Clinical Research Directory

First-in-Human Study of PLX-61639 in Locally Advanced or Metastatic Solid Tumors

A multicenter, single-arm, first-in-human study to investigate the safety, pharmacokinetics, and preliminary antitumor activity of PLX-61639 in participants with locally advanced or metastatic, relapsed/refractory, SMARCA4-deficient solid tumors who are intolerant of or have failed available, approved therapies. The study will be conducted in 3 parts: dose escalation (Part 1), dose optimization (Part 2), and cohort expansion (Part 3). Each part of the study will consist of a Screening Phase lasting up to 28 days during which participants will be assessed for eligibility, a Treatment Phase beginning on Cycle 1 Day 1 and consisting of consecutive 28-day cycles, an End of Treatment Visit, and a Post-Treatment Follow-Up Phase. Participants will receive their assigned dose of PLX-61639 administered orally, once daily until progression/relapse, intolerance, death, or withdrawal from study treatment by the Investigator or participant.

A Phase 1 Study Evaluating DISP-10 in Participants With Advanced Gastrointestinal Cancers

This is a Phase 1, multicenter, open-label study of DISP-10, a combination therapy consisting of DV-10 (adenovirus) and idecabtagene vicleucel (ide-cel, BCMA-directed chimeric antigen receptor \[CAR\] T), in adult participants with advanced gastrointestinal (GI) cancers. The study will consist of 2 parts: dose-escalation (Part 1) and dose-expansion (Part 2). Part 1 of the study will evaluate the safety and tolerability of increasing dose levels of DISP-10 to establish the recommended dose for expansion (RDE); Part 2 will evaluate the safety and efficacy of DISP-10 in participants treated at the RDE.

A Study of ASP2138 Given by Itself or Given With Other Cancer Treatments in Adults With Stomach Cancer, Gastroesophageal Junction Cancer, or Pancreatic Cancer

Claudin 18.2 protein, or CLDN18.2 is a protein found on cells in the digestive system. It is also found on some tumors. Researchers are looking at ways to attack CLDN18.2 to help control tumors. ASP2138 is thought to bind to CLDN18.2 and a protein on a type of immune cell called a T-cell. This "tells" the immune system to attack the tumor. ASP2138 is a potential treatment for people with stomach cancer, gastroesophageal junction cancer (GEJ cancer) or pancreatic cancer. GEJ is where the tube that carries food (esophagus) joins the stomach. Before ASP2138 is available as a treatment, the researchers need to understand how it is processed by and acts upon the body. In this study, ASP2138 will either be given by itself, or given together with standard treatments for gastric, GEJ and pancreatic cancer. Pembrolizumab and mFOLFOX6, and ramucirumab and paclitaxel are standard treatments for gastric and GEJ cancer. mFOLFIRINOX is a standard treatment for pancreatic cancer. This information will help find a suitable dose of ASP2138 given by itself and together with the standard cancer treatments and to check for potential medical problems from the treatments. The main aims of the study are: * To check the safety of ASP2138 and how well people can tolerate medical problems during the study. * To find a suitable dose of ASP2138 to be used later in the study. * These are done for ASP2138 given by itself and when given together with the standard cancer treatments. Adults 18 years or older with stomach cancer, GEJ cancer, or pancreatic cancer can take part. Their cancer is locally advanced unresectable or metastatic. Locally advanced means the cancer has spread to nearby tissue. Unresectable means the cancer cannot be removed by surgery. Metastatic means the cancer has spread to other parts of the body. There should also be the CLDN18.2 marker in a tumor sample. People cannot take part if they need to take medicines to suppress their immune system, have blockages or bleeding in their gut, have specific uncontrollable cancers, have specific infections, have a condition such as hemophagocytic lymphohistiocytosis (HLH) which is when the body over-reacts to a "trigger" such as infection, or have a specific heart condition ("New York Heart Association Class III or IV"). Phase 1: Lower to higher doses of ASP2138 * ASP2138 is either given through a vein (intravenous infusion) or just under the skin (subcutaneous injection). * Different small groups are given lower to higher doses of ASAP2138. * ASP2138 is either given by itself, or given with 1 of 3 standard treatments: * Pembrolizumab and mFOLFOX6 (first treatment for gastric GEJ cancer) * Ramacirumab and paclitaxel (Second treatment for gastric or GEJ cancer) * ASP2138 with mFOLFIRINOX (first treatment for pancreatic cancer) Phase 1b: doses of ASP2138 worked out from Phase 1 * ASP2138 is either given through a vein or just under the skin. This depends on the findings from Phase 1. * People with gastric cancer, GEJ cancer or pancreatic cancer are given doses of ASP2138, worked out from Phase 1. * This includes doses of ASP2138 given by itself and ASP2138 given with the standard cancer treatments. * The standard cancer treatments given depends on the type of cancer they have. End of treatment visit: This is 7 days after final dose of study treatment or if the study doctor decides to stop the person's treatment. People who have locally advanced unresectable pancreatic cancer will not receive ASP2138 by itself.

A Study of Pembrolizumab With Trastuzumab and Chemotherapy in People With Esophagogastric Cancer

The purpose of this study to find out whether adding trastuzumab and pembrolizumab to standard chemotherapy is an effective treatment for resectable HER2+ esophagogastric cancer.

Testing Immunotherapy (Atezolizumab) With or Without Chemotherapy in Locoregional MSI-H/dMMR Gastric and Gastroesophageal Junction (GEJ) Cancer

This phase II trial compares atezolizumab in combination with chemotherapy (docetaxel, oxaliplatin, leucovorin calcium, fluorouracil, capecitabine) to atezolizumab alone for controlling the growth and/or spreading of the disease in patients with gastric or gastroesophageal junction (JEG) cancer that has not spread from where it first started (local) or only has spread to nearby lymph nodes or tissue (locoregional) and has high microsatellite instability (MSI-H) and mismatch repair deficiency (dMMR). The mismatch repair (MMR) system in the body corrects errors made during the copying of DNA and serves as a proofreading function. If this system isn't working correctly, mutations (changes) in DNA occur which can allow the cancer to grow or spread. This is called dMMR (deficient mismatch repair) . MSI-H describes cancer cells that have a high number of mutations within microsatellites. For example, microsatellite testing that shows mutations in 30% or more microsatellites is called microsatellite instability-high (MSI-H). Microsatellites are short, repeated sequences of DNA. There is evidence that MSI-H/ dMMR gastric or GEJ tumors respond well to immunotherapy. Immunotherapy with monoclonal antibodies, such as atezolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Docetaxel is in a class of medications called taxanes. It stops tumor cells from growing and dividing and may kill them. Oxaliplatin is in a class of medications called platinum-containing antineoplastic agents. It damages the cell's DNA and may kill tumor cells. Capecitabine is in a class of medications called antimetabolites. It is taken up by tumor cells and breaks down into fluorouracil, a substance that kills tumor cells. Chemotherapy drugs such as leucovorin calcium and fluorouracil work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Using atezolizumab as immunotherapy with and following chemotherapy versus atezolizumab alone prior to and after surgery may shrink or stabilize the tumor in patients with MSI-H/dMMR localized gastric or GEJ cancer and may increase the length of time after treatment that cancer does not come back or get worse.

PULSAR Combined With Immunotherapy for Unresectable Locally Advanced Gastric Cancer

The purpose of this prospective, single-center, phase II study is to evaluate the clinical efficacy and safety of combining first-line systemic therapy plus immunotherapy with personalized ultrafractionated stereotactic adaptive radiation therapy (PULSAR) in patients with unresectable locally advanced gastric cancer.

Retlirafusp Alfa Combined With Apatinib and Nab-Paclitaxel as Second-line Treatment for Gastric or Gastroesophageal Junction Cancer

This is a prospective, single-arm, investigator-initiated phase II clinical study. The study evaluates the efficacy and safety of retlirafusp alfa (a PD-L1/TGF-βRII bifunctional fusion protein) combined with apatinib (a VEGFR-2 tyrosine kinase inhibitor) and nab-paclitaxel in patients with locally advanced unresectable, locally recurrent, or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma who have progressed after first-line immunotherapy-containing treatment.

A Phase II Study of Perioperative Paclitaxel in Patients With Gastric Adenocarcinoma and Carcinomatosis or Positive Cytology

To learn about the effects of paclitaxel and gastrectomy (surgery to remove all or part of the stomach) on improving outcomes in patients with gastric cancer.

Study of Denikitug (GS-1811) Given Alone or With Nivolumab or Chemotherapy in Adults With Metastatic Gastric, Gastroesophageal Junction (GEJ), and Esophageal Adenocarcinomas

The goal of this clinical study is to learn more about the study drug, Denikitug (DEN, GS-1811), to evaluate the efficacy and safety of Denikitug Monotherapy and Denikitug-based combinations in in participants with human epidermal growth factor receptor 2 (HER2)-Negative, unresectable, recurrent, and/or metastatic, gastroesophageal junction (GEJ), and esophageal adenocarcinomas. The primary objective of this study is to assess the effect of DEN as a monotherapy or in combination with nivolumab (NIVO) or ramucirumab (RAM) and paclitaxel (PAC) on objective response rate (ORR) as assessed by the investigator according to Response Evaluation Criteria in Solid Tumors (RECIST Version1.1).

AVA6103 in Subjects With Locally Advanced or Metastatic Selected Solid Tumors

This is a first-in-human (FIH), Phase 1 open-label, multicenter dose escalation study investigating AVA6103 monotherapy administered intravenously in patients with locally advanced (unresectable) or metastatic solid tumors that are likely to be FAP positive. The study consists of an initial Phase 1a dose escalation portion and a subsequent Phase 1b dose expansion portion upon completion of the dose escalation portion.

Testing the Addition of Paclitaxel Administered Into the Abdominal Cavity Combined With Chemotherapy for Patients With Gastric Cancer Spread to the Abdominal Cavity

This study is being done to answer the following questions: Can we lower the chance of your gastric cancer from growing or spreading by administering paclitaxel chemotherapy directly into your abdominal cavity in addition to chemotherapy given through a vein in your arm? Will administering paclitaxel chemotherapy directly into your abdominal cavity, in addition to chemotherapy given through a vein in your arm help you live longer? We are doing this study because we want to find out if this approach is better or worse than the usual approach for your gastric cancer. The usual approach is defined as care most people get for gastric cancer. If you decide to take part in this study, you will first receive a surgical procedure called a diagnostic laparoscopy. This will help the study doctors learn more about your gastric cancer. Laparoscopy is a minimally invasive surgery for which you will be placed under general anesthesia. Then the surgeon will make small incisions (5mm) on your belly through which a camera and thin instruments are introduced to evaluate the abdomen. This procedure takes about 1 hour to complete. Your study group will be assigned during the surgery. The study groups are described further in the 'What are the study groups?' section below. If you are placed into the study group 1, you will not have an intraperitoneal port (a small device which is placed under the skin and fat of your upper abdomen and a tube that is placed into the abdomen). If you are placed into the study group 2, you will have an intraperitoneal port placed. The reason is that in addition to standard chemotherapy, which is given through a vein in your arm, this port will be used to deliver the medication paclitaxel directly inside your abdomen when you are ready to start study treatment. It is important to know that you will not know your study group until after the surgery is over. This is because information that is learned during the surgery will help determine which study group you are put in. Once you have fully healed from this surgery, you will start study treatment. Depending on which study group you are assigned, you will either receive a standard chemotherapy regimen (the regimen will be chosen by you and your doctor) if you are in study group 1, or paclitaxel through a tube in your belly plus chemotherapy given through a vein in your arm if you are in study group 2. All participants will get treatment for three (3) months after which you will undergo reevaluation. If the disease is under control or responding to treatment, you may continue the assigned treatment until your disease gets worse, the side effects become too severe, or you may be offered a surgical procedure to remove the cancer if the amount of disease is low and can be completely removed as determined by a surgeon. There is a very small chance that during the laparoscopy surgical procedure, the doctor might find something called "intra-abdominal adhesions". These are areas where the stomach has healed previously and created scar tissue. If this scar tissue prevents the surgeon from being able to place a port in the correct area, you would be ineligible to receive the study treatment. If this happens, you may still receive standard of care therapy after your surgery, but you will not be able to continue on the study. If you have more questions about this, you can ask your surgeon or the study team to help. After you finish your study treatment, your doctor or study team will watch you for side effects. They will continue to follow your condition every three (3) months during the first two (2) years, then every six (6) months until year 5. You may be reevaluated with Chest/Abdomen/Pelvis scans every three-six (3-6) months for up to five (5) years if decided by your doctor.

JS107 in Combination With Toripalimab and Chemotherapy for the Treatment of CLDN18.2-positive Gastric or Gastroesophageal Junction Adenocarcinoma

This study is a multicenter, randomized, open-label, controlled Phase III clinical trial aimed at evaluating the efficacy and safety of JS107 combined with toripalimab XELOX versus sintilimab combined with XELOX as first-line treatment for patients with advanced G/GEJ adenocarcinoma. The research subjects were patients with unresectable locally advanced, recurrent or metastatic G/GEJ adenocarcinoma who were CLDN18.2-positive and HER2-negative and had not received systemic treatment before (except for neoadjuvant/adjuvant therapy that occurred more than 6 months after disease progression/recurrence from the last treatment). The study took BICR-PFS and OS as Dual primary endpoints.

Phase I-II, FIH, TROP2 ADC, Advanced Unresectable/Metastatic Solid Tumors, Refractory to Standard Therapies (KL264-01)

A Phase I-II, First-in-Human Study of SKB264 (Sac-TMT; MK-2870) in Patients with Locally Advanced Unresectable/Metastatic Solid Tumors who are refractory to Available Standard Therapies. Patient must have historically documented, incurable, locally advanced or metastatic cancer that are refractory to standard therapies of one of the following types: 1. Triple negative breast cancer 2. Epithelial ovarian cancer 3. Non-small cell lung cancer 4. Gastric adenocarcinoma/Gastroesophageal junction adenocarcinoma 5. Small cell lung cancer 6. HR+/ HER2-breast cancer 7. Head and neck squamous cell carcinoma 8. Endometrial carcinoma 9. Urothelial carcinoma 10. Cervical cancer

Phase 1/2 Study of BHB810 in Advanced Gastric and GEJ Adenocarcinoma

This study is looking at how safe BHB810 is in adults with gastric and gastroesophageal adenocarcinoma (GEJ). The purpose of this study is also to look at: how well the study drug works, how the study drug moves into, through, and out of the body, and how your body reacts to the study drug. Participants will get an IV infusion of BHB810 every 2 weeks while on study treatment.

Timing of Minimally Invasive Local Treatment After First-Line Systemic Therapy in Oligometastatic Esophageal or Gastric Adenocarcinoma

Purpose of the Study: This clinical study investigates whether a shorter or longer duration of systemic therapy before local treatment (surgery or radiation) results in better disease control in patients with esophageal or gastric cancer with a limited number of metastases, also known as oligometastases. Background: In about 25% of patients with advanced esophageal or gastric cancer, the disease spreads to only a few sites (oligometastatic disease). Prior studies suggest that local treatment after systemic therapy may extend survival in this subgroup. However, it is unclear how long systemic therapy should last before initiating local treatment. The OMEC-5 study aims to clarify this and identify potential biomarkers for treatment response. Study Design: Initiated by Amsterdam UMC and UMCU and conducted in multiple hospitals across Europe. Total of 414 patients to be enrolled. Duration: \~53 months (35 months enrollment + 18 months follow-up). Approved by the medical ethics committee at Amsterdam UMC. Procedure: Eligibility screening: Includes physical exam, blood tests (incl. circulating tumor cells), medical history review, and confirmation of oligometastases by an expert panel. Initial treatment: All participants receive 4 months of standard systemic therapy (chemotherapy + immunotherapy and/or targeted therapy depending on tumor markers like HER2 or Claudin 18.2). Response assessment (Review 1): Imaging and/or laparoscopic examination. If oligometastases persist and tumors have not progressed, participants are randomized into two groups: Group A (longer systemic therapy): 4 more months of systemic therapy, then local treatment if disease is stable, followed by 4 months of immunotherapy ± targeted therapy. Group B (shorter systemic therapy): Immediate local treatment followed by 4 months of systemic therapy, then reassessment and potentially 4 months of immunotherapy ± targeted therapy. Follow-up: Regular scans and quality-of-life questionnaires (5 times), and periodic blood sampling (4 times). Treatments Involved: Chemotherapy: CapOx or FOLFOX Immunotherapy: nivolumab or pembrolizumab Targeted therapy: trastuzumab (HER2-positive) or zolbetuximab (Claudin 18.2-positive) Potential Benefits and Risks: Patients may benefit from better disease control and a personalized treatment strategy. Known side effects relate to the standard treatments used (chemo, immuno, targeted therapies), and no extra medical risk is expected beyond routine care. Possible inconveniences include blood draws, scans, minor surgery (laparoscopy), and time investment. Data and Sample Handling: Personal data and tumor/blood samples are coded and securely stored. Data may be used for future cancer research if the patient consents. Participants can withdraw at any time. Confidentiality and Privacy: Patient data are kept confidential, and participants have rights to access or delete their data. Privacy measures comply with GDPR and Dutch law. Compensation and Insurance: Participation is voluntary, with no financial compensation. Standard treatment costs are covered by healthcare insurance. No extra insurance is required, as the treatment aligns with standard care practices.

Luso-Cor Stent Compared to Other Endoscopic Techniques for Management of Fistulas and Anastomotic Dehiscences(ES-LCCE-UDFM)

The global prevalence of obesity has prompted an increase in bariatric surgery, which is the only management strategy that provides long-term weight loss and improvement of obesity-related diseases. Bariatric surgeries include sleeve gastrectomy(SG), Roux-en-Y gastric bypass(RYGB),and laparoscopically adjustable gastric banding(LAGB). The incidence of adverse events depends on the type of bariatric surgery performed, with serious adverse events occurring in approximately 4% and mortality in 0.1% patients. The incidence of fistulas after SG varies between 0.2% to 2.5% and between 1% and 4.9% in patients who have undergone an RYGB. The incidence of strictures after SG is approximately 0.35%. Older, more obese, and male patients with multiple comorbidities related to obesity are at increased risk for the development of fistulas and mortality following bariatric surgery. Additionally, surgery after LAGB increases the risk of adverse events. This study will compare the efficacy and safety of the Luso-Cor esophageal stent versus conventional covered metallic stents versus endoscopic vacuum therapy in the management of fistulas and anastomotic dehiscences after oncologic or bariatric surgery on the stomach and esophagus.

Intraperitoneal and Intravenous Paclitaxel Chemotherapy With Oral Capecitabine for Gastric Adenocarcinoma With Peritoneal Carcinomatosis

Background: Three-fourths of people diagnosed with gastric cancer will die from it. Researchers want to see if giving cancer drugs in a new way can help people live longer and delay the time it takes for the cancer to grow. Objective: To find a better way to treat advanced stomach cancer. Eligibility: People ages 18 and older with stomach cancer that has spread throughout their belly. Design: Participants will be screened with: Medical history Physical exam Blood, urine, and heart tests Scans Cancer sample: If they do not have one, they will have a biopsy. Tests of performance of normal activities Dietary assessment Participants will have a laparoscopy. Small cuts are made into their abdomen. A thin camera with a light is inserted. Small instruments are used to take biopsies. This will be repeated during the study to monitor the cancer. During the first laparoscopy, a port with a catheter attached will be put into the abdomen. Participants may also have an endoscopy: A thin tube with a camera is inserted through the mouth and into the stomach. The tube collects samples to monitor the cancer. Participants will get paclitaxel every 3 weeks through the abdominal port and through a small plastic tube in an arm vein. They will also take capecitabine by mouth twice daily for the first 15 days of a 21-day cycle. After participants finish 3 cycles, they will have scans to see how they are doing. They may get another course of therapy. Participants will have visits every 3 weeks during treatment. Then they will have follow-up visits for 5 years. Then they will keep in touch with researchers for the rest of their life.

Safety and Efficacy of Single or Reduced Ports Laparoscopic Gastrectomy for Advanced Gastric Cancer (SPACE-01)

The aim of this study is to verify the safety and efficacy of single or reduced ports laparoscopic gastrectomy for advanced gastric cancer.

Conversion Therapy Plus Surgery and Radiotherapy for Retroperitoneal Nodal Metastases in Gastric Cancer

This is a randomized, controlled, multicenter phase II clinical trial evaluating the efficacy and safety of conversion therapy combined with radical gastrectomy and adjuvant radiotherapy targeting para-aortic (station 16) lymph nodes in patients with gastric adenocarcinoma and isolated station 16 nodal metastases. Eligible participants must have no evidence of peritoneal dissemination, visceral metastases, or non-regional lymphatic spread. Based on PD-L1 combined positive score (CPS), patients in the experimental arm will receive systemic therapy with SOX (S-1 plus oxaliplatin) with or without a PD-1 inhibitor, followed by D2 gastrectomy and postoperative adjuvant SOX chemotherapy, then intensity-modulated radiotherapy (IMRT) to the para-aortic region. The control arm will receive standard chemotherapy with CAPEOX or SOX, with or without immunotherapy, according to CPS status. The primary endpoint is progression-free survival (PFS), with secondary endpoints including overall survival (OS), objective response rate (ORR), disease control rate (DCR), and safety. This study aims to explore whether the addition of locoregional treatment to systemic therapy improves long-term outcomes in this select patient population.

PHASE II EVALUATION OF CYTOREDUCTION SURGERY AND HYPERTHERMIC INTRAPERITONEAL CHEMOTHERAPY (CRS/HIPEC) IN GASTRIC CANCER

This is a Phase II treatment study analyzing the role of preoperative chemotherapy, preoperative laparoscopic HIPEC, and gastrectomy with CRS/HIPEC in gastric adenocarcinoma patients with cytology-positive only carcinomatosis, radiologically-occult carcinomatosis, or radiology apparent peritoneal-surface only metastatic disease.

Evaluate the Safety, Tolerability, Pharmacokinetics and Efficacy of BL-M05D1 in Subjects With Solid Tumors

The objective of this study is to evaluate the Safety, Tolerability, Pharmacokinetics and Efficacy of BL-M05D1 in Subjects with Advanced or Metastatic Solid Tumors.

Anti-PD-1 mAb Plus Metabolic Modulator in Solid Tumor Malignancies

Patients with histologically or cytologically confirmed advanced melanoma, renal cell carcinoma, NSCLC, HCC (Child Pugh Class A only), MSI-High solid tumors, Urothelial Cancer, GE junction/Gastric Adenocarcinoma, or HNSCC for which current standard of care treatment for their stage of disease would be with Pembrolizumab or Nivolumab monotherapy, who meet eligibility criteria will undergo a biopsy (core or excisional/incisional; FNA not adequate) for baseline tissue. Patients will then be randomized to one of 3 arms: Anti-PD-1 mAb plus Metformin 500mg po BID, Anti-PD-1 mAb alone, Anti-PD-1 mAb plus Rosiglitazone 4mg po qdaily. Five weeks (+/- 7 days) after initiation of therapy a patient will undergo a repeat biopsy (core or excisional/incisional; FNA not adequate) for correlative analysis. The patient will then continue on study therapy for up to 2 years, or until progression of disease or unacceptable toxicity, whichever occurs first. RECIST 1.1 with modifications, to allow for continued therapy until progressive disease is confirmed if the patient is clinically stable, will be used in the trial.

Adebrelimab Combined With Nab-paclitaxel, Oxaliplatin and Tegafur (AOS) for Perioperative Treatment of Locally Advanced Resectable GC/GEJ

This study is a single-arm, prospective, phase II clinical trial. The patients are diagnosed with resectable locally advanced (cT3-4N+M0) gastric adenocarcinoma and esophageal gastric adenocarcinoma that had not been treated before. After signing the informed consent form, patients will be screened for the study treatment of Adebrelimab combined with AOS. After 2 cycles of treatment, MDT assessments before surgery will be carried out. Patients with no disease progression will receive one more cycle of treatment before surgery. For patients who have undergone radical surgery, they will continue to receive 3 cycles of the immunochemotherapy after the operation (a total of 6 cycles of combined treatment before and after surgery), followed by Adebrelimab single treatment for up to a year (16 cycles). Patients whose disease progressed that can not be surgically removed after preoperative treatment will be treated by the oncology physicians according to clinical routines.

Study of Suratadenoturev (OBP-301) in Combination With Pembrolizumab in Esophagogastric Adenocarcinoma

The goal of this study is to learn about of the research study drug, telomelysin (OBP-301), in combination with pembrolizumab in advanced or metastatic gastric or gastroesophageal junction (GEJ) cancer. The main question it aims to answer is whether this combination is safe and effective in this type of cancer. Participants will receive 5 injections of OBP-301, approximately every 2 weeks. OBP-301 will be injected directly into the tumor during an esophagogastroduodenoscopy (EGD). At the same time as the injection, a tumor biopsy will be taken. Participants will also receive pembrolizumab infusions every 6 weeks until disease progression or for a maximum of two years. Pembrolizumab infusions will occur on different days than OBP-301 injections.