This study is a phase I, dose escalation and dose expansion study of QLS1103, to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of QLS1103 in subjects with advanced solid tumors.

Inclusion Criteria:

• 1. Subjects must voluntarily agree to participate in the trial and sign a written informed consent form;
• 2. Aged ≥18 years old;
• 3. Histologically or cytologically confirmed advanced or recurrent or metastatic solid tumor;
• 4. Failure of adequate standard treatment, or no effective standard treatment;
• 5. Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1;
• 6. Life expectancy ≥12 weeks;

Exclusion Criteria:

• 1. Subjects received systemic anticancer therapy within 4 weeks prior to the first dose;
• 2. Subjects received experimental medication or therapy within 4 weeks prior to the first dose;
• 3. Subjects received major surgery within 4 weeks prior to the first dose;
• 4. Persistent toxicity of National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Grade >1 severity that is related to prior therapy;
• 5. Cardiovascular and cerebrovascular diseases with clinical significance;
• 6. Active gastrointestinal disease or other conditions that significantly interfere with drug absorption.