A Phase I Study of AK138D1 in the Treatment of Advanced Solid Tumors

Inclusion Criteria: 1. The subject must sign the written informed consent form (ICF) voluntarily; 2. At enrollment, aged ≥ 18 to ≤ 75 years, both males and females are eligible; 3. ECOG performance status score of 0 or 1; 4. Has a life expectancy of ≥ 3 months; 5. Subjects who have histologically or cytologically diagnosed locally advanced or metastatic solid tumor, which Is refractory to or intolerant to standard treatment; 6. At least 1 measurable lesion as per RECIST v1.1 that is suitable for repeated accurate measurement. 7. Adequate organ function. Exclusion Criteria: 1. Prior human epidermal growth factor receptor 3 (HER3) -targeted therapies, including antibodies, antibody-drug conjugates (ADCs), chimeric antigen receptor T-cell immunotherapy (CAR-T), and others; 2. Concomitant participation in another clinical study, unless it is a non-interventional clinical study or the follow-up period of an interventional study; 3. Presence of active central nervous system (CNS) metastases. 4. Patients with a history of non-infectious pneumonitis requiring systemic corticosteroid therapy; a history of interstitial lung disease (ILD) (including pulmonary fibrosis or radiation pneumonitis); currently suffering from ILD/pneumonitis or suspected of having such diseases based on imaging during screening; 5. Live vaccines or attenuated live vaccines administered within 4 weeks prior to the first dose, or planned to be administered during the study; use of inactivated vaccines is allowed; 6. Untreated subjects with active hepatitis B (HBsAg positive and HBV-DNA exceeding 1000 copies/mL (200 IU/mL) and above the lower limit of detection). For HBsAg-positive subjects, anti-hepatitis B therapy is required during the study; subjects with active hepatitis C (HCV antibody positive and HCV-RNA levels above the lower limit of detection) is also an exclusion; 7. Known active pulmonary tuberculosis (TB); subjects with suspected active TB must undergo appropriate clinical assessment to rule out the presence of active disease; 8. Active syphilis infection; 9. Subjects with known allergy to any component of any study drug; and with a history of known severe hypersensitivity reactions to other monoclonal antibodies; 10. Other reasons for ineligibility as evaluated by the investigator.