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Human epidermal growth factor receptor 2 ( HER2 , also known as ERBB2 ) amplification or overexpression occurs in approximately 20% of advanced gastric or gastro-oesophageal junction adenocarcinomas 1 – 3 . More than a decade ago, combination therapy with the anti-HER2 antibody trastuzumab and chemotherapy became the standard first-line treatment for patients with these types of tumours 4 . Although adding the anti-programmed death 1 (PD-1) antibody pembrolizumab to chemotherapy does not significantly improve efficacy in advanced HER2-negative gastric cancer 5 , there are preclinical 6 – 19 and clinical 20 , 21 rationales for adding pembrolizumab in HER2-positive disease. Here we describe results of the protocol-specified first interim analysis of the randomized, double-blind, placebo-controlled phase III KEYNOTE-811 study of pembrolizumab plus trastuzumab and chemotherapy for unresectable or metastatic, HER2-positive gastric or gastro-oesophageal junction adenocarcinoma 22 ( https://clinicaltrials.gov , NCT03615326). We show that adding pembrolizumab to trastuzumab and chemotherapy markedly reduces tumour size, induces complete responses in some participants, and significantly improves objective response rate. Interim analysis of a phase III clinical trial of HER2-positive gastric adenocarinoma shows pembrolizumab plus trastuzumab and chemotherapy improves response rates compared with trastuzumab and chemotherapy alone.

Initial results of the ChemoRadiotherapy for Oesophageal cancer followed by Surgery Study (CROSS) comparing neoadjuvant chemoradiotherapy plus surgery versus surgery alone in patients with squamous cell carcinoma and adenocarcinoma of the oesophagus or oesophagogastric junction showed a significant increase in 5-year overall survival in favour of the neoadjuvant chemoradiotherapy plus surgery group after a median of 45 months' follow-up. In this Article, we report the long-term results after a minimum follow-up of 5 years. Patients with clinically resectable, locally advanced cancer of the oesophagus or oesophagogastric junction (clinical stage T1N1M0 or T2–3N0–1M0, according to the TNM cancer staging system, sixth edition) were randomly assigned in a 1:1 ratio with permuted blocks of four or six to receive either weekly administration of five cycles of neoadjuvant chemoradiotherapy (intravenous carboplatin [AUC 2 mg/mL per min] and intravenous paclitaxel [50 mg/m2 of body-surface area] for 23 days) with concurrent radiotherapy (41·4 Gy, given in 23 fractions of 1·8 Gy on 5 days per week) followed by surgery, or surgery alone. The primary endpoint was overall survival, analysed by intention-to-treat. No adverse event data were collected beyond those noted in the initial report of the trial. This trial is registered with the Netherlands Trial Register, number NTR487, and has been completed. Between March 30, 2004, and Dec 2, 2008, 368 patients from eight participating centres (five academic centres and three large non-academic teaching hospitals) in the Netherlands were enrolled into this study and randomly assigned to the two treatment groups: 180 to surgery plus neoadjuvant chemoradiotherapy and 188 to surgery alone. Two patients in the neoadjuvant chemoradiotherapy group withdrew consent, so a total of 366 patients were analysed (178 in the neoadjuvant chemoradiotherapy plus surgery group and 188 in the surgery alone group). Of 171 patients who received any neoadjuvant chemoradiotherapy in this group, 162 (95%) were able to complete the entire neoadjuvant chemoradiotherapy regimen. After a median follow-up for surviving patients of 84·1 months (range 61·1–116·8, IQR 70·7–96·6), median overall survival was 48·6 months (95% CI 32·1–65·1) in the neoadjuvant chemoradiotherapy plus surgery group and 24·0 months (14·2–33·7) in the surgery alone group (HR 0·68 [95% CI 0·53–0·88]; log-rank p=0·003). Median overall survival for patients with squamous cell carcinomas was 81·6 months (95% CI 47·2–116·0) in the neoadjuvant chemoradiotherapy plus surgery group and 21·1 months (15·4–26·7) in the surgery alone group (HR 0·48 [95% CI 0·28–0·83]; log-rank p=0·008); for patients with adenocarcinomas, it was 43·2 months (24·9–61·4) in the neoadjuvant chemoradiotherapy plus surgery group and 27·1 months (13·0–41·2) in the surgery alone group (HR 0·73 [95% CI 0·55–0·98]; log-rank p=0·038). Long-term follow-up confirms the overall survival benefits for neoadjuvant chemoradiotherapy when added to surgery in patients with resectable oesophageal or oesophagogastric junctional cancer. This improvement is clinically relevant for both squamous cell carcinoma and adenocarcinoma subtypes. Therefore, neoadjuvant chemoradiotherapy according to the CROSS trial followed by surgical resection should be regarded as a standard of care for patients with resectable locally advanced oesophageal or oesophagogastric junctional cancer. Dutch Cancer Foundation (KWF Kankerbestrijding).

Adding pertuzumab to trastuzumab and chemotherapy improves survival in HER2-positive early breast cancer and metastatic breast cancer. We assessed the efficacy and safety of pertuzumab versus placebo in combination with trastuzumab and chemotherapy in first-line HER2-positive metastatic gastric or gastro-oesophageal junction cancer. JACOB was a double-blind, placebo-controlled, randomised, multicentre, phase 3 trial in patients aged 18 years or older with HER2-positive metastatic gastric or gastro-oesophageal junction cancer. Eligible patients had measurable or evaluable non-measurable disease at baseline, Eastern Cooperative Oncology Group performance status of 0 or 1, and baseline left ventricular ejection fraction of 55% or more. Patients at 197 oncology clinics (in 30 countries) were randomly assigned (1:1) to receive either pertuzumab (840 mg intravenously) or placebo every 3 weeks, with trastuzumab (8 mg/kg loading dose, then 6 mg/kg every 3 weeks intravenously), plus chemotherapy (cisplatin 80 mg/m2 every 3 weeks intravenously, oral capecitabine 1000 mg/m2 twice a day [2000 mg/m2 every 24 h] for 28 doses every 3 weeks, or 5-fluorouracil 800 mg/m2 every 24 h intravenously [120 h continuous infusion] every 3 weeks). Randomisation was by a central permuted block randomisation scheme (block size of 4) with an interactive voice or web response system, stratified by geographical region, previous gastrectomy, and HER2 positivity. The primary endpoint was overall survival in the intention-to-treat population. This trial is registered with Clinicaltrials.gov, number NCT01774786 (ongoing, but closed to enrolment). Between June 10, 2013, and Jan 12, 2016, of 3287 patients assessed, 780 eligible patients were randomly assigned to receive either pertuzumab plus trastuzumab and chemotherapy (pertuzumab group, n=388) or placebo plus trastuzumab and chemotherapy (control group, n=392). Median duration of follow-up was 24·4 months (95% CI 22·3–26·1) in the pertuzumab group and 25·0 months (22·3–28·9) in the control group. After 242 deaths in the pertuzumab group and 262 deaths in the control group (the study was not stopped at this point), overall survival was not significantly different between treatment groups (median overall survival 17·5 months [95% CI 16·2–19·3] in the pertuzumab group and 14·2 months [12·9–15·5] in the control group; hazard ratio 0·84 [95% CI 0·71–1·00]; p=0·057). Serious adverse events occurred in 175 (45%) of 385 patients in the pertuzumab group and 152 (39%) of 388 patients in the control group. Diarrhoea was the most common serious adverse event in both groups (17 [4%] patients in the pertuzumab group vs 20 [5%] patients in the control group). The most common grade 3–5 adverse events were neutropenia (116 [30%] patients in the pertuzumab group vs 108 [28%] patients in the control group), anaemia (56 [15%] vs 65 [17%]), and diarrhoea (51 [13%] vs 25 [6%]). Treatment-related deaths occurred in seven (2%) patients in the control group; no treatment-related deaths occurred in the pertuzumab group. Adding pertuzumab to trastuzumab and chemotherapy did not significantly improve overall survival in patients with HER2-positive metastatic gastric or gastro-oesophageal junction cancer compared with placebo. Further studies are needed to identify improved first-line treatment options in these types of cancer and to identify patients with HER2-driven tumours who might benefit from dual HER2-targeted therapy. F. Hoffmann-La Roche Ltd.

The multicentre RESOLVE trial examined the efficacy of perioperative and postoperative S-1 and oxaliplatin (SOX) compared with postoperative capecitabine and oxaliplatin (CapOx) in gastric or gastro-oesophageal junction cancer. Initial analyses did not encompass overall survival owing to the immature data. This paper provides an updated analysis of the survival data from the RESOLVE trial. In this randomised, open-label, phase 3 study, participants aged 18 years or older with cT4a N+ M0 or cT4b Nany M0 gastric or gastro-oesophageal junction adenocarcinoma who were feasible for D2 lymphadenectomy and had a Karnofsky performance score of 70 or higher were enrolled. Participants were randomly assigned in a 1:1:1 ratio via an interactive web response system, stratified by participating centres and Lauren classification, to receive adjuvant CapOx (eight postoperative cycles of intravenous oxaliplatin 130 mg/m2 on day 1 of each 21-day cycle plus oral capecitabine 1000 mg/m2 twice a day on days 1–14, adjuvant SOX (eight postoperative cycles of intravenous oxaliplatin 130 mg/m2 on day 1 of each 21-day cycle plus oral S-1 40–60 mg twice a day on days 1–14), or perioperative SOX (intravenous oxaliplatin 130 mg/m2 on day 1 of each 21-day cycle plus oral S-1 40–60 mg twice a day for three cycles preoperatively and five cycles postoperatively followed by three cycles of S-1 monotherapy. The primary endpoint, assessed in the modified intention-to-treat population, was 3-year disease-free survival to assess the superiority of perioperative-SOX compared with adjuvant-CapOx and the non-inferiority (hazard ratio [HR] non-inferiority margin of 1·33) of adjuvant-SOX compared with adjuvant-CapOx, and has been reported previously. This final report focuses on the secondary endpoint of 5-year overall survival, also assessed in the modified intention-to-treat population. Other secondary endpoints—R0 resection rate and safety—were not updated in this analysis. The study is registered at ClinicalTrials.gov, NCT01534546, and is complete. Between Aug 15, 2012, and Feb 28, 2017, 1094 patients were enrolled and randomly assigned, of whom 1022 participants were included in the modified intention-to-treat population: 345 (259 male, 86 female) in the adjuvant-CapOx group, 340 (238 male, 102 female) in the adjuvant-SOX group, and 337 (271 male, 66 female) in the perioperative-SOX group. As of April 7, 2022, the median duration of follow-up was 62·8 months (IQR 52·0–75·1). The 5-year overall survival rates were 52·1% (95% CI 46·3–57·5) for the adjuvant-CapOx group, 61·0% (55·3–66·2) for the adjuvant-SOX group, and 60·0% (54·2–65·3), for the perioperative-SOX group. Overall survival was significantly prolonged with perioperative-SOX (HR 0·79; 95% CI 0·62–1·00, p=0·049) and adjuvant-SOX (HR 0·77, 0·61–0·98, p=0·033), compared with adjuvant-CapOx. Consistent with the initial analysis of 3-year disease-free survival, the extended 5-year overall survival analysis from the RESOLVE trial confirmed the survival advantage of perioperative-SOX and adjuvant-SOX compared with the standard adjuvant-CapOx regimen. The SOX regimen, given perioperatively or as an adjuvant treatment, emerges as a potential standard treatment modality for locally advanced gastric or gastro-oesophageal junction cancer management in Asian patients. The National Key Research and Development Program of China, the National Natural Science Foundation of China, the Capital's Funds for Health Improvement and Research, the Beijing Natural Science Foundation, National Natural Science Foundation of China, the Beijing Natural Science Foundation, Taiho, Hengrui Pharmaceutical and Sanofi-Aventis. For the Chinese translation of the abstract see Supplementary Materials section.

VEGF and VEGF receptor 2 (VEGFR-2)-mediated signalling and angiogenesis can contribute to the pathogenesis and progression of gastric cancer. We aimed to assess whether the addition of ramucirumab, a VEGFR-2 antagonist monoclonal antibody, to first-line chemotherapy improves outcomes in patients with metastatic gastric or gastro-oesophageal junction adenocarcinoma. For this double-blind, randomised, placebo-controlled, phase 3 trial done at 126 centres in 20 countries, we recruited patients aged 18 years or older with metastatic, HER2-negative gastric or gastro-oesophageal junction adenocarcinoma, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and adequate organ function. Eligible patients were randomly assigned (1:1) with an interactive web response system to receive cisplatin (80 mg/m2, on the first day) plus capecitabine (1000 mg/m2, twice daily for 14 days), every 21 days, and either ramucirumab (8 mg/kg) or placebo on days 1 and 8, every 21 days. 5-Fluorouracil (800 mg/m2 intravenous infusion on days 1–5) was permitted in patients unable to take capecitabine. The primary endpoint was investigator-assessed progression-free survival, analysed by intention to treat in the first 508 patients. We did a sensitivity analysis of the primary endpoint, including a central review of CT scans. Overall survival was a key secondary endpoint. This study is registered with ClinicalTrials.gov, number NCT02314117. Between Jan 28, 2015, and Sept 16, 2016, 645 patients were randomly assigned to receive ramucirumab plus fluoropyrimidine and cisplatin (n=326) or placebo plus fluoropyrimidine and cisplatin (n=319). Investigator-assessed progression-free survival was significantly longer in the ramucirumab group than the placebo group (hazard ratio [HR] 0·753, 95% CI 0·607–0·935, p=0·0106; median progression-free survival 5·7 months [5·5–6·5] vs 5·4 months [4·5–5·7]). A sensitivity analysis based on central independent review of the radiological images did not corroborate the investigator-assessed difference in progression-free survival (HR 0·961, 95% CI 0·768–1·203, p=0·74). There was no difference in overall survival between groups (0·962, 0·801–1·156, p=0·6757; median overall survival 11·2 months [9·9–11·9] in the ramucirumab group vs 10·7 months [9·5–11·9] in the placebo group). The most common grade 3–4 adverse events were neutropenia (85 [26%] of 323 patients in the ramucirumab group vs 85 [27%] of 315 in the placebo group), anaemia (39 [12%] vs 44 [14%]), and hypertension (32 [10%] vs 5 [2%]). The incidence of any-grade serious adverse events was 160 (50%) of 323 patients in the ramucirumab group and 149 (47%) of 315 patients in the placebo group. The most common serious adverse events were vomiting (14 [4%] in the ramucirumab group vs 21 [7%] in the placebo group) and diarrhoea (11 [3%] vs 19 [6%]). There were seven deaths in each group, either during study treatment or within 30 days of discontinuing study treatment, which were the result of treatment-related adverse events. In the ramucirumab group, these adverse events were acute kidney injury, cardiac arrest, gastric haemorrhage, peritonitis, pneumothorax, septic shock, and sudden death (n=1 of each). In the placebo group, these adverse events were cerebrovascular accident (n=1), multiple organ dysfunction syndrome (n=2), pulmonary embolism (n=2), sepsis (n=1), and small intestine perforation (n=1). Although the primary analysis for progression-free survival was statistically significant, this outcome was not confirmed in a sensitivity analysis of progression-free survival by central independent review, and did not improve overall survival. Therefore, the addition of ramucirumab to cisplatin plus fluoropyrimidine chemotherapy is not recommended as first-line treatment for this patient population. Eli Lilly and Company.

Programmed cell death protein-1 (PD-1) inhibitors plus chemotherapy have been the standard of care in the first-line treatment of advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma; however, the survival benefits are modest in patients with low programmed death ligand 1 (PD-L1) expression. Here we investigated the efficacy and safety of cadonilimab (PD-1/cytotoxic T lymphocyte antigen-4 (CTLA-4) bispecific antibody) plus chemotherapy as first-line treatment in G/GEJ adenocarcinoma. The prespecified interim analysis is reported here. This was a randomized, double-blind, placebo-controlled phase 3 study. Eligible patients were adults with untreated, unresectable, locally advanced or metastatic G/GEJ adenocarcinoma. Patients were randomized 1:1 to receive cadonilimab (10 mg kg −1 every 3 weeks) or placebo plus chemotherapy (every 3 weeks). The primary endpoint was overall survival (OS) in the intention-to-treat population (one-sided significance level, P  = 0.025). Secondary endpoints included OS in patients with a PD-L1 combined positive score ≥5, progression-free survival, objective response rate, duration of response and safety. As of 18 August 2023, 610 patients from 75 study centers were randomized to cadonilimab ( n  = 305) or placebo ( n  = 305). With a median follow-up of 18.7 months, the cadonilimab group had a significantly longer median OS (14.1 versus 11.1 months; hazard ratio (HR) 0.66; 95% confidence interval (CI) 0.54–0.81; P  < 0.001) than the placebo group. The primary endpoint was met. The median progression-free survival was 7.0 months versus 5.3 months (HR 0.53, 95% CI 0.44–0.65). The median OS in patients with a PD-L1 combined positive score ≥5 was 15.3 months versus 10.9 months (HR 0.58, 95% CI 0.41–0.82). The objective response rate was 65.2% versus 48.9% with a median duration of response of 8.8 months versus 4.4 months. Grade ≥3 treatment-related adverse events occurred in 65.9% of the cadonilimab group and 53.6% of the placebo group, and the most common were decreased platelet count, decreased neutrophil count and anemia. Most of the immune-related adverse events were grade 1 or 2. No new safety signals were observed. Cadonilimab plus chemotherapy significantly improved OS with a manageable safety profile in patients with advanced G/GEJ adenocarcinoma. ClinicalTrials.gov registration: NCT05008783 . In a prespecified interim analysis of the randomized, double-blind phase 3 COMPASSION-15 trial, patients with advanced HER2-negative gastric/GEJ cancer treated with the anti-PD-L1/CTLA-4 bispecific Ab cadonilimab plus chemotherapy showed significantly improved overall survival compared with patients treated with placebo plus chemotherapy as first-line treatment.

BackgroundNivolumab showed improvement in overall survival (OS) in ATTRACTION-2, the first phase 3 study in patients with gastric/gastroesophageal junction (G/GEJ) cancer treated with ≥ 2 chemotherapy regimens. The 2-year follow-up results of ATTRACTION-2 are presented herein.MethodsATTRACTION-2 was a randomized, double-blind, placebo-controlled, phase 3 trial (49 sites; Japan, South Korea, and Taiwan). The median (min–max) follow-up period was 27.3 (24.1–36.3) months. The primary endpoint was OS. A subanalysis of OS was performed based on best overall response and tumor-programmed death ligand-1 (PD-L1) expression status.ResultsOverall, 493 of 601 screened patients were randomized (2:1) to receive nivolumab (330) or placebo (163). OS (median [95% confidence interval; CI]) was significantly longer in the nivolumab group (5.26 [4.60–6.37] vs 4.14 [3.42–4.86] months in placebo group) at the 2-year follow-up (hazard ratio [95% CI], 0.62 [0.51–0.76]; P < 0.0001). A higher OS rate was observed in the nivolumab vs placebo group at 1 (27.3% vs 11.6%) and 2 years (10.6% vs 3.2%). The OS benefit was observed regardless of tumor PD-L1 expression. Among patients with a complete or partial response (CR or PR) in the nivolumab group, the median OS (95% CI) was 26.6 (21.65—not applicable) months; the OS rates at 1 and 2 years were 87.1% and 61.3%, respectively. No new safety signals were identified.ConclusionsNivolumab treatment resulted in clinically meaningful long-term improvements in OS in patients with previously treated G/GEJ cancer. The long-term survival benefit of nivolumab was most evident in patients with a CR or PR.

The vascular endothelial growth factor pathway plays a key role in the pathogenesis of gastric cancer. In the multicenter, double-blind phase 3 FRUTIGA trial, 703 patients with advanced gastric or gastroesophageal junction adenocarcinoma who progressed on fluorouracil- and platinum-containing chemotherapy were randomized (1:1) to receive fruquintinib (an inhibitor of vascular endothelial growth factor receptor-1/2/3; 4 mg orally, once daily) or placebo for 3 weeks, followed by 1 week off, plus paclitaxel (80 mg/m 2 intravenously on days 1/8/15 per cycle). The study results were positive as one of the dual primary endpoints, progression-free survival (PFS), was met (median PFS, 5.6 months in the fruquintinib arm versus 2.7 months in the placebo arm; hazard ratio 0.57; 95% confidence interval 0.48–0.68; P  < 0.0001). The other dual primary endpoint, overall survival (OS), was not met (median OS, 9.6 months versus 8.4 months; hazard ratio 0.96, 95% confidence interval 0.81–1.13; P  = 0.6064). The most common grade ≥3 adverse events were neutropenia, leukopenia and anemia. Fruquintinib plus paclitaxel as a second-line treatment significantly improved PFS, but not OS, in Chinese patients with advanced gastric or gastroesophageal junction adenocarcinoma and could potentially be another treatment option for these patients. ClinicalTrials.gov registration: NCT03223376 . In a randomized, double-blind, placebo-controlled phase 3 trial, the anti-vascular endothelial growth factor receptor small-molecule inhibitor fruquintinib plus chemotherapy significantly extended progression-free survival, but not overall survival, as second-line therapy in patients with advanced gastric or gastroesophageal junction cancers.

Dysregulation of the hepatocyte growth factor (HGF)/MET pathway promotes tumour growth and metastasis. Rilotumumab is a fully human, monoclonal antibody that neutralises HGF. We aimed to assess the safety, efficacy, biomarkers, and pharmacokinetics of rilotumumab combined with epirubicin, cisplatin, and capecitabine (ECX) in patients with advanced gastric or oesophagogastric junction cancer. We recruited patients (≥18 years old) with unresectable locally advanced or metastatic gastric or oesophagogastric junction adenocarcinoma, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, who had not received previous systemic therapy, from 43 sites worldwide. Phase 1b was an open-label, dose de-escalation study to identify a safe dose of rilotumumab (initial dose 15 mg/kg intravenously on day 1) plus ECX (epirubicin 50 mg/m2 intravenously on day 1, cisplatin 60 mg/m2 intravenously on day 1, capecitabine 625 mg/m2 twice a day orally on days 1–21, respectively), administered every 3 weeks. The phase 1b primary endpoint was the incidence of dose-limiting toxicities in all phase 1b patients who received at least one dose of rilotumumab and completed the dose-limiting toxicity assessment window (first cycle of therapy). Phase 2 was a double-blind study that randomly assigned patients (1:1:1) using an interactive voice response system to receive rilotumumab 15 mg/kg, rilotumumab 7·5 mg/kg, or placebo, plus ECX (doses as above), stratified by ECOG performance status and disease extent. The phase 2 primary endpoint was progression-free survival (PFS), analysed by intention to treat. The study is registered with ClinicalTrials.gov, number NCT00719550. Seven of the nine patients enrolled in the phase 1b study received at least one dose of rilotumumab 15 mg/kg, only two of whom had three dose-limiting toxicities: palmar-plantar erythrodysesthesia, cerebral ischaemia, and deep-vein thrombosis. In phase 2, 121 patients were randomly assigned (40 to rilotumumab 15 mg/kg; 42 to rilotumumab 7·5 mg/kg; 39 to placebo). Median PFS was 5·1 months (95% CI 2·9–7·0) in the rilotumumab 15 mg/kg group, 6·8 months (4·5–7·5) in the rilotumumab 7·5 mg/kg group, 5·7 months (4·5–7·0) in both rilotumumab groups combined, and 4·2 months (2·9–4·9) in the placebo group. The hazard ratio for PFS events compared with placebo was 0·69 (80% CI 0·49–0·97; p=0·164) for rilotumumab 15 mg/kg, 0·53 (80% CI 0·38–0·73; p=0·009) for rilotumumab 7·5 mg/kg, and 0·60 (80% CI 0·45–0·79; p=0·016) for combined rilotumumab. Any grade adverse events more common in the combined rilotumumab group than in the placebo group included haematological adverse events (neutropenia in 44 [54%] of 81 patients vs 13 [33%] of 39 patients; anaemia in 32 [40%] vs 11 [28%]; and thrombocytopenia in nine [11%] vs none), peripheral oedema (22 [27%] vs three [8%]), and venous thromboembolism (16 [20%] vs five [13%]). Grade 3–4 adverse events more common with rilotumumab included neutropenia (36 [44%] vs 11 [28%]) and venous thromboembolism (16 [20%] vs four [10%]). Serious adverse events were balanced between groups except for anaemia, which occurred more frequently in the combined rilotumumab group (ten [12%] vs none). Rilotumumab plus ECX had no unexpected safety signals and showed greater activity than placebo plus ECX. A phase 3 study of the combination in MET-positive gastric and oesophagogastric junction cancer is in progress. Amgen Inc.

Perioperative FLOT (fluorouracil, oxaliplatin, and docetaxel) triplet chemotherapy is the standard of care for localised and resectable gastric and gastro-oesophageal junction adenocarcinoma. We aimed to compare a modified FLOT regimen (also known as TFOX) with FOLFOX as first-line treatment for patients with HER2-negative advanced gastric and gastro-oesophageal junction adenocarcinoma. PRODIGE 51-FFCD-GASTFOX is an open-label, multicentre, randomised, phase 3 trial conducted at 96 medical centres in France. Eligible individuals were aged 18 years or older, had histologically confirmed, HER2-negative adenocarcinoma of the stomach or gastro-oesophageal junction that was locally advanced unresectable or metastatic and previously untreated, measurable disease per Response Evaluation Criteria in Solid Tumours, an Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate organ function. Patients were randomly assigned (1:1), using the minimisation method, to receive FOLFOX (folinic acid 400 mg/m2, oxaliplatin 85 mg/m2, and 5-fluorouracil bolus 400 mg/m2 then 5-fluorouracil 2400 mg/m2 as a continuous 46 h infusion every 2 weeks) or TFOX (docetaxel 50 mg/m2, folinic acid 400 mg/m2, and oxaliplatin 85 mg/m2 then 5-fluorouracil 2400 mg/m2 as a continuous 46 h infusion every 2 weeks). Randomisation was stratified by centre, ECOG performance status, (neo)adjuvant chemotherapy or chemoradiotherapy, tumour stage, tumour location, and pathological histological subtype. The primary endpoint was progression-free survival (assessed in the intention-to-treat population), defined as time from randomisation to the first radiological or clinical progression (or both), or death due to any cause, whichever occurred first. Secondary endpoints included overall survival (defined as time from randomisation to death due to any cause) and objective response rate (defined as the proportion of patients with a best overall complete or partial response). Hazard ratio and 95% CIs were estimated using an unstratified Cox proportional hazards model. When the proportional hazards assumption was violated, the restricted mean survival time was used to estimate the treatment effect size. This study is registered with ClinicalTrials.gov, NCT03006432, and EudraCT, 2016–002331–16. Between Dec 19, 2016, and Dec 26, 2022, 507 patients were randomly assigned (254 to the TFOX group and 253 to the FOLFOX group [intention-to-treat population]). The median age was 64·2 years (IQR 56·7–70·8), and 399 (79%) participants were male and 108 (21%) were female. At median follow-up of 42·8 months (25·8–49·9), the median progression-free survival was 7·59 months (95% CI 7·06–7·95) in the TFOX group versus 5·98 months (5·65–6·97) in the FOLFOX group. The assumption of proportional hazards was violated (p=0·013); therefore, the 12-month restricted mean progression-free survival was calculated: 7·52 months (7·06–7·97) in the TFOX group versus 6·62 months (6·16–7·09) in the FOLFOX group (p=0·0072). The median overall survival was 15·08 months (13·70–16·72) in the TFOX group versus 12·65 months (10·94–14·00) in the FOLFOX group (proportional hazards assumption was confirmed; HR 0·82 [0·68–0·99]; p=0·048) and the objective response rate was 62·3% (56·0–68·3) versus 53·4% (47·0–59·8; p=0·045). The most common grade 3 and 4 treatment-emergent adverse events were diarrhoea (37 [15%] in the TFOX group vs 18 [7%] in the FOLFOX group), peripheral neuropathy (80 [32%] vs 49 [20%]), neutropenia (67 [27%] vs 44 [18%]), and fatigue (40 [16%] vs 20 [8%]). Serious treatment-related adverse events occurred in 66 (27%) participants in the TFOX group and 33 (13%) in the FOLFOX group. There were two (<1%) treatment-related deaths in the TFOX group (one due to septic shock and one due to gastrointestinal perforation) and one (<1%) in the FOLFOX group (due to septic shock). The modified FLOT/TFOX regimen significantly improved progression-free survival, overall survival, and objective response rate compared with FOLFOX in previously untreated patients with advanced HER2-negative gastric and gastro-oesophageal junction adenocarcinoma. The modified FLOT/TFOX regimen might represent a new first-line treatment option for patients eligible for this docetaxel triplet chemotherapy. Fédération Francophone de Cancérologie Digestive.