HER2-Positive Gastric Cancer and Antibody Treatment: State of the Art and Future Developments.

Despite a decreasing incidence in Western countries, gastric cancer is among the most common cancer subtypes globally and is associated with one of the highest tumor-related mortality rates. Biomarkers play an increasing role in the treatment against gastric cancer. HER2 was one of the first biomarkers that found its way into clinical practice. Since the ToGA trial, trastuzumab has been part of first-line palliative chemotherapy in metastatic or unresectable gastric cancer. HER2-targeting agents, such as the tyrosine kinase inhibitor lapatinib, the antibody drug conjugate (ADC) trastuzumab-emtansine or dual HER2 inhibition (pertuzumab and trastuzumab), have been investigated in the second-line setting but led to negative study results. More recently, the ADC trastuzumab-deruxtecan was authorized after the failure of trastuzumab-based treatment. However, further improvements in HER2-directed therapy are required as resistance mechanisms and HER2 heterogeneity limit the existing treatment options. This review aims to give an overview of the current standard-of-care HER2-directed therapy in gastric cancer, as well as its challenges and future developments.

Efficacy of ramucirumab combination chemotherapy as second-line treatment in patients with advanced adenocarcinoma of the stomach or gastroesophageal junction after exposure to checkpoint inhibitors and chemotherapy as first-line therapy.

FOLFOX plus nivolumab represents a standard of care for first-line therapy of advanced gastroesophageal cancer (aGEC) with positive PD-L1 expression. The efficacy of second-line VEGFR-2 inhibition with ramucirumab (RAM) plus chemotherapy after progression to immunochemotherapy remains unclear. Medical records of patients with aGEC enrolled in the randomized phase II AIO-STO-0417 trial after treatment failure to first-line FOLFOX plus nivolumab and ipilimumab were retrospectively analyzed. Patients were divided into two groups based on second-line therapy: RAM plus chemotherapy (RAM group) or treatment without RAM (control group). Eighty three patients were included. In the overall population, progression-free survival (PFS) in the RAM group was superior to the control (4.5 vs 2.9 months). Responders (CR/PR) to first-line immunochemotherapy receiving RAM containing second-line therapy had prolonged OS from start of first-line therapy (28.9 vs 16.5 months), as well as second-line OS (9.6 vs 7.5 months), PFS (5.6 vs 2.9 months) and DCR (53% vs 29%) compared to the control. PD-L1 CPS ≥1 was 42% and 44% for the RAM and the control, respectively. Patients with CPS ≥1 in the RAM group showed better tumor control (ORR 25% vs 10%) and improved survival (total OS 11.5 vs 8.0 months; second-line OS 6.5 vs 3.9 months; PFS 4.5 vs 1.6 months) compared to the control. Prior exposure to first-line FOLFOX plus dual checkpoint inhibition followed by RAM plus chemotherapy shows favorable response and survival rates especially in patients with initial response and positive PD-L1 expression and has the potential to advance the treatment paradigm in aGEC.

Perioperative Atezolizumab Plus Fluorouracil, Leucovorin, Oxaliplatin, and Docetaxel for Resectable Esophagogastric Cancer: Interim Results From the Randomized, Multicenter, Phase II/III DANTE/IKF-s633 Trial.

PURPOSE: This trial evaluates the addition of the PD-L1 antibody atezolizumab (ATZ) to standard-of-care fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) as a perioperative treatment for patients with resectable esophagogastric adenocarcinoma (EGA). METHODS: DANTE started as multicenter, randomized phase II trial, which was subsequently converted to a phase III trial. Here, we present the results of the phase II proportion, focusing on surgical pathology and safety outcomes on an exploratory basis. Patients with resectable EGA (≥cT2 or cN+) were assigned to either four preoperative and postoperative cycles of FLOT combined with ATZ, followed by eight cycles of ATZ maintenance (arm A) or FLOT alone (arm B). RESULTS: Two hundred ninety-five patients were randomly assigned (A, 146; B, 149) with balanced baseline characteristics between arms. Twenty-three patients (8%) had tumors with microsatellite instability (MSI), and 58% patients had tumors with a PD-L1 combined positive score (CPS) of ≥1. Surgical morbidity (A, 45%; B, 42%) and 60-day mortality (A, 3%; B, 2%) were comparable between arms. Downstaging favored arm A versus arm B (ypT0, 23% v 15% [one-sided P = .044]; ypT0-T2, 61% v 48% [one-sided P = .015]; ypN0, 68% v 54% [one-sided P = .012]). Histopathologic complete regression rates (pathologic complete response or TRG1a) were higher after FLOT plus ATZ (A, 24%; B, 15%; one-sided P = .032), and the difference was more pronounced in the PD-L1 CPS ≥10 (A, 33%; B, 12%) and MSI (A, 63%; B, 27%) subpopulations. Complete margin-free (R0) resection rates were relatively high in both arms (A, 96%; B, 95%). The incidence and severity of adverse events were similar in both groups. CONCLUSION: Within the limitations of the exploratory nature of the data, the addition of ATZ to perioperative FLOT is safe and improved postoperative stage and histopathologic regression.

German, Austrian, and Swiss guidelines for systemic treatment of gastric cancer.

The updated edition of the German, Austrian and Swiss Guidelines for Systemic Treatment of Gastric Cancer was completed in August 2023, incorporating new evidence that emerged after publication of the previous edition. It consists of a text-based "Diagnosis" part and a "Therapy" part including recommendations and treatment algorithms. The treatment part includes a comprehensive description regarding perioperative and palliative systemic therapy for gastric cancer and summarizes recommended standard of care for surgery and endoscopic resection. The guidelines are based on a literature search and evaluation by a multidisciplinary panel of experts nominated by the hematology and oncology scientific societies of the three involved countries.

Pembrolizumab and trastuzumab in combination with FLOT in the perioperative treatment of HER2-positive, localized esophagogastric adenocarcinoma-a phase II trial of the AIO study group (AIO STO 0321).

Background: Esophagogastric adenocarcinoma (EGA) presents a substantial global health challenge as the number of cases continues to rise. The current standard approach for treating localized EGA involves a combination of triplet chemotherapy, which consists of a platinum compound, a fluoropyrimidine, and a taxane (known as FLOT), followed by surgery. In cases of metastatic EGA with HER2-positive status or in certain studies with localized EGA, the use of HER2-targeted antibodies such as trastuzumab has shown improved responses. Recently, the addition of programmed cell death protein 1 (PD-1) inhibitors, such as pembrolizumab, when combined with 5-FU, platinum-based chemotherapy, and trastuzumab, has demonstrated significant enhancements in response rates for HER2-positive metastatic EGA. However, there is currently insufficient evidence regarding this treatment approach in localized HER2-positive disease. Methods: The PHERFLOT study is an open-label, single-arm, multicenter, exploratory phase II trial designed to assess the efficacy, safety, and tolerability of perioperative pembrolizumab, FLOT, and trastuzumab in patients with previously untreated localized HER2-positive EGA. In total, 30 patients will be recruited. The co-primary end points are pathological complete response rate and disease-free survival rate after 2 years. Secondary objectives include safety and tolerability, efficacy in terms of progression-free survival and objective response rate and translational markers, such as blood-based signatures (e.g., immune repertoire changes or emergence of anti-HER2 resistance variants) or microbiota signatures that may correlate with immune activation and therapy response. Discussion: Recent evidence from phase II clinical trials demonstrated improved efficacy through the addition of trastuzumab to perioperative FLOT. Furthermore, in advanced or metastatic EGA, the combination of trastuzumab, FLOT, and the PD1-inhibitor pembrolizumab significantly improved treatment response. The PHERFLOT study aims to assess the efficacy and safety of this treatment approach in HER2-positive-localized EGA, potentially identifying a promising new perioperative regimen for localized EGA, which then needs to be confirmed within a randomized trial. Furthermore, the accompanying translational program of the study might help to improve the stratification of suitable patients and to identify potential translational targets for future clinical trials. Clinical trial registration: https://clinicaltrials.gov, identifier NCT05504720.

Optimal use of granulocyte colony-stimulating factor prophylaxis to improve survival in cancer patients receiving treatment : An expert view.

BACKGROUND: Febrile neutropenia (FN) is a relatively common complication of cytotoxic chemotherapy. Prophylaxis with granulocyte colony-stimulating factor (G-CSF) can prevent FN and chemotherapy dose delays and enable the use of the higher dose intensities associated with a survival benefit; however, G­CSF is not always used optimally. Five medical oncologists with a special interest in supportive care met to discuss the evidence for prophylaxis with G­CSF to improve survival in cancer patients, identify reasons why this is not always done, and suggest potential solutions. The dose intensity of chemotherapy is critical for maximizing survival in cancer patients but may be reduced as a result of hematological toxicity, such as FN. Use of G­CSF has been shown to increase the chances of achieving the planned dose intensity in various cancers, including early-stage breast cancer and non-Hodgkin lymphoma. All physicians treating cancer patients should consider the use of G­CSF prophylaxis in patients receiving chemotherapy, paying particular attention to patient-related risk factors. KEY MESSAGES: Strategies to optimize G­CSF use include educating medical oncologists and pharmacists on the appropriate use of G­CSF and informing patients about the efficacy of G­CSF and its potential adverse effects. It is hoped that the evidence and opinions presented will help to encourage appropriate use of G­CSF to support cancer patients at risk of FN in achieving the best possible outcomes from chemotherapy.

Histology-Based Prediction of Therapy Response to Neoadjuvant Chemotherapy for Esophageal and Esophagogastric Junction Adenocarcinomas Using Deep Learning.

PURPOSE: Quantifying treatment response to gastroesophageal junction (GEJ) adenocarcinomas is crucial to provide an optimal therapeutic strategy. Routinely taken tissue samples provide an opportunity to enhance existing positron emission tomography-computed tomography (PET/CT)-based therapy response evaluation. Our objective was to investigate if deep learning (DL) algorithms are capable of predicting the therapy response of patients with GEJ adenocarcinoma to neoadjuvant chemotherapy on the basis of histologic tissue samples. METHODS: This diagnostic study recruited 67 patients with I-III GEJ adenocarcinoma from the multicentric nonrandomized MEMORI trial including three German university hospitals TUM (University Hospital Rechts der Isar, Munich), LMU (Hospital of the Ludwig-Maximilians-University, Munich), and UME (University Hospital Essen, Essen). All patients underwent baseline PET/CT scans and esophageal biopsy before and 14-21 days after treatment initiation. Treatment response was defined as a ≥35% decrease in SUVmax from baseline. Several DL algorithms were developed to predict PET/CT-based responders and nonresponders to neoadjuvant chemotherapy using digitized histopathologic whole slide images (WSIs). RESULTS: The resulting models were trained on TUM (n = 25 pretherapy, n = 47 on-therapy) patients and evaluated on our internal validation cohort from LMU and UME (n = 17 pretherapy, n = 15 on-therapy). Compared with multiple architectures, the best pretherapy network achieves an area under the receiver operating characteristic curve (AUROC) of 0.81 (95% CI, 0.61 to 1.00), an area under the precision-recall curve (AUPRC) of 0.82 (95% CI, 0.61 to 1.00), a balanced accuracy of 0.78 (95% CI, 0.60 to 0.94), and a Matthews correlation coefficient (MCC) of 0.55 (95% CI, 0.18 to 0.88). The best on-therapy network achieves an AUROC of 0.84 (95% CI, 0.64 to 1.00), an AUPRC of 0.82 (95% CI, 0.56 to 1.00), a balanced accuracy of 0.80 (95% CI, 0.65 to 1.00), and a MCC of 0.71 (95% CI, 0.38 to 1.00). CONCLUSION: Our results show that DL algorithms can predict treatment response to neoadjuvant chemotherapy using WSI with high accuracy even before therapy initiation, suggesting the presence of predictive morphologic tissue biomarkers.

HER-2-Positive Tumors: A Continuously Evolving Field in Cancer Research.

Almost 25 years ago, trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER2), was licensed for the treatment of patients with metastatic HER2-positive breast cancer in the United States of America (USA) [...].

Ramucirumab beyond progression plus TAS-102 in patients with advanced or metastatic esophagogastric adenocarcinoma, after treatment failure on a ramucirumab-based therapy.

Based on results of prior trials (TAGS, REGARD, RAINBOW), the combination of ramucirumab beyond progression with TAS-102 (trifluridine/tipiracil) seems to be promising in advanced esophagogastric adenocarcinoma (EGA). In this multicenter, non-randomized, open-label, investigator-initiated pilot trial, ramucirumab-pretreated patients with metastatic EGA received a maximum of 4 cycles of ramucirumab (8 mg/kg i.v. on day 1 and 15, Q2W) plus TAS-102 (35 mg/m2 p.o. bid on day 1-5 and day 8-12; Q2W). Primary endpoint was tolerability and toxicity, defining a positive trial if the SAE rate according to CTCAE 5.0 will increase <30% (up to 55%) compared to historical results from TAGS trial (SAE rate 43%). Secondary endpoints were further evaluation of safety and assessment of efficacy according to tumor response and overall and progression-free survival (OS/PFS). Twenty patients, 20% gastric and 80% GEJ cancers and 55% with ECOG 0 were enrolled. In total, nine SAEs were reported in 25% [95% CI: 8.7-49.1] of the patients, all without relationship to the systemic therapy. The median OS and PFS were 9.1 months [5.4-10.1] and 2.9 months [1.7-4.8], respectively. In addition, a disease control rate of 45% was obtained. The trial showed a favorable safety profile with a numerically lower incidence of SAEs for the combination of ramucirumab with TAS-102 compared to historical TAGS trial. Furthermore, the combination demonstrated efficacy in the beyond progression setting and therefore warrants further evaluation in a randomized trial compared to TAS-102 alone.

Ramucirumab plus irinotecan / leucovorin / 5-FU versus ramucirumab plus paclitaxel in patients with advanced or metastatic adenocarcinoma of the stomach or gastroesophageal junction, who failed one prior line of palliative chemotherapy: the phase II/III RAMIRIS study (AIO-STO-0415).

BACKGROUND: Paclitaxel in combination with ramucirumab is the standard of care second-line therapy in gastro-esophageal adenocarcinoma (GEA). As the number of taxane pretreated patients in the perioperative or first-line setting is increasing, it is unknown whether these patients benefit from re-applying a taxane in using the combination of paclitaxel and ramucirumab. Furthermore, the rates of neurotoxicity with first-line FOLFOX or FLOT range from 30%-70%, making second-line taxane-containing therapy less suitable to a meaningful portion of patients. This patient group is likely to benefit from a taxane-free second-line chemotherapy regimen, such as FOLFIRI and ramucirumab (FOLFIRI-Ram). Therefore, the RAMIRIS phase III trial evaluates the effects of the regimen of FOLFIRI-Ram in the second-line treatment after a taxane-based chemotherapy in patients with advanced GEA. METHODS: The RAMIRIS trial is a randomized, open-label, multicenter phase II/III study comparing treatment of FOLFIRI-Ram (arm A) with paclitaxel and ramucirumab (arm B). The Phase II is already closed with 111 enrolled patients. In the phase III, 318 taxane-pretreated patients with advanced GEA will be recruited and randomized 1:1 to FOLFIRI (5-FU 2400 mg/m2 over 46 h i.v., irinotecan 180 mg/m2 i.v.; 5-FU 400 mg/m2 bolus; leucovorin 400 mg/m2 i.v.; on day 1 and 15, q28) with ramucirumab 8 mg/kg every two weeks (Arm A) or paclitaxel 80 mg/m2 (days 1, 8, 15, q28) with ramucirumab 8 mg/kg every two weeks (Arm B). The primary endpoints are overall survival (OS) and objective overall response rate (ORR). Secondary endpoints are progression-free survival (PFS), disease control rate and safety and quality of life as assessed by EORTC-QLQ-C30 questionnaire. DISCUSSION: The already completed RAMIRIS phase II demonstrated feasibility and efficacy of FOLFIRI-Ram. Especially docetaxel-pretreated patients seemed to markedly benefit from FOLFIRI-Ram, with favorable response- and PFS rates and lower toxicity. This offers a rationale for the phase III trial. If the RAMIRIS III trial transfers and confirms the results, they will affect the current treatment guidelines, recommending the combination therapy of FOLFIRI-Ram for taxane-pretreated patients with advanced GEA. TRIAL REGISTRATION: NCT03081143 Date of registration: 13.11.2015.

Neoadjuvant and adjuvant approaches in gastroesophageal cancers.

PURPOSE OF REVIEW: Despite advances in the perioperative treatment of locally advanced (T2-4 and/or N+) gastroesophageal cancer with evolving chemoradiotherapy and chemotherapy regimens, prognosis remains poor. Biomarker-based approaches with targeted therapies and immune checkpoint inhibition present a new opportunity to improve response rate and overall survival. This review aims to shed light on the current treatment strategies and therapy options that are under investigation for the curatively intended perioperative treatment of gastroesophageal cancer. RECENT FINDINGS: A major step for patients with advanced esophageal cancer and insufficient response to chemoradiotherapy was the implementation of immune checkpoint inhibition in the adjuvant treatment with positive effects on survival duration and quality of life (CheckMate577). Various studies that seek to further integrate immunotherapy or targeted therapy into (neo-) adjuvant treatment are on their way and show promising results. SUMMARY: Ongoing clinical research tries to increase the effectivity of standard of care approaches for the perioperative treatment of gastroesophageal cancer. Biomarker based immunotherapy and targeted therapy bear the opportunity to further improve the outcome.

Microsatellite instability and sex-specific differences of survival in gastric cancer after neoadjuvant chemotherapy without and with taxane: An observational study in real world patients.

PURPOSE: To investigate the prognostic role of microsatellite instability (MSI) in association with sex of patients treated with platinum/fluoropyrimidine neoadjuvant chemotherapy (CTx) with or without a taxane-containing compound. METHODS: Of the 505 retrospectively analyzed patients with gastric or gastroesophageal adenocarcinoma, 411 patients were treated without taxane and 94 patients with a taxane-containing compound. MSI was determined using standard assays. RESULTS: Females demonstrated a better overall survival (OS) than males in the non-taxane group (HR, 0.59; 95% CI 0.41-0.86; p = 0.005), whereas no significant difference was found in the taxane group (HR 1.22; 95% CI 0.55-2.73, p = 0.630). MSI-High (-H) was associated with a better prognosis in both groups (without taxane: HR 0.56; 95% CI 0.33-0.97; p = 0.038; with taxane: HR 0.28; 95% CI 0.04-2.02, p = 0.204). In the non-taxane group, female MSI-H patients showed the best OS (HR 0.18, 95% CI 0.05-0.73; p = 0.016), followed by the female microsatellite stable (MSS) (HR 0.67, 95% CI 0.46-0.98, p = 0.040) and the male MSI-H group (HR 0.76; 95% CI 0.42-1.37, p = 0.760) taken the male MSS group as reference. In the taxane group, female and male MSI-H patients demonstrated the best OS (female MSI-H: HR 0.05, 95% CI 0.00-240.46; male MSI-H: HR 0.45, 95% CI 0.61-3.63, p = 0.438), whereas the female MSS group showed a decreased OS (HR 1.39 95% CI 0.62-3.12, p = 0.420) compared to male MSS patients. CONCLUSION: OS in gastric/gastroesophageal cancer after CTx might depend on sex and MSI status and may differ between patients treated with or without a taxane compound in the chemotherapeutic regimen.

Comprehensive biomarker analysis of long-term response to trastuzumab in patients with HER2-positive advanced gastric or gastroesophageal adenocarcinoma.

BACKGROUND: A subgroup of patients with HER2-positive metastatic gastric and gastroesophageal junction cancers shows long-term response under trastuzumab maintenance monotherapy. Obviously, HER2 status alone is not able to identify these patients. We performed this study to identify potential new prognostic biomarkers for this long-term responding patient group. PATIENTS AND METHODS: Tumour samples of 19 patients with HER2-positive metastatic gastric and gastroesophageal junction cancer who underwent trastuzumab treatment were retrospectively collected from multiple centres. Patients were divided into long-term responding (n = 7) or short-term responding group (n = 12) according to progression-free survival (PFS≥12 months vs. PFS < 12 months). Next-generation sequencing and microarray-based gene expression analysis were performed along with HER2 and PD-L1 immunohistochemistry. RESULTS: Long-term responding patients had significantly higher PD-L1 combined positive scores (CPS) and CPS correlated with longer progression-free survival. PD-L1 positivity (CPS ≥ 1) was further associated with an increased CD4+ memory T-cell score. The ERBB2 copy number as well as the tumour mutational burden could not discriminate between short-term and long-term responding patients. Genetic alterations and coamplifications in HER2 pathway associated genes such as EGFR, which were connected to trastuzumab resistance, were present in 10% of the patients and equally distributed between the groups. CONCLUSION: The study highlights the clinical relevance of PD-L1 testing also in the context of trastuzumab treatment and offers a biological rational by demonstrating elevated CD4+ memory T-cells scores in the PD-L1-positive group.

European-Australasian consensus on the management of advanced gastric and gastro-oesophageal junction cancer: current practice and new directions.

Gastric carcinoma and gastro-oesophageal junction (GC/GEJ) carcinoma remain a significant global problem, with patients presenting with symptoms often found to have advanced or metastatic disease. Treatment options for these patients have broadened in recent years with new chemotherapy agents, agents targeting angiogenic pathways and the development of immune checkpoint inhibitors (ICIs). Most initial advances have occurred in the refractory setting, where it is important to balance treatment benefits versus toxicity and patient quality of life. In the first-line treatment of advanced/metastatic GC/GEJ, platinum- and fluoropyrimidine-based chemotherapy protocols remain the backbone of therapy (with or without HER2-targeted therapy), with the FOLFIRI regimen offering an alternative in patients deemed unsuitable for a platinum agent. Microsatellite instability-high or mismatch repair-deficient cancers have been shown to benefit most from ICIs. In unselected patients previously treated with doublet or triplet platinum- and fluoropyrimidine-based chemotherapy and second-line chemotherapy with irinotecan or taxanes have formed the backbone of therapy with or without the addition of the vascular endothelial growth factor receptor-2 inhibitor ramucirumab in addition to paclitaxel. Beyond this, efficacy has been demonstrated with oral trifluridine/tipiracil and with single-agent nivolumab, in selected refractory patients. In this review, we highlight the positive evidence from key trials that have led to our current practice algorithm, with particular focus on the refractory advanced disease setting, discussing the areas of active research and highlighting the factors, including biomarkers and the influence of ethnicity, that contribute to therapeutic decision-making.

PET-directed combined modality therapy for gastroesophageal junction cancer: Results of the multicentre prospective MEMORI trial of the German Cancer Consortium (DKTK).

BACKGROUND: Positron emission tomography (PET) may differentiate responding and non-responding tumours early in the treatment of locally advanced gastroesophageal junction adenocarcinomas. Early PET non-responders (P-NR) after induction CTX might benefit from changing to chemoradiation (CRT). METHODS: Patients underwent baseline 18F-FDG PET followed by 1 cycle of CTX. PET was repeated at day 14-21 and responders (P-R), defined as ≥35% decrease in SUVmean from baseline, continued with CTX. P-NR switched to CRT (CROSS). Patients underwent surgery 4-6 weeks post-CTX/CRT. The primary objective was an improvement in R0 resection rates in P-NR above a proportion of 70%. RESULTS: In total, 160 patients with resectable gastroesophageal junction adenocarcinomas were prospectively investigated by PET scanning. Eighty-five patients (53%) were excluded. Seventy-five eligible patients were enrolled in the study. Based on PET criteria, 50 (67.6%)/24 (32.4%) were P-R and P-NR, respectively. Resection was performed on 46 responders, including one patient who withdrew the ICF, and 22 non-responders (per-protocol population). R0 resection rates were 95.6% (43/45) for P-R and 86.4% (19/22) for P-NR. No treatment related deaths occurred. With a median follow-up time of 24.5 months, estimated 18 months DFS was 75.4%/64.2% for P-R/P-NR, respectively. The estimated 18 months OS was 95.5% for P-R and 68.2% for P-NR. CONCLUSION: The primary endpoint of the study to increase the R0 resection rate in metabolic NR was not met. PET response after induction CTX is prognostic for outcome with a prolonged OS and DFS in PET responders. TRIAL REGISTRATION: NCT00002014-000860-16.