To Evaluate the Safety, Tolerability, Pharmacokinetics and Antitumor Activity of DAY301 in Participants With Locally Advanced or Metastatic Solid Tumors

Inclusion Criteria

• Patients with histologically or cytologically confirmed diagnosis of advanced or metastatic solid tumors of the following histologies:
• Ovarian cancer
• Esophageal squamous cell carcinoma
• Triple-negative breast cancer
• Non-small cell lung cancer
• Small cell lung cancer
• Head and neck squamous cell carcinoma
• Gastric/gastroesophageal junction adenocarcinoma
• Cervical squamous cell carcinoma
• Endometrial cancers (Patients must have been previously treated with standard of care systemic therapy, or for whom no standard therapy is available).
• Availability of tumor tissue sample (either an archival specimen or a fresh biopsy) at screening
• Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST v1.1).
• ECOG performance status of 0 or 1.
• Adequate organ function.

Exclusion Criteria

• Prior use of PTK7 targeting treatment.
• Active or progressing brain metastases or evidence of leptomeningeal disease.
• Persistent toxicities from previous systemic antineoplastic treatments of Grade >1, excluding alopecia and vitiligo.
• Systemic antineoplastic therapy within 5 half-lives or 4 weeks, whichever is shorter, prior to first dose of the study drug, including investigational agents. Note: Other protocol defined Inclusion/Exclusion criteria may apply.