Whole-transcriptome sequencing in advanced gastric or gastroesophageal cancer: A deep dive into its clinical potential

Advanced gastric and gastroesophageal junction cancers (GC/GEJCs) harbor diverse molecular signatures, highlighting the need for intricate evaluations to identify potential therapeutic targets. Although whole-transcriptome sequencing (WTS) has emerged as a useful tool for understanding these molecular intricacies, its clinical implications have yet to be fully elucidated. This study evaluated the correlation between immunohistochemistry (IHC) and WTS, compared their clinical significance, and identified potential therapeutic targets undetectable through IHC alone. We enrolled 140 patients with advanced GC/GEJC and assessed them using IHC for six pivotal biomarkers: claudin-18 (CLDN18), human epidermal growth factor receptor 2 (HER2), multiple receptor tyrosine kinases (RTKs), and programmed death ligand 1 (PD-L1). Concurrently, WTS was employed as part of the analyses in MONSTAR-SCREEN-2, a multicenter multiomics study. IHC analysis revealed 16.4% HER2, 39.3% CLDN18 (2+/3 + ≥75%), and 15.8% PD-L1 (combined positive score ≥ 10) positivity, among other molecular markers. Significant correlations were observed between IHC and WTS for all six pivotal biomarkers. Among nineteen HER2 IHC-positive patients treated with anti-HER2 therapeutics, ERBB2 status in WTS was significantly associated with progression-free survival (ERBB2-high vs. -low: median 9.0 vs. 5.6 months, log-rank p = 0.046). IHC-based molecular profiling revealed significantly high expression of CLDN18 in RTK-negative patients, with 78.4% positive for either CLDN18 or PD-L1. Additionally, WTS revealed elevated expression of pivotal biomarkers in patients displaying negative targetable biomarkers via IHC. Our findings highlighted the significant correlation between IHC and WTS, reinforcing the clinical utility of WTS. A subset with IHC-negative but WTS-positive status may benefit from specific biomarker-targeted therapies.

Phase II Study of the Liposomal Formulation of Eribulin (E7389-LF) in Combination with Nivolumab: Results from the Gastric Cancer Cohort

PURPOSE

E7389-LF is a liposomal formulation of the microtubule dynamics inhibitor eribulin and has shown preliminary efficacy in the treatment of gastric cancer. Study 120, a phase Ib/II open-label study, assessed efficacy and safety of E7389-LF in combination with nivolumab, a programmed cell death (PD)-1 inhibitor. This report focuses on the gastric cancer cohort within the expansion phase.

PATIENTS AND METHODS

Eligible patients had unresectable, measurable gastric cancer, progression following a platinum drug plus fluoropyrimidine (1L), and a taxane-containing regimen (2L). The primary objective of the expansion phase was objective response rate, secondary objectives included safety and PFS, and exploratory objectives included overall survival and biomarker evaluation. Patients received E7389-LF 2.1 mg/m2 in combination with nivolumab 360 mg every 3 weeks, both as intravenous infusions. Tumor responses were assessed every 6 weeks by the investigators per RECIST v1.1. Plasma and tumor biomarkers were assessed.

RESULTS

In the 31 patients who received E7389-LF in combination with nivolumab, the objective response rate was 25.8% [confidence interval (CI), 11.9-44.6]. The median progression-free survival was 2.69 months (95% CI, 1.91-2.99) and median overall survival was 7.85 months (95% CI, 4.47-not estimable). The most common treatment-related TEAE of any grade were neutropenia (77.4%), leukopenia (74.2%), and decreased appetite (51.6%). E7389-LF in combination with nivolumab significantly increased CD8-positive cells at C2D1 (P = 0.039), and six of seven vascular markers and four IFNγ-related markers showed increases from C1D1.

CONCLUSIONS

Promising antitumor activity was observed with E7389-LF in combination with nivolumab in patients with gastric cancer, and no new safety signals were observed, compared with either monotherapy.

[Chemotherapy for Unresectable Advanced, Metastatic or Recurrent Colorectal Cancer]

Colorectal cancer(CRC)is one of the most commonly diagnosed cancers worldwide. Unresectable advanced, metastatic or recurrent CRC(mCRC)remains incurable for most patients. Systemic chemotherapy is standard treatment for patients with mCRC. The goals of systemic chemotherapy include prolonging survival by stopping cancer progression and palliation. In recent years, advances in the treatment of mCRC have enabled personalized care based on the tumor's molecular profile with improved outcomes for some subtypes. Targeted biologic therapies and immune checkpoint inhibitors have changed the approach to management of uncommon molecularly defined subsets of mCRC. The development of chemotherapy using cytotoxic drugs, biologic monoclonal antibodies, and immune checkpoint inhibitors has prolonged median overall survival up to approximately 30 months. In this report, we describe the evolution of systemic chemotherapy for mCRC, recent advances in standard treatment, and future prospects for the treatment of mCRC.

Multiomic molecular characterization of the response to combination immunotherapy in MSS/pMMR metastatic colorectal cancer

BACKGROUND

Immune checkpoint inhibitor (ICI) combinations represent an emerging treatment strategies in cancer. However, their efficacy in microsatellite stable (MSS) or mismatch repair-proficient (pMMR) colorectal cancer (CRC) is variable. Here, a multiomic characterization was performed to identify predictive biomarkers associated with patient response to ICI combinations in MSS/pMMR CRC for the further development of ICI combinations.

METHODS

Whole-exome sequencing, RNA sequencing, and multiplex fluorescence immunohistochemistry of tumors from patients with MSS/pMMR CRC, who received regorafenib plus nivolumab (REGONIVO) or TAS-116 plus nivolumab (TASNIVO) in clinical trials were conducted. Twenty-two and 23 patients without prior ICI from the REGONIVO and TASNIVO trials were included in this study. A biomarker analysis was performed using samples from each of these studies.

RESULTS

The epithelial-mesenchymal transition pathway and genes related to cancer-associated fibroblasts were upregulated in the REGONIVO responder group, and the G2M checkpoint pathway was upregulated in the TASNIVO responder group. The MYC pathway was upregulated in the REGONIVO non-responder group. Consensus molecular subtype 4 was significantly associated with response (p=0.035) and longer progression-free survival (p=0.006) in the REGONIVO trial. CD8+ T cells, regulatory T cells, and M2 macrophages density was significantly higher in the REGONIVO trial responders than in non-responders. Mutations in the POLE gene and patient response were significantly associated in the TASNIVO trial; however, the frequencies of other mutations or tumor mutational burden were not significantly different between responders and non-responders in either trial.

CONCLUSIONS

We identified molecular features associated with the response to the REGONIVO and TASNIVO, particularly those related to tumor microenvironmental factors. These findings are likely to contribute to the development of biomarkers to predict treatment efficacy for MSS/pMMR CRC and future immunotherapy combinations for treatment.

Quantitative Analysis of the Concentration of Trifluridine in Tumor Hypoxic Regions Using a Novel Platform Combining Functional Endoscopy and Mass Spectrometry

Hypoxic regions in solid tumors are highly resistant to drugs and thus represents an obstacle in drug discovery. Currently, however, there are technical barriers in sampling human hypoxic tumors and examining drug delivery with high sensitivity and accuracy. Herein, we present a new platform combining functional endoscopy and highly sensitive liquid chromatography-mass spectrometry (LC-MS) to assess drug delivery to hypoxic regions. Because oxygen saturation endoscopic imaging (OXEI), a functional endoscopy, can evaluate lesions and hypoxia in real-time by simultaneously acquiring a pseudocolor map of oxygen saturation and conventional endoscopic images, this platform can be used to evaluate drug delivery with human samples from hypoxic regions. As the first clinical application of this platform, the relationship between hypoxic regions and the concentration of trifluridine (FTD) incorporated into DNA was evaluated in patients with advanced gastric cancer treated with FTD/tipiracil (FTD/TPI; n = 13) by obtaining and analysis of tissue samples by OXEI and LC-MS and vascular maturity index by CD31/α-SMA staining ex vivo. The results showed that the concentration of FTD was significantly higher in the normoxic region than in the hypoxic region (P < 0.05) and there were significantly more immature vessels in hypoxic regions than in normoxic regions (P < 0.05). These results indicate that the platform was sufficiently sensitive to evaluate differences in drug anabolism in different oxygenic regions of human tumor tissue. This new platform allows quantitative drug analysis in hypoxic regions and is expected to initiate a new era of drug discovery and development.

Potential Efficacy of Shiunko for Anti-Epidermal Growth Factor Receptor (EGFR) Monoclonal Antibody-Induced Skin Fissure: A Single Institutional Case Series

PURPOSE

Anti-epidermal growth factor receptor monoclonal antibody (anti-EGFR mAb) is the key drug for RAS/BRAF V600E wild-type metastatic colorectal cancer (mCRC). However, anti-EGFR mAb-induced skin fissures often affect a patient's quality of life. Shiunko, a traditional Japanese topical herbal medicine, is used for burns and dermatitis and may potentially have wound-healing effects. Herein, we report cases of patients with mCRC who were treated with Shiunko for anti-EGFR mAb-induced skin fissure.

METHODS

We retrospectively reviewed consecutive patients with mCRC who received an anti-EGFR mAb-containing regimen and were treated with Shiunko twice a day for skin fissures at the National Cancer Center Hospital East between March 2022 and December 2022. Skin fissures were assessed at baseline and at every visit until 28 days after Shiunko initiation according to CTCAE v5.0.

RESULTS

Among the 11 patients, 5 patients were female; the median age was 61 (range, 43-79) years. The median treatment duration with anti-EGFR mAb before Shiunko initiation was 13.1 (range, 6-52) weeks. Skin moisturizer and topical steroids were applied for skin fissures in 11 and 5 patients, respectively. All patients had grade 2 skin fissures at baseline of Shiunko initiation. Two weeks after Shiunko initiation, complete recovery was noted in 4 patients and improvement to grade 1 was noted in 6 patients. There were no Shiunko-related adverse events. Ten patients continued anti-EGFR mAb treatment until disease progression, while 1 patient discontinued anti-EGFR mAb treatment due to severe eruptions.

CONCLUSION

Shiunko could be a treatment option for anti-EGFR mAb-induced skin fissure. Further studies are warranted to investigate the efficacy and safety of Shiunko for anti-EGFR mAb-induced skin fissure.

Pembrolizumab plus trastuzumab and chemotherapy for HER2-positive gastric or gastro-oesophageal junction adenocarcinoma: interim analyses from the phase 3 KEYNOTE-811 randomised placebo-controlled trial

BACKGROUND

Evidence for the efficacy of combined PD-1 and HER2 blockade with chemotherapy on progression-free and overall survival in HER2-positive gastro-oesophageal cancer is scarce. The first interim analysis of the randomised, phase 3 KEYNOTE-811 study showed a superior objective response with pembrolizumab compared with placebo when added to trastuzumab plus fluoropyrimidine and platinum-based chemotherapy. Here, we report results from protocol-specified subsequent interim analyses of KEYNOTE-811.

METHODS

The randomised, phase 3 KEYNOTE-811 trial involved 168 medical centres in 20 countries worldwide. Patients aged 18 years or older with locally advanced or metastatic HER2-positive gastro-oesophageal junction adenocarcinoma, without previous first-line treatment, were randomly assigned (1:1) by an integrated interactive voice-response and web-response system to intravenous pembrolizumab 200 mg or placebo, both to be combined with standard chemotherapy (fluoropyrimidine and platinum-based therapy) plus trastuzumab every 3 weeks for up to 35 cycles or until disease progression, unacceptable toxic effects, or investigator or participant-initiated withdrawal. Randomisation used a block size of four and was stratified by region, PD-L1 status, and chemotherapy. Dual primary endpoints were progression-free and overall survival, analysed by intention to treat. Safety was assessed in all randomly assigned patients who received at least one dose of study treatment according to the treatment received. KEYNOTE-811 is registered with ClinicalTrials.gov (NCT03615326) and is active but not recruiting.

FINDINGS

Between Oct 5, 2018, and Aug 6, 2021, 698 patients were assigned to pembrolizumab (n=350) or placebo (n=348). 564 (81%) were male and 134 (19%) were female. At the third interim analysis, 286 (82%) of 350 patients in the pembrolizumab group and 304 (88%) of 346 in the placebo group who received treatment had discontinued treatment, mostly due to disease progression. At the second interim analysis (median follow-up 28·3 months [IQR 19·4-34·3] in the pembrolizumab group and 28·5 months [20·1-34·3] in the placebo group), median progression-free survival was 10·0 months (95% CI 8·6-11·7) in the pembrolizumab group versus 8·1 months (7·0-8·5) in the placebo group (hazard ratio [HR] 0·72, 95% CI 0·60-0·87; p=0·0002). Median overall survival was 20·0 months (17·8-23·2) versus 16·9 months (15·0-19·8; HR 0·87 [0·72-1·06]; p=0·084). At the third interim analysis (median follow-up 38·4 months [IQR 29·5-44·4] in the pembrolizumab group and 38·6 months [30·2-44·4] in the placebo group), median progression-free survival was 10·0 months (8·6-12·2) versus 8·1 months (7·1-8·6; HR 0·73 [0·61-0·87]), and median overall survival was 20·0 months (17·8-22·1) versus 16·8 months (15·0-18·7; HR 0·84 [0·70-1·01]), but did not meet prespecified criteria for significance and will continue to final analysis. Grade 3 or worse treatment-related adverse events occurred in 204 (58%) of 350 patients in the pembrolizumab group versus 176 (51%) of 346 patients in the placebo group. Treatment-related adverse events that led to death occurred in four (1%) patients in the pembrolizumab group and three (1%) in the placebo group. The most common treatment-related adverse events of any grade were diarrhoea (165 [47%] in the pembrolizumab group vs 145 [42%] in the placebo group), nausea (154 [44%] vs 152 [44%]), and anaemia (109 [31%] vs 113 [33%]).

INTERPRETATION

Compared with placebo, pembrolizumab significantly improved progression-free survival when combined with first-line trastuzumab and chemotherapy for metastatic HER2-positive gastro-oesophageal cancer, specifically in patients with tumours with a PD-L1 combined positive score of 1 or more. Overall survival follow-up is ongoing and will be reported at the final analysis.

FUNDING

Merck Sharp & Dohme.

Efficacy and safety of trifluridine/tipiracil plus ramucirumab in comparison with trifluridine/tipiracil monotherapy for patients with advanced gastric cancer-single institutional experience

BACKGROUND

Trifluridine/tipiracil plus VEGF inhibition with ramucirumab (RAM) for advanced gastric cancer (AGC) demonstrated clinical activity with an acceptable toxicity profile in previous phase II trial. However, little is known about its efficacy and safety in clinical practice in comparison with trifluridine/tipiracil monotherapy.

METHODS

We retrospectively investigated efficacy and safety of trifluridine/tipiracil plus RAM and trifluridine/tipiracil monotherapy as third or later line treatment for AGC patients.

RESULTS

Forty-one patients receiving trifluridine/tipiracil plus RAM and 60 patients receiving trifluridine/tipiracil monotherapy were analyzed. The objective response rate (ORR) and the disease control rate (DCR) were 13.5% and 64.9% in the trifluridine/tipiracil plus RAM group, and 3.8% and 42.3% in the trifluridine/tipiracil monotherapy group, respectively (ORR; P = 0.122, DCR; P = 0.052). The median progression-free survival (PFS) and the median overall survival (OS) were 3.0 months and 7.2 months in the trifluridine/tipiracil plus RAM group, and 1.8 months and 3.8 months in the trifluridine/tipiracil monotherapy group, respectively (HR for PFS = 0.66; P = 0.059, HR for OS = 0.50; P = 0.007). Multivariate analysis showed significantly longer PFS (HR = 0.52; P = 0.011) and OS (HR = 0.51; P = 0.031) in the trifluridine/tipiracil plus RAM group compared to the trifluridine/tipiracil monotherapy group. No unexpected adverse events were observed in both groups.

CONCLUSIONS

Trifluridine/tipiracil plus RAM might show favorable anti-tumor activity with an acceptable toxicity profile in comparison with trifluridine/tipiracil monotherapy, suggesting one treatment option for AGC patients in salvage line. The combination needs further evaluation in ongoing randomized trials.

Impact of Programmed Death-Ligand 1 Expression on Mismatch Repair Deficiency and Epstein-Barr Virus Status on Survival Outcomes in Patients with Stage II/III Gastric Cancer After Surgery

BACKGROUND

The aim of this study was to investigate the prognostic impact of mismatch repair (MMR) status, programmed death-ligand 1 (PD-L1) expression, and Epstein-Barr virus (EBV) status in stage II/III gastric cancer after surgery.

METHODS

This study included 679 patients diagnosed with pathological stage II/III gastric cancer who underwent curative gastrectomy followed by adjuvant chemotherapy (AC) or observation between 2007 and 2015. Clinical outcomes were retrospectively reviewed and compared with stratification by AC and other clinicopathological factors.

RESULTS

Patients were divided into AC (n = 484) or surgery alone (SA; n = 195) groups and were further stratified by MMR and EBV status: MMR-deficient (DMMR) and MMR-proficient (PMMR) groups. Comparing the AC-DMMR group versus the AC-PMMR group, 5-year overall survival was 92.0% versus 74.0% (log-rank p < 0.01), and comparing the SA-DMMR group versus the SA-PMMR group, 5-year overall survival was 71.1% versus 73.7% (log-rank p = 0.89). DMMR (hazard ratio 0.25, 95% confidence interval 0.07-0.81) was identified as an independent prognostic factor in the AC group but not in the SA group. In the subgroup analysis, PD-L1-negative patients among the EBV-positive patients or in the DMMR group had a poor prognosis in both the AC and SA groups. The prognosis of the PMMR and EBV-negative patients was similar regardless of PD-L1 expression.

CONCLUSIONS

DMMR was associated with a favorable prognosis in stage II/III gastric cancer after surgery and adjuvant therapy. PD-L1 expression may affect the prognosis of DMMR and EBV-positive gastric cancer.

Safety and Efficacy of Trifluridine/Tipiracil Administered After Anti-PD-1 Therapies for Advanced Gastric Cancer

BACKGROUND/AIM

The phase III TAGS trial of trifluridine/tipiracil showed a survival benefit compared with placebo as a third- or later-line treatment in patients with advanced gastric cancer (AGC), in which only a few patients had a history of previous treatment with immune checkpoint inhibitors.

PATIENTS AND METHODS

We retrospectively reviewed consecutive patients with AGC who received trifluridine/tipiracil monotherapy as third- or later-line chemotherapy at our institution. Clinical outcomes were assessed in both overall population and patients with previous anti-PD-1 therapies.

RESULTS

A total of 60 patients were included in this study. Eastern Cooperative Oncology Group performance status was 0, 1, and 2 in 37%, 52%, and 12% of patients, respectively. Median number of previous treatment regimens was 4 (range=2-7). Forty-nine (82%) patients had previously received anti-PD-1 therapies. In the overall population, the most common grade 3 or higher treatment-related adverse events were neutropenia (37%), anemia (32%) leukopenia (20%), thrombocytopenia (8%), and anorexia (7%). The frequencies of grade 3 or higher events were not increased among patients with previous anti-PD-1 therapies, and no delayed onset immune-related adverse events occurred. In the overall population, objective response rate (ORR), disease control rate (DCR), and median progression-free survival (PFS) were 4%, 42%, and 1.8 months, respectively. Efficacy results in patients with previous anti-PD-1 therapies (ORR 5%, DCR 47%, and median PFS 2.1 months) were almost comparable with those in the overall population.

CONCLUSION

Trifluridine/tipiracil monotherapy after exposure to anti-PD-1 therapies showed manageable safety profile and anti-tumor activity in AGC patients.

Outcomes and a prognostic classifier in patients with microsatellite instability-high metastatic gastric cancer receiving PD-1 blockade

BACKGROUND

Subgroup analyses of randomized trials suggest the superiority of immune checkpoint inhibitor-based therapy over chemotherapy in patients with mismatch-repair deficient (dMMR) and/or microsatellite instability-high (MSI-high) advanced gastric or gastroesophageal junction adenocarcinoma. However, these subgroups are small and studies examining prognostic features within dMMR/MSI-high patients are lacking.

METHODS

We conducted an international cohort study at tertiary cancer centers and collected baseline clinicopathologic features of patients with dMMR/MSI-high metastatic or unresectable gastric cancer treated with anti-programmed cell death protein-1 (PD-1)-based therapies. The adjusted HRs of variables significantly associated with overall survival (OS) were used to develop a prognostic score.

RESULTS

One hundred and thirty patients were included. At a median follow-up of 25.1 months, the median progression-free survival (PFS) was 30.3 months (95% CI: 20.4 to NA) and 2-year PFS rate was 56% (95% CI: 48% to 66%). Median OS was of 62.5 months (95% CI: 28.4 to NA) and 2-year OS rate was 63% (95% CI: 55% to 73%). Among the 103 Response Evaluation Criteria in Solid Tumors-evaluable patients, objective response rate was 66% and disease control rate 87% across lines of therapy. In the multivariable models, Eastern Cooperative Oncology Group Performance Status of 1 or 2, non-resected primary tumor, presence of bone metastases and malignant ascites were independently associated with poorer PFS and OS. These four clinical variables were used to build a three-category (ie, good, intermediate, and poor risk) prognostic score. Compared with patients with good risk, patients with intermediate risk score had numerically inferior PFS and OS (2-year PFS rate: 54.3% versus 74.5%, HR 1.90, 95% CI: 0.99 to 3.66; 2-year OS rate: 66.8% versus 81.2%, HR 1.86, 95% CI: 0.87 to 3.98), whereas patients with poor risk score had significantly inferior PFS and OS (2-year PFS rate: 10.6%, HR 9.65, 95% CI: 4.67 to 19.92; 2-year OS rate: 13.3%, HR 11.93, 95% CI: 5.42 to 26.23).

CONCLUSIONS

Overall outcomes with anti-PD-1-based therapies are favorable in MSI-high gastroesophageal adenocarcinomas. However, within this overall favorable subgroup a more accurate prognostication using baseline clinical characteristics might identify patients at higher risk of rapid disease progression who may deserve intensified immunotherapy combination strategies.

Phase 1 Study of the Liposomal Formulation of Eribulin (E7389-LF): Results From the Advanced Gastric Cancer Expansion Cohort

PURPOSE

In the dose-expansion part of this open-label, phase 1 study, we explored the efficacy and safety of E7389-LF (liposomal formulation of eribulin) in Japanese patients with advanced gastric cancer.

DESIGN

Patients with advanced gastric cancer who had been previously treated with ≥2 lines of chemotherapy received E7389-LF 2.0 mg/m2 every 3 weeks (the previously determined maximum tolerated dose, the primary objective of Study 114). Secondary objectives included objective response rate (ORR), progression-free survival (PFS), and safety; exploratory objectives included disease control rate (DCR) and clinical benefit rate (CBR), as well as pharmacodynamic measurements of serum biomarkers.

RESULTS

As of June 24, 2021, 34 patients were enrolled and treated (10 from the original dose-expansion cohort, expanded to include 24 additional patients). Six patients had partial responses, for an ORR of 17.6% (95% confidence interval [CI]: 6.8-34.5) and the median PFS was 3.7 months (95% CI 2.7-4.8). The DCR was 79.4% (95% CI 62.1-91.3), the CBR was 32.4% (95% CI 17.4-50.5). Overall, 32 patients (94.1%) experienced treatment-related adverse events, and 26 patients (76.5%) experienced grade ≥3 events, most commonly neutropenia (41.2%) and leukopenia (29.4%). Of the 8 endothelial cell/vasculature markers tested in this study, 7 were significantly increased among patients treated with E7389-LF; these changes were generally consistent regardless of best overall response.

CONCLUSIONS

E7389-LF 2.0 mg/m2 every 3 weeks was tolerable and showed preliminary activity for the treatment of patients with gastric cancer. www.

CLINICAL TRIALS

gov registration: NCT03207672.

A phase 1 study of E7386, a CREB-binding protein (CBP)/β-catenin interaction inhibitor, in patients (pts) with advanced solid tumors including colorectal cancer: Updated dose-escalation part

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Background: E7386 is a novel oral anticancer agent that inhibits the binding of β-catenin to its transcriptional co-activator, CBP, thereby modulating Wnt/β-catenin signaling. In preclinical studies, E7386 showed promising activity (eg, modulation of tumor angiogenesis, alteration of the immune microenvironment, and inhibition of tumor growth). At a prior cutoff point for the dose-escalation part of a phase 1 study of E7386 in pts with advanced solid tumors, we reported 2 dose-limiting toxicities (DLTs; both grade 3 decreased appetite) with E7386 160 mg twice daily (BID). Here we describe an update of the dose-escalation part of this phase 1 study—we mainly report updated safety, tolerability, and preliminary efficacy and biomarker results, which led to the inclusion of an additional dose level for investigation in the expansion part of this study. Methods: E7386 was administered orally in escalating doses on a BID continuous schedule in 28-day cycles. Adverse events (AEs) were graded using CTCAE v5.0. Tolerability was judged by DLTs during cycle 1 (C1). Tumor response was assessed every 8 weeks from C1 day (D) 1, or sooner if clinically indicated, and at the end of treatment by investigators using RECIST v1.1. Samples for pharmacokinetic analyses were collected on C1D1 and C1D8; samples for biomarker analyses were collected at protocol-defined time points. To determine the appropriate dose(s) for the expansion part of this study, additional investigation of the dose-escalation part was conducted. Results: As of the data cutoff (DCO) date (30 June 2022), 36 pts (24 men, 12 women; median age, 61.5 y) were enrolled in E7386 dose cohorts (10 to 160 mg BID). Doses were tolerable up to 120 mg BID. The most common treatment-related AEs (all grades; > 10%) were nausea (80.6%), vomiting (58.3%), aspartate aminotransferase increased (16.7%), and alanine aminotransferase increased, decreased appetite, and diarrhea (13.9% each). Nausea and vomiting were well-controlled with antiemetics such as 5HT3 antagonists, except in the 160 mg BID cohort. Two pts with a Wnt-related adenomatous polyposis coli (APC)- mutation (small bowel adenocarcinoma and desmoid tumor) showed a partial response. As of the DCO date, 2 pts (who continued on-treatment as of that date) had received over 1.5 y of E7386 treatment. The preliminary PK analysis showed plasma exposure of E7386 generally increased with an increasing dose over the assessed dose range. FGF21 levels in plasma increased following E7386 administration. Conclusions: E7386 120 mg BID was tolerated and determined as the recommended dose for the expansion part. Based on additional analyses of the dose-escalation part of this study, further investigation of safety, preliminary efficacy, PK, and biomarker analyses of E7386 is ongoing using 2 dose levels (100 and 120 mg BID) in the expansion part. Clinical trial information: NCT03833700 .

The esophageal cancer cohort of a phase 2 trial of E7389-LF (liposomal formulation of eribulin) + nivolumab

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Background: E7389-LF is a liposomal formulation of the microtubule dynamics inhibitor, eribulin. Treatment with E7389-LF plus the programmed cell death 1 inhibitor nivolumab may result in an increased antitumor effect through vascular remodeling. The phase 1b part of the open-label Study 120 assessed dosing and safety of E7389-LF combined with nivolumab in patients (pts) with solid tumors; the phase 2 part assessed efficacy and safety in expansion cohorts, including an esophageal cancer (EGC) cohort. Methods: For the EGC cohort in the phase 2 part of Study 120, pts were required to have unresectable, measurable (by RECIST v1.1) EGC lesion(s) that showed progression during or after first-line chemotherapy with no other systemic chemotherapy. The primary objective of the phase 2 part was to assess objective response rate (ORR), with success defined as Bayesian posterior probability over 85% beyond threshold (20%) for best overall response (ie, 9 responders of planned 32 pts enrolled). Secondary objectives included assessment of safety and progression-free survival (PFS). The recommended phase 2 dosing regimen was previously determined to be E7389-LF 2.1 mg/m2 every 3 weeks (Q3W) plus nivolumab 360 mg Q3W. Tumor assessments were performed by RECIST v1.1 every 6 weeks. All adverse events (AEs) were monitored and recorded. Results: In the EGC cohort, 35 pts were included. Most pts (88.6%) were male, and the median age was 69.0 years (range 47–85). At data cutoff (May 31, 2022), 5 pts (14.3%) were still undergoing treatment. Discontinuations occurred in 30 pts (85.7%)—25 (71.4%) due to disease progression, 4 (11.4%) due to an adverse event, and 1 (2.9%) due to patient preference. ORR with E7389-LF + nivolumab was 22.9% (95% CI 10.4–40.1) and the disease control rate (DCR) was 62.9% (95% CI 44.9–78.5). Median PFS was 2.81 months (95% CI 1.31–4.17) and the 6-month PFS rate was 20.2% (95% CI 8.7–35.0). Median OS was not reached (95% CI 6.54–not estimable), and the 6-month OS rate was 71.4% (95% CI 53.4–83.5). Treatment-related treatment-emergent (TE) AEs of any grade and of grade ≥3 occurred in 94.3% and 80.0% of pts, respectively. The most common treatment-related TEAEs of any grade were neutropenia (65.7%), leukopenia (57.1%), and decreased appetite (45.7%). The most common treatment-related TEAEs of grade ≥3 were neutropenia (54.3%), leukopenia (34.3%), and febrile neutropenia (22.9%). TEAEs led to dose reduction of E7389-LF in 17 pts (48.6%). TEAEs led to withdrawal of either E7389-LF or nivolumab in 5 pts (14.3%): pneumonia (n=2), traumatic hemothorax (n=1), acute kidney injury (n=1), and pneumonitis (n=1). Conclusions: E7389-LF combined with nivolumab showed an ORR of 22.9% in pts with EGC. Despite this modest ORR, the DCR of 62.9% was notable. No new safety signals were observed compared to the known profiles of each monotherapy. Clinical trial information: NCT04078295 .

Gastric cancer (GC) cohort of a phase 2 trial of E7389-LF (liposomal formulation of eribulin) in combination with nivolumab

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Background: Due to a lack of efficacy and long-term survival seen in previously-studied therapies, new therapies for pretreated advanced GC are warranted. E7389-LF is a new formulation that uses liposomes to encapsulate eribulin; this is anticipated to improve eribulin concentration in tumor tissues. E7389-LF and nivolumab have both shown efficacy as monotherapy in pretreated GC. E7389-LF may also synergize well with PD-1 inhibitors by acting as a cytotoxic therapy and by modulating the tumor microenvironment. Methods: Patients (pts) with unresectable and measurable GC, esophageal cancer, or small cell lung cancer who were previously treated with 1 (2 for GC) chemotherapy regimens were enrolled in the phase 2 part of Study 120 and treated with E7389-LF 2.1 mg/m2 plus nivolumab 360 mg every 3 weeks (Q3W). In the GC cohort, pts had to show disease progression from combination therapy including a platinum drug + fluoropyrimidine (1st-line therapy) and a taxane-containing regimen (2nd-line therapy). The primary objective of the phase 2 part was to evaluate the objective response rate (ORR); secondary objectives included safety, progression-free survival (PFS), and pharmacokinetics. Other efficacy (including overall survival [OS]) and biomarker objectives were exploratory. Tumor responses were assessed by the investigators per RECIST v1.1. Results: 31 GC pts were included; median age was 63 years; 18 pts were male, 13 were female. By the data cutoff date (May 31, 2022), 29 pts discontinued (26 due to disease progression, 3 due to adverse events). 8 Pts had a partial response (PR); the ORR was 25.8% (95% CI 11.9–44.6). The median PFS was 2.69 months (95% CI 1.91–2.99). The median OS was 7.85 months (95% CI 4.47–not estimable). The 6-month OS rate was 61.3%; the 9-month OS rate was 44.7%. 30 Pts had ≥1 treatment-related TEAE, most commonly neutropenia (n = 24); 25 pts had at least 1 grade ≥3 treatment-related TEAE, most commonly neutropenia (n = 22). 16 Pts had ≥1 TEAE resulting in dose reduction of E7389-LF. 4 Pts had ≥1 TEAE resulting in withdrawal of E7389-LF or nivolumab, including asthma, cerebral hemorrhage, decreased appetite, pulmonary edema, and upper gastrointestinal hemorrhage (each n = 1). 29 Pts had an evaluable PD-L1 combined positive score (CPS); 5 of 20 pts (25.0%) with a CPS of < 5 and 2 of 9 (22.2%) with a CPS of ≥5 had a PR. Increases in pharmacodynamic markers including vasculature-related markers were observed; antitumor immunity was observed per changes in interferon gamma (IFNγ) and IFNγ-related markers. Conclusions: E7389-LF 2.1 mg/m2 in combination with nivolumab 360 mg Q3W had promising efficacy for pretreated GC, as evidenced by the notable ORR of 25.8% as well as by PFS and OS. No new safety signals were identified for this combination. Biomarker changes suggested vascular remodeling activity and enhancement of antitumor immunity via IFNγ signaling. Clinical trial information: NCT04078295 .

Comprehensive clinical and molecular characterization of claudin 18.2 expression in advanced gastric or gastroesophageal junction cancer

BACKGROUND

We conducted comprehensive clinical and molecular characterization of claudin 18.2 expression (CLDN18.2) in advanced gastric or gastroesophageal junction cancer (GC/GEJC).

PATIENTS AND METHODS

Patients with advanced GC/GEJC who received systemic chemotherapy from October 2015 to December 2019 with available tumor specimens were analyzed. We evaluated clinicopathological features of CLDN18.2 expression with four molecular subtypes: mismatch repair deficient, Epstein-Barr virus-positive, human epidermal growth factor receptor 2-positive, and others. In addition, programmed death-ligand 1 (PD-L1) combined positive score (CPS), genomic alterations, and the expression of immune cell markers were assessed. Clinical outcomes of standard first- or second-line chemotherapy and subsequent anti-programmed cell death protein 1 (anti-PD-1) therapy were also investigated according to CLDN18.2 expression.

RESULTS

Among 408 patients, CLDN18.2-positive (moderate-to-strong expression in ≥75%) was identified in 98 patients (24.0%) with almost equal distribution in the four molecular subtypes or CPS subgroups. CLDN18.2-positive was associated with Borrmann type 4, KRAS amplification, low CD16, and high CD68 expression. Overall survival with first-line chemotherapy was not significantly different between CLDN18.2-positive and -negative groups [median 18.4 versus 20.1 months; hazard ratio 1.26 (95% confidence interval 0.89-1.78); P = 0.191] regardless of stratification by PD-L1 CPS ≥5. Progression-free survival and objective response rates of first- and second-line chemotherapy, and anti-PD-1 therapy also showed no significant differences according to CLDN18.2 status.

CONCLUSIONS

CLDN18.2 expression in advanced GC/GEJC was associated with some clinical and molecular features but had no impact on treatment outcomes with chemotherapy or checkpoint inhibition. CLDN18.2-positive also had no impact on overall survival. This information could be useful to interpret the results from currently ongoing clinical trials of CLDN18.2-targeted therapies for advanced GC/GEJC and to consider a treatment strategy for CLDN18.2-positive GC/GEJC.

Phase 1 trial of zolbetuximab in Japanese patients with CLDN18.2+ gastric or gastroesophageal junction adenocarcinoma

Zolbetuximab is a chimeric monoclonal antibody that targets claudin-18.2, a candidate biomarker in patients with advanced gastric/gastroesophageal cancer. This nonrandomized phase 1 study (NCT03528629) enrolled previously treated Japanese patients with claudin-18.2-positive locally advanced/metastatic gastric/gastroesophageal cancer in two parts: Safety (Arms A and B, n = 3 each) and Expansion (n = 12). Patients received intravenous zolbetuximab 800 mg/m² on cycle 1, day 1 followed by 600 mg/m² every 3 weeks (Q3W; Safety Part Arm A and Expansion) or 1000 mg/m² Q3W (Safety Part Arm B). For the Safety Part, the primary endpoint was safety (i.e., dose-limiting toxicities [DLTs]) and a secondary endpoint was objective response rate (ORR) by investigator. For the Expansion Part, the primary endpoint was ORR by investigator and secondary endpoints included ORR by central review and safety. Additional secondary endpoints for both the Safety and Expansion Parts were disease control rate (DCR), overall survival (OS), progression-free survival (PFS), duration of response, pharmacokinetics, and immunogenicity. In 18 patients, no DLTs (Safety Part) or drug-related treatment-emergent adverse events (TEAEs) grade ≥3 were observed. Most TEAEs were gastrointestinal. In 17 patients with measurable lesions, best overall response was stable disease (64.7%) or progressive disease (35.3%). The DCR was 64.7% (95% confidence interval 38.3-85.8). In Arm A and Expansion combined (n = 15), median OS was 4.4 months (2.6-11.4) and median PFS was 2.6 months (0.9-2.8). In Arm B (n = 3), median OS was 6.4 months (2.9-6.8) and median PFS was 1.7 months (1.2-2.1). Zolbetuximab exhibited no new safety signals with limited single-agent activity in Japanese patients.

Role of Nivolumab in the Management of First-Line Unresectable Advanced or Recurrent Gastric Cancer in Combination with Chemotherapy: Lessons from the Japanese Experience

Recently, immune checkpoint inhibitor (ICI), such as anti-programmed cell death-1 (PD-1) or programmed cell death ligand-1 (PD-L1) monoclonal antibodies, has provided clinical benefits in various cancer types including advanced gastric cancer (AGC). Nivolumab, a monoclonal anti-PD-1 antibody, firstly showed an improvement in the overall survival (OS) in patients with AGC in the ATTRACTION-2 trial. Recently, chemotherapy plus nivolumab, as a first-line treatment for AGC, showed both OS and progression-free survival (PFS) benefits in patients with PD-L1 combined positive score (CPS) ≥5 in the global CheckMate-649 trial, and demonstrated PFS benefit irrespective of CPS status in the Asian ATTRACTION-4 trial. Based on these results, chemotherapy plus nivolumab in a first-line treatment was approved worldwide. However, the approval requirements and recommendations are different according to the approval agent or country. Thus, this review summarized the clinical trials of chemotherapy plus anti-PD1 antibody as a first-line treatment and focused on the role of nivolumab combined with chemotherapy mainly from the viewpoint of the Japanese experience.

Updated Efficacy Outcomes of Anti-PD-1 Antibodies plus Multikinase Inhibitors for Patients with Advanced Gastric Cancer with or without Liver Metastases in Clinical Trials

PURPOSE

We previously reported preliminary activity of regorafenib plus nivolumab (REGONIVO) or lenvatinib plus pembrolizumab (LENPEM) in advanced gastric cancer (AGC). Meanwhile, several studies demonstrated liver metastases are less responsive to immunotherapy.

PATIENTS AND METHODS

Combined efficacy outcomes with a longer follow-up in a phase Ib trial of REGONIVO and a phase II trial of LENPEM were examined in AGC with or without liver metastases (REGONIVO plus LENPEM cohort). We also investigated the efficacy of anti-PD-1 monotherapies (anti-PD-1 monotherapy cohort). A comparison of the immune microenvironment between gastric primary tumors and liver metastases was also conducted by multiplex IHC.

RESULTS

In the REGONIVO plus LENPEM cohort, with a median follow-up of 14.0 months, objective response rate (ORR), median progression-free survival (mPFS), and median overall survival (mOS) were 46%, 7.8 months, and 15.6 months in patients with liver metastases, while 69%, 6.9 months, and 15.5 months in those without. In the anti-PD-1 monotherapy cohort, with a median follow-up of 27.6 months, ORR, mPFS, and mOS were 9%, 1.4 months, and 6.4 months in patients with liver metastases, while 22%, 2.3 months, and 9.0 months in those without. Multiplex IHC revealed liver metastases were associated with an abundance of immune-suppressive cells, such as tumor-associated macrophages and regulatory T cells, with fewer CD8+ T cells compared with gastric primary tumors.

CONCLUSIONS

Anti-PD-1 antibodies plus regorafenib or lenvatinib for AGC showed promising antitumor activity with a longer follow-up, irrespective of liver metastases status, despite a more immune-suppressive tumor microenvironment in liver metastases.

Mixed Response to Cancer Immunotherapy is Driven by Intratumor Heterogeneity and Differential Interlesion Immune Infiltration

Some patients experience mixed response to immunotherapy, whose biological mechanisms and clinical impact have been obscure. We obtained two tumor samples from lymph node (LN) metastatic lesions in a same patient. Whole exome sequencing for the both tumors and single-cell sequencing for the both tumor-infiltrating lymphocytes (TIL) demonstrated a significant difference in tumor clonality and TILs' characteristics, especially exhausted T-cell clonotypes, although a close relationship between the tumor cell and T-cell clones were observed as a response of an overlapped exhausted T-cell clone to an overlapped neoantigen. To mimic the clinical setting, we generated a mouse model of several clones from a same tumor cell line. Similarly, differential tumor clones harbored distinct TILs, and one responded to programmed cell death protein 1 (PD-1) blockade but the other did not in this model. We further conducted cohort study (n = 503) treated with PD-1 blockade monotherapies to investigate the outcome of mixed response. Patients with mixed responses to PD-1 blockade had a poor prognosis in our cohort. Particularly, there were significant differences in both tumor and T-cell clones between the primary and LN lesions in a patient who experienced tumor response to anti-PD-1 mAb followed by disease progression in only LN metastasis. Our results underscore that intertumoral heterogeneity alters characteristics of TILs even in the same patient, leading to mixed response to immunotherapy and significant difference in the outcome.

Significance

Several patients experience mixed responses to immunotherapies, but the biological mechanisms and clinical significance remain unclear. Our results from clinical and mouse studies underscore that intertumoral heterogeneity alters characteristics of TILs even in the same patient, leading to mixed response to immunotherapy and significant difference in the outcome.

Characteristics and clinical outcomes of patients with advanced gastric or gastroesophageal cancer treated in and out of randomized clinical trials of first-line immune checkpoint inhibitors

BACKGROUND

Although several randomized trials (RCTs) showed survival benefits of immune checkpoint inhibitor (ICI) plus first-line chemotherapy for advanced gastric or gastroesophageal cancer (AGC), these trials could enroll patients who fulfilled the strict eligibility criteria or waited for certain screening period for central assessment of PD-L1 status.

METHODS

We retrospectively compared characteristics and clinical outcomes of the patients with AGC who received first-line chemotherapy in control arm of RCTs with ICIs (control group) or clinical practice (practice group) at our institution from February 2016 to April 2019.

RESULTS

The control group had a better baseline Eastern Cooperative Oncology Group performance status (PS0, 81.2% vs. 51.4%, p < 0.001) and a longer interval from first visit to first-line chemotherapy initiation (19 days vs. 9 days, p < 0.001) than the practice group. Median overall survival (OS) was 20.3 months in control group and 15.7 months in practice group, with a trend of longer OS in control group than that in practice group (hazard ratio, 0.71; p = 0.062). More patients in control group were treated with subsequent chemotherapy including ICIs.

CONCLUSION

Patients with AGC in RCTs of ICIs had a better PS or a higher chance to receive subsequent chemotherapy, resulting in a better prognosis than those treated in clinical practice. This information should be considered when interpreting RCT results and applying new treatments into clinical practice.

Phase 2 study of trastuzumab deruxtecan in the neoadjuvant treatment for patients with HER2-positive gastric and gastroesophageal junction adenocarcinoma (EPOC2003)

TPS4161

Background: Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate consisting of an anti-HER2 antibody, a cleavable tetrapeptide-based linker, and a cytotoxic topoisomerase I inhibitor. DESTINY-Gastric01 study showed significantly higher objective response rate with T-DXd than physician's choice of chemotherapy (51.3%, vs. 14.3%, Shitara K, et al. NEJM 2020) as well as prolonged overall survival (median 12.5 vs. 8.4 months, hazard ratio 0.59). Considering that high response rate or major pathological response (MPR), which is defined as the proportion of subjects with < 10% residual tumor may be associated with favorable survival outcomes after preoperative chemotherapy, T-DXd could be a promising neoadjuvant treatment for patients with gastric and gastroesophageal junction (GEJ) cancer. However, to our knowledge, there is no currently ongoing study of T-DXd as a neoadjuvant setting for patients with gastric and GEJ cancers. Methods: This is an open-label, single-arm, multicenter, investigator initiated phase 2 trial to evaluate antitumor activity of T-DXd as the neoadjuvant treatment for patients with HER2 positive gastric and GEJ adenocarcinoma. Eligible patients should have previously untreated locally advanced gastric and GEJ adenocarcinoma with clinical stage of T2-4 and/or N+ without distant metastasis. The main cohort will enroll patients with HER2 overexpression defined as immunohistochemistry （IHC）3+ or IHC2+/ in situ hybridization（ISH）+ by local assessment. According to the results of exploratory biomarker analysis of DESTINY-Gastric01 study (Shitara K, et al. ESMO-GI2021), patients with HER2-low expression (IHC1+ or 2+ with ISH negative) with HER2-extra cellular domein (ECD) higher than 11.6 ng/ml also will be enrolled into the exploratory cohort. Patients will receive 3 cycles of T-DXd (6.4mg/kg) by intravenous infusion every 3 weeks followed by surgery at 3 to 8 weeks after last T-DXd infusion.The primary endpoint is MPR rate. The threshold in the main cohort is defined as 20%, and the expected MPR rate was set at 45%. The minimum sample size of this trial is 23 patients in the main cohort (α- and β-error probabilities, 0.1 and 0.15, respectively). Total number of patients will be increased up to 27 patients depending on the enrollment. In addition, 10 patients will be recruited into the exploratory cohort. Secondary endpoints are pathologic complete response (pCR) rate, curative resection rate, and adverse event rate. Biomarker analyses including whole exome sequencing, RNA sequencing, proteomics, and ctDNA changes will also be conducted using pre- and post-treatment tumor and blood samples. Enrollment is ongoing at six sites in Japan from November 2021. Clinical trial information: NCT05034887.

Transcriptomic Profiling of MSI-H/dMMR Gastrointestinal Tumors to Identify Determinants of Responsiveness to Anti-PD-1 Therapy

PURPOSE

Transcriptomic profiling was performed for microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) gastrointestinal tumors to determine the predictors of response to PD-1 blockade.

EXPERIMENTAL DESIGN

Thirty-six patients with MSI-H/dMMR gastrointestinal tumors, including gastric cancer, colorectal cancer, cholangiocarcinoma, small intestine cancer, and pancreatic cancer, being treated with PD-1 blockade were analyzed. We conducted the transcriptomic analysis of gastrointestinal tumors using RNA sequencing data, including the consensus molecular subtypes (CMS) of colorectal cancer.

RESULTS

Gene set enrichment analysis (GSEA) demonstrated that non-responders had upregulations of epithelial-mesenchymal transition, angiogenesis, hypoxia, mTORC1, TNF-α, KRAS, Wnt/β-catenin, TGF-β, and various metabolism-related signaling pathways. Meanwhile, the IFNγ pathway was enriched in responders. On the basis of the leading-edge analysis of GSEA, VEGF-A was significantly correlated with enriched pathways in non-responders. Patients with high VEGF-A expression, compared with those with low expression, had significantly shorter progression-free survival [PFS; median 4.8 months vs. not reached (NR), P = 0.032] and overall survival (median 11.1 months vs. NR, P = 0.045). Among 13 patients with colorectal cancer evaluable for CMS classification, the objective response rate was 100%, 0%, 0%, and 16.7% in CMS1, CMS2, CMS3, and CMS4, respectively. Patients with CMS1 had significantly longer PFS (NR vs. 4.8 months, P = 0.017) than those with CMS2, CMS3, or CMS4.

CONCLUSIONS

Several transcriptomic features, including CMS classification and related genes, were associated with response to PD-1 blockade in MSI-H/dMMR gastrointestinal tumors. These findings can help develop predictive biomarkers or combination immunotherapies.

HLA Class I Analysis Provides Insight Into the Genetic and Epigenetic Background of Immune Evasion in Colorectal Cancer With High Microsatellite Instability

BACKGROUND & AIMS

A detailed understanding of antitumor immunity is essential for optimal cancer immune therapy. Although defective mutations in the B2M and HLA-ABC genes, which encode molecules essential for antigen presentation, have been reported in several studies, the effects of these defects on tumor immunity have not been quantitatively evaluated.

METHODS

Mutations in HLA-ABC genes were analyzed in 114 microsatellite instability-high colorectal cancers using a long-read sequencer. The data were further analyzed in combination with whole-exome sequencing, transcriptome sequencing, DNA methylation array, and immunohistochemistry data.

RESULTS

We detected 101 truncating mutations in 57 tumors (50%) and loss of 61 alleles in 21 tumors (18%). Based on the integrated analysis that enabled the immunologic subclassification of microsatellite instability-high colorectal cancers, we identified a subtype of tumors in which lymphocyte infiltration was reduced, partly due to reduced expression of HLA-ABC genes in the absence of apparent genetic alterations. Survival time of patients with such tumors was shorter than in patients with other tumor types. Paradoxically, tumor mutation burden was highest in the subtype, suggesting that the immunogenic effect of accumulating mutations was counterbalanced by mutations that weakened immunoreactivity. Various genetic and epigenetic alterations, including frameshift mutations in RFX5 and promoter methylation of PSMB8 and HLA-A, converged on reduced expression of HLA-ABC genes.

CONCLUSIONS

Our detailed immunogenomic analysis provides information that will facilitate the improvement and development of cancer immunotherapy.

Clinical Validity of Plasma-Based Genotyping for Microsatellite Instability Assessment in Advanced GI Cancers: SCRUM-Japan GOZILA Substudy

PURPOSE

Circulating tumor DNA (ctDNA) genotyping may guide targeted therapy for patients with advanced GI cancers. However, no studies have validated ctDNA genotyping for microsatellite instability (MSI) assessment in comparison with a tissue-based standard.

PATIENTS AND METHODS

The performance of plasma-based MSI assessment using Guardant360, a next-generation sequencing–based ctDNA assay, was compared with that of tissue-based MSI assessment using a validated polymerase chain reaction–based method in patients with advanced GI cancers enrolled in GOZILA study, a nationwide ctDNA profiling study. The primary end points were overall percent agreement, positive percent agreement (PPA), and negative percent agreement. The efficacy of immune checkpoint inhibitor therapy was also evaluated.

RESULTS

In 658 patients with advanced GI cancers who underwent both plasma and tissue testing for MSI, the overall percent agreement, PPA, and negative percent agreement were 98.2% (95% CI, 96.8 to 99.1), 71.4% (95% CI, 47.8 to 88.7), and 99.1% (95% CI, 98.0 to 99.7), respectively. In patients whose plasma samples had a ctDNA fraction ≥ 1.0%, the PPA was 100.0% (15/15; 95% CI, 78.2 to 100.0). Three patients with MSI-high (MSI-H) tumors detected only by ctDNA genotyping achieved clinical benefits after receiving anti–programmed cell death 1 therapy with the progression-free survival ranging from 4.3 to 16.7 months. One patient with an aggressive cancer of an unknown primary site benefited from pembrolizumab after rapid detection of MSI-H by ctDNA genotyping.

CONCLUSION

ctDNA genotyping was able to detect MSI with high concordance to validated tissue-based MSI testing, especially in patients with tumors that have sufficient ctDNA shedding. Furthermore, ctDNA genotyping enabled identification of patients with MSI-H tumors who benefited from immune checkpoint inhibitor treatment.

The New Era of Immunotherapy in Gastric Cancer

Simple Summary

Advanced gastric cancer remains a malignancy with a poor prognosis, with a median survival of about 12–15 months. In recent years, immune checkpoint inhibitors have emerged as a new standard of care for several malignancies, including advanced gastric cancer, and have demonstrated good clinical benefit in some populations. In this review paper, we describe the current status of immunotherapy in gastric cancer, with a focus on molecular and immunological profiles, biomarkers, major clinical trials, and novel immunotherapies.

Abstract

Immune checkpoint inhibitors (ICIs) such as anti-programmed cell death-1 (PD-1) or programmed cell death ligand-1 (PD-L1) monoclonal antibodies have prolonged survival in various types of malignancies, including advanced gastric cancer (AGC). Nivolumab, a monoclonal anti-PD-1 antibody, showed an improvement in overall survival at a later-line therapy in unselected AGC patients in the ATTRACTION-2 study or in combination with chemotherapy as first-line therapy in the global CheckMate-649 study. Another monoclonal anti-PD-1 antibody, pembrolizumab, showed single agent activity in tumors with high microsatellite instability or high tumor mutational burden. Furthermore, a recent KEYNOTE-811 study demonstrated significant improvement in response rate with pembrolizumab combined with trastuzumab and chemotherapy for HER2-positive AGC. Based on these results, ICIs are now incorporated into standard treatment for AGC patients. As a result of pivotal clinical trials, three anti-PD-1 antibodies were approved for AGC: nivolumab combined with chemotherapy as first-line treatment or nivolumab monotherapy as third- or later-line treatment in Asian countries; pembrolizumab for previously treated microsatellite instability-high (MSI-H) or tumor mutational burden-high AGC, or pembrolizumab combined with trastuzumab and chemotherapy for HER2-positive AGC in the United States; and dostarlimab for previously treated MSI-H AGC in the United States. However, a substantial number of patients have showed resistance to ICIs, highlighting the importance of the better selection of patients or further combined immunotherapy. This review focused on molecular and immunological profiles, pivotal clinical trials of ICIs with related biomarkers, and investigational immunotherapy for AGC.

Lactic acid promotes PD-1 expression in regulatory T cells in highly glycolytic tumor microenvironments

The balance of programmed death-1 (PD-1)-expressing CD8⁺ T cells and regulatory T (Treg) cells in the tumor microenvironment (TME) determines the clinical efficacy of PD-1 blockade therapy through the competition of their reactivation. However, factors that determine this balance remain unknown. Here, we show that Treg cells gain higher PD-1 expression than effector T cells in highly glycolytic tumors, including MYC-amplified tumors and liver tumors. Under low-glucose environments via glucose consumption by tumor cells, Treg cells actively absorbed lactic acid (LA) through monocarboxylate transporter 1 (MCT1), promoting NFAT1 translocation into the nucleus, thereby enhancing the expression of PD-1, whereas PD-1 expression by effector T cells was dampened. PD-1 blockade invigorated the PD-1-expressing Treg cells, resulting in treatment failure. We propose that LA in the highly glycolytic TME is an active checkpoint for the function of Treg cells in the TME via upregulation of PD-1 expression.

Topical corticosteroid therapy for facial acneiform eruption due to EGFR inhibitors in metastatic colorectal cancer patients: a randomized controlled trial comparing starting with a very strong or a weak topical corticosteroid (FAEISS study, NCCH1512, colorectal part)

BACKGROUND

Although pre-emptive therapy with oral tetracycline, moisturizer, sunscreen, and topical corticosteroid is useful for preventing acneiform eruption (AfE) due to epidermal growth factor receptor (EGFR) inhibitors, no studies have examined the efficacy of topical corticosteroids themselves, or investigated the optimal potency of corticosteroid for treating facial AfE (FAfE).

PATIENTS AND METHODS

Screened patients with RAS wild-type colorectal cancer started pre-emptive therapy with oral minocycline and moisturizer on initiation of cetuximab or panitumumab therapy. Patients who developed grade 1 or 2 FAfE were randomly allocated to two groups: a ranking-down (RD) group that started with a very strong corticosteroid and serially ranked down every 2 weeks unless FAfE exacerbated; and a ranking-up (RU) group that started with a weak corticosteroid and serially ranked up at exacerbation. FAfE grade, patient quality of life, and adverse events (AEs) with topical corticosteroid were evaluated every 2 weeks. The primary endpoint was the total number of times grade 2 or higher FAfE was identified in the central review of the 8-week treatment period.

RESULTS

No significant differences in total numbers of grade 2 or higher FAfE or in AEs caused by topical corticosteroids were observed between groups during the 8 weeks. Incidence of grade 2 or higher FAfE tended to be lower in the RD group during the first 2 weeks.

CONCLUSION

Considering the long-term care of FAfE, the RU regimen appears suitable and should be considered the standard treatment for FAfE due to EGFR inhibitor therapy.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN000024113).

Ascites and resistance to immune checkpoint inhibition in dMMR/MSI-H metastatic colorectal and gastric cancers

Background

Despite unprecedented benefit from immune checkpoint inhibitors (ICIs) in patients with mismatch repair deficient (dMMR)/microsatellite instability high (MSI-H) advanced gastrointestinal cancers, a relevant proportion of patients shows primary resistance or short-term disease control. Since malignant effusions represent an immune-suppressed niche, we investigated whether peritoneal involvement with or without ascites is a poor prognostic factor in patients with dMMR/MSI-H metastatic colorectal cancer (mCRC) and gastric cancer (mGC) receiving ICIs.

Methods

We conducted a global multicohort study at Tertiary Cancer Centers and collected clinic-pathological data from a cohort of patients with dMMR/MSI-H mCRC treated with anti-PD-(L)1 ±anti-CTLA-4 agents at 12 institutions (developing set). A cohort of patients with dMMR/MSI-high mGC treated with anti-PD-1 agents±chemotherapy at five institutions was used as validating dataset.

Results

The mCRC cohort included 502 patients. After a median follow-up of 31.2 months, patients without peritoneal metastases and those with peritoneal metastases and no ascites had similar outcomes (adjusted HR (aHR) 1.15, 95% CI 0.85 to 1.56 for progression-free survival (PFS); aHR 0.96, 95% CI 0.65 to 1.42 for overall survival (OS)), whereas inferior outcomes were observed in patients with peritoneal metastases and ascites (aHR 2.90, 95% CI 1.70 to 4.94; aHR 3.33, 95% CI 1.88 to 5.91) compared with patients without peritoneal involvement. The mGC cohort included 59 patients. After a median follow-up of 17.4 months, inferior PFS and OS were reported in patients with peritoneal metastases and ascites (aHR 3.83, 95% CI 1.68 to 8.72; aHR 3.44, 95% CI 1.39 to 8.53, respectively), but not in patients with only peritoneal metastases (aHR 1.87, 95% CI 0.64 to 5.46; aHR 2.15, 95% CI 0.64 to 7.27) when compared with patients without peritoneal involvement.

Conclusions

Patients with dMMR/MSI-H gastrointestinal cancers with peritoneal metastases and ascites should be considered as a peculiar subgroup with highly unfavorable outcomes to current ICI-based therapies. Novel strategies to target the immune-suppressive niche in malignant effusions should be investigated, as well as next-generation ICIs or intraperitoneal approaches.

An open-label phase 2 study of lenvatinib plus pembrolizumab in the neoadjuvant and adjuvant treatment for patients with gastric and gastroesophageal junction adenocarcinoma (EPOC2001)

TPS372

Background: Lenvatinib, a multikinase inhibitor of VEGF receptors and other receptor tyrosine kinases, substantially decreased the tumor-associated macrophages and increased infiltration of CD8-positive T cells and enhanced anti-tumor activity of PD-1 inhibitors in vivo model. A phase 2 study demonstrated remarkable clinical activity of lenvatinib plus pembrolizumab for advanced gastric cancer with objective response rate of 69% (Kawazoe A, et al. Lancet Oncol. 2020), leading to the global phase 3 LEAP-015 trial at first-line (NCT04662710). The objective of this study is to evaluate anti-tumor activity of lenvatinib with pembrolizumab as neoadjuvant and adjuvant treatment for patients with gastric and gastroesophageal junction adenocarcinoma. Methods: The study is an open-label, single-arm, single-center, phase 2 clinical trial. Eligible patients are with previously untreated gastric and gastroesophageal junction adenocarcinoma as defined by cT2-4 and/or cN+ without evidence of metastatic disease. Patients will receive 3 cycles of 20 mg oral lenvatinib daily plus 200 mg intravenous pembrolizumab every 3 weeks as the neoadjuvant treatment followed by surgery, and then 3 cycles of lenvatinib plus pembrolizumab followed by 11 cycles of pembrolizumab monotherapy as the adjuvant treatment. The primary endpoint is major pathological response rate, and the secondary endpoints are pathological complete response rate, tumor shrinkage effect on primary lesions, radical resection rate, treatment completion rate until surgery or adjuvant treatment, event-free survival, overall survival, and incidence of adverse events. We also investigate several biomarkers using pre- and post-treatment tumor and blood samples. First patient will be enrolled in November 2021. Clinical trial information: NCT04745988.

TAS-116 (Pimitespib), an Oral HSP90 Inhibitor, in Combination with Nivolumab in Patients with Colorectal Cancer and Other Solid Tumors: An Open-Label, Dose-Finding, and Expansion Phase Ib Trial (EPOC1704)

PURPOSE

This is a phase Ib trial of TAS-116, an oral HSP90 inhibitor, plus nivolumab for colorectal cancer and other solid tumors.

PATIENTS AND METHODS

Enrolled patients received TAS-116 plus nivolumab in a dose-finding part to estimate the recommended dose. Additional patients were enrolled in a dose-expansion part. TAS-116 monotherapy (orally once daily, 80-160 mg) was administered for 2 weeks followed by the combination with nivolumab (intravenously every 2 weeks, 3 mg/kg). The primary endpoint was dose-limiting toxicities (DLT). We also conducted biomarker research using paired samples from repeated blood collections and tumor biopsies.

RESULTS

A total of 44 patients with colorectal cancer (n = 29), gastric cancer (n = 8), sarcoma (n = 5), non-small cell lung cancer (n = 1), and melanoma (n = 1) were enrolled. Eleven patients had previously received immune-checkpoint inhibitors. No DLTs were observed at all dose levels, and TAS-116 160 mg was determined as recommended dose. The common grade 3 or worse treatment-related adverse events included liver transaminase increased (7%), creatinine increased (5%), and platelet count decreased (5%). Objective tumor response was observed in 6 patients, including 4 microsatellite stable (MSS) colorectal cancers, 1 microsatellite instability-high colorectal cancer, and 1 leiomyosarcoma, resulting in an objective response rate of 16% in MSS colorectal cancer without prior immune-checkpoint inhibitors. Biomarker analysis showed that TAS-116 inhibited the activity of regulatory T cells in peripheral blood mononuclear cells and tumor-infiltrating lymphocytes.

CONCLUSIONS

TAS-116 160 mg plus nivolumab had manageable safety profiles and antitumor activity, especially for MSS colorectal cancer patients.

Phase 1 study of the liposomal formulation of eribulin (E7389-LF): Results from the advanced gastric cancer expansion cohort

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Background: Eribulin has proven efficacy in previously treated metastatic breast cancer and liposarcoma. E7389-LF is a new formulation that uses liposomes to encapsulate eribulin, which is anticipated to improve eribulin concentration in tumor tissues. In the dose-expansion part of a phase 1 study of E7389-LF, the safety profile was acceptable and 2 patients (pts) out of 10 with gastric cancer (GC) had an objective response. Thus, the GC cohort was expanded for further evaluation. Here, we report efficacy and safety data from the phase 1 expansion cohort of pts with advanced GC who were treated with E7389-LF. Methods: Eligible pts were those with GC who had no alternative standard or effective therapy options after ≥2 prior chemotherapy regimens. Target total enrollment was 32 pts (10 pts in the initial GC cohort plus an additional 22 pts in the expanded cohort). E7389-LF 2.0 mg/m2 was administered intravenously once every 3 weeks. Tumor responses were assessed every 6 weeks (± 1 week) by RECIST v1.1. Results: At data cutoff (Oct 16, 2020), 34 pts with GC were enrolled (10 pts in the initial GC cohort; 24 pts in the expanded GC cohort) with a median of 5 prior therapies (range, 2–11). Previous immune checkpoint inhibitor (ICI) therapy was reported for 26 (76.5%) pts. All pts were evaluable for objective response rate (ORR) and progression-free survival (PFS), and 30 pts were evaluable for overall survival (OS). Among all pts with GC, the ORR was 17.6% (95% CI 6.8–34.5) and the disease control rate was 79.4% (95% CI 62.1–91.3). Median PFS was 3.7 months (95% CI 2.7–4.3) and median OS was 7.6 months (95% CI 6.7–15.4). The ORRs were 19.2% (95% CI 6.6–39.4) in ICI-pretreated pts and 12.5% (95% CI 0.3–52.7) in pts without prior ICI therapy. Median PFS was similar regardless of prior treatment with ICIs (3.7 months [95% CI 2.7–5.6] in ICI-pretreated pts vs 3.4 months [95% CI 1.0–4.3] in pts without prior ICI therapy); however, the PFS rate at 6 months in ICI-pretreated pts was higher vs the rate in pts without prior ICI therapy (35.9% [95% CI 17.2–55.1] vs 0%, respectively). Median OS was also longer in ICI-pretreated pts (evaluable pts, n = 23) vs pts without prior ICI therapy (evaluable pts, n = 7) (10.0 months [95% CI 6.7–not estimable] vs 6.7 months [95% CI 3.1–8.5], respectively). Common grade ≥3 adverse events included neutropenia (41.2%), leukopenia (29.4%), and anemia (26.5%). In cycle 1, there were no cases of febrile neutropenia among the 22 pts treated with prophylactic peg-GCSF; among pts who did not receive prophylactic peg-GCSF, 16.7% of pts had febrile neutropenia. Conclusions: E7389-LF had a manageable safety profile and encouraging activity in pts with heavily treated GC. In pts with GC, prior treatment with ICIs might enhance the potential efficacy of E7389-LF. These results support further development of E7389-LF for advanced GC. Clinical trial information: NCT03207672.

Pembrolizumab plus trastuzumab and chemotherapy for HER2+ metastatic gastric or gastroesophageal junction (G/GEJ) cancer: Initial findings of the global phase 3 KEYNOTE-811 study

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Background: Trastuzumab (tras) plus chemotherapy (chemo) is standard-of-care (SOC) 1L therapy for HER2+ metastatic G/GEJ cancer. In two phase 2 studies, tras, chemo, and pembrolizumab (pembro) in combination showed promising efficacy and manageable safety. The ongoing global, randomized, double-blind, placebo-controlled phase 3 KEYNOTE-811 study is assessing whether adding pembro to SOC improves efficacy vs SOC alone for HER2+ metastatic G/GEJ cancer (NCT03615326). Methods: Eligible patients (pts) with previously untreated, unresectable or metastatic HER2+ G/GEJ cancer and ECOG PS 0 or 1 are randomized 1:1 to pembro 200 mg IV Q3W or placebo IV Q3W. All pts receive tras and investigator’s choice of 5-fluorouracil and cisplatin (FP) or capecitabine and oxaliplatin (CAPOX). Treatment is given up to 2 y or until intolerable toxicity or PD. Dual primary end points are PFS per RECIST v1.1 by blinded, independent central review (BICR) and OS. Secondary end points are ORR and DOR per RECIST v1.1 by BICR and safety. Planned enrollment in the global cohort is 692 pts; accrual is almost complete. The protocol-specified first interim analysis (IA1) was to occur when the first 260 pts enrolled had ≥8.5 mo of follow-up and tested whether pembro + SOC significantly improved ORR; the superiority boundary was P = 0.002. The ORR difference was calculated using the Miettinen and Nurminen method stratified by the randomization stratification factors of geographic region, PD-L1 status, and chemo choice. Efficacy is presented for the first 264 pts enrolled. Safety is presented for all treated pts enrolled as of Jun 17, 2020. Results: Among the first 264 pts enrolled, 133 were randomized to pembro + SOC, 131 to placebo + SOC; 0.8% had MSI-H tumors, CAPOX was chosen for 87.1%, and median study follow-up was 12.0 mo (range, 8.5-19.4). Confirmed ORR (95% CI) was 74.4% (66.2-81.6) for pembro + SOC vs 51.9% (43.0-60.7) for placebo + SOC (difference, 22.7 percentage points [95% CI, 11.2-33.7], P = 0.00006); CR rate was 11.3% vs 3.1% and DCR (95% CI) was 96.2% (91.4-98.8) vs 89.3 (82.7-94.0). Median (range) DOR was 10.6 mo (1.1+ to 16.5+) for pembro + SOC vs 9.5 mo (1.4+ to 15.4+) for placebo + SOC; KM estimates of DOR ≥6 mo and ≥9 mo were 70.3% vs 61.4% and 58.4% vs 51.1%. As of data cutoff, 433/434 enrolled pts were treated (217/217 pembro + SOC, 216/217 placebo + SOC). AEs were grade 3-5 in 57.1% of pts with pembro + SOC vs 57.4% with placebo + SOC, led to death in 3.2% vs 4.6%, and led to discontinuation of any drug in 24.4% vs 25.9%. Conclusions: Adding pembro to tras and chemo resulted in a substantial, statistically significant increase in ORR versus trastuzumab and chemo alone as 1L therapy for HER2+ metastatic G/GEJ cancer; responses were durable and safety was manageable. These initial data support pembro plus tras and chemo as a potential new treatment option for this population. Clinical trial information: NCT03615326.

Short-term safety of adjuvant chemoradiotherapy after local resection for patients with high-risk submucosal invasive rectal cancer: a single-arm, multicenter phase II trial

Background

Surgery is recommended for patients with high-risk submucosal invasive rectal cancer (SM-RC) after local resection but affects the quality of life due to stoma placement or impaired anal function; therefore, alternative treatment approaches are needed to prevent local metastasis. The purpose of this study was to assess the short-term safety of adjuvant chemoradiotherapy with capecitabine in patients with high-risk submucosal invasive rectal cancer after local resection.

Methods

This single-arm, multicenter, phase II trial included patients undergoing local resection for high-risk submucosal invasive rectal cancer within 12 weeks prior to enrollment. High-risk submucosal invasive rectal cancer was defined as the presence of at least one of the following factors: poor differentiation of adenocarcinoma, submucosal invasion depth > 1 mm, presence of lymphovascular invasion and grade-2 or -3 tumour budding. Protocol treatment comprised 45.0 Gy radiotherapy with conventional fractionation and 1650 mg/m² capecitabine given twice daily until radiotherapy completion. The primary endpoint was treatment completion rate with an expected rate of 95% and a threshold of 80%.

Results

Twenty-nine patients from six institutions were enrolled between May 2015 and February 2018. One patient was ineligible. Twenty-three patients completed treatment, with a completion rate of 82% (80% confidence interval, 69–91%); the remaining five patients completed treatment with protocol deviation. The median relative dose intensity of capecitabine was 100% (range, 58–100%). Common adverse events included radiation dermatitis (54%), anal pain (39%) and anal mucositis (29%). No grade-3 or higher adverse events were reported.

Conclusions

Adjuvant chemoradiotherapy using capecitabine demonstrated acceptable short-term safety profiles in patients with high-risk submucosal invasive rectal cancer after local resection.

A Low Tumor Mutational Burden and PTEN Mutations Are Predictors of a Negative Response to PD-1 Blockade in MSI-H/dMMR Gastrointestinal Tumors

PURPOSE

This study performed a comprehensive molecular characterization of microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) gastrointestinal (GI) tumors to elucidate predictors of response to PD-1 blockade.

EXPERIMENTAL DESIGN

Forty-five patients with MSI-H/dMMR GI tumors, including gastric cancer, colorectal cancer, cholangiocarcinoma, small intestine cancer, pancreatic cancer, and duodenal cancer, receiving PD-1 blockade were analyzed. We conducted the genomic profiling of GI tumors by whole-exome sequencing or targeted next-generation sequencing. The tumor microenvironment was evaluated by transcriptomic analysis and multiplex fluorescence IHC.

RESULTS

Patients with low tumor mutational burdens (TMBs) had lower objective response rates (ORRs; 0% vs. 48.8%) and a significantly shorter progression-free survival (PFS; 2.3 vs. 15.6 months; HR, 6.20; P = 0.002) than those with high TMBs. Among common gene alterations in GI tumors, only PTEN mutations, which were mutually exclusive with a low TMB, were significantly associated with a lower ORRs than wild-type PTEN (21.4 vs. 54.8%; odds, 4.45; P = 0.045). Compared with wild-type PTEN, PTEN mutations in the phosphatase domain were associated with significantly lower ORRs (12.5 vs. 54.8%; P = 0.049), shorter PFS (2.6 vs. 15.6 months; HR, 5.04; P < 0.001), lower intratumoral CD8⁺ T-cell levels, higher intratumoral CD204⁺ macrophage levels, and PI3K/AKT/mTOR pathway enrichment, whereas PTEN mutations in the C2 domain were not.

CONCLUSIONS

Low TMBs and PTEN mutations, especially mutations in the phosphatase domain associated with an immunosuppressive environment, were mutually exclusive and might be negative predictors of PD-1 blockade responses in patients with MSI-H/dMMR GI tumors.

Efficacy and safety of trifluridine/tipiracil plus bevacizumab and trifluridine/tipiracil or regorafenib monotherapy for chemorefractory metastatic colorectal cancer: a retrospective study

Background:

The C-TASK-FORCE phase I/II and Danish randomized phase II trials reported the promising efficacy of trifluridine/tipiracil (TAS102) plus bevacizumab (BEV) in patients with chemorefractory metastatic colorectal cancer (mCRC). However, there had been no direct comparative phase III trial to compare the efficacy between TAS102 plus BEV and standard therapy with either TAS102 or regorafenib monotherapy.

Methods:

We retrospectively reviewed the medical records of patients with mCRC who received TAS102 plus BEV, TAS102 monotherapy, or regorafenib monotherapy after standard chemotherapies during 2013–2019.

Results:

Patients received TAS102 plus BEV (n = 139), TAS102 monotherapy (n = 153), or regorafenib monotherapy (n = 133). With a median follow-up of 25.3 months, median overall survival (OS) was 11.5 months [95% confidence interval (CI), 9.9–13.9] for TAS102 plus BEV, 8.1 months (95% CI, 6.8–9.2) for TAS102 monotherapy, and 6.8 months (95% CI, 5.7–8.5) for regorafenib monotherapy. The hazard ratios were 0.67 (95% CI, 0.51–0.88) for TAS102 plus BEV versus TAS102 monotherapy and 0.71 (95% CI, 0.54–0.94) for TAS102 plus BEV versus regorafenib monotherapy. Median progression-free survival (PFS) was 4.4 months (95% CI, 3.7–5.4) for TAS102 plus BEV, 2.5 months (95% CI, 1.6–2.3) for TAS102 monotherapy, and 2.1 months (95% CI, 1.6–2.3) for regorafenib monotherapy. The hazard ratios were 0.57 (95% CI, 0.45–0.73) for TAS102 plus BEV versus TAS102 monotherapy and 0.44 (95% CI, 0.34–0.58) for TAS102 plus BEV versus regorafenib monotherapy. On multivariate analysis, TAS102 plus BEV was independently correlated with better OS and PFS. No unexpected adverse events were observed in any group.

Conclusion:

Our study shows that OS and PFS are longer in patients treated with TAS102 plus BEV than in those treated with TAS102 or regorafenib monotherapy.

Safety and activity of trifluridine/tipiracil and ramucirumab in previously treated advanced gastric cancer: an open-label, single-arm, phase 2 trial

BACKGROUND

Findings of preclinical and clinical trials in colorectal cancer have shown promising antitumour effects of the co-formulation trifluridine/tipiracil and VEGF inhibition. We aimed to investigate the safety and activity of trifluridine/tipiracil and ramucirumab for previously treated advanced gastric cancer.

METHODS

We did an open-label, single-arm, two-cohort, phase 2 study at eight centres in Japan. We enrolled patients with unresectable advanced gastric cancer or gastro-oesophageal junction adenocarcinoma. Cohort A included patients previously treated with one line of chemotherapy without ramucirumab and cohort B included patients previously treated with two to four lines of chemotherapy, including ramucirumab. Patients received trifluridine/tipiracil (35 mg/m2) orally twice daily on days 1-5 and days 8-12 of each 28-day treatment cycle, plus intravenous ramucirumab (8 mg/kg) on days 1 and 15. The primary endpoint was the disease control rate, assessed by investigators and defined as the proportion of patients with a confirmed best overall response, according to Response Evaluation Criteria in Solid Tumors version 1.1. This trial is registered on JapicCTI (JapicCTI-194596) and is ongoing but not recruiting.

FINDINGS

Between April 8 and Oct 11, 2019, 64 patients were enrolled and included in the safety and activity analyses, 33 in cohort A and 31 in cohort B. In cohort A, the disease control rate was 85% (95% CI 68-95; 28 of 33 patients) and in cohort B it was 77% (59-90; 24 of 31 patients). Common treatment-related adverse events of grade 3 or worse were neutrophil count decreased (27 [82%] in cohort A and 23 [74%] in cohort B), white blood cell count decreased (eight [24%] and seven [23%]), and platelet count decreased (eight [24%] and four [13%]). Serious treatment-related adverse events were recorded in three patients in cohort A (fatigue and neutrophil count decreased; large intestine perforation; and febrile neutropenia, platelet count decreased, and anaemia). No patients in cohort B had a serious treatment-related adverse event, and no treatment-related deaths were reported in either cohort.

INTERPRETATION

Trifluridine/tipiracil and ramucirumab showed an acceptable safety profile and clinical activity in patients with previously treated advanced gastric cancer regardless of previous ramucirumab exposure.

FUNDING

Taiho Pharmaceutical and Eli Lilly.

Quadruplet regimen with capecitabine, irinotecan, oxaliplatin, and bevacizumab in chemo-naive patients with metastatic colorectal cancer: Results from the safety lead-in of QUATTRO-II study

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Background: FOLFOXIRI plus bevacizumab (BEV) is regarded as the standard of care for selected patients (pts) with metastatic colorectal cancer (mCRC), despite the high incidence of neutropenia and diarrhea. The AXEPT phase III study showed that the modified capecitabine (CAP) + irinotecan (IRI) + BEV (CAPIRI+BEV) [CAP 1600 mg/m2, IRI 200 mg/m2, and BEV 7.5 mg/kg q3wk] treatment was non-inferior to FOLFIRI+BEV, with a lower incidence of hematologic toxicity. We hypothesized that the modified CAPIRI combined with oxaliplatin (OX) and BEV (CAPOXIRI+BEV) would be more feasible than FOLFOXIRI+BEV, without compromising efficacy. Methods: The QUATTRO-II study is an open-label, multicenter, randomized phase II study. In Step 1, the recommended doses (RD) of OX and IRI were investigated as a safety lead-in. In Step 2, pts are randomized to either the RD of CAPOXIRI+BEV or FOLFOXIRI+BEV. In Step 1, four dose levels of CAPOXIRI (fixed dose of CAP 1600 mg/m2 and BEV 7.5 mg/kg plus escalated or de-escalated doses of OX and IRI, q3wk) were investigated in a 3+3 manner. A dose level of ≤ 2/6 of dose-limiting toxicity (DLT) cases was expected as the RD. Results: A total of 9 pts (3 at Level 0, 6 at Level 1) were included in Step 1. The baseline characteristics were as follows: the median age was 62 years; 6 were male; 6 presented with a left-sided tumor; 8 had a performance status of 0; all wild type/ RAS mutant/ BRAF V600E mutant were 8/1/0; and UGT1A1 wild type/*6 single hetero/*28 single hetero were 7/0/2. In Level 0 (IRI 200 mg/m2, OX 100 mg/m2), one grade 4 neutropenia and one grade 3 anorexia were observed, but without DLT. In Level 1 (IRI 200 mg/m2, OX 130 mg/m2), two grade 4 neutropenia and one grade 3 colitis were observed, with 1 DLT (febrile neutropenia) case, fully recovered without G-CSF administration. No treatment-related deaths were observed. Although dose modifications were needed in 4 of the 6 pts, no further safety concerns related to treatment continuity were observed in the 2nd or subsequent cycles. Thus, we determined that the dose administered in Level 1 is the RD for Step 2. According to the preliminary efficacy results at 8 weeks after initiating study treatment, 6 pts achieved a partial response (2 in Level 0 and 4 in Level 1). Conclusions: The RD of CAPOXIRI+BEV was 200 mg/m2 IRI, 130 mg/m2 OX, 1600 mg/m2 CAP, and 7.5mg/kg BEV. The randomized phase II Step (Step 2) of QUATTRO-II is ongoing. Clinical trial information: NCT04097444.

Current status of immunotherapy for advanced gastric cancer

Recently, immune checkpoint inhibitors such as anti-programmed cell death-1 (PD-1) or programmed cell death ligand-1 (PD-L1) monoclonal antibodies have improved the overall survival of various types of cancers including advanced gastric cancer (AGC). Until now, two ant-PD-1 inhibitors were approved for AGC in Japan: nivolumab as third- or later-line treatment for AGC and pembrolizumab for previously treated patients with microsatellite instability-high tumours. However, a limited number of patients achieved clinical benefit, highlighting the importance of the better selection of patients or additional treatment to overcome resistance to PD-1/PD-L1 blockade. This review focused on pivotal clinical trials, biomarkers and novel combination therapy of immune checkpoint inhibitors forAGC.

A multicenter phase II study of TAS-114 in combination with S-1 in patients with pretreated advanced gastric cancer (EPOC1604)

BACKGROUND

This is a phase 2 study aimed at evaluating the efficacy and safety of TAS-114, a novel deoxyuridine triphosphatase inhibitor, combined with S-1 in patients with advanced gastric cancer (AGC).

METHODS

Eligible patients had AGC with measurable lesions, according to the Response Evaluation Criteria in Solid Tumors (RECIST, v1.1), with two or more previous chemotherapy regimens including fluoropyrimidines, platinum agents, and taxanes or irinotecan. The primary endpoint was objective response rate (ORR) according to the RECIST, v1.1. Twenty-nine patients were required according to Simon's optimal two-stage design, with one-sided a = 5% and power = 80%. Threshold and expected ORRs were 5% and 25%. Patients received TAS-114 (400 mg/body, twice a day) and S-1 (30 mg/m², twice a day) for 14 days, followed by 7 days of rest in one 3-week cycle. Protein expression levels of dUTPase and BRCA1 in tumor samples were determined by immunohistochemistry.

RESULTS

Accrual was terminated in June 2018 because meeting the predefined efficacy criteria was considered difficult. ORR and disease control rate were 5.0% [95% confidence interval (CI), 0.1-24.9%] and 70.0% (95% CI, 45.7-88.1%), respectively, for all 20 patients enrolled. Median progression-free survival (PFS) and overall survival were 2.4 months (95% CI, 1.2-3.3 months) and 7.1 months (95% CI, 5.2-9.4 months), respectively. Median PFS in the groups with high and low dUTPase protein expression in the cytoplasm was 2.8 months (95% CI, 1.4-3.9) and 1.6 months (95% CI, 0.6-2.4), respectively [hazard ratio, 0.40 (95% CI, 0.16-1.04), log-rank test two-sided p = 0.047]. Grade 3 or higher treatment-related adverse events included anemia (20%), leucopenia (15%), neutropenia (10%), rash (10%), thrombocytopenia (5%), and lymphopenia (5%) CONCLUSIONS: TAS-114 with S-1 showed only modest antitumor activity with acceptable safety profiles for patients heavily pretreated with AGC.

Retrospective cohort study of nanoparticle albumin-bound paclitaxel plus ramucirumab versus paclitaxel plus ramucirumab as second-line treatment in patients with advanced gastric cancer

BACKGROUND

Nanoparticle albumin-bound paclitaxel (nab-PTX) has shown non-inferiority to paclitaxel (PTX) as second-line therapy for advanced gastric cancer (AGC) with fewer infusion-related reactions. The efficacy and safety of nab-PTX plus ramucirumab (RAM) was reported in a phase II trial; however, there is no randomized trial comparing this regimen with PTX plus RAM in patients with AGC. This retrospective study aimed to investigate the efficacy and safety of nab-PTX plus RAM versus PTX plus RAM in patients with AGC.

METHODS

This study included patients with AGC who received nab-PTX plus RAM from September 2017 to January 2019 or PTX plus RAM from June 2015 to August 2017 as second-line chemotherapy in our hospital.

RESULTS

A total of 113 and 138 patients who received nab-PTX plus RAM and PTX plus RAM, respectively, were analyzed. Median progression-free survival (PFS) was 3.9 months (95% confidence interval [CI]: 3.4-4.3) in the nab-PTX plus RAM group and 3.9 months (95% CI: 3.1-4.7) in the PTX plus RAM group (hazard ratio [HR]: 1.08; 95% CI: 0.83-1.40; P = 0.573). Median overall survival (OS) was 10.9 months (95% CI: 9.3-12.7) in the nab-PTX plus RAM group and 10.3 months (95% CI: 8.5-12.0) in the PTX plus RAM group (hazard ratio: 0.82; 95% CI: 0.61-1.10; P = 0.188). In patients with moderate/massive ascites, favorable outcomes for progression-free survival were observed in the nab-PTX plus RAM group compared with the PTX plus RAM group. Although anemia and fatigue (any grade) were more frequent in the nab-PTX plus RAM group, discontinuation of study treatment was not increased in the nab-PTX plus RAM group. There was no occurrence of hypersensitivity reaction in the nab-PTX plus RAM group, while two patients (1.4%) experienced grade 3 hypersensitivity reactions in the PTX plus RAM group.

CONCLUSIONS

The combination of nab-PTX plus RAM showed a similar efficacy and safety profile to PTX plus RAM as second-line treatment for patients with AGC.

The PD-1 expression balance between effector and regulatory T cells predicts the clinical efficacy of PD-1 blockade therapies

Immune checkpoint blockade has provided a paradigm shift in cancer therapy, but the success of this approach is very variable; therefore, biomarkers predictive of clinical efficacy are urgently required. Here, we show that the frequency of PD-1⁺CD8⁺ T cells relative to that of PD-1⁺ regulatory T (T_reg) cells in the tumor microenvironment can predict the clinical efficacy of programmed cell death protein 1 (PD-1) blockade therapies and is superior to other predictors, including PD ligand 1 (PD-L1) expression or tumor mutational burden. PD-1 expression by CD8⁺ T cells and T_reg cells negatively impacts effector and immunosuppressive functions, respectively. PD-1 blockade induces both recovery of dysfunctional PD-1⁺CD8⁺ T cells and enhanced PD-1⁺ T_reg cell-mediated immunosuppression. A profound reactivation of effector PD-1⁺CD8⁺ T cells rather than PD-1⁺ T_reg cells by PD-1 blockade is necessary for tumor regression. These findings provide a promising predictive biomarker for PD-1 blockade therapies.

Enhanced tumor response to radiotherapy after PD-1 blockade in metastatic gastric cancer

BACKGROUND

Immune checkpoint inhibitors may enhance the efficacy of radiotherapy (RT) in cancer treatment but the effect remains unknown in metastatic gastric cancer (mGC). This study aimed to compare the tumor shrinkage by palliative RT for mGC patients with or without previous exposure to anti-PD-1 therapy.

METHODS

Data of 36 mGC patients who had received palliative RT from April 2013 to May 2019 were analyzed. Primary tumor responses were evaluated through a volumetric measurement-based method using computed tomography (CT) and endoscopic responses were evaluated in patients who underwent endoscopy before and after RT. Tumor microenvironment (TME) immune status was investigated by analyzing tumor-infiltrating lymphocytes by flow cytometry.

RESULTS

Among 36 patients, 18 had previous exposure to anti-PD-1 before RT showing no significant differences in baseline characteristics with the other 18 patients without exposure to anti-PD-1 treatment. Tumor responses were observed in 28% (5/18) and none (0/18) in the anti-PD-1-exposed vs. naïve group, respectively (P = 0.045). Five out of eight patients in the anti-PD-1-exposed group, who underwent endoscopy after RT showed partial response, but none in the anti-PD-1-naïve patients showed response (P = 0.026). Increase in the CD8⁺ T cell/effector regulatory T cell ratio in TILs after anti-PD-1 therapy was noted in three responders to RT, but not in the other three non-responders.

CONCLUSIONS

Prior exposure to anti-PD-1 therapy increases tumor response to RT. Immune profiling suggests that anti-PD-1 therapy may enhance the efficacy of RT by immunoactivation in the TME.

Safety of pembrolizumab in recurrent or advanced gastric cancer expressing PD-L1 refractory to platinum and fluoropyrimidine

INTRODUCTION

Pembrolizumab is a highly selective fully human immunoglobulin 4 monoclonal antibody against programmed death 1 (PD-1). Phase II and III trials have demonstrated that pembrolizumab has antitumor activity in previously treated patients with advanced gastric cancer (AGC).

AREA COVERED

Pembrolizumab was approved by the US Food and Drug Administration in September 2017 as third-line or later treatment of AGC in patients positive for programmed death ligand 1 (PD-L1). In this article, we review the development of pembrolizumab, its pharmacology, and its safety profile as monotherapy in patients with PD-L1 positive previous treated AGC.

EXPERT OPINION

Pembrolizumab has demonstrated durable response and acceptable safety profile in patients receiving two previous courses of systemic chemotherapy. It has become a treatment option in patients with AGC. Currently, there are several ongoing clinical trials of pembrolizumab in combination with cytotoxic chemotherapy or molecular targeting agents AGC.