New therapeutic target molecules for gastric and gastroesophageal junction cancer.

Molecularly targeted therapy for receptor tyrosine kinases (RTKs) has faced limitations in gastric and gastroesophageal junction (G/GEJ) cancer except for HER2-targeted agents, possibly due to inappropriate assay selection that has hindered identification of sensitive patients, in addition to coexisting genetic abnormalities as well as intratumoral heterogeneity. Immunohistochemistry of RTKs has, thus, proved largely unsuccessful for patient selection, and detection of RTK gene amplification as a true oncogenic driver is problematic given the small numbers of affected individuals. FGFR2 amplification is associated with poor prognosis in G/GEJ cancer, and immunohistochemistry of the FGFR2b protein isoform has proved effective for the detection of such FGFR2-dependent tumors. Phase III and Ib/III trials of the FGFR2-targeted antibody bemarituzumab for G/GEJ cancer overexpressing FGFR2b are ongoing based on the promising result in a phase II trial, especially in cases with an FGFR2b positivity of ≥ 10%. Challenges to EGFR- and MET-targeted therapies are being tackled with antibody-drug conjugates (ADCs) and bispecific antibodies. CLDN18.2 is expressed in some G/GEJ tumors but lacks oncogenic driver potential, and the CLDN18.2-targeted antibody zolbetuximab prolonged the survival of CLDN18.2-positive G/GEJ cancer patients in phase III trials. Antibody-drug conjugates and ADCs that target CLDN18.2 are also being pursued for treatment of such patients. Similarly, targeting of nondriver molecules such as DKK1, TROP2, and CEACAM5 is under investigation in early-stage clinical trials. This shift in focus from target molecules with driver potential to markers for precise drug delivery should increase the number of possible targets in G/GEJ cancer.

Anti-integrin αvß6 autoantibodies are a potential biomarker for ulcerative colitis-like immune checkpoint inhibitor-induced colitis.

BACKGROUND: No specific biomarker for immune checkpoint inhibitor (ICI)-induced colitis has been established. Previously, we identified anti-integrin αvß6 autoantibodies in >90% of patients with ulcerative colitis (UC). Given that a subset of ICI-induced colitis is similar to UC, we aimed to clarify the relationship between such autoantibodies and ICI-induced colitis. METHODS: Serum anti-integrin αvß6 autoantibody levels were compared between 26 patients with ICI-induced colitis and 157 controls. Endoscopic images of ICI-induced colitis were centrally reviewed. Characteristics of anti-integrin αvß6 autoantibodies in the ICI-induced colitis patients were compared with those of UC patients. RESULTS: Anti-integrin αvß6 autoantibodies were found in 8/26 (30.8%) patients with ICI-induced colitis and 3/157 (1.9%) controls (P < 0.001). Patients with anti-integrin αvß6 autoantibodies had significantly more typical UC endoscopic features than those without the autoantibodies (P < 0.001). Anti-integrin αvß6 autoantibodies in ICI-induced colitis patients were associated with grade ≥3 colitis (P = 0.001) and steroid resistance (P = 0.005). Anti-integrin αvß6 autoantibody titers correlated with ICI-induced colitis disease activity. Anti-integrin αvß6 autoantibodies of ICI-induced colitis exhibited similar characteristics to those of UC. CONCLUSIONS: Anti-integrin αvß6 autoantibodies may serve as potential biomarkers for the diagnosis, classification, risk management, and monitoring the disease activity, of ICI-induced colitis.

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

PURPOSE: E7389-LF is a liposomal formulation of eribulin that contributes to tumor vascular remodeling. The phase II part of this phase Ib/II study assessed the efficacy/safety of E7389-LF in combination with nivolumab in several disease cohorts; herein, we report results from the small cell lung cancer (SCLC) cohort. EXPERIMENTAL DESIGN: Patients with unresectable/measurable SCLC and disease progression with first-line platinum-based chemotherapy with/without an immune checkpoint inhibitor (ICI) were enrolled to receive E7389-LF 2.1 mg/m2 plus nivolumab 360 mg intravenously every 3 weeks. The primary objective of this part was to assess the objective response rate (ORR). Secondary objectives included assessments of safety and progression-free survival (PFS); exploratory assessments included overall survival (OS) and biomarkers. RESULTS: Thirty-four patients were enrolled. By the data cut-off date (May 31, 2022), 29 (85.3%) had discontinued. Efficacy/biomarker analyses included 33 patients (1 had their diagnosis changed postenrollment); the ORR of E7389-LF plus nivolumab was 24.2% [95% confidence interval (CI): 11.1-42.3], the median PFS was 3.98 months (95% CI: 2.63-4.40), and, at a median follow-up of 10.6 months, the median OS was not reached (95% CI: not estimable). Notably, 27 of 33 patients (81.8%) had received an ICI as their prior first-line therapy. Treatment-related, treatment-emergent adverse events occurred in 97.1% (any grade) and 82.4% (grade ≥3) of enrolled patients; the most common event was neutropenia. Changes in vascular and immune-related plasma markers were observed. CONCLUSIONS: E7389-LF 2.1 mg/m2 in combination with nivolumab 360 mg every 3 weeks showed notable antitumor activity as second-line therapy for SCLC; no new safety signals were observed compared with either agent as monotherapy. SIGNIFICANCE: This phase II part of a phase Ib/II study assessed liposomal eribulin (E7389-LF) plus nivolumab in 34 patients with pretreated SCLC; 8 of 33 evaluable patients (including 6/27 pretreated with ICIs) had objective responses. The combination was tolerable; increases in vasculature-related biomarkers tended to correlate with responses.

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.

Exploratory Biomarker Analysis Using Plasma Angiogenesis-Related Factors and Cell-Free DNA in the TRUSTY Study: A Randomized, Phase II/III Study of Trifluridine/Tipiracil Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer.

BACKGROUND: The TRUSTY study evaluated the efficacy of second-line trifluridine/tipiracil (FTD/TPI) plus bevacizumab in metastatic colorectal cancer (mCRC). OBJECTIVE: This exploratory biomarker analysis of TRUSTY investigated the relationship between baseline plasma concentrations of angiogenesis-related factors and cell-free DNA (cfDNA), and the efficacy of FTD/TPI plus bevacizumab in patients with mCRC. PATIENTS AND METHODS: The disease control rate (DCR) and progression-free survival (PFS) were compared between baseline plasma samples of patients with high and low plasma concentrations (based on the median value) of angiogenesis-related factors. Correlations between cfDNA concentrations and PFS were assessed. RESULTS: Baseline characteristics (n = 65) were as follows: male/female, 35/30; median age, 64 (range 25-84) years; and RAS status wild-type/mutant, 29/36. Patients in the hepatocyte growth factor (HGF)-low and interleukin (IL)-8-low groups had a significantly higher DCR (risk ratio [95% confidence intervals {CIs}]) than patients in the HGF-high (1.83 [1.12-2.98]) and IL-8-high (1.70 [1.02-2.82]) groups. PFS (hazard ratio {HR} [95% CI]) was significantly longer in patients in the HGF-low (0.33 [0.14-0.79]), IL-8-low (0.31 [0.14-0.70]), IL-6-low (0.19 [0.07-0.50]), osteopontin-low (0.39 [0.17-0.88]), thrombospondin-2-low (0.42 [0.18-0.98]), and tissue inhibitor of metalloproteinase-1-low (0.26 [0.10-0.67]) groups versus those having corresponding high plasma concentrations of these angiogenesis-related factors. No correlation was observed between cfDNA concentration and PFS. CONCLUSION: Low baseline plasma concentrations of HGF and IL-8 may predict better DCR and PFS in patients with mCRC receiving FTD/TPI plus bevacizumab, however further studies are warranted. CLINICAL TRIAL REGISTRATION NUMBER: jRCTs031180122.

Phase II study of S-1 plus docetaxel as first-line treatment for older patients with advanced gastric cancer (OGSG 0902).

BACKGROUND: Although there is insufficient evidence for the treatment of older patients with advanced gastric cancer, fluorouracil combined with platinum chemotherapy has been recognized as a standard first-line treatment for such populations in Japan despite the lack of efficacy and toxicity data. METHODS: Patients aged 75 years or older with advanced gastric cancer were enrolled. S-1 plus docetaxel (docetaxel: 40 mg/m2, day 1; S-1: 80 mg/m2, days 1-14; q21 days) was repeated every 3 weeks. The primary endpoint was overall response rate. Secondary endpoints were safety, progression-free survival, time to treatment failure, and overall survival. The sample size was calculated as 30 under the hypothesis of an expected response rate of 40% and a threshold response rate of 20%, at a power of 90% and a two-sided alpha value of 5%. RESULTS: From February 2010 to January 2015, 31 patients were enrolled and assessed for efficacy and toxicity. The response rate was 45.2% (95% CI 27.3%-64.0%; p = 0.001) and it exceeded the expected response rate set at 40%. Median progression-free survival was 5.8 months, the 1-year survival rate was 58.1%, and the median survival time was 16.1 months. The major grade 3/4 adverse events were neutropenia (58%), febrile neutropenia (13%), anemia (10%), anorexia (10%), and fatigue (6%). CONCLUSIONS: These findings indicate that S-1 plus docetaxel as first-line treatment for older patients is feasible and that it has promising efficacy against advanced gastric cancer.

Trifluridine/Tipiracil Plus Bevacizumab for Vulnerable Patients With Pretreated Metastatic Colorectal Cancer: A Retrospective Study (WJOG14520G).

BACKGROUND: Trifluridine/tipiracil (FTD/TPI) plus bevacizumab has shown clinical benefit for metastatic colorectal cancer (mCRC) refractory to standard therapy. However, few data have been available for patients with pretreated mCRC who are intolerant of intensive therapy (vulnerable). METHODS: We performed a multicenter retrospective study (WJOG14520G; TWILIGHT) of FTD/TPI plus bevacizumab for vulnerable patients with pretreated mCRC. Eligibility criteria included previous chemotherapy (although patients treated with all key cytotoxic agents, a fluoropyrimidine, oxaliplatin, and irinotecan, were excluded) and intolerance of full-dose combination therapy with oxaliplatin or irinotecan at the start of FTD/TPI plus bevacizumab. RESULTS: The median age of 93 evaluable patients was 79 years (range, 21-90). Intolerance of intensive therapy was attributable to an older age in 60 (65%) patients, serious concomitant disease in 24 (26%) patients, and a poor performance status in 19 (20%) patients. FTD/TPI plus bevacizumab was administered as second-line treatment in 74 (80%) patients and as third- or fourth-line treatment in 19 (20%) patients. The objective response rate was 4.9% (95% confidence interval [CI], 1.4%-12.2%), and the disease control rate was 67.9% (95% CI, 56.6%-77.8%). With a median follow-up time of 21.6 months, median overall survival and progression-free survival were 18.6 months (95% CI, 12.1-23.2) and 6.3 months (95% CI, 5.0-8.3), respectively. Neutropenia of grade ≥3 developed in 50 (54%) patients, whereas 2 (2%) patients experienced febrile neutropenia, and no treatment-related death was observed. CONCLUSION: Our data show the potential efficacy and acceptable safety profile of FTD/TPI plus bevacizumab for vulnerable patients with pretreated mCRC.

The combination of soluble forms of PD-1 and PD-L1 as a predictive marker of PD-1 blockade in patients with advanced cancers: a multicenter retrospective study.

Introduction: The clinical relevance of soluble forms of programmed cell death-1 (sPD-1) and programmed cell death-ligand 1 (sPD-L1) remains unclear. We here investigated the relation between the efficacy of PD-1 blockade and pretreatment plasma levels of sPD-1 and sPD-L1 across a broad range of cancer types. Methods: We retrospectively analyzed clinical data from 171 patients with advanced solid tumors who received nivolumab or pembrolizumab monotherapy regardless of treatment line. The concentrations of sPD-1 and sPD-L1 were measured with a fully automated immunoassay (HISCL system). Results: The study subjects comprised patients with head and neck cancer (n = 50), urothelial cancer (n = 42), renal cell cancer (n = 37), gastric cancer (n = 20), esophageal cancer (n = 10), malignant pleural mesothelioma (n = 6), or microsatellite instability-high tumors (n = 6). High or low levels of sPD-1 or sPD-L1 were not significantly associated with progression-free survival (PFS) or overall survival (OS) for PD-1 blockade in the entire study population. Comparison of treatment outcomes according to combinations of high or low sPD-1 and sPD-L1 levels, however, revealed that patients with low sPD-1 and high sPD-L1 concentrations had a significantly poorer PFS (HR of 1.79 [95% CI, 1.13-2.83], p = 0.01) and a tendency toward poorer OS (HR of 1.70 [95% CI, 0.99-2.91], p = 0.05) compared with all other patients. Conclusion: Our findings suggest that the combination of low sPD-1 and high sPD-L1 levels is a potential negative biomarker for PD-1 blockade therapy.

Real-World Treatment Sequencing in Vulnerable Patients with Metastatic Colorectal Cancer: A Multicenter Retrospective Study.

BACKGROUND: Data regarding treatment sequence for vulnerable patients with metastatic colorectal cancer (mCRC) in a real-world setting are lacking. OBJECTIVE: We aimed to assess treatment outcomes in second-line or later chemotherapy for vulnerable patients with mCRC in a real-world setting. PATIENTS AND METHODS: Vulnerable patients with mCRC who received less intensive treatment ('vulnerable') regimens, i.e. fluoropyrimidines with or without biologics (FP), reduced-dose doublet regimens with or without biologics (Doublet), and anti-epidermal growth factor receptor monotherapy (Anti-EGFR), as first-line therapy between June 2015 and December 2018 were retrospectively reviewed. RESULTS: A total of 210 patients from 15 hospitals were analyzed. The median age was 78 years (range 28-90), and 44 patients (21%) had an Eastern Cooperative Oncology Group performance status (ECOG PS) score of 2. In the entire population, the median time to treatment failure (TTF) and overall survival (OS) were 7.6 and 21.4 months, respectively. Following the failure of first-line therapy in 195 patients, 74 (38%), 24 (12%), and 13 (7%) patients received vulnerable regimens, full-dose doublet regimens with or without biologics, and other regimens, respectively, whereas 84 (43%) received best supportive care (BSC). In patients receiving vulnerable regimens as second-line therapy, the median TTF and OS were 4.4 and 13.7 months, respectively, while response rate and disease control rate were 18% and 62%, respectively. In 84 patients who received BSC, the median OS was 3.5 months. CONCLUSIONS: Second-line chemotherapy for vulnerable patients with mCRC showed clinically meaningful outcomes; however, few patients received second-line therapy, and survival among patients who received BSC was dismal.

Randomised phase II trial of trifluridine/tipiracil (FTD/TPI) plus ramucirumab (RAM) versus trifluridine/tipiracil for previously treated patients with advanced gastric or esophagogastric junction adenocarcinoma (RETRIEVE study, WJOG15822G).

BACKGROUND: Trifluridine/tipiracil (FTD/TPI) prolongs survival in the third- or later-line treatment for advanced gastric cancer (GC), esophagogastric junction (EGJ) adenocarcinoma, and colorectal cancer. While single-arm phase II trials showed promising outcomes of FTD/TPI plus ramucirumab (RAM) as third- or later-line treatments for advanced GC or EGJ cancer, there have been no clinical trials to directly compare FTD/TPI plus RAM with FTD/TPI monotherapy. Therefore, we have started a randomised phase II trial to evaluate the efficacy and safety of FTD/TPI plus RAM compared with FTD/TPI monotherapy as third- or later-line treatments in patients with advanced GC and EGJ adenocarcinoma. METHODS: This RETREVE trial (WJOG15822G) is a prospective, open-label, randomised, multicentre phase II trial comparing FTD/TPI plus RAM versus FTD/TPI monotherapy in a third- or later-line setting. Eligibility criteria include age of > 20 years; performance status of 0 or 1; unresectable or recurrent gastric or EGJ adenocarcinoma; confirmed HER2 status; refractory or intolerant to fluoropyrimidine, taxane or irinotecan; refractory to RAM (not intolerant); and at least a measurable lesion per RECIST 1.1. FTD/TPI (35 mg/m2 twice daily, evening of day 1 to morning of day 6 and evening of day 8 to morning of day 13) was administered orally every 4 weeks, and RAM (8 mg/kg) was administered intravenously every 2 weeks. The primary endpoint is progression-free survival (PFS), and the secondary endpoints are overall survival, objective response rate, disease control rate, and safety. The expected hazard ratio of PFS is set as 0.7, assuming 4-month PFS rate of 27% in FTD/TPI monotherapy and 40% in FTD/TPI plus RAM. The number of subjects was 110, with a one-sided alpha error of 0.10 and power of 0.70. DISCUSSION: This study will clarify the additional effect of RAM continuation beyond disease progression on FTD/TPI in the third- or later-line setting for patients with advanced GC or EGJ cancer. TRIAL REGISTRATION: jRCTs041220120.

Meta-analysis of three randomized trials of capecitabine plus cisplatin (XP) versus S-1 plus cisplatin (SP) as first-line treatment for advanced gastric cancer.

BACKGROUND: S-1 plus cisplatin (SP) and capecitabine plus cisplatin (XP) are standard first-line regimens for advanced gastric cancer (AGC) worldwide. We conducted a meta-analysis using individual participant data (IPD) to investigate which is more suitable. METHODS: IPD from three randomized trials were collected. In these trials, patients with AGC were randomly allocated to SP (S-1 80-120 mg for 21 days plus cisplatin 60 mg/m2 (q5w)) or XP (capecitabine 2000 mg/m2 for 14 days plus cisplatin 80 mg/m2 (q3w)). RESULTS: In 211 eligible patients, median overall survival (OS) for SP versus XP was 13.5 and 11.7 months (hazard ratio [HR], 0.787; p = 0.114), progression-free survival (PFS) was 6.2 and 5.1 months (HR, 0.767; P = 0.076), and TTF was 5.1 and 4.0 months (HR, 0.611; P = 0.001). The most common grade ≥ 3 adverse events with SP or XP were neutropenia (18% vs. 29%) and anorexia (16% vs.18%). Subgroup analysis demonstrated significant interaction between treatment effect and performance status > 1 (HR, 0.685; P = 0.036), measurable lesion (HR, 0.709; P = 0.049), primary upper third tumor (HR, 0.539; P = 0.040), and differentiated type (HR, 0.549; interaction, 0.236; P = 0.019). For the differentiated type, OS was significantly longer in the SP group (13.2 months) than in the XP group (11.1 months) (HR, 0.549; P = 0.019). For the undifferentiated type, OS was similar in the SP group (14.2 months) and in the XP group (12.4 months) (HR, 0.868; P = 0.476). CONCLUSIONS: SP and XP were both effective and well tolerated. SP might be suitable for the pathological differentiated subtype of AGC. CLINICAL TRIAL REGISTRATION: The HERBIS-2, HERBIS-4A, and XParTS II trials were registered with UMIN-CTR as UMIN000006105, UMIN000006755, and UMIN000006045, respectively.

Role of plasma angiogenesis factors in the efficacy of first-line chemotherapy combined with biologics in RAS wild-type metastatic colorectal cancer: Results from the GI-SCREEN CRC-Ukit study.

BACKGROUND: Several biomarkers have been established for metastatic colorectal cancer (mCRC). We investigated whether plasma angiogenesis factors could predict the efficacy of biologics combined with chemotherapy in first-line (1L) treatment in patients with RAS wild-type mCRC and the dynamics of plasma angiogenesis factors at progression during 1L treatment. METHODS: In this multicenter prospective observational study, serial plasma samples were prospectively collected at pretreatment and progression stages; 17 plasma angiogenesis factors were analyzed using the multiplex assay with Luminex® technology. Interactions between the pretreatment measurements and treatment groups on progression-free survival (PFS) and overall survival (OS) in patients with RAS wild-type were assessed using the propensity-score weighted Cox proportional hazards model. RESULTS: From February 2018 to September 2020, 202 patients were enrolled in the 1L cohort; 133 patients had RAS wild-type (chemotherapy plus bevacizumab [BEV group, n = 33] and plus anti-epidermal growth factor receptor monoclonal antibodies [aEGFR group, n = 100]). A trend of strong interaction on PFS was observed for interleukin-8 (IL-8) (p = 0.0752) and soluble vascular cell adhesion molecule-1 (sVCAM-1) (p = 0.0156). Regarding OS, IL-8 (p = 0.0283), soluble vascular endothelial growth factor-receptor-1 (sVEGFR-1) (p = 0.0777) and sVCAM-1 (p = 0.0011) tended to differentiate the treatment effect. In 112 patients, plasma samples were evaluable for dynamic analysis (57 and 55 from the BEV and aEGFR groups, respectively). In the BEV group, six factors significantly increased during progression, whereas two decreased. In the aEGFR group, three factors significantly increased, and six decreased. CONCLUSION: Pretreatment plasma IL-8 and sVCAM-1 levels could be predictive biomarkers to distinguish BEV and anti-EGFR mAbs when combined with chemotherapy in the 1L treatment of RAS wild-type mCRC. Several plasma angiogenesis factors showed significant change at progression in 1L chemotherapy plus biologics for RAS wild-type mCRC, which are potential biomarkers for selecting an optimal angiogenesis inhibitor in second-line treatment.

Mutational spectrum of TP53 gene correlates with nivolumab treatment efficacy in advanced gastric cancer (TP53MUT study).

BACKGROUND: Although nivolumab has a high efficacy, reliable biomarkers are needed to predict the efficacy. We evaluated the nivolumab efficacy according to the TP53 mutation in advanced gastric cancer patients enrolled in the GI-SCREEN project. METHODS: Sequence data of tumour specimens and clinicopathological information of 913 patients with advanced gastric cancer who were enrolled between April 2015 and March 2017 were obtained from the GI-SCREEN database. The follow-up information of 266 patients treated with nivolumab was also provided. RESULTS: Among 266 patients treated with nivolumab, the objective response rate (ORR) of TP53 wild type (wt) patients (24.6%) was higher than that of TP53 mutant patients (14.8%). Among TP53 mutant patients, the ORR of the frameshift type tended to be higher than the transition and transversion type (23.1%, 13.6%, and 13.0%, respectively). The median progression-free survival (PFS) was statistically longer in TP53 wt patients than in mutant patients (3.3 vs 2.1 months, HR 1.4, 95% CI 1.1-1.9). Among TP53 mutant patients, PFS was statistically longer in the frameshift type than in the transversion type. CONCLUSION: Nivolumab showed better efficacy in TP53 wt patients than in mutant patients. Among TP53 mutant patients, the frameshift type may have efficacy from nivolumab treatment.

Phase I dose-escalation study on irinotecan, cisplatin, and S-1 combination in chemotherapy-naïve patients with HER2-negative advanced gastric cancer (HERBIS-4B, OGSG 1106).

BACKGROUND: The development of triplet regimens for advanced gastric cancer is challenging. The aim of this phase I dose-escalation study was to determine the maximum tolerated dose and recommended dose of the combination of irinotecan, cisplatin, and S-1 in chemotherapy-naïve patients with HER2-negative advanced gastric cancer. METHODS: The 3 + 3 design was adopted. Every 4 weeks, patients received an escalating dose of intravenous irinotecan (100-150 mg/m2) on day 1 and fixed doses of intravenous cisplatin (60 mg/m2) on day 1 and oral S-1 (80 mg/m2) on days 1 to 14. RESULTS: Twelve patients were enrolled in two dose level cohorts. In the level 1 cohort (irinotecan 100 mg/m2, cisplatin 60 mg/m2, and S-1 80 mg/m2), dose-limiting toxicity including grade 4 neutropenia and febrile neutropenia occurred in one of six patients, whereas in the level 2 cohort (irinotecan 125 mg/m2, cisplatin 60 mg/m2, and S-1 80 mg/m2), dose-limiting toxicities including grade 4 neutropenia developed in two of six patients. Thus, the level 1 and 2 doses were determined to be the recommended and maximum tolerated doses, respectively. Common grade 3 or higher adverse events were neutropenia (75%; n = 9), anemia (25%; n = 3), anorexia (8%; n = 1), and febrile neutropenia (17%; n = 2). Irinotecan, cisplatin, and S-1 combination therapy achieved an overall response rate of 67% with a median progression-free survival and overall survival of 19.3 and 22.4 months, respectively. CONCLUSIONS: The potential treatment efficacy of this triplet regimen in HER2-negative advanced gastric cancer warrants further evaluation, especially in patients requiring intensive chemotherapy.

Survival impact of microsatellite instability in stage II gastric cancer patients who received S-1 adjuvant monotherapy after curative resection.

Adjuvant S-1 monotherapy is the standard of care for stage II gastric cancer (GC) after curative resection in Japan, but its efficacy for microsatellite instability-high (MSI-H) tumors has remained unknown. Among a multi-institutional cohort of patients with stage II GC who underwent R0 resection followed by S-1 adjuvant chemotherapy between February 2008 and December 2018, we assessed MSI status with an MSI-IVD Kit (Falco). MSI status was assessable for 184 (88.5%) of the 208 enrolled patients, with MSI-H being identified in 24 (13.0%) individuals. Although neither relapse-free survival (RFS) (hazard ratio [HR] = 1.00, p = 0.997) nor overall survival (OS) (HR = 0.66, p = 0.488) differed between MSI-H versus microsatellite-stable (MSS) patients, MSI-H patients showed a nonsignificant but better RFS (HR = 0.34, p = 0.064) and OS (HR = 0.22, p = 0.057) than did MSS patients after adjustment for background characteristics by propensity score (PS) analysis. Gene expression analysis in the PS-matched cohort suggested that recurrence was associated with the immunosuppressive microenvironment in MSI-H tumors but with expression of cancer/testis antigen genes in MSS tumors. Our data reveal a better adjusted survival for MSI-H versus MSS stage II GC treated with S-1 adjuvant therapy, and they suggest that mechanisms of recurrence differ between MSI-H and MSS tumors.

Final results of DESTINY-CRC01 investigating trastuzumab deruxtecan in patients with HER2-expressing metastatic colorectal cancer.

DESTINY-CRC01 (NCT03384940) was a multicenter, open-label, phase 2 trial assessing the efficacy and safety of trastuzumab deruxtecan (T-DXd) in patients with HER2-expressing metastatic colorectal cancer (mCRC) that progressed after ≥2 prior regimens; results of the primary analysis are published. Patients received T-DXd 6.4 mg/kg every 3 weeks and were assigned to either: cohort A (HER2-positive, immunohistochemistry [IHC] 3+ or IHC 2+/in situ hybridization [ISH]+), cohort B (IHC 2+/ISH-), or cohort C (IHC 1+). Primary endpoint was objective response rate (ORR) by independent central review in cohort A. Secondary endpoints included ORR (cohorts B and C), duration of response, disease control rate, progression-free survival, overall survival, pharmacokinetics, and safety of T-DXd. 86 patients were enrolled (53 in cohort A, 15 in cohort B, and 18 in cohort C). Results of the primary analysis are published, reporting an ORR of 45.3% in cohort A. Here, we report the final results. No responses occurred in cohorts B or C. Median progression-free survival, overall survival, and duration of response were 6.9, 15.5, and 7.0 months, respectively. Overall serum exposure (cycle 1) of T-DXd, total anti-HER2 antibody, and DXd were similar regardless of HER2 status. Most common grade ≥3 treatment-emergent adverse events were decreased neutrophil count and anemia. Adjudicated drug-related interstitial lung disease/pneumonitis occurred in 8 patients (9.3%). These findings support the continued exploration of T-DXd in HER2-positive mCRC.

Effect of the number of cycles of docetaxel + S-1 therapy on long-term survival in adjuvant chemotherapy for stage III gastric cancer. A pooled analysis of the OGSG0604 and OGSG1002 trials.

BACKGROUND: S-1 plus docetaxel (DS) therapy followed by S-1 is the standard of care in Japan in postoperative adjuvant chemotherapy for stage III gastric cancer, but long-term survival and the number of DS cycles required are unclear. The purpose of this study was to investigate the impact of the number of cycles of DS therapy on the 5-year survival in stage III gastric cancer in a pooled analysis of two phase II trials (OGSG0604 and OGSG1002). PATIENTS AND METHODS: Patients with histologically confirmed stage III gastric cancer who underwent gastrectomy with D2 lymphadenectomy were enrolled in this pooled analysis. They received DS therapy for four or eight cycles, followed by S-1 until 1 year postgastrectomy. The 5-year overall survival (OS) and the 5-year disease free survival (DFS) by the landmark analysis was evaluated. RESULTS: In total, 113 patients from the OGSG0604 and OGSG1002 trials were enrolled in this study. The landmark analysis showed a 5-year OS that was better with four to eight cycles of DS therapy than with one to three cycles of DS therapy, with the best 5-year OS of 77.4% (95% confidence interval, 66.5-90.1%) for eight cycles. The 5-year DFS was approximately 66% when four or eight cycles of DS therapy were given. CONCLUSION: Although eight cycles of DS therapy may prolong prognosis, the present study did not provide a clear conclusion as to how many DS therapy cycles are needed to improve prognosis after D2 gastrectomy for stage III gastric cancer. TRIAL REGISTRATION: Registration number: UMIN00000714 and UMIN000004440.

Efficacy and safety of maintenance therapy with pamiparib versus placebo for advanced gastric cancer responding to first-line platinum-based chemotherapy: Phase 2 study results.

BACKGROUND: Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) are approved for the treatment of various solid tumors. In gastric cancer, genes commonly harbor mutations in the homologous recombination DNA repair pathway, potentially increasing sensitivity to PARPi. Pamiparib (BGB-290) is a small molecule inhibitor of PARP1 and PARP2. METHODS: The PARALLEL-303 study (NCT03427814) investigated the efficacy and safety of pamiparib 60 mg orally (PO) twice daily (BID) versus placebo PO BID as maintenance therapy in patients with inoperable locally advanced or metastatic gastric cancer that responded to platinum-based first-line chemotherapy. The primary endpoint of this double-blind, randomized, global phase 2 study was progression-free survival (PFS) (RECIST version 1.1; per investigator assessment). Secondary endpoints included overall survival (OS) and safety. RESULTS: In total, 136 patients were randomized 1:1 to receive pamiparib (n = 71) or placebo (n = 65). Median PFS was numerically longer with pamiparib versus placebo but did not reach statistical significance (3.7 months [95% confidence interval (CI): 1.9, 5.3] vs. 2.1 months [95% CI: 1.9, 3.8]; hazard ratio 0.8 [95% CI: 0.5, 1.2]; p = 0.1428). Median OS was 10.2 months (95% CI: 8.7, 16.3) in the pamiparib arm versus 12.0 months (95% CI: 8.2, not estimable) in the placebo arm. Overall, 8 patients (11.3%) in the pamiparib arm and 2 patients (3.1%) in the placebo arm experienced ≥1 TEAE leading to treatment discontinuation. CONCLUSIONS: Maintenance pamiparib did not meet statistical significance for superiority versus placebo for PFS, but was well tolerated with few treatment discontinuations; no unexpected safety signals were identified.

A Phase II Trial of Trifluridine/Tipiracil in Combination with Cetuximab Rechallenge in Patients with RAS Wild-Type mCRC Refractory to Prior Anti-EGFR Antibodies: WJOG8916G Trial.

BACKGROUND: Trifluridine/tipiracil (FTD/TPI) improved the overall survival in patients with metastatic colorectal cancer (mCRC) who had previously received standard chemotherapies; however, the clinical outcomes remain poor. OBJECTIVE: A multicenter phase II study aimed to assess the efficacy and safety of FTD/TPI plus cetuximab rechallenge. PATIENTS AND METHODS: Patients with histologically confirmed RAS wild-type mCRC refractory to prior anti-epidermal growth factor receptor (anti-EGFR) antibody were enrolled and treated with FTD/TPI (35 mg/m2 twice daily on days 1-5 and 8-12) plus cetuximab (initially 400 mg/m2, followed by weekly 250 mg/m2) every 4 weeks. The primary endpoint was disease control rate (DCR), expecting a target DCR of 65% and null hypothesis of 45% with 90% power and 10% one-sided alpha error. Gene alterations of RAS, BRAF, EGFR, PIK3CA, ERBB2, and MET in pre-treatment circulating tumor DNA were evaluated using the Guardant360 assay. RESULTS: A total of 56 patients (median age 60 years; left-sided tumors 91%; objective partial or complete response during the prior anti-EGFR therapy 61%) were enrolled. The DCR was 54% (80% confidence interval [CI] 44-63; P = 0.12), with a partial response rate of 3.6%. Median progression-free survival (PFS) was 2.4 months (95% CI 2.1-3.7). In the circulating tumor DNA analysis, patients without any alterations of the six genes (n = 20) demonstrated higher DCR (75% vs. 39%; P = 0.02) and longer PFS (median 4.7 vs. 2.1 months; P < 0.01) than those with any gene alterations (n = 33). The most common grade 3/4 hematologic adverse event was neutropenia (55%). No treatment-related deaths occurred. CONCLUSIONS: FTD/TPI plus cetuximab rechallenge did not demonstrate clinically meaningful efficacy in all mCRC patients, but might be beneficial for the molecularly selected population.