated a syngeneic peritoneal carcinomatosis model of colon cancer. Mice were intraperitoneally treated with either STING agonist (MIW815, also known as ADU-S100) or PD-1 blockade or both. The tumor microenvironment was comprehensively analyzed using multiplexed immunofluorescence imaging, flow cytometry, and NanoString immune profiling.

Results

Intraperitoneal colon cancer cells induce a massive influx of immunosuppressive M2-like macrophages, upregulate immune checkpoints, and impair effector T cell functions during peritoneal dissemination; these collectively create a highly angiogenic and immunosuppressive milieu that is resistant to anti-PD-1 monotherapy. Intraperitoneal administration of a STING agonist suppressed aberrant angiogenesis, increased pericyte coverage, and normalized tumor vessels, thereby facilitating the infiltration of activated CD8⁺ T cells into peritoneal tumor nodules. Moreover, STING activation reprogramed tumor-associated macrophages toward the M1 phenotype. STING activation converted immunologically cold peritoneal tumors into T-cell-inflamed tumors in a type-I interferon-dependent manner. Lastly, the STING agonist synergistically cooperated with PD-1 and/or COX2 blockade to further suppress the peritoneal dissemination of colon cancer, resulting in complete eradication of tumor and ascites, and inducing durable antitumor immunity.

Conclusions

STING activation can normalize the peritoneal vascular and immune microenvironment, providing a rationale for a novel combination therapeutic strategy for peritoneal carcinomatosis in colon cancer.

ARID1A mutation to predict disease progression during first-line chemotherapy in biliary tract cancer patients

4105

Background: Biliary tract cancer (BTC) is a retractable disease showing a dismal prognosis with therapeutic resistance. There are clinical unmet needs on predicting therapeutic response and precise strategy for the patient classification according to clinically relevant tumor biology in the patients with BTC. We aimed to identify clinically detectable genomic alteration predicting therapeutic response after first-line chemotherapy in BTC using real-world data. Methods: A comprehensive genomic analysis of multi-institutional cohorts of BTC cases was performed using next-generation sequencing (NGS) with targeted DNA panel and patients’ clinicopathologic data. Results: A total of 200 BTC patients with NGS panel tests from three cancer centers were included in this study. The genomic alteration of TP53 (55.5%), KRAS (23%), ARID1A (10%), and ERBB2 amplification (10%) were the most frequent alteration events in the BTC. Pathologically-proved BTC including extrahepatic (n = 52), ampulla of Vater (n = 4), gallbladder (n = 56), intrahepatic (n = 88) cancers showed a distinct pattern of genomic alterations in terms of ARID1A for extrahepatic BTC and ERBB2 amplification, RB1, ARID2 for GB cancer, and KRAS, IDH1, PBRM1, BAP1 for intrahepatic BTC respectively (chi-square test, P < 0.05). The oncologic outcomes for progression-free and overall survival were significantly stratified according to the best response after the first-line chemotherapy (log-rank test, P < 0.001). The logistic regression test revealed that ARID1A, BRCA2, and STK11 could significantly predict disease progression during first-line chemotherapy. ARID1A, especially, was the only independent predictive marker in the multivariate regression model in total BTC (OR 3.91, 95%CI 1.25-11.66, P = 0.015) and extrahepatic BTC (OR 5.71, 95%CI 1.23-28.98, P = 0.027). The predictive performance of significant genomic alteration was enhanced with the tumor marker CA19-9 (DeLong’s test, Z = 1.933, P = 0.053, AUC 0.73, 95%CI 0.623-0.837). Conclusions: Clinically available NGS test showed distinct genomic alterations in terms of different deterioration patterns for oncogenic molecular pathways according to the anatomic locations of BTC. Integrative analysis using the data for genomic alteration and therapeutic response for the first-line chemotherapy uncover that the patients with ARID1A mutation show a significant disease progression rate during initial treatment for BTC, especially in the extrahepatic BTC. Prospective translational studies revealing underlying biology and precision strategy should be followed to improve the therapeutic response of BTC.

Effect of different types of sugar on gut physiology and microbiota in overfed goose

To explored the difference of goose fatty liver formation induced-by different types of sugar from the intestinal physiology and the gut microflora, an integrated analysis of intestinal physiology and gut microbiota metagenomes was performed using samples collected from the geese including the normal-feeding geese and the overfed geese which were overfed with maize flour or overfeeding dietary supplementation with 10% sugar (glucose, fructose or sucrose, respectively), respectively. The results showed that the foie gras weight of the fructose group and the sucrose group was heavier (P < 0.05) than other groups. Compared with the control group, the ileum weight was significantly higher (P < 0.01), and the cecum weight was significantly lower in the sugar treatment groups (P < 0.001). Compared with the control group, the ratio of villi height to crypt depth in the fructose group was the highest in jejunum (P < 0.05); the trypsin activity of the ileum was higher in the fructose group and the sucrose group (P < 0.05). At the phylum level, Firmicutes, Proteobacteria and Bacteroidetes were the main intestinal flora of geese; and the abundance of Firmicutes in the jejunum was higher in the sugar treatment groups than that of the maize flour group. At the genus level, the abundance of Lactobacillus in the jejunum was higher (P < 0.05) in the sugar treatment groups than that of the maize flour group. In conclusion, forced-feeding diet supplementation with sugar induced stronger digestion and absorption capacity, increased the abundance of Firmicutes and Bacteroidetes and the abundance of Lactobacillus (especially fructose and sucrose) in the gut. So, the fructose and sucrose had higher induction on hepatic steatosis in goose fatty liver formation.

Liposomal irinotecan plus fluorouracil/leucovorin versus FOLFIRINOX as the second-line chemotherapy for patients with metastatic pancreatic cancer: a multicenter retrospective study of the Korean Cancer Study Group (KCSG)

Background

There is no clear consensus on the recommended second-line treatment for patients with metastatic pancreatic cancer who have disease progression following gemcitabine-based therapy. We retrospectively evaluated the clinical outcomes of liposomal irinotecan (nal-IRI) plus fluorouracil/leucovorin (FL) and FOLFIRINOX (fluorouracil, leucovorin, irinotecan, and oxaliplatin) in patients who had failed on the first-line gemcitabine-based therapy.

Patients and methods

From January 2015 to August 2019, 378 patients with MPC who had received nal-IRI/FL (n = 104) or FOLFIRINOX (n = 274) as second-line treatment across 11 institutions were included in this retrospective study.

Results

There were no significant differences in baseline characteristics between groups, except age and first-line regimens. With a median follow-up of 6 months, the median progression-free survival (PFS) was 3.7 months with nal-IRI/FL versus 4.6 months with FOLFIRINOX (P = 0.44). Median overall survival (OS) was 7.7 months with nal-IRI/FL versus 9.7 months with FOLFRINOX (P = 0.13). There was no significant difference in PFS and OS between the two regimens in the univariate and multivariate analyses. The subgroup analysis revealed that younger age (<70 years) was associated with better OS with FOLFIRINOX. In contrast, older age (≥70 years) was associated with better survival outcomes with nal-IRI/FL. Adverse events were manageable with both regimens; however, the incidence of grade 3 or higher neutropenia and peripheral neuropathy was higher in patients treated with FOLFIRINOX than with nal-IRI/FL.

Conclusions

Second-line nal-IRI/FL and FOLFIRINOX showed similar effectiveness outcomes after progression following first-line gemcitabine-based therapy. Age could be the determining factor for choosing the appropriate second-line therapy.

•

This multicenter retrospective study investigated nal-IRI/FL and FOLFIRINOX outcomes after gemcitabine-based therapy.

•

We found no significant differences in outcome between nal-IRI/FL and FOLFIRINOX treatment.

•

Both regimens were well tolerated; however, neutropenia and peripheral neuropathy were more frequent with FOLFIRINOX.

•

Age (cut-off, 70 years) showed differential efficacy between chemotherapy regimens.

Hyperprogressive disease during PD-1 blockade in patients with advanced hepatocellular carcinoma

BACKGROUND & AIMS

Programmed cell death-1 (PD-1) inhibitor treatment can cause hyperprogressive disease (HPD), but the incidence, outcome, and predictive factors of HPD are unknown in patients with hepatocellular carcinoma (HCC). Herein, we assessed the existence and factors predictive of HPD in patients with advanced HCC treated with nivolumab.

METHODS

We enrolled 189 patients with advanced HCC treated with nivolumab. Occurrence of HPD was investigated using tumour growth dynamics based on tumour growth kinetics (TGK) and tumour growth rate (TGR) before and after treatment, or time to treatment failure. We additionally analysed patients treated with regorafenib (n = 95) or best supportive care (BSC)/placebo (n = 103) after progression on sorafenib to compare tumour growth dynamics.

RESULTS

Flare-up of tumour growth was observed in a fraction of patients upon PD-1 blockade, indicating the occurrence of HPD. Based on distinct patterns of disease progression exclusively observed in the nivolumab-treated cohort, but not in the regorafenib- or BSC/placebo-treated cohorts, 4-fold increases in TGK and TGR ratios as well as a 40% increase in TGR were the cut-off values used to define HPD; 12.7% of the patients (24/189) treated with nivolumab met all these criteria. Patients with HPD had worse progression-free survival (hazard ratio [HR] 2.194; 95% CI 1.214-3.964) and overall survival (HR 2.238; 95% CI 1.233-4.062) compared to patients with progressive disease without HPD. More than 90% of patients with HPD missed the opportunity for subsequent treatment because of rapid clinical deterioration. An elevated neutrophil-to-lymphocyte ratio (>4.125) was associated with HPD and an inferior survival rate.

CONCLUSIONS

HPD occurs in a fraction of patients with HCC who receive PD-1 inhibitor treatment. Analyses of the baseline immune profile and on-treatment tumour growth dynamics could enable optimal patient selection and earlier identification of HPD.

LAY SUMMARY

Hyperprogressive disease is an unexpected response pattern observed in patients treated with an immune checkpoint inhibitor. This study revealed that hyperprogressive disease occurs in a fraction of patients with advanced hepatocellular carcinoma treated with an anti-PD-1 antibody, providing evidence to encourage careful monitoring of patients to prevent clinical deterioration induced by PD-1 blockade.

Characterization of hyperprogressive disease in patients with advanced biliary tract cancer treated with anti-PD-1 inhibitor: A multicenter retrospective study

339

Background: Immunotherapy, including anti-PD-1 inhibitor, represents a promising breakthrough treatment in poor prognostic cancers such as biliary tract cancer (BTC). However, subset of pts suffer from unexpected acceleration of tumor growth following the initiation of immunotherapy, termed hyperprogressive disease (HPD). We assessed HPD in BTC pts treated with anti-PD-1 inhibitor in association with clinicopathologic features. Methods: This retrospective study included pts with BTC who were treated with pembrolizumab 200mg IV as palliative second or third line treatment in 4 tertiary hospitals in South Korea. Previous proposed tumor dynamic parameters including time to treatment failure (TTF), tumor growth kinetics (TGK) and tumor growth rate (TGR) were calculated per RECIST v1.1. Neural network modeling technique was adopted to find clinicopathologic features that can predict HPD. Results: Total of 223 pts with BTC were treated with palliative second or third line pembrolizumab between December 2015 to August 2020. ORR was 11.2% (n=1 for CR, n=24 for PR, n=70 for SD, n=118 for PD, and 10 pts not evaluable). Among patients with best response as PD (n=118), 41 patients (18.4% from total pts) met the criteria for HPD definition (>2-fold increase in both TGK and TGR in the experimental period compared to the reference period). HPD pts had worse prognosis compared to non-HPD pts in terms of TTF (median 1.4 vs 2.7 months, P =<0.0001) and OS (median 3.57 vs 5.27 months, P =0.03). Clinicopathologic features including age, ECOG performance status, primary tumor site, pathology, metastatic organ, previous treatment history (surgery or radiotherapy), pretreatment PD-L1 score, tumor markers, and baseline laboratory results (LDH, albumin, or neutrophil-to-lymphocyte ratio) did not predict HPD (compared to non-HPD pts or PD without HPD pts). By neural network modeling and plotting with hidden vectors, we could define HPD-high-risk cluster (n=37) and HPD-lower-risk cluster (n=80). Higher CA 19-9-to-lymphocyte ratio ( P =0.0004) or higher platelet-to-PD-L1 CPS (combined positivity score) ratio ( P =0.002) predicted HPD-high-risk-cluster. HPD pts (n=41) tend to have progression due to liver (73.2% vs 45.6%, P =0.0026) or peritoneum (53.7% vs 21.4%, P=<0.0001) metastases, compared to non-HPD pts (n=182). Conclusions: This study for the first time describe the clinicopathologic features of HPD among pembrolizumab treated BTC pts. Baseline pathology and laboratory tests may help optimal patient selection for immunotherapy to avoid HPD in BTC pts. Further validation of BTC-specific HPD predictive features and definition (TGK or TGR ratio cut-off) will be presented after comparison with clinicopathologic features among second line 5FU-based chemotherapy treated BTC pts.

Phase Ib trial of varlitinib plus weekly paclitaxel in EGFR/HER2 co-expressing advanced gastric cancer (AGC)

227

Background: EGFR and HER2 are over-expressed in gastric cancer, and activation of EGFR signaling in HER2-overexpressing gastric cancer can confer resistance to HER2-directed treatment like trastuzumab. Varlitinib (also known as ASLAN001) is a small-molecule, adenosine triphosphate competitive inhibitor of the tyrosine kinases - EGFR, HER2, and HER4. We present phase 1b results of the phase1b/2 study to evaluate the safety and efficacy of varlitinib in combination with weekly paclitaxel in EGFR/HER2 co-expressing AGC patients as a second-line treatment. (KCT0003583). Methods: An open-label phase Ib trial was conducted using a 3+3 design. AGC patients who had failed first-line fluoropyrimidine-containing chemotherapy, with evidence of both EGFR and HER2 overexpression by IHC (≥1+), were enrolled. The primary objective was to assess the dose limiting toxicity (DLT) and recommended phase 2 dose (RP2D) of varlitinib [Dose 1: 300 mg BID, Dose -1: 300mg intermittent dose] and weekly paclitaxel (80 mg/m2 D1,8,15) every 4 weeks along with evaluation of anti-tumor activity. Results: From July 2019 to May 2020, 9 patients were enrolled at Dose 1 level of varlitinib 300mg bid and 6 patients were evaluable for safety per protocol. Two patients did not finish DLT period: one patient withdrew after 1 week and one patient received palliative surgery for panperitonitis caused by gastric cancer metastasis. One patient had major violation in IP administration as the patient took varlitinib intermittently. Among the 6 evaluable patients, there was 1 DLT of G4 AST/ALT elevation and G3 hyperbilirubinemia, which resolved after 3 weeks. The most common treatment related adverse events (TRAEs) were neutropenia (n=5), all of which were grade ≥ 3, but no lasting more than 7 days. Grade 2 TRAEs included rash (n=2), mucositis (n=2) and peripheral sensory neuropathy (n=2). After a median follow-up of 3.0 (range, 1.9~ 6.2) months, the best responses were stable disease in 4 patients. Currently, 4 patients are ongoing. Conclusions: The combination of varlitinib 300mg bid and weekly paclitaxel 80mg showed manageable safety profiles and determined as RP2D. Currently, multi-site phase 2 part is now underway. Clinical trial information: KCT0003583.

A multi-institutional phase Ib/II trial of first-line triplet regimen (Pembrolizumab, Trastuzumab, Chemotherapy) for HER2-positive advanced gastric and gastroesophageal junction cancer (PANTHERA Trial): Molecular profiling and clinical update

218

Background: We report the updated clinical data and molecular profiling results of a multi-institutional phase Ib/II trial of triple combination (pembrolizumab, trastuzumab, and chempotherapy) as first line therapy for HER2 positive advanced gastric and gastroesophageal junction (AGC/GEJ) cancer. (PANTHERA trial; NCT02901301). Methods: Pembrolizumab 200mg IV D1, Trastuzumab 6mg/kg (after 8mg/kg load) D1, Capecitabine 1000mg/m2 bid D1-14, and Cisplatin 80mg/m2 D1 every 3 weeks was selected as recommended phase II dose. The primary endpoint for phase II was ORR per RECIST v1.1. Secondary endpoints included PFS, OS, DOR, safety, and predictive biomarker analysis by targeted NGS. Results: At the time of data lock on Aug 31, 2020, total of 43 patients were treated with median follow up of 18.2 months, and 3 patients remained on the treatment, and 6 patients finished 2-year treatment without progression. ORR was 76.7% (CR 16.3%, PR 60.5%, conversion surgery 4.6%) with 26 pts (56.6%) showing more than 50% of tumor burden reduction. Median PFS was 8.6 months (95% CI 7.2-16.5) and median OS was 19.3 months (95% CI 16.5-NR). There were no MSI-H/dMMR or EBV-positive pts. No patient discontinued pembrolizumab because of immune-related adverse events. Clinical features including PD-L1 status (55.3% of pts ≥ CPS 1 and 13.2% of pts ≥ CPS 10 among available 38 pts), metastatic organ or baseline tumor burden was not related to the survival. Ninety-eight tumor tissues from 39 pts (paired tumor tissues from 22 pts) were analyzed with targeted NGS. Although every pts were HER2 IHC-positive, baseline HER2 amplification by NGS was related to the survival ( HER2 amp (n=8) vs HER2 non-amp (n=23); mPFS, not reached vs 7.7 months, P=0.0178; mOS, not reached vs 17.9 months, P=0.044) but no other signaling pathways predicted pts’ survival. HER2 mutations including L869R or D769H were related to the acquired resistance. High TMB showed a tendency toward better survival (mPFS; High (n=7) vs Low (n=24) TMB, 22.0 vs 8.2, P=0.2835) due to small number of patients. Updated immune markers and serial NGS analyses will be presented. Conclusions: First-line triplet regimen (Pembrolizumab, Trastuzumab, and Chemotherapy) showed promising efficacy based on HER2 amplification by NGS regardless of PD-L1 status in AGC/GEJ cancer. Correlative biomarkers found from NGS study need to be validated through on-going phase III Keynote-811 study. Clinical trial information: NCT02901301. [Table: see text]

Efficacy and safety of nab-paclitaxel plus gemcitabine-cisplatin (GemCis/nab-P) in Korean patients with advanced biliary tract cancers (aBTC): Multicenter retrospective analysis

274

Background: A recent phase II trial (NCT02392637) demonstrated prolonged survival by treatment with GemCis/nab-P in patients (pts) with aBTC. Further evaluation in real-world setting is necessary to measure the clinical outcomes of GemCis/nab-P in daily practice in Asian pts. Methods: This is a multicenter retrospective analysis of data from 3 institutes in Korea. Between September 2019 and August 2020, a total of 104 pts who received GemCis/nab-P for the management of aBTC were included in this analysis. Results: Median age was 64 years (range, 34-84), and 60 pts (57.7%) were male. GemCis/nab-P was used as the starting regimen in 60 pts (57.7%), 16 pts (15.4%) received GemCis/nab-P after failure of GemCis ± investigational drug (mainly immune checkpoint inhibitors), and 28 pts (26.9%) added nab-P to initial Gem/Cis without progressive disease. Baseline characteristics were as follows: Intrahepatic cholangiocarcinoma (CCC)/extrahepatic CCC/gallbladder cancer in 42 (40.4%)/33 (31.7%)/29 (27.9%); metastatic or recurred/locally advanced in 82 (78.8%)/22 (21.2%) pts. According to RECIST v 1.1, objective response rates (ORR) and disease control rate (DCR) were 30.8% and 81.8% of all pts, 33.4% and 88.4% in initial GemCis/nab-P, 28.6% and 73.8% in intrahepatic CCC, 36.3% and 96.9% in extrahepatic CCC, and 27.6% and 75.9% in gallbladder cancer groups, respectively. In nab-P addition group, while the ORR and DCR of pts without GemCis failure were 39.3% and 85.7%, those with GemCis failure were 6.3%, 50.0%, respectively. Median overall survival and progression-free survival were not reached, with a median follow-up duration of 3.3 months (95% confidence interval [CI], 2.9-6.7). The most common grade 3-4 toxicities were neutropenia (n=36, 34.6%), anemia (n=17, 16.4%), thrombocytopenia (n=10, 9.6%), and febrile neutropenia (n=9, 8.1%). In patients with locally advanced BTC (n=22), 5 patients (22.7%) were converted to resectable disease and underwent surgery. Conclusions: GemCis/nab-P showed consistent real-life efficacy and safety outcomes for Korean aBTC pts compared with those from the phase 2 trial. [Table: see text]

Comparison of overfeeding effects on gut physiology and microbiota in two goose breeds

To have a better understanding of how the “gut–liver axis” mediates the lipid deposition in the liver, a comparison of overfeeding influence on intestine physiology and microbiota between Gang Goose and Tianfu Meat Goose was performed in this study. After force-feeding, compared with Gang Goose, Tianfu Meat Goose had better fat storage capacity in liver (397.94 vs. 166.54 for foie gras weight (g), P < 0.05; 6.37 vs. 2.92% for the ratio of liver to body, P < 0.05; 60.01 vs. 46.64% for fat content, P < 0.05) and the less subcutaneous adipose tissue weight (1240.96 g vs. 1440.46 g, P < 0.05). After force-feeding, the digestion–absorption capacity of Tianfu Meat Goose was higher than that of Gang Goose (5.56 vs. 3.64 and 4.63 vs. 3.68 for the ratio of villus height to crypt depth in duodenum and ileum, respectively, P < 0.05; 1394.96 vs. 782.59 and 1314.76 vs. 766.17 for the invertase activity (U/mg-prot), in duodenum and ileum, respectively, P < 0.05; 6038.36 vs. 3088.29 and 4645.29 vs. 3927.61 for the activity of maltase (U/mg-prot), in duodenum and ileum, respectively, P < 0.05). Force-feeding decreased the gene expression of Escherichia coli in the ileum of Tianfu Meat Goose; force-feeding increased the number of gut microbiota Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction band in Tianfu Meat Goose and decreased the number in Gang Goose. In conclusion, compared with Gang Goose, the lipid deposition in the liver and the intestine digestion–absorption capacity and stability were higher in Tianfu Meat Goose. Thereby, Tianfu Meat Goose is the better breed for foie gras production for prolonged force-feeding; Gang Goose possesses better fat storage capacity in subcutaneous adipose tissue. However, Gang Goose has lower gut stability responding to force-feeding, so Gang Goose is suited to force-feeding in a short time to gain the body weight and subcutaneous fat as an overfed duck for roast duck.