This is a Phase 1/2 open label study consisting of dose escalation cohorts (Phase 1) followed by expansion cohorts (Phase 2). The Phase 1 dose escalation population includes subjects with advanced solid tumors that are refractory to standard of care therapy or for whom no standard of care options are available. Once the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of single agent LCB02A is determined, the study will proceed to Phase 2 expansion cohorts in selected tumor types.

Key Inclusion Criteria:

• Phase 1 Dose Escalation: histologically or cytologically confirmed advanced solid tumors that are Claudin 18.2 positive and refractory to standard of care treatment.

• Phase 2 Dose Expansion: selected histologically or cytologically confirmed advanced solid tumors that are Claudin 18.2 positive and refractory to standard of care treatment. Expansion cohort indications will be prioritized based on data from the Phase 1 dose escalation portion.

• Prior treatment with Claudin 18.2 directed therapy is permitted.

• Measurable disease as defined by RECIST v1.1

• Willingness to provide archival tumor tissue when available, or to undergo a pre-treatment biopsy if archival tissue is not available.

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

• Adequate organ function as defined by:

  • Absolute neutrophil count ≥ 1.5 × 109/L , without colony stimulating factor support for the past 14 days
  • Platelet count ≥ 100 × 109/L
  • Hemoglobin level ≥ 9.0 g/dL
  • Total bilirubin ≤ 1.5× upper limit of normal (ULN) or <3 x ULN with Gilbert's syndrome or liver metastases at baseline
  • Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ≤ 2.5× ULN (≤ 5.0× ULN for subjects with liver metastases)
  • Albumin ≥ 2.5 g/dL
  • Serum creatinine ≤ 1.5× ULN or creatinine clearance ≥ 50 mL/min

Key Exclusion Criteria:

• Prior exposure to ADCs with a Topo1 inhibitor payload.
• Known active central nervous system (CNS) metastases and/or carcinomatous meningitis.

Note: Patients may be considered for enrollment if they have previously treated brain metastases that are clinically stable or radiologically stable for at least 14 days prior to the first dose.

• Received radiotherapy within 21 days prior to the first dose of study drug. Note: For palliative radiotherapy for symptomatic improvement of non-central nervous system (CNS) lesions (total duration of radiotherapy ≤ 14 days), a radiation washout period of 7 days is required prior to the first dose.
• Any medical conditions that may confound the study results, interfere with the patient's compliance, or impair the interests of the subject, as assessed by the Investigator.