Claudin 18.2-Targeted Chimeric Antigen Receptor T-cells in Subjects With Unresectable, Locally Advanced, or Metastatic Gastric, Gastroesophageal Junction (GEJ), Esophageal, or Pancreatic Adenocarcinoma

Inclusion Criteria:

1. Be willing and able to provide written informed consent

2. Be a female or male ≥ 18 and ≤ 75 years old at the time of signing of the informedconsent

3. For Part A and B: subjects with histologically/cytologically confirmed unresectable,locally advanced or metastatic adenocarcinoma of the stomach, GEJ, or distalesophagus for which standard treatment is considered intolerable, unlikely to confersignificant clinical benefit, is no longer effective, does not exist, or subject isineligible or declines standard therapy. For Part B only: subjects with histologically/cytological confirmed unresectable,locally advanced or metastatic adenocarcinoma of the pancreas for which standardtreatment is considered intolerable, unlikely to confer significant clinicalbenefit, is no longer effective, does not exist, or subject is ineligible ordeclines standard therapy.

4. Subjects must have received prior therapy as follows:

• For gastric, GEJ, or esophageal adenocarcinoma, previous treatment must haveincluded a fluoropyrimidine and/or platinum containing regimen. Subjects withHER2-neu-positive (HER2+) disease must have also received prior anti-HER2+therapy.

• For pancreatic adenocarcinoma, previous treatment must have includedfluoropyrimidine and/or gemcitabine containing regimen.

5. Presence of CLDN18.2 positive tumors with staining intensity of ≥ 1+ in ≥ 50% oftumor cells by immunohistochemistry (performed by central laboratory duringPrescreening)

6. Presence of ≥ 1 radiologically measurable lesion per Response Evaluation Criteria InSolid Tumors (RECIST) Version 1.1.

7. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

8. Life expectancy of at least 4 months per investigator judgment.

9. Have adequate organ function

10. Women of childbearing potential must have a negative pregnancy test at screening

11. All Subject must agree to practice a highly effective method of contraception fromthe time of signing the ICF to 1 year after receiving a LB1908 infusion.

12. Women and men must agree not to donate eggs (ova, oocytes) or sperm, respectively,until at least 1 year after receiving a LB1908 infusion.

Exclusion Criteria:

1. Prior treatment with cellular immunotherapy (e.g., CAR-T) or gene therapy product.

2. Prior treatment with claudin 18.2-targeted therapy.

3. Antitumor therapy prior to apheresis during the protocol-defined window

4. Subjects who have a history of esophageal or gastric resection that the investigatorconsiders is at increased risk of bleeding or perforation;

5. Unstable/active ulcer, varices, or digestive tract bleeding or recent digestivesurgery that may have increased risk of bleeding;

6. Clinically significant ascites, pleural or peritoneal effusions requiring weeklyclinical intervention at screening.

7. Patients requiring anticoagulant therapy such as warfarin or heparin

8. Patients requiring long-term antiplatelet therapy

9. Primary immunodeficiency

10. Known brain metastasis or leptomeningeal metastasis.

11. Subjects with heavy tumor burden such as significant lung disease or extensive livermetastases.

12. Active autoimmune disease receiving immunosuppressants (e.g., cyclosporine or highdose systemic steroids) within 2 weeks or 5 half-lives prior to screening

13. Impaired cardiac function or clinically significant cardiac disease as defined bythe protocol

14. Previous or concurrent malignancy not meeting protocol-defined exceptions

15. Serious and /or uncontrolled medical condition that, in the Investigator's judgment,would cause unacceptable safety risk, interfere with study procedures or results, orcompromise compliance with the protocol:

16. Current known active infection with human immunodeficiency virus (HIV), hepatitis B,and/or hepatitis C virus (HBV/HCV).

17. Contraindications or life-threatening allergies, hypersensitivity, or intolerance toLB1908 excipients, such as dimethyl sulfoxide; or to fludarabine, cyclophosphamide,or tocilizumab.

18. Ongoing toxicity from previous anticancer therapy that has not resolved to Grade 2or less, except for alopecia, fatigue, nausea, and constipation.

19. Major surgery within 4 weeks prior to apheresis, or planned within 4 weeks afterLB1908 administration.

20. Pregnant or breast-feeding.

21. Plans to become pregnant or breastfeed, or father a child within 1 year afterreceiving a LB1908 infusion.

22. Previous history of allogeneic HSCT, organ transplant, or in preparation for organtransplant.