Exploratory analysis of serum HER2 extracellular domain for HER2 positive gastric cancer treated with SOX plus trastuzumab.

BACKGROUND: The aim of this study was to explore the clinical utility of serum HER2 extracellular domain (sHER2 ECD) using data from a clinical trial evaluating trastuzumab combined S-1 plus oxaliplatin (SOX) in HER2 positive gastric cancer. METHODS: sHER2 ECD were prospectively measured at baseline and subsequent treatment courses. Based on each quantile point of baseline sHER2 ECD levels and its early changes, patients were divided into two groups and compared clinical outcomes. RESULTS: 43 patients were enrolled, and 17 patients (39.5%) were positive for baseline sHER2 ECD. Higher baseline sHER2 ECD levels tended to have lower hazard ratios (HRs). When divided into two groups by baseline sHER2 ECD of 19.1 ng/ml, median progression-free survival (PFS) and overall survival (OS) was longer in the higher group (mPFS: 16.8 vs 8.7 months, p = 0.359. mOS: 35.5 vs 20.6 months, p = 0.270), respectively. After initiation of treatment, sHER2 ECD significantly decreased up until the third cycle. Higher reduction rates of sHER2 ECD within 3 cycles also tended to have lower HRs. When divided into two groups by reduction rate of 42.5%, mPFS and mOS was longer in the higher reduced group (mPFS: 17.2 vs 8.7 months, p = 0.095. mOS: 65.0 vs 17.8 months, p = 0.047), respectively. Furthermore, higher reduction rates could surrogate higher objective response rates (ORR) (ORR: 90% vs 63.2% for 29.5%, p = 0.065. 100% vs 70% for 42.5%, p = 0.085), respectively. CONCLUSIONS: Baseline sHER2 ECD levels and its early decline may be useful biomarkers for SOX plus trastuzumab efficacy in HER2 positive gastric cancer.

Remarkable response as a new indicator for endoscopic evaluation of local efficacy of non-surgical treatments for esophageal cancer.

In Japan, standard of care of the patients with resectable esophageal cancer is neoadjuvant chemotherapy (NAC) followed by esophagectomy. Patients unfitted for surgery or with unresectable locally advanced esophageal cancer are generally indicated with definitive chemoradiotherapy (CRT). Local disease control is undoubtful important for the management of patients with esophageal cancer, therefore endoscopic evaluation of local efficacy after non-surgical treatments must be essential. The significant shrink of primary site after NAC has been reported as a good indicator of pathological good response as well as favorable survival outcome after esophagectomy. And patients who could achieve remarkable shrink to T1 level after CRT had favorable outcomes with salvage surgery and could be good candidates for salvage endoscopic treatments. Based on these data, "Japanese Classification of Esophageal Cancer, 12th edition" defined the new endoscopic criteria "remarkable response (RR)", that means significant volume reduction after treatment, with the subjective endoscopic evaluation are proposed. In addition, the finding of local recurrence (LR) at primary site after achieving a CR was also proposed in the latest edition of Japanese Classification of Esophageal Cancer. The findings of LR are also important for detecting candidates for salvage endoscopic treatments at an early timing during surveillance after CRT. The endoscopic evaluation would encourage us to make concrete decisions for further treatment indications, therefore physicians treating patients with esophageal cancer should be well-acquainted with each finding.

A phase III randomized controlled trial comparing local field with additional prophylactic irradiation in chemoradiotherapy for clinical-T1bN0M0 esophageal cancer: ARMADILLO trial (JCOG1904).

Chemoradiotherapy has been considered as one of the standard treatment options for clinical T1bN0M0 esophageal squamous cell carcinoma with organ preservation. However, 20% of patients develop locoregional recurrence after chemoradiotherapy, which requires salvage treatment including salvage surgery and endoscopic resection. Salvage surgery can cause complications and treatment-related death. Interestingly, chemoradiotherapy with elective nodal irradiation has been reported to reduce the locoregional recurrence of advanced esophageal squamous cell carcinoma. Hence, we are conducting a clinical trial to confirm whether modified chemoradiotherapy with elective nodal irradiation was superiority to that without elective nodal irradiation for the patients with cT1bN0M0 esophageal squamous cell carcinoma. The primary endpoint is major progression-free survival, defined as the time from randomization to the date of death or disease progression, excluding successful curative resection through salvage endoscopic resection. We plan to enroll 280 patients from 54 institutions over 4 years. This trial has been registered in the Japan Registry of Clinical Trials (jRCTs031200067).

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.

Concurrent chemoradiotherapy using proton beams can reduce cardiopulmonary morbidity in esophageal cancer patients: a systematic review.

This systematic review was performed to investigate the superiority of proton beam therapy (PBT) to photon-based radiotherapy (RT) in treating esophageal cancer patients, especially those with poor cardiopulmonary function. The MEDLINE (PubMed) and ICHUSHI (Japana Centra Revuo Medicina) databases were searched from January 2000 to August 2020 for studies evaluating one end point at least as follows; overall survival, progression-free survival, grade ≥ 3 cardiopulmonary toxicities, dose-volume histograms, or lymphopenia or absolute lymphocyte counts (ALCs) in esophageal cancer patients treated with PBT or photon-based RT. Of 286 selected studies, 23 including 1 randomized control study, 2 propensity matched analyses, and 20 cohort studies were eligible for qualitative review. Overall survival and progression-free survival were better after PBT than after photon-based RT, but the difference was significant in only one of seven studies. The rate of grade 3 cardiopulmonary toxicities was lower after PBT (0-13%) than after photon-based RT (7.1-30.3%). Dose-volume histograms revealed better results for PBT than photon-based RT. Three of four reports evaluating the ALC demonstrated a significantly higher ALC after PBT than after photon-based RT. Our review found that PBT resulted in a favorable trend in the survival rate and had an excellent dose distribution, contributing to reduced cardiopulmonary toxicities and a maintained number of lymphocytes. These results warrant novel prospective trials to validate the clinical evidence.

Clinical factors associated with noncurative endoscopic submucosal dissection for the expanded indication of intestinal-type early gastric cancer: Post hoc analysis of a multi-institutional, single-arm, confirmatory trial (JCOG0607).

OBJECTIVES: The multi-institutional, single-arm, confirmatory trial JCOG0607 showed excellent efficacy of endoscopic submucosal dissection (ESD) for the expanded indication of intramucosal intestinal-type early gastric cancer (EGC), which consists of two groups: lesions >2 cm if clinical finding of ulcer (cUL)-negative, or those ≤3 cm if cUL-positive because of the expected low risk of lymph node metastasis. However, the proportion of noncurative resections (NCR) requiring additional surgery was high (32.4%). This post hoc analysis aimed to explore the clinical factors associated with NCR. METHODS: As the expanded indication includes two different groups, we explored the clinical factors associated with NCR separately in cUL-negative (>2 cm) and cUL-positive (≤3 cm) groups using the log-linear model. RESULTS: Two hundred and sixty cUL-negative and 206 cUL-positive EGCs were analyzed. The proportions of NCR were 33.8% in the cUL-negative group and 29.6% in the cUL-positive group. A multivariable analysis demonstrated that moderately differentiated predominant histology diagnosed in pretreatment biopsy (risk ratio [RR] 1.93, 95% confidence interval [CI] 1.34-2.77, P < 0.001) and lesion in the upper stomach (RR 1.75, 95% CI 1.03-2.96, P = 0.038) in the cUL-negative EGCs, and tumor size >2 cm (RR 1.78, 95% CI 1.22-2.58, P = 0.003) and female sex (RR 1.62, 95% CI 1.07-2.44, P = 0.021) in the cUL-positive EGCs were independent factors associated with NCR. CONCLUSIONS: Clinical risk factors associated with NCR were different between cUL-negative and cUL-positive EGCs. To avoid NCR, we need to take these factors into account when deciding expanded indications for ESD.

A Single-Arm Confirmatory Study of Definitive Chemoradiation Therapy Including Salvage Treatment for Clinical Stage II/III Esophageal Squamous Cell Carcinoma (JCOG0909 Study).

PURPOSE: Definitive chemoradiotherapy (CRT) is the standard treatment for patients with locally advanced esophageal cancer (EC) who refuse surgery as the initial therapy. However, poor survival, a high incidence of late toxicities, and severe complications after salvage surgery remain issues to be resolved. This single-arm multicenter trial (JCOG0909) aimed to confirm the efficacy of CRT modifications, including salvage treatment for reducing CRT-related toxicities and facilitating salvage treatment for improved survival. METHODS AND MATERIALS: Patients with clinical stage II/III EC (International Union Against Cancer sixth edition, non-T4) were eligible. Chemotherapy comprised cisplatin (75 mg/m2 on days 1 and 29) and 5-fluorouracil (1000 mg/m2/d on days 1-4 and 29-32). Radiation therapy was administered at a total dose of 50.4 Gy. Good responders received 1 to 2 additional cycles of chemotherapy. For residual or recurrent disease, salvage endoscopic resection or salvage surgery was performed based on specific criteria. The primary endpoint was 3-year overall survival (OS). The calculated sample size was 95 patients, with a 1-sided alpha of 5% and a power of 80%. The expected and threshold 3-year OS were 55% and 42%, respectively. RESULTS: Overall, 96 patients were enrolled, and 94 were included in the efficacy analysis. A complete response was achieved in 55 patients (59%). Salvage endoscopic resection and salvage surgery were performed in 5 (5%) and 25 patients (27%), respectively. R0 resection by salvage surgery was achieved in 19 patients (76%). Five patients (20%) showed grade 3 or 4 early operative complications, and 9 patients (9.6%) showed grade 3 late toxicities during the long-term follow-up. The 3-year OS was 74.2% (90% confidence interval, 65.9%-80.8%). CONCLUSION: The combination of definitive CRT and salvage treatment has lower CRT-related toxicities and yields good OS, thus making it a promising novel treatment option for patients with locally advanced EC.

Association of ERBB2 Copy Number and Gene Coalterations With Trastuzumab Efficacy and Resistance in Human Epidermal Growth Factor Receptor 2-Positive Esophagogastric and Gastric Cancer.

PURPOSE: ERBB2 copy number (CN), measured using next-generation sequencing, is a predictive biomarker for trastuzumab efficacy in human epidermal growth factor receptor 2 (HER2)-positive advanced esophagogastric and gastric cancer (AGC). We aimed to investigate the association of ERBB2 amplification and gene coalterations with response and resistance to trastuzumab-combined chemotherapy. METHODS: The SCRUM-Japan GI-SCREEN was a comprehensive genomic profiling project of GI cancer tissues using Oncomine Cancer Research Panel and Oncomine Comprehensive Assay. From 885 patients with AGC who successfully underwent gene profiling, 74 with ERBB2 amplification (CN ≥ 4.0) and who received first-line trastuzumab-combined chemotherapy were selected, and ERBB2 CN and gene coalterations were assessed. RESULTS: ERBB2 CN did not differ in tumor response to trastuzumab-combined chemotherapy (one-way analysis of variance test, P = .37). Multivariate analysis using the Cox proportional hazard model revealed that ERBB2 CN (continuous log2-converted CN, hazard ratio, 0.76; 95% CI, 0.62 to 0.93; P < .01) and receptor/oncogene amplifications in the HER2 signaling pathway (hazard ratio, 2.5; 95% CI, 1.2 to 5.3; P = .01) were significant predictors for progression-free survival (PFS). ERBB2 variants coexisted in five patients (7%) and were missense mutations. Two patients with low variant allele frequencies (VAFs; 8%, 12%) showed high ERBB2 CN (55, 80) and durable response (≥ 20 months), whereas three patients with high VAFs (66%-90%) showed low ERBB2 CN (8-11) and no response with short PFS (1-10 months). CONCLUSION: ERBB2 CN and gene coamplification in the HER2 signaling pathway were positive and negative predictors of PFS in trastuzumab-treated HER2-positive AGC patients, respectively. HER2-positive AGC patients with a high VAF of ERBB2 showed poor outcomes and may need HER2 tyrosine kinase inhibitors and trastuzumab deruxtecan.

Phase IIb study of pembrolizumab combined with S-1 + oxaliplatin or S-1 + cisplatin as first-line chemotherapy for gastric cancer.

The KEYNOTE-659 study evaluated the efficacy and safety of first-line pembrolizumab plus S-1 and oxaliplatin (SOX) (cohort 1) or S-1 and cisplatin (SP) (cohort 2) for advanced gastric/gastroesophageal junction (G/GEJ) cancer in Japan. Herein, we update the results of cohort 1 and describe the results of cohort 2. This open-label phase IIb study enrolled patients with advanced programmed death-ligand 1 (PD-L1)-positive (combined positive score ≥ 1) human epidermal growth factor receptor 2 (HER2)-negative G/GEJ adenocarcinoma. The primary end-point was the objective response rate (ORR). Other end-points were duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. One hundred patients were enrolled. In cohorts 1 and 2, median follow-up time was 16.9 and 17.1 months; ORR (central review), 72.2% and 80.4%; DOR, 10.6 and 9.5 months; DCR (central review), 96.3% and 97.8%; median PFS (central review), 9.4 and 8.3 months; and median OS, 16.9 and 17.1 months, respectively. Treatment-related adverse events (TRAEs) occurred in all patients, including peripheral sensory neuropathy (94.4%, cohort 1), decreased neutrophil count (82.6%, cohort 2), nausea (59.3% and 60.9% in cohorts 1 and 2), and decreased appetite (61.1% and 60.9% in cohorts 1 and 2). Grade 3 or higher TRAEs were reported by 59.3% (cohort 1) and 78.3% (cohort 2), including decreased platelet count (14.8%, cohort 1) and decreased neutrophil count (52.2%, cohort 2). Pembrolizumab in combination with SOX or SP showed favorable efficacy and safety in patients with PD-L1-positive, HER2-negative G/GEJ adenocarcinoma.

An exploration of trifluridine/tipiracil in combination with irinotecan in patients with pretreated advanced gastric cancer.

BACKGROUND: Trifluridine/tipiracil (FTD/TPI) and irinotecan are treatment options for heavily pretreated patients with advanced gastric cancer, but their efficacies are limited. We investigated the combination of FTD/TPI and irinotecan for such patients. METHODS: Patients who were refractory to fluoropyrimidine, platinum and taxane were enrolled into four cohorts (Level 1A/1B/2A/2B) and treated with irinotecan (100 [Level 1] or 125 [Level 2] mg/m2 on days 1 and 15) and FTD/TPI (35 mg/m2/dose, twice daily, on days 1-5 and 8-12 [Level A] or on days 1-5 and days 15-19 [Level B]) of a 28-day cycle. The primary endpoints were the maximum tolerated dose, dose-limiting toxicities (DLTs), and recommended phase II dose (RP2D); the secondary endpoint was the disease control rate (DCR). RESULTS: Eleven patients were enrolled: 2 at Level 1A, 3 at Level 1B, and 6 at Level 2B. DLTs occurred in 2/2 patients at Level 1A and 2/6 patients at Level 2B. Grade 3 or higher treatment-related adverse events were neutropenia (90.9%), leukopenia (54.5%), anemia (45.5%) and febrile neutropenia (18.2%). One patient at Level 2B achieved a partial response, and the DCR was 72.7% (95% CI, 39.0%-94.0%). The median progression-free survival and overall survival periods were 3.0 months (95% CI, 0.92-not reached) and 10.2 months (95% CI, 2.2-not reached), respectively. CONCLUSION: The RP2D of FTD/TPI combined with irinotecan was determined to be Level 1B; this level was associated with manageable hematologic toxicities and feasible non-hematologic toxicities. Further evaluation of the efficacy of RP2D treatment is necessary.

Effect of chemoradiation on the development of second primary cancers after endoscopic resection of T1 esophageal squamous cell carcinoma.

BACKGROUND: Patients with early esophageal squamous cell carcinoma (ESCC) may develop multiple second primary ESCC and cancers in other organs even after curative endoscopic resection (ER). We investigated whether administration of chemoradiotherapy (CRT) after ER decreases the incidence of second primary cancers. METHODS: We conducted a post hoc analysis of the prospective study. Among the registered 170 patients with clinical submucosal ESCC, 74 underwent ER alone, and 96 underwent ER followed by CRT (ER + CRT) because of pathological results of submucosal or lympho-vascular invasion. We compared the incidence of second primary cancers in esophagus and in other organs between two treatment groups. A univariate analysis was performed to investigate the related risk factors. All patients were followed up with esophagogastroduodenoscopy and CT every 4 months for the first 3 years and every 6 months thereafter. RESULTS: Sixty-one ESCC were detected in 32 patients, and the 3-year cumulative incidence of multiple ESCCs was not different between ER + CRT and ER alone (10.4% vs. 13.5%). Sixty-three second primary cancers in other organs were detected in 45 patients, and there was no difference in the cumulative incidence between two groups. The risk factors for multiple ESCCs were high alcohol consumption and grade C multiple Lugol-voiding lesions. Heavy drinker or patients with grade C multiple Lugol-voiding lesion rather than CRT were at risk for second primary ESCC. CONCLUSION: CRT after ER did not decrease the cumulative incidence of second primary ESCC nor cancers in other organs comparing with ER alone.

Exploration of predictors of benefit from nivolumab monotherapy for patients with pretreated advanced gastric and gastroesophageal junction cancer: post hoc subanalysis from the ATTRACTION-2 study.

BACKGROUND: The phase 3 ATTRACTION-2 study demonstrated that nivolumab monotherapy was superior to placebo for patients with pretreated advanced gastric or gastroesophageal junction cancer, but early progression of tumors in some patients was of concern. METHODS: This post hoc analysis statistically explored the baseline characteristics of the ATTRACTION-2 patients and extracted a single-factor and double-factor combinations associated with early disease progression or early death. In the extracted patient subgroups, the 3-year restricted mean survival times of progression-free survival and overall survival were compared between the nivolumab and placebo arms. RESULTS: Two single factors (age and peritoneal metastasis) were extracted as independent predictors of early progression, but none of them, as a single factor, stratified patients into two subgroups with significant differences in restricted mean survival time. In contrast, two double-factor combinations (serum sodium level and white blood cell count; serum sodium level and neutrophil-lymphocyte ratio) stratifying patients into two subgroups with significant differences in the restricted mean survival time were extracted. Additional exploratory analysis of a triple-factor combination showed that patients aged < 60 years with peritoneal metastasis and low serum sodium levels (approximately 7% of all patients) might receive less benefit from nivolumab, and patients aged ≥ 60 years with no peritoneal metastasis and normal serum sodium levels might receive higher benefit. CONCLUSIONS: A combination of age, peritoneal metastasis, and serum sodium level might predict benefit from nivolumab as salvage therapy in advanced gastric or gastroesophageal junction cancer patients, especially less benefit for patients having all three risk factors.

Cancer-related FGFR2 overexpression and gene amplification in Japanese patients with gastric cancer.

OBJECTIVE: Fibroblast growth factor receptor 2 (FGFR2) has been proposed as a novel druggable target in unresectable gastric cancer. FGFR2 alteration has been reported as associated with poor prognosis even in patients with gastric cancer who received systemic chemotherapy. This study aimed to evaluate the frequency of FGFR2 overexpression and gene amplification in clinical specimens from Japanese patients with recurrent or unresectable gastric cancer. METHODS: This observational study enrolled patients who were histologically or cytologically confirmed with unresectable HER2-negative or unknown gastric or gastroesophageal junctional adenocarcinoma treated with at least one previous chemotherapy. FGFR2 overexpression and gene amplification in the specimens were evaluated by immunohistochemical staining and fluorescence in situ hybridization methods, respectively. RESULTS: In a total of 173 eligible cases, FGFR2 immunohistochemistry score was evaluated as 0, 1, 2, 3 and 4 for 20, 80, 35, 28 and 10 cases, respectively. In 151 evaluable cases with FGFR2 immunohistochemistry scores of 1-4, FGFR2 copy number expressed as fluorescence in situ hybridization signals were detected as <4, ≥4 < 10 and ≥10 copies for 123, 16 and 12 cases, respectively. FGFR2 copy number showed an increasing tendency along with higher FGFR2 immunohistochemistry scores in the corresponding specimen. The response rate and time to treatment failure for first line chemotherapy did not have any obvious relationship to FGFR2 immunohistochemistry score and FGFR2 copy number. CONCLUSIONS: Although FGFR2 overexpression and gene amplification were shown in Japanese patients with unresectable gastric cancer, these alterations did not impact the effects of cytotoxic agents as first line chemotherapy.

Five-year follow-up of nivolumab treatment in Japanese patients with esophageal squamous-cell carcinoma (ATTRACTION-1/ONO-4538-07).

BACKGROUND: In the phase II ATTRACTION-1 study, nivolumab demonstrated a promising antitumor activity among Japanese patients with treatment-refractory advanced esophageal cancer. Here, we report the follow-up results of ATTRACTION-1 of > 5 years. METHODS: We enrolled patients with esophageal cancer that was refractory or intolerant to a standard chemotherapy. Then, nivolumab (3 mg/kg) was administered every 2 weeks. The primary endpoint was a centrally assessed objective response rate. RESULTS: Nivolumab was administered to 65 patients with esophageal squamous-cell carcinoma (ESCC). The centrally assessed objective response rate was 17.2%. The overall survival rates at 3 and 5 years were 10.9% and 6.3%, respectively. Three-year survivors tended to have more reduced target lesions. A total of 63.1% of the patients exhibited treatment-related adverse events, and no new safety signal was observed. Patients with select adverse events tended to have better overall survival than those without. No apparent chronological order was observed between the first response and the onset of select adverse events. CONCLUSION: Our follow-up analysis of more than 5 years is currently the longest and is the first to demonstrate that nivolumab has long-term efficacy and safety for advanced ESCC.

Nivolumab in previously treated advanced gastric cancer (ATTRACTION-2): 3-year update and outcome of treatment beyond progression with nivolumab.

BACKGROUND: ATTRACTION-2 demonstrated that nivolumab improved overall survival (OS) vs placebo in patients with advanced gastric cancer treated with ≥ 2 chemotherapy regimens. However, its long-term efficacy and outcome of treatment beyond progression (TBP) with nivolumab have not been clarified. METHODS: The 3-year follow-up data were collected. A subset analysis was performed to explore the efficacy of TBP by assessing postprogression survival (PPS) after the first event of disease progression. RESULTS: Overall, 493 patients were randomized (2:1) to receive nivolumab (n = 330) or placebo (n = 163). With a median follow-up of 38.5 (range 36.1-47.5) months, OS of the nivolumab group was significantly longer compared to the placebo group (median 5.3 vs 4.1 months; 3-year survival rate, 5.6% vs 1.9%; hazard ratio [HR], 0.62 [95% confidence interval (CI) 0.50-0.75], P < 0.0001). The median OS of responders (n = 32) who achieved complete response or partial response was 26.7 months and the 3-year survival rate was 35.5% in the nivolumab group. Overall, 109 patients in the nivolumab group and 37 patients in the placebo group received TBP. PPS tended to be longer in the nivolumab group vs placebo group (median 5.8 vs 4.5 months; HR [95% CI], 0.69 [0.47-1.01], P = 0.057). In contrast, PPS was similar between both treatment groups in non-TBP patients (median 2.3 vs 2.2 months; HR 0.90, P = 0.42). CONCLUSIONS: Long-term efficacy of nivolumab was confirmed at the 3-year follow-up, and a survival benefit of TBP with nivolumab was suggested. Biomarkers for selecting patients suitable for TBP with nivolumab should be identified in the future.