Zolbetuximab Claudin18.2 Positive, HER2 Negative, Advanced Gastric Cancer

Inclusion Criteria:

1. Patient is ≥ 19 years of age at the time of consent.

2. The patient must have histologically confirmed locally advanced, unresectable, ormetastatic gastric or gastroesophageal junction adenocarcinoma

3. Patient whose tumor expresses CLDN18.2 in ≥ 75% of tumor cells demonstratingmoderate to strong membranous CLDN18 staining as determined by local or central IHCtesting.

4. The tumor sample must be HER2-negative (IHC 0, 1+, or IHC 2+/ISH-).

5. The patient must have received Zolbetuximab as a first-line treatment.

6. 1 Patient has ECOG performance status 0 or 1.

7. Patient must meet all of the following criteria based on the locally analyzedlaboratory tests collected.

• Hb ≥8 g/dL (For patients who require a transfusion, it is appropriate if Hb ≥9g/dL after transfusion)

• ANC ≥1.0 x 10^9/L

• Platelet ≥75 x 10^9/L

• Total bilirubin ≤1.5 x ULN without liver metastasis, or <3.0 x ULN if livermetastasis is present

• AST or ALT ≤2.5 x ULN without liver metastasis, or ≤5 x ULN if liver metastasisis present

• Estimated creatinine clearance ≥30 mL/min

Exclusion Criteria:

1. Patient has previously received treatment in a clinical trial of zolbetuximab, or aclinical trial that included zolbetuximab as 1 of the treatment options, even if thepatient was not given zolbetuximab

2. History of known or suspected hypersensitivity to Zolbetuximab, other monoclonalantibodies, or components of the used formulations.

3. Patient has received prior systemic chemotherapy for locally advanced unresectableor metastatic gastric or GEJ adenocarcinoma. However, patient may have receivedeither neo-adjuvant or adjuvant chemotherapy, immunotherapy or other systemicanticancer therapies as long as it was completed at least 6 months prior toparticipation.

4. Patients who have received systemic immunosuppressive therapy, including systemiccorticosteroids, within 14 days before enrollment. However, patients usingphysiological replacement doses of hydrocortisone or its equivalent (maximumhydrocortisone 30 mg/day or prednisone 10 mg/day), those who have received a singledose of systemic corticosteroid, or those who have received systemic corticosteroidsas premedication for radiologic contrast agents are allowed.

5. Patient has a complete gastric outlet syndrome or a partial gastric outlet syndromewith persistent/recurrent vomiting

6. Per investigator judgment, patient has significant gastric bleeding and/or untreatedgastric ulcers that would exclude the patient from participation per investigatorJudgment

7. Patient has any other condition, which, in the opinion of the treating physician,makes the patient unsuitable to receive or tolerate zolbetuximab.