A Trial to Evaluate Safety and Tolerability of TST001 in Advanced or Metastatic Solid Tumors

Inclusion Criteria:

* Male or female ≥ 18 years.
* Patients with histologically or cytologically confirmed, locally advanced or metastatic solid tumors.

Part A only:

\* Patients must be: a) progressed after standard therapies, b) intolerant of standard therapies, or c) with a tumor type without standard therapy.

Part B only:

* Cohort A: Patients with previously untreated, unresectable, locally advanced or metastatic GC/GEJ adenocarcinoma; prior adjuvant or neoadjuvant therapy are allowed only if disease progressed or recurred at least 6 months after completion of these treatments. Patients may have received one infusion of mFOLFOX6 plus nivolumab during the screening period.
* Cohort B: Patients with GC/GEJ adenocarcinoma who have radiologically progressed following one or two prior systemic therapies; adjuvant or neoadjuvant therapy could be regarded as one line of therapy only if disease progressed or recurred during these treatments or within 6 months or less after completion of these treatments.
* Cohort C: Patients with previously untreated, unresectable, locally advanced or metastatic histologically confirmed pancreatic adenocarcinoma; prior adjuvant or neoadjuvant therapy are allowed only if disease progressed or recurred at least 6 months after completion of these treatments. Patients may have received up to 2 infusions of Gemcitabine + albumin-bound paclitaxel (with one week between each infusion) during the screening period.
* Eastern Cooperative Oncology Group Performance Status (ECOG PS): 0-1 .
* Patients with adequate cardiac, liver, renal function, etc.

Exclusion Criteria

* Symptomatic central nervous system metastases.
* Prior treatment with any CLDN18.2 target agents
* Allergy or sensitivity to TST001 or known allergies to comparable drugs
* Documented history of multiple other allergies requiring interventions
* Severe cardiovascular disease, including CVA, TIA, myocardial infarction, or unstable angina, NYHA class III or IV heart failure or uncontrolled arrhythmia within 6 months of study entry, severe QTc prolongation, concomitant risks for QTc prolongation.
* Concurrent malignancy within 5 years prior to entry except adequately treated certain types of cancer
* Active and clinically significant infections, known uncontrolled infections with hepatitis B, hepatitis C, known human immunodeficiency virus with acquired immunodeficiency syndrome related illness
* Any condition that the investigator or primary physician believes may not be appropriate for participating in the study.

Other protocol-defined Inclusion/Exclusion Criteria could apply.

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