Publications by authors named "Geoffrey Ku"

Purpose: Givastomig is a bispecific antibody that targets CLDN18.2 and conditionally activates local 4-1BB-expressing T cells. This first-in-human study evaluated the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activity of givastomig in advanced solid tumors.

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Background: Zanidatamab, a dual human epidermal growth factor receptor 2 (HER2)-targeted bispecific antibody, previously demonstrated encouraging antitumour activity and a manageable safety profile in patients with treatment-refractory HER2-expressing gastro-oesophageal adenocarcinoma. Here, we evaluated the antitumour activity and safety of zanidatamab plus chemotherapy in first-line HER2-positive advanced gastro-oesophageal adenocarcinoma.

Methods: This phase 2 trial enrolled patients in Canada, South Korea, and the USA who were aged 18 years and older with untreated, metastatic, or advanced HER2-positive gastro-oesophageal adenocarcinoma (HER2 IHC 3+ or 2+ by local or central assessment [part 1]; HER2 IHC 3+ or 2+ with FISH+ by central assessment [part 2]).

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Article Synopsis
  • The LEAP-015 study compared the effectiveness of first-line treatment combining lenvatinib and pembrolizumab with chemotherapy against chemotherapy alone in patients with advanced gastroesophageal adenocarcinoma.
  • Participants over 18 with untreated, HER2-negative cancer were randomly assigned to receive either the new treatment combination or traditional chemotherapy, with the study focusing on progression-free survival (PFS) and overall survival (OS).
  • Results showed improved PFS and objective response rates in those taking lenvatinib and pembrolizumab compared to chemotherapy, although there was no significant difference in overall survival at final analysis.
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Purpose: The Cancer Genome Atlas (TCGA) project defined four distinct molecular subtypes of esophagogastric adenocarcinoma: microsatellite instable (MSI), Epstein-Barr virus (EBV)-associated, genomically stable (GS), and chromosomally instable (CIN). However, an association between molecular subtypes and clinical outcomes has not been clearly demonstrated. Given few actionable biomarkers, we investigated the clinical relevance of TCGA classification system.

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Article Synopsis
  • A phase 2 study showed that neoadjuvant treatment with dostarlimab, a PD-1 blocker, resulted in high rates of clinical complete response in patients with dMMR solid tumors, eliminating the need for surgery in many cases.
  • Among 117 patients, 84 demonstrated a clinical complete response, with a significant percentage opting for nonoperative management, leading to a recurrence-free survival rate of 92% over two years.
  • Most adverse events were mild and reversible, with 95% of patients experiencing grade 1 or 2 side effects, indicating that this approach is not only effective but also relatively safe.
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Background: The response of gastric cancer (GC) patients to first-line programmed cell death 1 (PD-1) blockade and S-1 plus oxaliplatin (SOX) chemotherapy varies considerably, and the underlying mechanisms driving this variability remain elusive. Exosomal microRNAs (miRNAs or miRs) have emerged as potential biomarkers for efficacy prediction due to their roles in GC biology and stable expression in serum. In this study, we aimed to identify biomarkers to predict patients' response to anti-PD-1 therapy and further elucidate the potential mechanisms by which these exosomal miRNAs modulate the immune response in GC.

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Objective: We sought to determine whether aggressive local treatment provides a benefit in patients with stage IV esophageal adenocarcinoma and to determine factors associated with survival.

Methods: Patients with clinical stage IV esophageal adenocarcinoma at diagnosis who underwent esophagectomy from 2010 to 2023 were identified from our prospectively maintained database. Clinicopathologic and demographic characteristics were compared among patients by stage.

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Purpose: 4-1BB (CD137) is a costimulatory immune receptor expressed on activated T cells, activated B cells, NK cells, and tumor-infiltrating lymphocytes, making it a promising target for cancer immunotherapy. Cinrebafusp alfa, a monoclonal antibody-like bispecific protein targeting HER2 and 4-1BB, aims to localize 4-1BB activation to HER2-positive tumors. This study evaluated the safety, tolerability, and preliminary efficacy of cinrebafusp alfa in patients with previously treated HER2-positive malignancies.

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Purpose Of Review: This review critically evaluates the evolution and current status of human epidermal growth factor receptor 2 (HER2)-directed therapies in upper gastrointestinal (GI) malignancies, a timely and relevant inquiry given the dynamic shifts in therapeutic strategies over the past decade. Initial enthusiasm following the Trastuzumab for Gastric Cancer (ToGA) study's demonstration of trastuzumab's efficacy, however, encountered hurdles due to subsequent trials showing limited progress, underscoring the necessity for a reevaluation of therapeutic approaches and the exploration of novel agents.

Recent Findings: The review highlights significant breakthroughs in the form of immune checkpoint inhibitors and innovative therapeutic technologies, which have redefined treatment paradigms and shown promising efficacy in HER2-positive cases.

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The Trastuzumab for Gastric Cancer (ToGA) trial marked a pivotal moment in the adoption of trastuzumab for treating advanced human epidermal growth factor receptor 2 (HER2)-positive esophagogastric (EG) cancer. The KEYNOTE-811 trial brought to light the synergistic effect of immune modulation and HER2 targeting. Additionally, the emergence of trastuzumab deruxtecan (T-DXd) highlighted the potential of new pharmaceutical technologies to extend response, particularly for patients who have advanced beyond initial HER2-targeted therapies.

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Anti-programmed death 1 (PD-1) inhibitors are the standard of care for advanced gastroesophageal cancer. Although recommendations and approval by regulatory agencies are often based on programmed death ligand 1 (PD-L1) expression, pathologic assessments of PD-L1 status have several limitations. Single-site biopsies do not adequately capture disease heterogeneity within individual tumor lesions or among several lesions within the same patient, the PD-L1 combined positive score is a dynamic biomarker subject to evolution throughout a patient's disease course, and repeated biopsies are invasive and not always feasible.

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Background: PET-CT-based patient metabolic profiling is a novel concept to incorporate patient-specific metabolism into gastric cancer care.

Methods: Staging PET-CTs, demographics, and clinicopathologic variables of gastric cancer patients were obtained from a prospectively maintained institutional database. PET-CT avidity was measured in tumor, liver, spleen, four paired muscles, and two paired fat areas in each patient.

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Outcomes for patients with esophageal cancer have improved over the last decade with the implementation of multimodality therapy. There are currently no comprehensive guidelines addressing multidisciplinary management of esophageal cancer that have incorporated the input of surgeons, radiation oncologists, and medical oncologists. To address the need for multidisciplinary input in the management of esophageal cancer and to meet current best practices for clinical practice guidelines, the current guidelines were created as a collaboration between The Society of Thoracic Surgeons (STS), American Society for Radiation Oncology (ASTRO), and the American Society of Clinical Oncology (ASCO).

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Outcomes for patients with esophageal cancer have improved over the last decade with the implementation of multimodality therapy. There are currently no comprehensive guidelines addressing multidisciplinary management of esophageal cancer that have incorporated the input of surgeons, radiation oncologists, and medical oncologists. To address the need for multidisciplinary input in the management of esophageal cancer and to meet current best practices for clinical practice guidelines, the current guidelines were created as a collaboration between The Society of Thoracic Surgeons (STS), American Society for Radiation Oncology (ASTRO), and the American Society of Clinical Oncology (ASCO).

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Background: The rate of esophagogastric cancer is rising among individuals under 50 years of age. It remains unknown whether early-onset esophagogastric cancer represents a unique entity. This study investigated the clinical and molecular characteristics of early-onset and average-onset esophagogastric cancer .

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Article Synopsis
  • The study investigates the safety and effectiveness of the drug regorafenib combined with nivolumab and chemotherapy for treating advanced oesophagogastric adenocarcinoma in adults who haven't received treatment before.
  • Conducted at Memorial Sloan Kettering Cancer Center, the trial included 39 patients and aimed for at least 24 to remain progression-free after 6 months to validate the treatment's potential.
  • Results showed that 35 patients were evaluable for progress at 6 months, establishing a foundation for assessing the regimen's efficacy and safety in future studies.
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Background: Residual tumor at the proximal or distal margin after esophagectomy is associated with worse survival outcomes; however, the significance of the circumferential resection margin (CRM) remains controversial. In this study, we sought to evaluate the prognostic significance of the CRM in patients with esophageal cancer undergoing resection.

Materials And Methods: We identified patients who underwent esophagectomy for pathologic T3 esophageal cancer from 2000 to 2019.

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Objective: Here, we characterize differences in the genetic and microbial profiles of GC in patients of African (AFR), European, and Asian ancestry.

Background: Gastric cancer (GC) is a heterogeneous disease with clinicopathologic variations due to a complex interplay of environmental and biological factors, which may affect disparities in oncologic outcomes..

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  • Perioperative chemotherapy is commonly used to treat serious stomach cancer, but some patients can't finish their treatment after surgery due to complications.
  • A study looked at 149 patients to see if giving all chemotherapy before surgery (called total neoadjuvant therapy, or TNT) would help more patients complete their treatment.
  • Results showed that while patients who received TNT didn’t have more problems after surgery, both groups had similar chances of survival and completing their treatment cycles, but TNT patients took more types of chemotherapy.
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Purpose: We report updated clinical outcomes from a phase II study of pembrolizumab, trastuzumab, and chemotherapy (PTC) in metastatic esophagogastric cancer in conjunction with outcomes from an independent Memorial Sloan Kettering (MSK) cohort.

Patients And Methods: The significance of pretreatment 89Zr-trastuzumab PET, plasma circulating tumor DNA (ctDNA) dynamics, and tumor HER2 expression and whole exome sequencing was evaluated to identify prognostic biomarkers and mechanisms of resistance in patients treated on-protocol with PTC. Additional prognostic features were evaluated using a multivariable Cox regression model of trastuzumab-treated MSK patients (n = 226).

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Article Synopsis
  • * The trial included adult patients who had progressed after previous treatments and aimed to determine the drug's effectiveness and safety, using a single-arm, phase 2 study design across 24 sites.
  • * Initial and updated analyses reported objective response rates and safety outcomes with data cutoffs in April and November 2021, showing promising results for the HER2-targeted therapy.
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Esophageal adenocarcinoma, including adenocarcinoma of the gastroesophageal junction, is uncommon in the United States, but is associated with a rising incidence in young adults, and has a traditionally poor prognosis. Despite the incremental benefits that have been made with multimodality approaches to locally advanced disease, most patients will go on to develop metastatic disease, and long-term outcomes remain suboptimal. Over the last decade, PET-CT has emerged as a key tool in the management of this disease, with several prospective and retrospective studies evaluating its role in this disease.

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Gastrointestinal (GI) cancers, including esophageal, gastroesophageal junction, gastric, duodenal and distal small bowel, biliary tract, pancreatic, colon, rectal, and anal cancer, comprise a heterogeneous group of malignancies that impose a significant global burden. Immunotherapy has transformed the treatment landscape for several GI cancers, offering some patients durable responses and prolonged survival. Specifically, immune checkpoint inhibitors (ICIs) directed against programmed cell death protein 1 (PD-1), either as monotherapies or in combination regimens, have gained tissue site-specific regulatory approvals for the treatment of metastatic disease and in the resectable setting.

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Objective: To determine the safety and efficacy of adding the anti-PD-L1 antibody durvalumab to induction FOLFOX and preoperative chemotherapy in locally advanced esophageal adenocarcinoma.

Background: Neoadjuvant induction FOLFOX followed by positron emission tomography (PET) directed chemoradiation has demonstrated improved survival for esophageal adenocarcinoma. There is clear benefit now for the addition of immune checkpoint inhibitors both in early and advanced stage disease.

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Importance: Clonal hematopoiesis (CH) has been associated with development of atherosclerosis and leukemia and worse survival among patients with cancer; however, the association with cancer therapy efficacy, in particular immune checkpoint blockade (ICB), and toxicity has not yet been established. Given the widespread use of ICB and the critical role hematopoietic stem cell-derived lymphocytes play in mediating antitumor responses, CH may be associated with therapeutic efficacy and hematologic toxicity.

Objective: To determine the association between CH and outcomes, hematologic toxicity, and therapeutic efficacy in patients with metastatic gastrointestinal tract cancers being treated with systemic therapy, both in the first-line metastatic treatment setting and in ICB.

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