Exploring Molecular Genetic Alterations and RAF Fusions in Melanoma: A Belvarafenib Expanded Access Program in Patients with RAS/RAF-Mutant Melanoma

BACKGROUND

Melanoma incidence is on the rise in East Asia, yet studies of the molecular landscape are lacking in this population. We examined patients with melanoma who underwent next-generation sequencing (NGS) at a single tertiary center in South Korea, focusing on patients harboring NRAS or RAF alterations who received belvarafenib, a pan-RAF dimer inhibitor, through the Expanded Access Program (EAP).

PATIENTS AND METHODS

Data were collected from 192 patients with melanoma who underwent NGS between November 2017 and May 2023. Variant call format data were obtained and annotated. Patients in the EAP received 450 mg twice daily doses of belvarafenib.

RESULTS

Alterations in the RAS/RTK pathway were the most prevalent, with BRAF and NRAS alteration rates of 22.4% and 17.7%, respectively. NGS enabled additional detection of fusion mutations, including 6 BRAF and 1 RAF1 fusion. Sixteen patients with NRAS or RAF alterations received belvarafenib through the EAP, and disease control was observed in 50%, with 2 patients demonstrating remarkable responses.

CONCLUSIONS

Our study highlights the value of NGS in detecting BRAF, NRAS mutations and RAF fusions, expanding possibilities for targeted therapies in malignant melanoma. Belvarafenib showed clinical benefit in patients harboring these alterations. Ongoing trials will provide further insights into the safety and efficacy of belvarafenib.

A phase II open-label randomized clinical trial of preoperative durvalumab or durvalumab plus tremelimumab in resectable head and neck squamous cell carcinoma

PURPOSE

Clinical implications of neoadjuvant immunotherapy in patients with locally advanced but resectable head and neck squamous cell carcinoma (HNSCC) remain largely unexplored.

PATIENTS AND METHODS

Patients with resectable HNSCC were randomized to receive a single dose of preoperative durvalumab (D) with or without tremelimumab (T) before resection, followed by postoperative (chemo)radiation based on multidisciplinary discretion and 1-year D treatment. Artificial intelligence (AI)-powered spatial distribution analysis of tumor-infiltrating lymphocytes and high-dimensional profiling of circulating immune cells tracked dynamic intratumoral and systemic immune responses.

RESULTS

Of the 48 patients enrolled (D: 24 patients, D+T: 24 patients), 45 underwent surgical resection per protocol (D: 21 patients; D+T: 24 patients). D+/-T had a favorable safety profile and did not delay surgery. Distant recurrence-free survival (DRFS) was significantly better in patients treated with D+T than in those treated with D monotherapy. AI-powered whole-slide image analysis demonstrated that D+T significantly reshaped the tumor microenvironment toward immune-inflamed phenotypes, in contrast to D monotherapy or cytotoxic chemotherapy. High-dimensional profiling of circulating immune cells revealed a significant expansion of T cell subsets characterized by proliferation and activation in response to D+T therapy, which was rare following D monotherapy. Importantly, expansion of specific clusters in CD8+ T cells and non-regulatory CD4+ T cells with activation and exhaustion programs was associated with prolonged DRFS in patients treated with D+T.

CONCLUSIONS

Preoperative D+/-T is feasible and may benefit patients with resectable HNSCC. Distinct changes in the tumor microenvironment and circulating immune cells were induced by each treatment regimen, warranting further investigation.

Prior antibiotic administration disrupts anti-PD-1 responses in advanced gastric cancer by altering the gut microbiome and systemic immune response

Evidence on whether prior antibiotic (pATB) administration modulates outcomes of programmed cell death protein-1 (PD-1) inhibitors in advanced gastric cancer (AGC) is scarce. In this study, we find that pATB administration is consistently associated with poor progression-free survival (PFS) and overall survival (OS) in multiple cohorts consisting of patients with AGC treated with PD-1 inhibitors. In contrast, pATB does not affect outcomes among patients treated with irinotecan. Multivariable analysis of the overall patients treated with PD-1 inhibitors confirms that pATB administration independently predicts worse PFS and OS. Administration of pATBs is associated with diminished gut microbiome diversity, reduced abundance of Lactobacillus gasseri, and disproportional enrichment of circulating exhaustive CD8+ T cells, all of which are associated with worse outcomes. Considering the inferior treatment response and poor survival outcomes by pATB administration followed by PD-1 blockade, ATBs should be prescribed with caution in patients with AGC who are planning to receive PD-1 inhibitors.

Trastuzumab Combined With Ramucirumab and Paclitaxel in Patients With Previously Treated Human Epidermal Growth Factor Receptor 2-Positive Advanced Gastric or Gastroesophageal Junction Cancer

PURPOSE

Trastuzumab-containing chemotherapy is the recommended first-line regimen for human epidermal growth factor receptor 2 (HER2)-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer. We evaluated the safety and efficacy of trastuzumab combined with ramucirumab and paclitaxel as second-line treatment for HER2-positive G/GEJ cancer.

PATIENTS AND METHODS

Patients with HER2-positive advanced G/GEJ cancer who progressed after first-line treatment with trastuzumab-containing chemotherapy were enrolled from five centers in the Republic of Korea. Patients were administered a 28-day cycle of trastuzumab (once on days 1, 8, 15, and 22: 2 mg/kg followed by 4 mg/kg loading dose), ramucirumab (once on days 1 and 15: 8 mg/kg), and paclitaxel (once on days 1, 8, and 15: dose level 1, 80 mg/m2; or dose level -1, 70 mg/m2). Phase II was conducted with the recommended phase II dose (RP2D). Primary end points were determination of RP2D during phase Ib and investigator-assessed progression-free survival (PFS) in patients treated with RP2D.

RESULTS

Dose-limiting toxicity at dose level 1 was not documented during phase Ib, and a full dose combination was selected as the RP2D. Among 50 patients with a median follow-up duration of 27.5 months (95% CI, 17.4 to 37.6), median PFS and overall survival were 7.1 months (95% CI, 4.8 to 9.4) and 13.6 months (95% CI, 9.4 to 17.7), respectively. Objective response rate was 54% (27 of 50, including one complete response), and disease control rate was 96% (48 of 50). Loss of HER2 expression was observed in 34.8% (8 of 23) patients after first-line treatment, and no definite association between HER2 expression and the outcome was revealed. Safety profiles were consistent with previous reports.

CONCLUSION

Trastuzumab combined with ramucirumab and paclitaxel showed appreciable efficacy with manageable safety profiles in patients with previously treated HER2-positive G/GEJ cancer.

Abstract 3234: OCT-598, a novel EP2/EP4 dual antagonist, promotes anti-tumor immune responses in syngeneic mouse tumor models in combination with standard-of-care chemo- and immunotherapies

Prostaglandin E2 (PGE2) is widely recognized as one of the major bioactive lipids that, with the striking regenerative potential, promote drug-resistance in cancer cells as well as immune evasion in the tumor microenvironment (TME). Primarily driven by apoptotic cell death, PGE2 is thought to elicit wound-healing responses to help provide an immunosuppressive and proliferative niche that supports cancer stem cell repopulation and thereby therapy-resistance. While COX1/2 inhibitors that attenuate PGE2 production have shown promising anti-cancer effects in various (pre-)clinical settings, the gastrointestinal- and cardiotoxicities precluded their development as anti-cancer agents. It is anticipated that specific targeting of PGE2 signaling via its cognate receptors constitutes a safer and potentially more effective approach. Of the receptor subtypes EP1-4, Gα,s-coupled EP2 and EP4 are believed to be directly involved in immunosuppressive effects of PGE2.OCT-598 is a novel, highly potent and selective EP2/EP4 dual antagonist with Ki values of 23 nM and 0.2 nM vs EP2 and EP4, respectively. PGE2 inhibited normal differentiation of human monocytes into CD1a+CD16- dendritic cells under the presence of GM-CSF and IL-4 and promoted differentiation towards CD1a-CD16+ macrophages in vitro. However, EP2/EP4 dual inhibition by OCT-598 reversed this phenomenon to a greater extent than either EP2- or EP4-specific inhibitor alone. In vivo, OCT-598 effected tumor growth inhibition in multiple syngeneic mouse models as a single agent as well as in combination with an immune checkpoint blocker (ICB). Furthermore, the addition of OCT-598 to the lung cancer standard-of-care regimen (anti-PD-1 plus chemotherapy) in TC-1 mouse lung adenocarcinoma model gave rise to complete tumor regression. In conclusion, dual blockade of EP2 and EP4 by OCT-598 is shown to be a compelling strategy to reinforce antitumor effects by thwarting PGE2-mediated therapy resistance and immune evasion.Findings from this study provide a rationale for clinical development of OCT-598 as a therapeutic option for human malignant cancers.

Citation Format: Youngrae Lee, Sujeong Baek, Dong Kwon Kim, Yeri Lee, Donggeon Kim, Seongin Jo, Sang Kyun Lim, Young Sook Shin, Soonsang Kwon, Seung Min Yang, Young Taek Kim, Seong-San Kang, Chun-Bong Synn, Kwangmin Na, Mi Hyun Kim, Heekyung Han, Yu Jin Han, Sungwoo Lee, Jae Hwan Kim, Mi Ran Yun, Youngseon Byeon, Young Seob Kim, Ji Yun Lee, Jii Bum Lee, Chang Gon Kim, Min Hee Hong, Sun Min Lim, Kyoung-Ho Pyo, Byoung Chul Cho, Taeyoung Yoon. OCT-598, a novel EP2/EP4 dual antagonist, promotes anti-tumor immune responses in syngeneic mouse tumor models in combination with standard-of-care chemo- and immunotherapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3234.

Abstract 5865: Combinatorial activity of amivantamab and pembrolizumab in head and neck squamous cell carcinoma and lung squamous cell carcinoma expressing wild-type EGFR and MET

Introduction: Unmet needs exist for immunotherapy targeting PD-1/PD-L1 in head and neck squamous cell carcinoma (HNSCC) and lung squamous cell carcinoma (LUSC) due to its suboptimal response. Amivantamab, a bispecific antibody targeting epidermal growth factor receptor (EGFR) and c-Met, has been demonstrated to induce antibody-dependent cytotoxicity and trogocytosis in tumor cells. We hypothesized that combination of amivantamab with pembrolizumab may synergistically enhance antitumor immunity. In this study, we present comprehensive immunomodulatory and synergistic antitumor efficacy of amivantamab and pembrolizumab in humanized HNSCC and LUSC mice models.

Methods: EGFR and MET-expressing tumors from a HNSCC and a LUSC patient were transplanted into Hu-CD34-NSG to establish humanized patient-derived xenograft (PDX) models. Tumor-bearing PDXs were treated with vehicle, pembrolizumab (10mpk, Q5D, n=10), amivantamab (10mpk, BIW, n=10), or a combination of pembrolizumab and amivantamab (n=10). Analysis of immune modulatory responses within the tumor microenvironment (TME) using multiplexed IHC, flow cytometry, and single cell RNA sequencing was performed.

Results: Combination of amivantamab and pembrolizumab showed a significant reduction of tumor volume (p<0.001) compared to vehicle or single treatment in both models. Additionally, significantly longer survival was observed for combination treated compared to the vehicle treated groups (p<0.0001). Multispectral imaging of tumor indicated that granzyme B-producing CD8+ T cells were significantly increased within the tumor in the combination group (p<0.01). Further analysis of T cell subsets suggested that central memory type CD8+ T cells were increased upon combination treatment. This group also demonstrated significantly higher CEA-tetramer positive CD8+ T cells in the tumor (p<0.01), suggesting that cytotoxic T cells recognizing tumor specific antigens enhanced antitumor immune response. Single cell RNA sequencing analysis of HNSCC showed that an EGFRhighMEThigh cluster was enriched in the TME after pembrolizumab treatment. This subcluster had elevated glycolysis and lactic acid pathway-related genes compared to EGFRlowMETlow cluster. Lactate transporter, MCT4 (SLC16A3) and LDHA genes were dramatically increased in the EGFRhighMEThigh cluster. Elevated lactic acid pathway may lead to immune evasion in the tumor, dampening the activity of pembrolizumab. Interestingly, combination treatment with amivantamab could reduce EGFRhighMEThigh cluster, and could effectively control tumor via creating favorable immune TME.

Conclusion: Our study demonstrated combinatorial benefits of amivantamab and pembrolizumab by effectively remodeling TME, providing a preclinical rationale to clinically combine amivantamab and PD-1 blockade treatments.

Citation Format: Sun Min Lim, Chun-Bong Synn, Seong-san Kang, DongKwon Kim, Soo-Hwan Lee, Sujeong Baek, Seung Min Yang, Yu Jin Han, Mi hyun Kim, Heekyung Han, Kwangmin Na, Young Taek Kim, Sungwoo Lee, Mi Ran Yun, Jae Hwan Kim, Youngseon Byeon, Young Seob Kim, Jii Bum Lee, Ji Yun Lee, Chang Gon Kim, Min Hee Hong, Kyoung-Ho Pyo, Joshua Curtin, Bharvin Patel, Isabelle Bergiers. Combinatorial activity of amivantamab and pembrolizumab in head and neck squamous cell carcinoma and lung squamous cell carcinoma expressing wild-type EGFR and MET [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5865.

Abstract 6780: Characterization of immunological heterogeneity in the tumor microenvironment by integrated analyses using single cell RNAseq, spatial RNAseq and multiplex IHC

Heterogeneity in resistant to immunotherapies of tumor microenvironment (TME) has been implicated in immunotherapies to cause immune evasion or drug resistance. This study was conducted to explore the heterogeneity of TME through multiplex IHC, spatial and RNA sequencing analysis. We selected a sample from a lung adenocarcinoma patient without EGFR-activating mutation and expressing 30% of PD-L1. For quantitative analysis by multiplex IHC, various markers including CD4, CD8, FoxP3, granzyme B, CD20 and pan-cytokeratin were stained with 7 different fluorescence dyes, which was imaged with Vectra Polaris (Akoya). For scRNAseq and spatial RNAseq, we used 5’ chromium library kit (10X Genomics) to make library construction. Integrated raw data was generated using Cell ranger, Seurat pipeline and Azimuth package. The tumor area was divided into 16 clusters in which we selected 2 clusters based on CD3/45 expression. There was a noticeable distinction between the two clusters which were defined as the ‘High’ region (CD45highCD3high cluster) and the ‘Low’ region (CD45lowCD3low cluster). By multiplex IHC, percentage of CD8+T cells was higher in the ‘High’ region than in the ‘Low’ region (8.5% vs. 0.8%, respectively). Subsequent analysis of two clusters using spatial and single cell RNA seq, the ‘Low’ region was characterized by increased hypoxia-associated gene expressions including HIF1A, HIF3A and VEGFA. Various immune cells were abundant in the ‘High’ region and CD45 expression level was 11-fold higher in the ‘High’ region compared to the ‘Low’ region. Cytokine/chemokine network analysis via spatial RNAseq revealed that gene expression of tumor necrosis factor (TNF) family-associated factors increased in the 'High' region compared to the ‘Low’ region (TNF, FAS, TRAIL, RANKL and CD40), which is well-known to promotes apoptosis, programmed cell death, or necrosis of certain cancer. Additionally, the ‘High’ region also had elevated levels of the PD-1/PD-L1, CD155, CD122/TIGIT, Siglec10/CD24, LAG3/LAGLS3, and CD47/CD172a axes, suggesting active immune responses. Intriguingly, combined analyses showed that ‘High’ region showed enhanced level of CD44 expression as the leading-edged gene, which suggests the metastatic potential of tumor cells. Furthermore, scRNA analysis confirmed that CD44 expression was mainly higher in macrophages, suggesting that tumor-associated macrophages partially affected tumor cell metastasis in the ‘High’ region. Our finding suggests that understanding the intratumoral immunological heterogeneity of lung adenocarcinoma can help to study the mechanism of tumor heterogeneity by integrated spatial RNAseq and scRNAseq analyses. This type of technique could be applied to understand complex networks of anti-tumor immune activities, drug resistance mechanisms and immunotherapeutic response of cancer.

Citation Format: Seul Lee, Jae-Hwan Kim, Kwangmin Na, Seung Min Yang, Dong Kwon Kim, Sujeong Baek, Seong-san Kang, Yu Jin Han, Chun-Bong Synn, Mi hyun Kim, Heekyung Han, Young Taek Kim, Sungwoo Lee, Youngseon Byeon, Young Seob Kim, Ji Yun Lee, Jii Bum Lee, Chang Gon Kim, Min Hee Hong, Sun Min Lim, Kyoung-Ho Pyo, Byoung Chul Cho. Characterization of immunological heterogeneity in the tumor microenvironment by integrated analyses using single cell RNAseq, spatial RNAseq and multiplex IHC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6780.

Abstract 5107: A novel AhR inhibitor ‘DA-4505’ improved the anti-cancer efficacy of surgical and chemotherapy via synergistic anti-tumor effects of aPD-1

Background: The Aryl hydrocarbon receptor (AhR) is one of the most predominant regulators of cancer metabolism. The AhR exerts important immunosuppressive functions by activating Treg cells and myeloid-derived suppressor cells and repressing CD8+ effector T cells. Here, we propose that a best-in-class AhR inhibitor, DA-4505, improves anti-tumor efficacy via modulation of tumor immune surveillance compared to BAY2416964, an AHR antagonist drug candidate being studied in the clinical phase.

Methods: To evaluate anti-tumor effects of DA-4505 and BAY2416964, the two AhR inhibitors were dosed at 10 mg/kg once daily alone or in combination with aPD-1 (10 mg/kg) in surgical and chemotherapy models, and a PDX model (YHIM2004). Tumor volume, relapse, and survival were evaluated, and immune profiles were analyzed with IHC, flow cytometry, and scRNAseq.

Results: A significant tumor reduction appeared in the CT26 and 4T1 tumor models after the DA-4505 treatment compared to vehicle group (P<0.05). In contrast, DA-4505 treatment did not induce significant tumor regression compared to vehicle group in tumor-bearing NOG mice, suggesting that anti-tumor effects of DA-4505 were driven by immunologic mechanisms. To evaluate the role of DA-4505 in conjunction with surgery, DA-4505 alone or in combination with anti-PD-1 was given prior to and following resection of the tumors in 4T1 tumor-bearing mice. Survival of mice treated with DA-4505 alone or DA-4505 combined with anti-PD-1 was significantly prolonged after resection compared to aPD-1 treatment group (P<0.05). In addition, there were four mice that did not have a relapse by treating DA-4505 with or without aPD-1 after surgery (4/5). A tumor regression also appeared in the YHIM2004-engrafted humanized mouse study. A tumor reduction was shown by treating DA-4505 alone or in combination with pembrolizumab compared to vehicle group (P<0.05). Next, we co-administered an AhR inhibitor and aPD-1 as a partner to improve the antitumor effects of chemotherapy. The DA-4505 add-on group showed tumor regression when compared with the combination therapy group treated with aPD-1 and chemotherapy (P<0.0001). In addition, a significant increase in survival rate was shown in the group treated with a DA-4505 add-on compared to vehicle group (P<0.001). Analysis of scRNAseq showed that M1 macrophage expressing CCL7 and CCL8 were increased in DA-4505 treated group compared to the vehicle and aPD-1 groups. This suggests that immune modulatory effect of DA-4505 may be due to enhanced recruitment of immune cells into the tumor site by macrophages with high chemotactic activity.

Conclusion: The AhR inhibitor DA-4505 demonstrated an improvement in anti-tumor efficacy. In addition, it has shown a synergistic effect when combined with aPD-1. Discoveries from this study provide a preclinical rationale for future clinical implications in solid tumor.

Citation Format: DongKwon Kim, Sujeong Baek, Seung Min Yang, Yu Jin Han, Seong-san Kang, Chun-Bong Synn, Mi Hyun Kim, Heekyung Han, Kwangmin Na, Young Taek Kim, Sungwoo Lee, Taedong Han, Hyounmie Doh, Jongho Cho, Dajeong Kim, Daewon Cha, Jae Hwan Kim, Youngseon Byeon, Young Seob Kim, Mi Ran Yun, Ji Yun Lee, Jii Bum Lee, Chang Gon Kim, Min Hee Hong, Sun Min Lim, Byoung Chul Cho, Kyoung-Ho Pyo. A novel AhR inhibitor ‘DA-4505’ improved the anti-cancer efficacy of surgical and chemotherapy via synergistic anti-tumor effects of aPD-1. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5107.

Abstract 3884: Targeting the ARID1A mutations overcomes primary resistance to ALK inhibitors in EML4-ALK posistive NSCLC

Introduction: Anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitors (TKIs) have improved an initial clinical response of non-small-cell lung cancer (NSCLC) patients with ALK-rearrangements. However, a subset of patients shows a poor response to ALK-TKIs. Here, we aimed to identify novel mechanism of primary resistance in preclinical model from a patient who presented an impressive resistance to sequential treatment with ALK TKIs.

Experimental design: The PDC YU-1076 cells were established from pleural effusion of the patient at the time he was receiving chemotherapy and radiotherapy after failure of ALK-TKI treatment. Sanger sequencing confirmed ML4-ALK variant 1 detected at the initial diagnosis. No resistance mutations in the ALK kinase domain were detected. To investigate co-occurring genetic alterations, we performed whole exome sequencing (WES) on YU-1076 cells and the matched blood sample. We further investigated the molecular profile of YU-1076 cells using RNA-sequencing analysis.

Results: YU-1076 cells exhibited cross-resistance to clinically available ALK-TKIs including crizotinib, ceritinib, alectinib, and lorlatinib. However, immunoblot analysis of YU-1076 cells treated with incremental doses of TKIs unexpectedly revealed an effective reduction of ALK

activity and downstream signals. We noticed that YU-1076 cells gradually changed from a small, round shape to a fibroblast-like shape following the treatment of ALK-TKIs. Transcriptome analysis confirmed enrichment for gene signatures related epithelial-to-mesenchymal transition (EMT) in ALK TKI-treated YU-1076 cells, suggesting that ALK-TKIs treatment promotes YU-1076 cells toward a more mesenchymal phenotype. WES analysis identified a major chromatin remodeling complex subunit, AT-rich interacting domain 1A (ARID1A), as well as MYC amplification, CDKN2A loss, and TP53 mutations. We focused on a synthetic lethal strategies using the SFK inhibitor dasatinib and the EZH2 inhibitor GSK126 in ARID1A mutant cancers. The combination of dasatinib with ALK-TKIs restored the sensitivity to the ALK TKIs in YU-1076 cells, accompanied by suppression of EMT marker genes VIM and CDH2 and increase of apoptotic markers BIM, PARP, and CAS3. Congruently, dasatinib significantly impaired tumor growth in YU-1076-xenografts. GSK126 also induced synergistic inhibition of cell growth with upregulation of apoptosis marker genes in YU-1076 cells, but did not affect the expression of EMT marker genes.

Conclusion: Our data indicate that ARID1A could be potentially used as a predictive biomarker for unfavorable ALK-TKI response. In this context, a combination strategy of ALK TKI with dasatinib may be effective in overcoming primary resistance.

Citation Format: Seung Yeon Oh, You Won Lee, Eun Ji Lee, Ju Young Kim, Sewon Park, Ju Yeon Park, Su-Jin Choi, Mi Ra Yu, Jii Bum Lee, Jiyun Lee, Chang Gon Kim, Sun Min Lim, Min Hee Hong, Mi Ran Yun, Byoung Chul Cho. Targeting the ARID1A mutations overcomes primary resistance to ALK inhibitors in EML4-ALK posistive NSCLC. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3884.

Association of T Cell Senescence with Radiation Pneumonitis in Patients with Non-small Cell Lung Cancer

PURPOSE

Associations between immunosenescence and radiation pneumonitis (RP) are largely unknown. We aimed to identify a peripheral blood T cell senescence biomarker to predict RP in patients with non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Patients with locally advanced NSCLC who received definitive concurrent chemoradiotherapy (dCRT) were prospectively registered (cohort 1, n=23; cohort 2, n=31). Peripheral blood was collected at baseline, during dCRT, and at 1 month post-dCRT. Patients were dichotomized to grade ≥2 (G2+) RP and grade 0-1 (G0-1) RP. Flow cytometry was performed to assess phenotypes and functional properties of T cell subsets. RP incidence was estimated via competing risk analysis.

RESULTS

Five and six patients exhibited G2+ RP following dCRT in cohorts 1 and 2, respectively. Patients with G2+ RP exhibited a more aged T cell pool and higher frequencies of senescent CD57⁺CD28^-CD8⁺ T cells than patients with G0-1 RP at baseline, during dCRT, and at 1 month post-dCRT. These senescent cells exhibited increased granzyme B, IFN-γ, and TNF-α production. Higher baseline frequency of CD57⁺CD28^-CD8⁺ T cells was an independent predictor of G2+ RP (hazard ratio, 8.42; 95% confidence interval, 2.58-27.45; P<0.001). Recursive partitioning analysis revealed three distinct risk groups stratified by baseline CD57⁺CD28^-CD8⁺ T cell frequency and lung V_{20 Gy}, with 1-year cumulative G2+ RP incidences of 50.0%, 16.7%, and 0% for high-, intermediate-, and low-risk groups, respectively (P=0.002).

CONCLUSIONS

Higher baseline frequencies of CD57⁺CD28^-CD8⁺ T cells correlated with increased G2+ RP risks. Our results suggest the need for further investigation of the role of T cell senescence on radiation-induced organ damage.

Atezolizumab plus bevacizumab in patients with child-Pugh B advanced hepatocellular carcinoma

Background

Atezolizumab plus bevacizumab (Ate/Bev) demonstrated promising efficacy and safety in patients with advanced hepatocellular carcinoma (HCC) in the phase III IMbrave150 trial. However, patients with Child-Pugh B HCC were excluded in the abovementioned prospective trial. Therefore, we aimed to investigate the efficacy and safety of Ate/Bev in patients with Child-Pugh B HCC.

Methods

This multicenter retrospective study included 36 patients with Child-Pugh B advanced HCC who received Ate/Bev at four cancer referral centers between May 2020 and August 2021. Comparative analyses were performed with an independent cohort of patients with Child-Pugh A HCC from the same registry (n = 133).

Results

All patients received Ate/Bev as first-line systemic treatment for advanced HCC. The objective response and disease control rates of patients in the Child-Pugh groups B and A were 11.1% and 58.3% and 34.6% and 76.7%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 3.0 months [95% confidence interval (CI), 1.7-4.3) and 7.7 months (95% CI, 4.8-10.6) in the Child-Pugh B group, whereas the median PFS and OS were 9.6 months (95% CI, 5.1-14.2) and not reached (95% CI, not available) in the Child-Pugh A group, respectively. Compared to the Child-Pugh A group, grade 3-4 adverse events (AEs) were more common in the Child-Pugh B group (44.4% versus 15.8, p < 0.001), with the most frequent grade 3-4 AEs being gastrointestinal bleeding (n = 6, 16.7%), neutropenia (n = 5, 13.9%), and thrombocytopenia (n = 4, 11.1%).

Conclusions

In the Child-Pugh B subgroup of patients with advanced HCC, Ate/Bev treatment showed modest clinical activity. However, due to the increased frequency of serious AEs, careful evaluation of treatment response and AE management is required in this subgroup of patients.

On-treatment derived neutrophil-to-lymphocyte ratio and survival with palbociclib and endocrine treatment: analysis of a multicenter retrospective cohort and the PALOMA-2/3 study with immune correlates

BACKGROUND

Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors have been established as a standard treatment for hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC); however, predictive biomarkers with translational relevance have not yet been elucidated.

METHODS

Data from postmenopausal women who received the CDK4/6 inhibitor palbociclib and letrozole for HR-positive, HER2-negative ABC from tertiary referral centers were analyzed (N = 221; exploratory cohort). Pre- and on-treatment neutrophil-to-lymphocyte ratio (NLR) and derived NLR (dNLR; neutrophil/[leukocyte-neutrophil]) were correlated with survival outcomes. Data from the PALOMA-2 (NCT01740427) and PALOMA-3 studies (NCT01942135) involving patients treated with endocrine treatment with or without palbociclib were also analyzed (validation cohort). Prospectively enrolled patients (N = 20) were subjected to immunophenotyping with circulating immune cells to explore the biological implications of immune cell dynamics.

RESULTS

In the exploratory cohort, palbociclib administration significantly reduced leukocyte, neutrophil, and lymphocyte counts on day 1 of cycle 2. Although the baseline dNLR was not significantly associated with progression-free survival (PFS), higher on-treatment dNLRs were associated with worse PFS (hazard ratio = 3.337, P < 0.001). In the PALOMA-2 validation cohort, higher on-treatment dNLRs were associated with inferior PFS in patients treated with palbociclib and letrozole (hazard ratio = 1.498, P = 0.009), and reduction in the dNLR after treatment was predictive of a survival benefit (hazard ratio = 1.555, P = 0.026). On-treatment dNLRs were also predictive of PFS following palbociclib and fulvestrant treatment in the PALOMA-3 validation cohort. Using flow cytometry analysis, we found that the CDK4/6 inhibitor prevented T cell exhaustion and diminished myeloid-derived suppressor cell frequency.

CONCLUSIONS

On-treatment dNLR significantly predicted PFS in patients with HR-positive, HER2-negative ABC receiving palbociclib and endocrine treatment. Additionally, we observed putative systemic immune responses elicited by palbociclib, suggesting immunologic changes upon CDK4/6 inhibitor treatment.

Fusobacterium nucleatum induces a tumor microenvironment with diminished adaptive immunity against colorectal cancers

Background & Aims

Fusobacterium nucleatum (FN) plays a pivotal role in the development and progression of colorectal cancer by modulating antitumor immune responses. However, the impact of FN on immune regulation in the tumor microenvironment has not been fully elucidated.

Methods

The abundance of FN was measured in 99 stage III CRC tumor tissues using quantitative polymerase chain reaction. Gene expression profiles were assessed and annotated using consensus molecular subtypes (CMS), Gene Ontology (GO) analysis, and deconvolution of individual immune cell types in the context of FN abundance. Immune profiling for tumor infiltrating T cells isolated from human tumor tissues was analyzed using flow cytometry. Ex vivo tumor-infiltrating T cells were stimulated in the presence or absence of FN to determine the direct effects of FN on immune cell phenotypes.

Results

Gene expression profiles, CMS composition, abundance of immune cell subtypes, and survival outcomes differed depending on FN infection. We found that FN infection was associated with poorer disease-free survival and overall survival in stage III CRC patients. FN infection was associated with T cell depletion and enrichment of exhausted CD8⁺ and FoxP3⁺ regulatory T cells in the tumor microenvironment. The presence of FN in tumors was correlated with a suppressive tumor microenvironment in a T cell-dependent manner.

Conclusion

FN enhanced the suppressive immune microenvironment with high depletion of CD8⁺ T cells and enrichment of FoxP3⁺ regulatory T cells in human colorectal cancer cases. Our findings suggest a potential association for FN in adaptive immunity, with biological and prognostic implications.

YH29407 with anti-PD-1 ameliorates anti-tumor effects via increased T cell functionality and antigen presenting machinery in the tumor microenvironment

Among cancer cells, indoleamine 2, 3-dioxygenase1 (IDO1) activity has been implicated in improving the proliferation and growth of cancer cells and suppressing immune cell activity. IDO1 is also responsible for the catabolism of tryptophan to kynurenine. Depletion of tryptophan and an increase in kynurenine exert important immunosuppressive functions by activating regulatory T cells and suppressing CD8⁺ T and natural killer (NK) cells. In this study, we compared the anti-tumor effects of YH29407, the best-in-class IDO1 inhibitor with improved pharmacodynamics and pharmacokinetics, with first and second-generation IDO1 inhibitors (epacadostat and BMS-986205, respectively). YH29407 treatment alone and anti-PD-1 (aPD-1) combination treatment induced significant tumor suppression compared with competing drugs. In particular, combination treatment showed the best anti-tumor effects, with most tumors reduced and complete responses. Our observations suggest that improved anti-tumor effects were caused by an increase in T cell infiltration and activity after YH29407 treatment. Notably, an immune depletion assay confirmed that YH29407 is closely related to CD8⁺ T cells. RNA-seq results showed that treatment with YH29407 increased the expression of genes involved in T cell function and antigen presentation in tumors expressing ZAP70, LCK, NFATC2, B2M, and MYD88 genes. Our results suggest that an IDO1 inhibitor, YH29407, has enhanced PK/PD compared to previous IDO1 inhibitors by causing a change in the population of CD8⁺ T cells including infiltrating T cells into the tumor. Ultimately, YH29407 overcame the limitations of the competing drugs and displayed potential as an immunotherapy strategy in combination with aPD-1.

First-line pembrolizumab versus dabrafenib/trametinib treatment for BRAF V600-mutant advanced melanoma

BACKGROUND

Limited data are available to assist the selection between immune checkpoint inhibitors and BRAF/mitogen-activated protein kinase kinase inhibitors as first-line treatment for patients with BRAF-mutant advanced malignant melanoma.

OBJECTIVE

To investigate the outcomes associated with first-line pembrolizumab or dabrafenib/trametinib treatment for advanced melanoma with activating BRAF V600 mutation.

METHODS

Data of patients with BRAF V600-mutant melanoma who were treated with first-line pembrolizumab (n = 40) or dabrafenib/trametinib (n = 32) were analyzed. Tumor response, progression-free survival, and overall survival were evaluated. Immune evasion accompanied with emerging resistance to BRAF/mitogen-activated protein kinase kinase inhibitors was assessed.

RESULTS

A longer overall survival was observed after first-line pembrolizumab treatment than after first-line dabrafenib/trametinib treatment (hazard ratio = 2.910, 95% CI: 1.552-5.459), although there were no significant differences in progression-free survival (P = .375) and response rate (P = .123). Emergence of resistance to dabrafenib/trametinib co-occurred with immune evasion, enabling melanoma cells to escape recognition and killing by Melan-A-specific CD8⁺ T cells.

LIMITATIONS

Analysis was conducted in a retrospective manner.

CONCLUSION

Pembrolizumab may be recommended over BRAF/mitogen-activated protein kinase kinase inhibitors as the first-line treatment in patients with advanced BRAF V600-mutant melanoma.

The presence and size of intrahepatic tumors determine the therapeutic efficacy of nivolumab in advanced hepatocellular carcinoma

Purpose:

Inter-tumoral heterogeneity at the differential lesion level raises the possibility of distinct organ-specific responses to immune checkpoint inhibitors (ICIs). We aimed to comprehensively examine the clinicopathological factors to predict and assess the efficacy of nivolumab, programmed cell death protein 1 (PD-1) blockade at an individual tumor site-specific level in patients with advanced hepatocellular carcinoma (aHCC).

Patients and Methods:

We enrolled 261 aHCC patients treated with nivolumab between 2012 and 2018. Eighty-one clinicopathological factors were comprehensively collected and analyzed. The association between all variables and survival outcomes was evaluated. According to tumor site, the organ-specific responses were assessed based on the Response Evaluation Criteria in Solid Tumors, version 1.1.

Results:

The liver was the most commonly involved organ (75.1%), followed by the lungs (37.5%) and lymph nodes (LNs, 11.5%). The liver of nonresponders was more frequently the organ of progression, while the lungs of responders were more frequently the organs of response. Among the 455 individual lesions (liver, n = 248; lung, n = 124; LN, n = 35; others including bone or soft tissues, n = 48), intrahepatic tumors showed the least response (10.1%), followed by lung (24.2%) and LN tumors (37.1%), indicating the presence of distinct organ-specific responses to nivolumab. In intrahepatic tumors, the organ-specific response rate decreased as the size increased (13% for ⩽50 mm, 8.1% for 50–100 mm, and 5.5% for >100 mm). In the subgroup analysis according to tumor location, patients with lung only metastasis (⩾30 mm) showed the best progression-free survival (PFS) and overall survival (OS). In contrast, primary HCC (⩾100 mm) without lung metastasis had the worst PFS and OS. Comprehensive analyses also revealed that liver function and systemic inflammatory indices, such as neutrophil-to-lymphocyte ratio (NLR), were significantly associated with PFS and OS.

Conclusion:

The presence and size of liver tumors, liver function, and NLR are key factors determining the response to nivolumab in aHCC. These clinical factors should be considered when treating patients with advanced HCC with PD-1 blockade.

Hyperprogressive disease during PD-1 blockade in patients with advanced gastric cancer

BACKGROUND

Investigations for programmed cell death-1 (PD-1) blockade-induced hyperprogressive disease (HPD) have not been stringently conducted in patients with advanced gastric cancer (AGC). We explored the occurrence of HPD and its clinical implications in patients with AGC and treated with PD-1 inhibitors.

METHODS

We enrolled 169 patients with AGC and treated with either the PD-1 blockade (nivolumab or pembrolizumab; N = 112) or irinotecan monotherapy (N = 57) as a single agent. Tumour growth dynamics based on tumour growth kinetics and tumour growth rate (TGR) and time to treatment failure were analysed to define HPD. The incidence, clinical consequences and predictive markers of HPD were investigated.

RESULTS

The optimal criteria for HPD were 4-fold increases in both tumour growth kinetics and TGR ratios and a 40% increase in TGR based on the analysis for patients treated with irinotecan. In total, 10.7% (12/112) of patients experienced HPD after PD-1 inhibitor treatment. Patients with HPD had both shorter progression-free survival (hazard ratio: 2.318; 95% confidence interval: 1.205-4.460) and overall survival (hazard ratio: 2.542; 95% confidence interval: 1.314-4.918) than patients with progressive disease without HPD, losing opportunities for subsequent systemic treatments. Although other variables including PD-L1 expression were not associated with the occurrence of HPD, hypoalbuminemia (<3.25 mg/dL) at baseline was significantly associated with the occurrence of HPD (P < 0.001) and inferior survival outcomes.

CONCLUSIONS

HPD occurs in a proportion of patients with AGC and treated with PD-1 inhibitors. PD-1 inhibitor-induced HPD is associated with worse outcome, loss of eligibility for subsequent treatment and hypoalbuminemia, warranting further investigation.

Abstract LB544: Targeting adaptive metabolic program as a novel treatment approach for TKIs-failed ALK-positive NSCLCs

Introduction: Acquired resistance to ALK-tyrosine kinase inhibitors (ALK-TKIs) treatment, particularly target-off resistance, remains a clinical challenge for ALK-rearranged non-small cell lung cancer (NSCLC). To explore novel vulnerabilities of ALK TKI-resistant cancer cells, we focused on their distinct metabolic pathways for growth and survival.

Experimental Design: To investigate metabolic pathways in resistance mechanisms, we generated ALK-TKIs -acquired-resistant in vitro/vivo models. We screened metabolite mechanisms using metabolite assay kit, Seahorse Extracellular Flux Analyzer, real-time PCR, western blot, RNA-seq in resistant models.

Results: Through an integrated transcriptomic and metabolic assay screening approach, we identified the enhanced reliance on glutamine metabolism in target-off ALK-TKIs-resistant cells. Specifically, resistant cells were characterized by upregulation of glutaminase 1 (GLS1), a mitochondrial enzyme hydrolyzing glutamine into glutamate, simultaneously with downregulation of mitochondrial oxidative phosphorylation (OXPHOS). We demonstrated that this metabolic state intensively accelerates glutaminolysis and subsequent mitochondrial glutamine-derived aspartate synthesis, resulting in TKI resistance by reinforcing antioxidant capacity with increase of NADPH and glutathione. Mechanistically, GLS1 inhibition elicited a marked reduction of cell growth with increase of reactive oxygen species (ROS) in resistant cells, which was restored by supplementation of exogenous aspartate. The antitumor activity of GLS1 inhibition against resistant tumor cells was further validated in in vivo experiments, patient-derived xenograft (PDX) and EML4-ALK transgenic mice. More importantly, glutaminase inhibitor CB-839 enhanced the therapeutic efficacy of anti-PD-L1 treatment in immune checkpoint blockade (ICB)-resistant EML4-ALK transgenic mice.

Conclusion: Our findings highlight a new metabolic vulnerability of ALK-TKIs resistant tumors and provide a rationale for targeting GLS1 as a potential treatment option to overcome ALK-TKIs resistance.

Citation Format: You Won Lee, Hun Mi Choi, Seung Yeon Oh, Eun Ji Lee, Kyoung-Ho Pyo, Jae Hwan Kim, Youngseon Byeon, Seong Gu Heo, Sun Min Lim, Min Hee Hong, Chang Gon Kim, Hye Ryun Kim, Mi Ran Yun, Byoung Chul Cho. Targeting adaptive metabolic program as a novel treatment approach for TKIs-failed ALK-positive NSCLCs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB544.

Preoperative durvalumab (D) with or without tremelimumab (T) for resectable head and neck squamous cell carcinoma (HNSCC): Updated results with high dimensional profiling of circulating immune cells

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Background: Although PD-1 blockade has improved survival in patients with recurrent and/or metastatic HNSCC, safety and efficacy of neoadjuvant immunotherapy with PD-L1 inhibitor with or without CTLA-4 inhibitor has not been investigated. Here, we report the updated results of the safety and efficacy of a preoperative D with or without T (D+/-T) in patients with resectable HNSCC, accompanied with high dimensional profiling of circulating immune cells. Methods: Patients with locally advanced but resectable HNSCC were eligible. Enrolled patients were randomized into D or D+T, stratified by primary site and human papilloma virus (HPV) infection status. A single dose of preoperative D (1500mg) or D+T (1500mg+75mg) was administered, with surgery planned 2 to 8 weeks later for curative resection. Postoperative (chemo) radiation was prescribed based on standard guidelines, followed by maintenance with D every 4 weeks for 1 year. Dynamic changes in circulating immune cells were tracked with mass cytometry. The primary objective was to determine the local recurrence rate. Secondary endpoints included pathologic response, safety, survival outcome, and exploration of immune dynamics. Results: As of January 25th 2022 for the interim analysis, a total of 45 patients were completely enrolled and received surgical resection (D: 21 patients, D+T: 24 patients). Oropharyngeal cancer was most common (n = 23; 51.1%) and HPV-mediated cancer was observed in 20 patients (44.4%). Neoadjuvant D+/-T had acceptable safety profiles and was not associated with delays in surgery or unexpected adverse events. Tumor shrinkage was observed in 31 patients (68.9%), with 15.6% of average tumor shrinkage (range; 100.0% to -80.0%). Major pathologic response (no more than 10% of viable tumor cells) was achieved in 3 patients (6.7%), including 2 cases with pathologic complete response (4.4%). During median follow-up duration of 407 days after surgery, local recurrence and systemic recurrence were documented in 9 patients (20.0%) and 7 patients (15.6%), respectively. Median disease-free survival and overall survival was 910 days and not reached, respectively. High dimensional immune profiling with mass cytometry revealed that D+T disproportionally increased the frequency of regulatory T cells accompanied with the upregulation of their functional markers, which was absent in patients treated with D monotherapy. Conclusions: These updated data suggested that preoperative D+/-T was safe and feasible and had the potential to provide clinical benefits for patients with resectable HNSCC. Distinct immunologic changes in circulating immune cells were induced by each treatment regimen, warranting further investigation. The trial is ongoing and the updated outcomes with immune correlates will be presented in this ASCO. Clinical trial information: NCT03737968.

Phase II clinical trial of Eribulin-gemcitabine combination therapy in previously treated patients with advanced liposarcoma or leiomyosarcoma

PURPOSE

Monotherapy with eribulin or gemcitabine has been found to be moderately effective in treating soft-tissue sarcomas (STS). In this study, we evaluated the efficacy and safety of eribulin-gemcitabine combination therapy for the two most common histologic types of STS, liposarcoma and leiomyosarcoma.

PATIENTS AND METHODS

In this non-randomized, multicenter, phase II study, we included patients with progressive disease who had received one or two courses of chemotherapy that included doxorubicin. Patients were administered 1.4 mg/m2 eribulin and 1,000 mg/m2 gemcitabine on days 1 and 8 every 3 weeks. The primary endpoint was progression-free survival rate at 12 weeks (PFSR12wks), with null and alternative hypotheses of PFSR12wks {less than or equal to}20.0% and {greater than or equal to}40.0%, respectively. Exploratory biomarker analyses with next-generation sequencing (NGS) were performed on pretreatment tumor samples.

RESULTS

Among the 37 patients included, the overall PFSR12wks was 73.0%, achieving the primary endpoint. The objective response rate, disease control rate, median progression-free survival, and median overall survival were 16.2%, 78.4%, 5.6 months, and 31.9 months, respectively, without differences according to histologic type. New safety signals and treatment-related deaths were not documented. NGS-based transcriptome analysis revealed that functional enrichment in the transforming growth factor-ß pathway was mostly associated with a poor outcome, whereas single genetic alterations largely failed to predict treatment outcome.

CONCLUSIONS

Eribulin-gemcitabine combination therapy showed promising activity and an acceptable safety profile in patients with liposarcoma or leiomyosarcoma. Gene expression profiling with pathway enrichment analysis would have possibilities to have predictive value for survival outcome, necessitating further investigation to confirm.

Atezolizumab plus bevacizumab in Child-Pugh B advanced hepatocellular carcinoma patients

397

Background: Atezolizumab plus bevacizumab (Ate/Bev) demonstrated promising efficacy and safety in patients with advanced hepatocellular carcinoma (aHCC) in the phase III IMbrave 150 trial. However, despite the high unmet need in Child-Pugh B patients, this subgroup of patients was not included in this study. Therefore, we aimed to investigate the efficacy and safety of Ate/Bev in Child-Pugh B HCC patients. Methods: This multicenter retrospective study included 27 HCC patients classified as Child-Pugh B who received Ate/Bev at four cancer referral centers between May 2020 and August 2021. Comparative analyses were performed with an independent cohort of Child-Pugh A patients from the same registry (n=130). Results: All patients received Ate/Bev as first-line systemic treatment for aHCC. The objective response rates of patients in Child-Pugh groups B and A were 14.8% and 32.3%, and the disease control rates were 55.5% and 76.1%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 3.0 months (95% CI, 1.6-4.3) and 6.0 months (95% CI, 4.9-7.0) in Child-Pugh B patients, while the median PFS was 6.0 months (95% CI, 4.6-13.4) and the median OS was not-reached (95% CI not available) in Child-Pugh A group. Compared to Child-Pugh A group, grade 3-4 adverse events (AEs) were more common in the Child-Pugh B group (48.1% vs 17.7%, p=0.001), with the most frequent grade 3-4 AEs being thrombocytopenia (11.1%) and AST elevation (11.1%). The rate of treatment discontinuation due to AEs was higher in the Child-Pugh B group (14.8% vs 3.1%, p=0.030), and the reasons for discontinuation were gastrointestinal (GI) bleeding (n=2), GI perforation (n=1) and interstitial pneumonitis (n=1). Conclusions: In the Child-Pugh B subgroup of patients with aHCC, Ate/Bev treatment showed modest clinical activity. However, due to the increased frequency of serious AEs, careful evaluation of treatment response and AE management is required in this subgroup patients. [Table: see text]

Multicenter phase Ib/II study of second-line trastuzumab, ramucirumab, and paclitaxel in patients with HER2-positive advanced gastric or gastroesophageal junction cancer: Updated HER-RAM study with biomarker analysis

330

Background: HER-RAM study is the phase Ib/II multicenter study to evaluate the safety and efficacy of adding trastuzumab to ramucirumab and paclitaxel as a second-line treatment in HER2-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer progressed from trastuzumab containing chemotherapy. We report survival follow up and exploratory biomarker results. Methods: Patients with HER2-positive advanced G/GEJ cancer who progressed after first-line trastuzumab containing chemotherapy were enrolled. Trastuzumab 4mg/kg on day 1 followed by 2mg/kg on days 8, 15, and 22, ramucirumab 8mg/kg on days 1 and 15, and paclitaxel (dose level 1: 80mg/m2, dose level -1: 70 mg/m2) on days 1, 8, and 15 of a 28-day cycle was tested. After safety analysis of lead-in safety cohort (phase 1b), phase 2 part was conducted to evaluate the primary endpoint of progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety. Results: No dose limiting toxicity at the dose level 1 was observed at the phase Ib part, the dose level 1 with full dose combination was determined as recommended phase 2 dose. At the time of data lock on September 7th, 2021, 50 patients including 3 patients from the phase 1b part were evaluable for response and safety. Median age was 60 years old (range 29-82) and most patients were male (40/50). At baseline, 39 patients had tumors with HER-2 3+ by immunohistochemistry (IHC) and 11 had those with HER-2 2+ by IHC with ERBB2 amplification by in situ hybridization. With median follow-up duration of 18.8 months, median PFS and OS were 7.0 months (95% confidence interval [CI]: 4.9-9.2 months) and 13.6 months (95% CI: 9.5-17.6 months), respectively. ORR was 54% (27/50, complete response = 1, partial response = 26) and DCR was 96% (48/50), respectively. On the exploratory analysis, HER-2 positivity of tumor tissue was lost after fist-line chemotherapy in 8 of 23 patients (34.7%) without any definite association between loss of HER-2 and outcomes. Most common hematologic adverse event (AE) was neutropenia (all grade: 64%, grade 3/4: 52%) with 1 case of febrile neutropenia (2%). Most common non-hematologic AE was peripheral sensory neuropathy and anorexia (all grade: 32%, grade 3: 2%, respectively). Gastrointestinal (GI) bleeding occurred in 6 cases (grade 3 upper GI bleeding: 3 patients, grade 1/2 lower GI bleeding: 3 patients), whereas GI perforation was not observed. Hypertension occurred in 3 patients (grade 1/2: 1 patient, grade 3: 2 patients). No new or unexpected AEs were observed. Conclusions: The continuous use of trastuzumab in combination with ramucirumab and paclitaxel showed promising activity and manageable safety profile in HER2-positive G/GEJ cancer patients who progressed after trastuzumab containing chemotherapy. Clinical trial information: NCT04888663.

Predicting treatment outcomes using 18F-FDG PET biomarkers in patients with non-small-cell lung cancer receiving chemoimmunotherapy

Background

Predictive markers for treatment response and survival outcome have not been identified in patients with advanced non-small-cell lung cancer (NSCLC) receiving chemoimmunotherapy. We aimed to evaluate whether imaging biomarkers of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) and routinely assessed clinico-laboratory values were associated with clinical outcomes in patients with advanced NSCLC receiving pembrolizumab plus platinum-doublet chemotherapy as a first-line treatment.

Methods

We retrospectively enrolled 52 patients with advanced NSCLC who underwent baseline ¹⁸F-FDG PET/CT before treatment initiation. PET/CT parameters and clinico-laboratory variables, constituting the prognostic immunotherapy scoring system, were collected. Optimal cut-off values for PET/CT parameters were determined using the maximized log-rank test for progression-free survival (PFS). A multivariate prediction model was developed based on Cox models for PFS, and a scoring system was established based on hazard ratios of the predictive factors.

Results

During the median follow-up period of 16.7 months (95% confidence interval: 15.7-17.7 months), 43 (82.7%) and 31 (59.6%) patients experienced disease progression and death, respectively. Objective response was observed in 23 (44.2%) patients. In the multivariate analysis, maximum standardized uptake value, metabolic tumour volume_2.5, total lesion glycolysis_2.5, and bone marrow-to-liver uptake ratio from the PET/CT variables and neutrophil-to-lymphocyte ratio (NLR) from the clinico-laboratory variables were independently associated with PFS. The scoring system based on these independent predictive variables significantly predicted the treatment response, PFS, and overall survival.

Conclusion

PET/CT variables and NLR were useful biomarkers for predicting outcomes of patients with NSCLC receiving pembrolizumab and chemotherapy as a first-line treatment, suggesting their potential as effective markers for combined PD-1 blockade and chemotherapy.

Patritumab Deruxtecan: Paving the Way for EGFR-TKI-Resistant NSCLC

HER3 is ubiquitously expressed in EGFR-mutant non-small cell lung cancer (NSCLC) irrespective of resistant mechanisms to EGFR tyrosine kinase inhibitors, thus garnering attention as a valuable therapeutic target. In this issue of Cancer Discovery, Jänne and colleagues highlight early clinical data supporting patritumab deruxtecan as a potentially appreciable agent for previously treated EGFR-mutant NSCLC.See related article by Jänne et al., p. 74.

SKI-G-801, an AXL kinase inhibitor, blocks metastasis through inducing anti-tumor immune responses and potentiates anti-PD-1 therapy in mouse cancer models

Objectives

AXL‐mediated activation of aberrant tyrosine kinase drives various oncogenic processes and facilitates an immunosuppressive microenvironment. We evaluated the anti‐tumor and anti‐metastatic activities of SKI‐G‐801, a small‐molecule inhibitor of AXL, alone and in combination with anti‐PD‐1 therapy.

Methods

In vitro pAXL inhibition by SKI‐G‐801 was performed in both human and mouse cancer cell lines. Immunocompetent mouse models of tumor were established to measure anti‐metastatic potential of SKI‐G‐801. Furthermore, SKI‐G‐801, anti‐PD‐1 or their combination was administered as an adjuvant or neoadjuvant in the 4T1 tumor model to assess their potential for clinical application.

Results

SKI‐G‐801 robustly inhibited pAXL expression in various cell lines. SKI‐G‐801 alone or in combination with anti‐PD‐1 potently inhibited metastasis in B16F10 melanoma, CT26 colon and 4T1 breast models. SKI‐G‐801 inhibited the growth of B16F10 and 4T1 tumor‐bearing mice but not immune‐deficient mice. An antibody depletion assay revealed that CD8⁺ T cells significantly contributed to SKI‐G‐801‐mediated survival. Anti‐PD‐1 and combination group were observed the increased CD8⁺Ki67⁺ and effector T cells and M1 macrophage and decreased M2 macrophage, and granulocytic myeloid‐derived suppressor cell (G‐MDSC) compared to the control group. The neoadjuvant combination of SKI‐G‐801 and anti‐PD‐1 therapy achieved superior survival benefits by inducing more profound T‐cell responses in the 4T1 syngeneic mouse model.

Conclusion

SKI‐G‐801 significantly suppressed tumor metastasis and growth by enhancing anti‐tumor immune responses. Our results suggest that SKI‐G‐801 has the potential to overcome anti‐PD‐1 therapy resistance and allow more patients to benefit from anti‐PD‐1 therapy.

Antibody-Drug Conjugates: A New Addition to the Treatment Landscape of EGFR-Mutant Non-Small Cell Lung Cancer

The emergence of treatment resistance to targeted agents is currently inevitable and inherently heterogeneous in cancer, presenting significant challenges for improving survival outcomes in patients. This is not an exception for cancers harboring EGFR mutations, one of the most prevalently observed oncogenic alterations in non-small cell lung cancer (NSCLC) targeted clinically. Currently, numerous efforts have attempted to delay or overcome acquired resistance to EGFR-tyrosine kinase inhibitors (TKI), changing the treatment landscape of EGFR-mutant NSCLC. Haikala and colleagues have developed a unique strategy using patritumab deruxtecan, an antibody-drug conjugate targeting human epidermal growth factor receptor 3 (HER3) linked to exatecan derivatives, for treating EGFR-mutant NSCLC. By incorporating EGFR TKIs to upregulate surface HER3 expression, the antitumor efficacy of patritumab deruxtecan was augmented in various preclinical models. In parallel, Jänne and colleagues reported the clinical activity of patrimumab deruxtecan in patients with EGFR-mutant NSCLC with prior EGFR TKI treatment. These two studies provide the grounds for hopeful anticipation for a novel strategy that concurrently targets compensatory feedback loops in addition to oncogenic signaling pathways.See related article by Haikala et al., p. 130.

Primary Tumor Suppression and Systemic Immune Activation of Macrophages through the Sting Pathway in Metastatic Skin Tumor

PURPOSE

Agonists of the stimulator of interferon genes (STING) play a key role in activating the STING pathway by promoting the production of cytokines. In this study, we investigated the antitumor effects and activation of the systemic immune response of treatment with DMXAA (5,6-dimethylxanthenone-4-acetic acid), a STING agonist, in EML4-ALK lung cancer and CT26 colon cancer.

MATERIALS AND METHODS

The abscopal effects of DMXAA in the treatment of metastatic skin nodules were assessed. EML4-ALK lung cancer and CT26 colon cancer models were used to evaluate these effects after DMXAA treatment. To evaluate the expression of macrophages and T cells, we sacrificed the tumor-bearing mice after DMXAA treatment and obtained the formalin-fixed paraffin-embedded (FFPE) tissue and tumor cells. Immunohistochemistry and flow cytometry were performed to analyze the expression of each FFPE and tumor cell.

RESULTS

We observed that highly infiltrating immune cells downstream of the STING pathway had increased levels of chemokines after DMXAA treatment. In addition, the levels of CD80 and CD86 in antigen-presenting cells were significantly increased after STING activation. Furthermore, innate immune activation altered the systemic T cell-mediated immune responses, induced proliferation of macrophages, inhibited tumor growth, and increased numbers of cytotoxic memory T cells. Tumor-specific lymphocytes also increased in number after treatment with DMXAA.

CONCLUSION

The abscopal effect of DMXAA treatment on the skin strongly reduced the spread of EML4-ALK lung cancer and CT26 colon cancer through the STING pathway and induced the presentation of antigens.

Distinct exhaustion features of T lymphocytes shape the tumor-immune microenvironment with therapeutic implication in patients with non-small-cell lung cancer

Background

Reinvigoration of T-cell exhaustion with antibodies has shown promising efficacy in patients with non-small-cell lung cancer (NSCLC). However, the characteristics of T-cell exhaustion with regard to tumor-infiltrating lymphocytes (TILs) are poorly elucidated in NSCLC. Here, we investigated the exhaustion status of TILs in NSCLC patients at the intraindividual and interindividual levels.

Methods

We obtained paired peripheral blood, normal adjacent tissues, peritumoral tissues, and tumor tissues from 96 NSCLC patients. Features of T-cell exhaustion were analyzed by flow cytometry. T cells were categorized according to their programmed cell death-1 (PD-1) expression (PD-1^high, PD-1^int, and PD-1^neg cells). Patients were classified based on the presence or absence of discrete PD-1^high CD8⁺ TILs. Production of effector cytokines by CD8⁺ TILs was measured after T-cell stimulation with or without antibodies against immune checkpoint receptors.

Results

Progressive T-cell exhaustion with marked expression of exhaustion-related markers and diminished production of effector cytokines was observed in PD-1^high CD8⁺ TILs compared with PD-1^int and PD-1^neg CD8⁺ TILs. Patients with distinct PD-1^high CD8⁺ TILs (PD-1^high expressers) exhibited characteristics associated with a favorable anti-PD-1 response compared with those without these lymphocytes (non-PD-1^high expressers). Combined inhibition of dual immune checkpoint receptors further restored effector cytokine production by CD8⁺ TILs following T-cell stimulation. PD-1^high CD8⁺ T lymphocyte populations in the peripheral blood and tumors were significantly correlated.

Conclusions

T-cell exhaustion was differentially regulated among individual patients and was prominent in a subgroup of NSCLC patients who may benefit from PD-1 blockade or combined blockade of other immune checkpoint receptors.

Modeling Clinical Responses to Targeted Therapies by Patient-Derived Organoids of Advanced Lung Adenocarcinoma

PURPOSE

Patient-derived organoids (PDO) of lung cancer has been recently introduced, reflecting the genomic landscape of lung cancer. However, clinical relevance of advanced lung adenocarcinoma organoids remains unknown. Here, we examined the ability of PDOs to predict clinical responses to targeted therapies in individual patients and to identify effective anticancer therapies for novel molecular targets.

EXPERIMENTAL DESIGN

Eighty-four organoids were established from patients with advanced lung adenocarcinoma. Formalin-fixed, paraffin-embedded tumor specimens from corresponding patients were analyzed by whole-exome sequencing (n = 12). Organoids were analyzed by whole-exome sequencing (n = 61) and RNA sequencing (n = 55). Responses to mono or combination targeted therapies were examined in organoids and organoid-derived xenografts.

RESULTS

PDOs largely retained somatic alterations including driver mutations of matching patient tumors. PDOs were able to recapitulate progression-free survival and objective responses of patients with non-small cell lung cancer receiving clinically approved tyrosine kinase inhibitors. PDOs recapitulated activity of therapeutic strategies under clinical investigation. YUO-071 harboring an EGFR exon 19 deletion and a BRAF G464A mutation and the matching patient responded to dabrafenib/trametinib combination therapy. YUO-004 and YUO-050 harboring an EGFR L747P mutation was sensitive to afatinib, consistent with the response in the matching patient of YUO-050. Furthermore, we utilized organoids to identify effective therapies for novel molecular targets by demonstrating the efficacy of poziotinib against ERBB2 exon 20 insertions and pralsetinib against RET fusions.

CONCLUSIONS

We demonstrated translational relevance of PDOs in advanced lung adenocarcinoma. PDOs are an important diagnostic tool, which can assist clinical decision making and accelerate development of therapeutic strategies.

Eribulin and gemcitabine in previously treated patients with advanced liposarcoma or leiomyosarcoma: A multicenter, single-arm, phase 2-trial

11516

Background: Eribulin and gemcitabine have shown encouraging efficacy in soft-tissue sarcoma (STS) as a monotherapy. Here, we evaluated the activity and safety of combined use of eribulin and gemcitabine in two most common histologic types of STS, liposarcoma and leiomyosarcoma. Methods: In this non-randomized, multi-center phase 2 study, patients were included if they had progressive disease after one or two prior chemotherapy including doxorubicin. Patient were given eribulin 1.4 mg/m2 and gemcitabine 1,000 mg/m2 on day1 and day 8 every 3 weeks. The primary endpoint was progression-free survival rate at 12 weeks (PFSR12wks) with null and alternative hypothesis of PFSR12wks≤20.0% and ≥40.0%, respectively. Results: Of 37 patients included, 22 had leiomyosarcoma, and 15 had liposarcoma. At 12-weeks after treatment, 16 and (72.7%) 11 (73.3%) patients in leiomyosarcoma and liposarcoma were progression-free. Overall PFSR12wks was 73.0%, satisfying the primary endpoint. Objective response rate, disease control rate, median progression-free survival, and median overall survival were 16.2%, 78.4%, 23.9 weeks, and 88.9 weeks, without any statistical differences according to histologic subtypes. No new safety signals and treatment-related death were observed. Conclusions: Eribulin and gemcitabine showed promising activity and manageable safety profile in patients with STS of liposarcoma and leiomyosarcoma histology. Updated outcomes for ongoing patients will be presented. Clinical trial information: NCT03810976.

Multicenter phase Ib/II study of second-line trastuzumab, ramucirumab, and paclitaxel in patients with HER2-positive advanced gastric or gastroesophageal junction cancer (HER-RAM study)

4063

Background: We evaluated the safety and efficacy of adding trastuzumab to ramucirumab and paclitaxel (TRP) as a second line treatment in human epidermal growth factor receptor 2 (HER-2)-positive advanced gastric or gastroesophageal junction (G/GEJ) cancer progressed from trastuzumab containing chemotherapy. Methods: Patients with HER-2-positive advanced G/GEJ cancer who progressed after first-line chemotherapy with trastuzumab in combination with fluoropyrimidine and platinum were eligible. Trastuzumab (Herzuma[CT-P6], Celltrion Inc.) 4mg/kg on day 1 followed by 2mg/kg on days 8, 15, and 22, ramucirumab 8mg/kg on days 1 and 15, and paclitaxel (dose level 1: 80mg/m2, dose level -1: 70 mg/m2) on days 1, 8, and 15 of a 28-day cycle was tested. After safety analysis of lead-in safety cohort (phase 1b), phase 2 part was conducted to evaluate the primary endpoint of progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety. Results: At the phase 1b part, as there was no dose limiting toxicity in 3 patients at the dose level 1, dose level 1 with full dose combination was determined as recommended phase 2 dose. At the time of data lock on Jan. 31, 2021, 45 patients among enrolled 50 patients were evaluable for response and safety including 3 patients from phase 1b part. Median age was 59 years old (range 30-82) and most patients were male (37/45). At baseline, 33 patients had tumors with HER-2 3+ by immunohistochemistry (IHC) and 12 had those with HER-2 2+ by IHC with ERBB2 amplification by in situ hybridization. With median follow-up duration of 11.6 months, median PFS and OS were 7.2 months (95% confidence interval [CI]: 6.0-8.5 months) and 13.6 months (95% CI: 10.3-16.9 months), respectively. ORR was 55.6% (25/45, complete response = 1, partial response = 24) and DCR was 95.6% (43/45), respectively. Most common hematologic adverse event (AE) was neutropenia (all grade: 64.4%, grade 3/4: 51.1%) with 1 case of febrile neutropenia (2.2%). Most common non-hematologic AE was peripheral sensory neuropathy (all grade: 33.3%, grade 3: 2.2%). Gastrointestinal (GI) bleeding occurred in 4 patients (grade 3 upper GI bleeding: 6.7%, grade 1 lower GI bleeding: 2.2%), whereas GI perforation was not observed. Hypertension occurred in 3 patients (all grade: 6.7%, grade 3: 4.4%). No new or unexpected AEs resulting in treatment cessation were observed with this combination regimen. Conclusions: The continuous use of trastuzumab beyond progression in combination with ramucirumab and paclitaxel showed promising activity and manageable safety profile in HER2 positive G/GEJ cancer patients who progressed after trastuzumab containing chemotherapy. Updated outcomes for ongoing patients will be presented.

On-treatment derived neutrophil-to-lymphocyte ratio and response to palbociclib and letrozole: Analysis of a multicenter retrospective cohort and the PALOMA-2 study

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Background: Relevant predictive biomarkers for cyclin dependent kinase 4 and 6 (CDK4/6) inhibitors have not been identified in hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer (ABC). We investigated whether dynamic changes in the peripheral immune cells can predict therapeutic response to CDK4/6 inhibitors in ABC with translational relevance. Methods: Postmenopausal women who received palbociclib and letrozole for HR-positive, HER2-negative ABC from tertiary referral centers were analyzed (n = 221; exploratory cohort). Pre- and on-treatment leucocyte, neutrophil, lymphocytes counts, neutrophil-to-lymphocyte ratio (NLR), and derived NLR (dNLR; neutrophil/[leucocyte-neutrophil]) were correlated with survival outcomes. Patients from the PALOMA-2 study (NCT01740427) treated with letrozole with or without palbociclib (n = 410 and 209, respectively) were analyzed for validation (validation cohort). Prospectively enrolled patients were subjected to immunophenotyping with flow cytometry to explore the immune cell dynamics after CDK4/6 inhibitor treatment. Results: In the exploratory cohort, palbociclib administration significantly reduced leucocyte, neutrophil, and lymphocyte counts on cycle 2 day 1. Not baseline, but on-treatment neutrophil and lymphocyte counts were associated with superior and inferior outcomes, providing predictive significance to on-treatment NLR and dNLR for progression-free survival (PFS; HR = 1.64 and 2.52; all P< 0.001). In the validation cohort, higher on-treatment dNLR was associated with inferior PFS in patients treated with palbociclib and letrozole (HR = 1.50 and P= 0.009 with 1.04 cut-off), whereas not correlated with outcome in placebo and letrozole-administered patients. Exploratory analysis revealed that CDK4/6 inhibitor prevented T cell exhaustion and diminished relative frequencies of myeloid-derived suppressor cells, both of which trigger antitumor immunity. Conclusions: On-treatment dNLR significantly predicted treatment outcome in HR-positive, HER2-negative ABC treated with palbociclib and letrozole, allowing early prediction of treatment response with mechanistic insights. Clinical trial information: NCT01740427 .

Interim analysis for window of opportunity trial of single dose preoperative durvalumab (D) with or without tremelimumab (T) for operable head and neck squamous cell carcinoma (HNSCC)

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Background: We aim to evaluate the efficacy and safety for single dose of preoperative D with or without T in patients with operable HNSCC with immune correlates. Methods: Patients with histologically confirmed, potentially resectable, stage II, III, and IVA HNSCC were eligible. Enrolled patients were randomized into D or D+T, stratified by primary site and human papilloma (HPV) infection status assessed by p16 expression. A single dose of preoperative D (1500mg) or D+T (1500mg+75mg) was administered and followed 2 to 8 weeks later by surgical tumor resection with curative intent. Postoperative (chemo) radiation (PO-CRT) was planned based on standard guidelines, followed by maintenance with D every 4 weeks for one year. Pathology response was quantified as the proportion of the resection bed with viable tumor, tumor necrosis, fibrosis, and inflammation. The primary objective was to determine the local recurrence rate. Secondary endpoints included pathologic response, safety and tolerability, disease-free survival, and immune dynamics incorporating multiple immunofluorescence and single cell transcriptomic analysis. A total 48 patients are planned to be enrolled. Results: As of Jan. 31, 2021, a total 36 patients were enrolled and received surgical resections with available data for pathologic response (D: 16 patients, D+T: 20 patients). Patient characteristics of both arms were well-balanced: hypopharynx/larynx/oral cavity as primary site (12.5%/12.5%/18.8%/56.3% in D, 20.0%/10.0%/10.0%/60.0% in D+T); HPV positivity (50.0% in D, 50.0% in D+T); cT1/T2/T3/T4 (6.3%/37.5%/31.3%/25.0% in D, 10.0%/25.0%/40.0%/25.0% in D+T); cN0/N1/N2/N3 (25.0%/18.8%/50.0%/6.3% in D, 30.0%/30.0%/40.0%/0% in D+T). Significant tumor shrinkage defined as more than 30% of size reduction was observed in 43.7% (7/16), including 2 patients with complete response in D and 20.0% (4/20) in D+T. During 128 days of median follow-ups, local recurrence was observed in 2 patients of D+T arm (5.6%). HPV positivity was numerically associated with favorable treatment response (average tumor shrinkage; -21.8% in p16-positive vs. -6.4% in p16-negative). Meaningful pathologic response was achieved in terms of tumor necrosis (average 10.3% in D, 5.5% in D+T), fibrosis (average 13.4% in D, 10.3% in D+T), and inflammation (average 15.0% in D, 5.8% in D+T), without significant differences according to HPV positivity. After preoperative D or D+T, serious adverse events and unexpected surgical complications did not occur. Conclusions: These early data suggested that preoperative D or D+T in patients with operable HNSCC was safe and feasible and had the potential to provide clinical benefits. The trial is ongoing and the updated outcomes with immune correlates including immunofluorescence and single cell transcriptomic analysis will be presented. Clinical trial information: NCT03737968.

Adaptive Natural Killer Cells Facilitate Effector Functions of Daratumumab in Multiple Myeloma

PURPOSE

To investigate the different roles of heterogeneous natural killer (NK)-cell subpopulations in multiple myeloma and to identify NK-cell subsets that support the robust anti-myeloma activity of daratumumab via antibody-dependent cellular cytotoxicity (ADCC).

EXPERIMENTAL DESIGN

We performed single-cell RNA sequencing of NK cells from patients with newly diagnosed multiple myeloma (NDMM) and delineated adaptive NK cells in their bone marrow (BM). We further characterized the distinct immunophenotypic features and functions of adaptive NK cells by multicolor flow cytometry in 157 patients with NDMM.

RESULTS

Adaptive NK cells exhibit a significantly lower level of CD38 expression compared with conventional NK cells, suggesting that they may evade daratumumab-induced fratricide. Moreover, adaptive NK cells exert robust daratumumab-mediated effector functions ex vivo, including cytokine production and degranulation, compared with conventional NK cells. The composition of adaptive NK cells in BM determines the daratumumab-mediated ex vivo functional activity of BM NK cells in patients with NDMM. Unlike conventional NK cells, sorted adaptive NK cells from the BM of patients with NDMM exert substantial cytotoxic activity against myeloma cells in the presence of daratumumab.

CONCLUSIONS

Our findings indicate that adaptive NK cells are an important mediator of ADCC in multiple myeloma and support direct future efforts to better predict and improve the treatment outcome of daratumumab by selectively employing adaptive NK cells.

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

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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.

Dynamic changes in circulating PD-1+CD8+ T lymphocytes for predicting treatment response to PD-1 blockade in patients with non-small-cell lung cancer

BACKGROUND

The predictive value of immune monitoring with circulating CD8⁺ T lymphocytes for treatment response to programmed cell death protein 1 (PD-1) inhibitors has not been explored in non-small-cell lung cancer (NSCLC), prompting us to investigate whether dynamic changes in PD-1⁺CD8⁺ T lymphocytes have predictive value for durable clinical benefit (DCB) and survival after PD-1 blockade.

METHODS

Patients with recurrent and/or metastatic NSCLC treated with PD-1 inhibitors were enrolled (discovery cohort; n = 94). Peripheral blood was obtained immediately before and after one cycle of treatment with PD-1 blockade. Phenotyping of circulating CD8⁺ T lymphocytes was conducted using multi-colour flow cytometry. Predictive values of dynamic changes in circulating PD-1⁺CD8⁺ T lymphocytes during the first cycle were validated in an independent cohort (validation cohort; n = 54) of a prospective trial with a PD-1 inhibitor (NCT03486119).

RESULTS

Circulating PD-1⁺CD8⁺ T lymphocytes were enriched with effector/memory populations with elevated expression of activation- and exhaustion-related markers. Reduction in the frequency of PD-1⁺ cells among CD8⁺ T lymphocytes after one cycle of treatment was associated with a higher probability of DCB and superior survival outcomes in the discovery cohort. Similar results were obtained in the analysis of tumour antigen NY-ESO-1-specific CD8⁺ T lymphocytes and the validation cohort. Mechanistically, PD-1 molecule expression on CD8⁺ T lymphocytes suppresses the effector functions of tumour antigen-specific CD8⁺ T lymphocytes.

CONCLUSIONS

Dynamic changes in circulating PD-1⁺CD8⁺ T lymphocytes predict clinical, and survival benefit from PD-1 blockade treatment in NSCLC, providing a useful tool to identify patient subgroups who will optimally benefit from PD-1 inhibitors.

Clinical Significance of Preoperative Serum Carcinoembryonic Antigen Within the Normal Range in Colorectal Cancer Patients Undergoing Curative Resection

BACKGROUND

Serum carcinoembryonic antigen (CEA) is a widely used tumor marker in colorectal cancer (CRC), but within normal range of preoperative CEA levels the clinical significance of CEA is unknown.

OBJECTIVE

The aim of this study was to evaluate the usefulness of CEA within the normal range as a prognosticator of non-metastatic CRC.

METHODS

This retrospective cohort study included 2021 CRC patients with normal preoperative CEA who underwent elective curative surgery (discovery group). We determined the optimal cut-off value for disease-free survival (DFS) discrimination using the Contal and O'Quigley method. We also assessed the prognostic significance of the cut-off value in a prospective cohort of 171 stage III colon cancer patients treated with oxaliplatin-based adjuvant chemotherapy (validation group).

RESULTS

The optimal cut-off CEA value was 2.1 ng/mL in the discovery group. The DFS rates were significantly poorer in patients with high-normal preoperative CEA levels (2.1-5.0 ng/mL) than in those with low-normal CEA levels (< 2.1 ng/mL) in both groups. A high-normal CEA level was an independent risk factor for DFS in both groups, and was associated with inferior DFS in patients with stage II and III disease and in never or former smokers. The correlation between DFS and CEA levels was more distinct in left-sided colon and rectal cancer.

CONCLUSIONS

A high-normal preoperative CEA level (≥ 2.1 ng/mL), even within the normal range, was an independent prognosticator for poor DFS in CRC. The usefulness of CEA was influenced by smoking status and tumor location in addition to tumor stage.

Functions of human liver CD69+CD103-CD8+ T cells depend on HIF-2α activity in healthy and pathologic livers

BACKGROUND & AIMS

Human liver CD69⁺CD8⁺ T cells are ~95% CD103^- and ~5% CD103⁺. Although CD69⁺CD103⁺CD8⁺ T cells show tissue residency and robustly respond to antigens, CD69⁺CD103^-CD8⁺ T cells are not yet well understood.

METHODS

Liver perfusate and paired peripheral blood were collected from healthy living donors and recipients with cirrhosis during liver transplantation. Liver tissues were obtained from patients with acute hepatitis A. Phenotypic and functional analyses were performed by flow cytometry. Gene expression profiles were determined by microarray and quantitative reverse transcription PCR. PT-2385 was used to inhibit hypoxia-inducible factor (HIF)-2α.

RESULTS

Human liver CD69⁺CD103^-CD8⁺ T cells exhibited HIF-2α upregulation with a phenotype of tissue residency and terminal differentiation. CD103^- cells comprised non-hepatotropic virus-specific T cells as well as hepatotropic virus-specific T cells, but CD103⁺ cells exhibited only hepatotropic virus specificity. Although CD103^- cells were weaker effectors on a per cell basis than CD103⁺ cells, following T cell receptor or interleukin-15 stimulation, they remained the major CD69⁺CD8⁺ effector population in the liver, surviving with less cell death. An HIF-2α inhibitor suppressed the effector functions and survival of CD69⁺CD103^-CD8⁺ T cells. In addition, HIF-2α expression in liver CD69⁺CD103^-CD8⁺ T cells was significantly increased in patients with acute hepatitis A or cirrhosis.

CONCLUSIONS

Liver CD69⁺CD103^-CD8⁺ T cells are tissue resident and terminally differentiated, and their effector functions depend on HIF-2α. Furthermore, activation of liver CD69⁺CD103^-CD8⁺ T cells with HIF-2α upregulation is observed during liver pathology.

LAY SUMMARY

The immunologic characteristics and the role of CD69⁺CD103^-CD8⁺ T cells, which are a major population of human liver CD8⁺ T cells, remain unknown. Our study shows that these T cells have a terminally differentiated tissue-resident phenotype, and their effector functions depend on a transcription factor, HIF-2α. Furthermore, these T cells were activated and expressed higher levels of HIF-2α in liver pathologies, suggesting that they play an important role in immune responses in liver tissues and the pathogenesis of human liver disease.

Different organ-specific response to nivolumab to determine the survival outcome of patients with advanced hepatocellular carcinoma (aHCC)

4584

Background: Previously, two phase III clinical trials of immune checkpoint inhibitors (ICI) failed to meet their primary endpoints, leading to doubts regarding the clinical activity of ICI monotherapy in patients with aHCC. Here, we comprehensively examined clinicopathological factors and estimated their association with survival outcomes in aHCC patients treated with nivolumab. Methods: A total of 261 eligible patients from 5 high-volume centers who were treated with nivolumab between June 9, 2012 and March 14, 2018 and had measurable diseases were reviewed. We reviewed more than 80 clinicopathological factors and categorized them into 6 areas: 1) demographics (n = 16); 2) baseline laboratory values (n = 19); 3) tumor burden (n = 12); 4) previous treatment (n = 12); 5) treatment response (n = 5); 6) toxicity profiles (n = 18). Their association with survival outcomes were evaluated, and organ-specific response evaluation, adapted from RECIST 1.1, was conducted. Results: Of the 261 patients, 218 (84%) had extrahepatic spread. The median follow-up time was 4.5 months. The median progression-free survival (PFS) and overall survival (OS) were 2.3 months (95% CI, 1.8-2.8) and 6.3 months (95% CI, 5.0-8.2). Objective response rate was 15%. Subgroup analyses revealed that compensated liver function (Child-Pugh score A5/6), surrogate markers for low tumor burden (low AFP, low PIVKA, and low LDH level), inflammatory markers (low C-reactive protein [CRP], low erythrocyte sedimentation rate [ESR], low neutrophil-to-lymphocyte ratio [NLR], high lymphocyte-to-monocyte ratio [LMR]), and low intrahepatic tumor burden were significantly associated with longer OS. A total of 456 individual lesions (liver, n = 249; lung, n = 124; lymph node, n = 35; others such as boner soft tissues, n = 48) were examined. Organ-specific response rates (hepatic tumor, 9%; lung, 25%; lymph node, 37%; others metastasis, 15%) were different, of which intrahepatic tumor was the least responsive organ to ICI treatment in aHCC. Conclusions: Underlying liver function, the tumor extent and burden, and the degree of plasma lymphocytes are crucial for determining tumor response to ICI in aHCC. Antitumor immune response to ICI differs in an organ-specific manner. The hepatic tumors of HCC may be less responsive to nivolumab than extrahepatic lesions.

Dynamic changes in circulating PD-1+CD8+ T lymphocytes for predicting treatment response to PD-1 blockade in patients with non-small cell lung cancer

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Background: The predictive value of dynamic changes in the expression of programmed cell death-1 (PD-1) among circulating CD8+ T lymphocytes for treatment response to PD-1 inhibitors has not been explored in non-small-cell lung cancer (NSCLC). This study aimed to investigate whether dynamic changes in PD-1+CD8+ T lymphocytes have predictive value with respect to durable clinical benefit (DCB) and survival after PD-1 blockade. Methods: Patients with recurrent and/or metastatic NSCLC treated with PD-1 inhibitors were enrolled between March 2016 and August 2018 (discovery cohort; n = 94). Peripheral blood was obtained immediately before and after one cycle of treatment with PD-1 blockade. Phenotyping of circulating CD8+ T lymphocytes was conducted using multi-color flow cytometry. Predictive values of dynamic changes in circulating PD-1+CD8+ T lymphocytes during the first cycle were validated in an independent cohort (validation cohort; n = 54) of a prospective trial with PD-1 inhibitor (NCT03486119). Results: Circulating PD-1+CD8+ T lymphocytes were enriched with effector/memory populations with elevated expression of activation- and exhaustion-related markers. Reduction in the frequency of PD-1+ cells among CD8+ T lymphocytes after one cycle of treatment was associated with a higher probability of DCB and superior survival outcomes in the discovery cohort. Similar results were obtained in analysis of tumor antigen NY-ESO-1-specific CD8+ T lymphocytes and in the validation cohort. Conclusions: Dynamic changes in circulating PD-1+CD8+ T lymphocytes predict clinical and survival benefit from PD-1 blockade treatment in NSCLC. Thus, tracking these changes may be useful for identifying NSCLC patients who will optimally benefit from the treatment.

PD-1 blockade-unresponsive human tumor-infiltrating CD8+ T cells are marked by loss of CD28 expression and rescued by IL-15

Blockade of programmed death-1 (PD-1) reinvigorates exhausted CD8⁺ T cells, resulting in tumor regression in cancer patients. Recently, reinvigoration of exhausted CD8⁺ T cells following PD-1 blockade was shown to be CD28-dependent in mouse models. Herein, we examined the role of CD28 in anti-PD-1 antibody-induced human T cell reinvigoration using tumor-infiltrating CD8⁺ T cells (CD8⁺ TILs) obtained from non-small-cell lung cancer patients. Single-cell analysis demonstrated a distinct expression pattern of CD28 between mouse and human CD8⁺ TILs. Furthermore, we found that human CD28⁺CD8⁺ but not CD28^-CD8⁺ TILs responded to PD-1 blockade irrespective of B7/CD28 blockade, indicating that CD28 costimulation in human CD8⁺ TILs is dispensable for PD-1 blockade-induced reinvigoration and that loss of CD28 expression serves as a marker of anti-PD-1 antibody-unresponsive CD8⁺ TILs. Transcriptionally and phenotypically, PD-1 blockade-unresponsive human CD28^-PD-1⁺CD8⁺ TILs exhibited characteristics of terminally exhausted CD8⁺ T cells with low TCF1 expression. Notably, CD28^-PD-1⁺CD8⁺ TILs had preserved machinery to respond to IL-15, and IL-15 treatment enhanced the proliferation of CD28^-PD-1⁺CD8⁺ TILs as well as CD28⁺PD-1⁺CD8⁺ TILs. Taken together, these results show that loss of CD28 expression is a marker of PD-1 blockade-unresponsive human CD8⁺ TILs with a TCF1^- signature and provide mechanistic insights into combining IL-15 with anti-PD-1 antibodies.

4-1BB Delineates Distinct Activation Status of Exhausted Tumor-Infiltrating CD8+ T Cells in Hepatocellular Carcinoma

BACKGROUND AND AIMS

Targeting costimulatory receptors with agonistic antibodies is a promising cancer immunotherapy option. We aimed to investigate costimulatory receptor expression, particularly 4-1BB (CD137 or tumor necrosis factor receptor superfamily member 9), on tumor-infiltrating CD8⁺ T cells (CD8⁺ tumor-infiltrating lymphocytes [TILs]) and its association with distinct T-cell activation features among exhausted CD8⁺ TILs in hepatocellular carcinoma (HCC).

APPROACH AND RESULTS

Tumor tissues, adjacent nontumor tissues, and peripheral blood were collected from HCC patients undergoing surgical resection (n = 79). Lymphocytes were isolated and used for multicolor flow cytometry, RNA-sequencing, and in vitro functional restoration assays. Among the examined costimulatory receptors, 4-1BB was most prominently expressed on CD8⁺ TILs. 4-1BB expression was almost exclusively detected on CD8⁺ T cells in the tumor-especially on programmed death 1 (PD-1)^high cells and not PD-1^int and PD-1^neg cells. Compared to PD-1^int and 4-1BB^neg PD-1^high CD8⁺ TILs, 4-1BB^pos PD-1^high CD8⁺ TILs exhibited higher levels of tumor reactivity and T-cell activation markers and significant enrichment for T-cell activation gene signatures. Per-patient analysis revealed positive correlations between percentages of 4-1BB^pos cells among CD8⁺ TILs and levels of parameters of tumor reactivity and T-cell activation. Among highly exhausted PD-1^high CD8⁺ TILs, 4-1BB^pos cells harbored higher proportions of cells with proliferative and reinvigoration potential. Our 4-1BB-related gene signature predicted survival outcomes of HCC patients in the The Cancer Genome Atlas cohort. 4-1BB agonistic antibodies enhanced the function of CD8⁺ TILs and further enhanced the anti-PD-1-mediated reinvigoration of CD8⁺ TILs, especially in cases showing high levels of T-cell activation.

CONCLUSION

4-1BB expression on CD8⁺ TILs represents a distinct activation state among highly exhausted CD8⁺ T cells in HCC. 4-1BB costimulation with agonistic antibodies may be a promising strategy for treating HCCs exhibiting prominent T-cell activation.

Peripheral blood immune cell-based biomarkers in anti-PD-1/PD-L1 therapy

Immune checkpoint blockade targeting PD-1 and PD-L1 has resulted in unprecedented clinical benefit for cancer patients. Anti-PD-1/PD-L1 therapy has become the standard treatment for diverse cancer types as monotherapy or in combination with other anti-cancer therapies, and its indications are expanding. However, many patients do not benefit from anti-PD-1/PD-L1 therapy due to primary and/or acquired resistance, which is a major obstacle to broadening the clinical applicability of anti-PD-1/PD-L1 therapy. In addition, hyperprogressive disease, an acceleration of tumor growth following anti-PD-1/PD-L1 therapy, has been proposed as a new response pattern associated with deleterious prognosis. Anti-PD-1/PD-L1 therapy can also cause a unique pattern of adverse events termed immune-related adverse events, sometimes leading to treatment discontinuation and fatal outcomes. Investigations have been carried out to predict and monitor treatment outcomes using peripheral blood as an alternative to tissue biopsy. This review summarizes recent studies utilizing peripheral blood immune cells to predict various outcomes in cancer patients treated with anti-PD-1/PD-L1 therapy.

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

550

Background: Immune checkpoint blockade with PD-1 inhibitors has shown promising clinical efficacy in patients with hepatocellular carcinoma (HCC). However, emerging evidences show that PD-1 blockade can sometimes lead to a flare-up of tumor growth with rapid clinical deterioration (hyperprogressive disease, HPD). This study aimed to evaluate the incidence and pattern of HPD in a multicenter, real-world cohort of East Asian patients with advanced HCC treated with PD-1 blockade. Methods: We enrolled 148 advanced HCC patients treated with nivolumab between March 2016 and December 2018 in Korea. Clinicopathologic variables, tumor growth dynamic, and treatment outcomes were comprehensively analyzed. Progressive disease was assessed using tumor growth kinetics (TGK), tumor growth rate (TGR), and time to treatment failure (TTF), and patient with HPD were defined as those who met the criteria of progressive disease by both TGK and TGR. Results: In this large cohort of HCC patients, the median age was 60 years and the majority were male (85%) and HBV-infected (72%). The objective response rate was 17.6% including two complete responders (1.4%). Ongoing responses were seen in 46% of responders at data cut-off. The incidence of HPD after PD-1 blockade was 23%. HCC patients with HPD had dismal prognosis with worse progression-free survival (PFS) and overall survival (OS) (HR, 1.947; 95% CI, 1.226-3.093 and HR, 1.839; 95% CI, 1.108-3.055, respectively) than progressive disease without HPD. Among various baseline clinicopatholgic parameters, elevated neutrophil-to-lymphocyte ratio (NLR) was only significantly associated with HPD. The optimal cut-off value of NLR for HPD prediction was 3.74 determined by ROC curves, and NLR > 3.74 was associated with worse PFS and OS. Conclusions: The real-world efficacy of PD-1 blockade in HCC patients was consistent with previous studies. However, there was also a corresponding risk of HPD as well as a clinical benefit. Therefore, careful patient selection using immunologic biomarkers, such as NLR, could enhance the therapeutic benefit of PD-1 blockade in clinical trials and real-world practice of HCC

PD-1 Blockade Reinvigorates Bone Marrow CD8+ T Cells from Patients with Multiple Myeloma in the Presence of TGFβ Inhibitors

PURPOSE

Immune-checkpoint inhibitors have shown therapeutic efficacy in various malignant diseases. However, anti-programmed death (PD)-1 therapy has not shown clinical efficacy in multiple myeloma.

EXPERIMENTAL DESIGN

Bone marrow (BM) mononuclear cells were obtained from 77 newly diagnosed multiple myeloma patients. We examined the expression of immune-checkpoint receptors in BM CD8⁺ T cells and their functional restoration by ex vivo treatment with anti-PD-1 and TGFβ inhibitors.

RESULTS

We confirmed the upregulation of PD-1 and PD-L1 expression in CD8⁺ T cells and myeloma cells, respectively, from the BM of multiple myeloma patients. PD-1-expressing CD8⁺ T cells from the BM of multiple myeloma patients coexpressed other checkpoint inhibitory receptors and exhibited a terminally differentiated phenotype. These results were also observed in BM CD8⁺ T cells specific to myeloma antigens NY-ESO-1 and HM1.24. BM CD8⁺ T cells from multiple myeloma patients exhibited reduced proliferation and cytokine production upon T-cell receptor stimulation. However, anti-PD-1 did not increase the proliferation of BM CD8⁺ T cells from multiple myeloma patients, indicating that T-cell exhaustion in multiple myeloma is hardly reversed by PD-1 blockade alone. Intriguingly, anti-PD-1 significantly increased the proliferation of BM CD8⁺ T cells from multiple myeloma patients in the presence of inhibitors of TGFβ, which was overexpressed by myeloma cells.

CONCLUSIONS

Our findings indicate that combined blockade of PD-1 and TGFβ may be useful for the treatment of multiple myeloma.

Abstract C132: Fusobacterium nucleatum in colorectal carcinoma and expression of multiple immune checkpoint molecules on T cells

Background: Fusobacterium nucleatum (Fn) appears to play a role in colorectal cancer carcinogenesis through suppression of antitumor immune response. This study aims to characterize immune-related signatures, including the expression of multiple immune checkpoint molecules in tumor-infiltrating T cells. Methods: We measured Fn DNA by quantitative PCR in a total of 155 colorectal cancer tissues. Gene expression profile was studied using microarray technology to determine the consensus molecular subtypes (CMS) and immune-related signatures using CIBERSORT and Gene Set Enrichment Analysis (GSEA), respectively. Expression of immune checkpoint molecules (PD-1, TIM-3, and TIGIT) on CD8+ cytotoxic T cells and the ratio of FOXP3-CD4-/FOXP3+CD4 were examined using multicolor flow cytometric analysis. Results: All patients had stage III disease underwent curative surgery. Fn infection was observed in 43% of patients and was associated with recurrence (Fisher’ exact test, P=0.002) and decreased overall survival (log-rank test, P&lt;0.001). The distribution of CMS subtypes was CMS1/2/3/4/mixed (14%/24%/15%/27%/20%), which is comparable to previous data. Fn infection was associated with the platinum-resistant signature, hypoxia pathway, and stem cell pathways in the GSEA. Interestingly, Patients with Fn infection showed a trend toward enrichment in CMS4, mesenchymal subtype with the inflamed immune phenotype (9% vs. 17% with Fn-infection, P=0.24). The number of cytotoxic CD8+ T cells showed a trend toward decreased expression in patients with Fn infection. Furthermore, higher expression of inhibitory immune checkpoints (PD-1, P&lt;0.01; TIM-3, P&lt;0.05; TIGIT, P&lt;0.05) was observed on CD8+ cytotoxic T cells of patients with Fn infection, compared to that of Fn negative cases. Besides, the regulatory FOXP3+CD4+ cells were increased in patients with Fn infection, supporting the suppressive role of Fn infection in the tumor immune microenvironment (P&lt;0.05). Conclusions: The adverse prognostic impact of Fn infection depends on the suppression of T cell-mediated immune response by increased expression of inhibitory immune checkpoints on cytotoxic T cell and by increased regulatory T cells.

Citation Format: Han Sang Kim, Wonkyu Kim, Chang Gon Kim, Jinseon Yoo, Soonmyung Paik, Eui-Cheol Shin, Tae-Min Kim, Hoguen Kim, Joong Bae Ahn. Fusobacterium nucleatum in colorectal carcinoma and expression of multiple immune checkpoint molecules on T cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C132. doi:10.1158/1535-7163.TARG-19-C132

VEGF-A drives TOX-dependent T cell exhaustion in anti–PD-1–resistant microsatellite stable colorectal cancers

Although immune checkpoint blockade therapies have demonstrated clinical efficacy in cancer treatment, harnessing this strategy is largely encumbered by resistance in multiple cancer settings. Here, we show that tumor-infiltrating T cells are severely exhausted in the microsatellite stable (MSS) colorectal cancer (CRC), a representative example of PD-1 blockade–resistant tumors. In MSS CRC, we found wound healing signature to be up-regulated and that T cell exhaustion is driven by vascular endothelial growth factor-A (VEGF-A). We report that VEGF-A induces the expression of transcription factor TOX in T cells to drive exhaustion-specific transcription program in T cells. Using a combination of in vitro, ex vivo, and in vivo mouse studies, we demonstrate that combined blockade of PD-1 and VEGF-A restores the antitumor functions of T cells, resulting in better control of MSS CRC tumors.