First-in-human Study of DB-1305/BNT325 for Advanced/Metastatic Solid Tumors

Inclusion Criteria:

• Male or female adults (defined as ≥ 18 years of age or acceptable age according tolocal regulations at the time of voluntarily signing of informed consent).

• Histologically or cytologically confirmed unresectable advanced/ metastatic solidtumors who have relapsed or progressed on or after standard systemic treatments orfor which no standard treatment is available.

• At least one measurable lesion as assessed by the investigator according to RECISTversion 1.1 criteria.

• Has a life expectancy of ≥ 3 months.

• Has an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1.

• Has Left Ventricular Ejection Fraction (LVEF) ≥ 50% by either echocardiography (ECHO) or multiple-gated acquisition (MUGA) within 28 days before enrollment.

• Has adequate organ functions within 7 days prior to Day 1 of Cycle 1.

• Has adequate treatment washout period prior to Day 1 of Cycle 1.

• Is willing to provide pre-existing resected tumor samples or undergo fresh tumorbiopsy for the measurement of Trop-2 level and other biomarkers if notcontraindicated.

• Is capable of comprehending study procedures and risks outlined in the informedconsent and able to provide written consent and agree to comply with therequirements of the study and the schedule of assessments.

Exclusion Criteria:

• Has a medical history of symptomatic congestive heart failure (CHF) (New York HeartAssociation [NYHA] classes II-IV) or serious cardiac arrhythmia requiring treatment.

• Has a medical history of myocardial infarction or unstable angina within 6 monthsbefore enrollment.

• Has an average of Fredericia's formula-QT corrected interval (QTcF) prolongation to > 470 millisecond (ms) in males and females based on a 12-lead electrocardiogram (ECG) in triplicate.

• Has a medical history of non-infectious Interstitial Lung Diseases (ILD)/pneumonitisor where suspected ILD/pneumonitis cannot be ruled out by imaging at screening.

• Has a lung-specific intercurrent clinically significant illness.

• Has an uncontrolled infection requiring IV injection of antibiotics, antivirals, orantifungals.

• Subjects have human immunodeficiency virus (HIV) infection with acquired immunedeficiency syndrome (AIDS) defining illness are not eligible for enrollment;However, subjects have had HIV infection with a cluster of differentiation 4 (CD4)+T cell count > 350 cells/µL and no history of an AIDS-defining illness are eligiblefor entry.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.