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 ormetastatic 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 repeatedaccurate measurement.

7. Adequate organ function.

Exclusion Criteria:

1. Prior human epidermal growth factor receptor 3 (HER3) -targeted therapies, includingantibodies, antibody-drug conjugates (ADCs), chimeric antigen receptor T-cellimmunotherapy (CAR-T), and others;

2. Concomitant participation in another clinical study, unless it is anon-interventional clinical study or the follow-up period of an interventionalstudy;

3. Presence of active central nervous system (CNS) metastases.

4. Patients with a history of non-infectious pneumonitis requiring systemiccorticosteroid therapy; a history of interstitial lung disease (ILD) (includingpulmonary fibrosis or radiation pneumonitis); currently suffering fromILD/pneumonitis or suspected of having such diseases based on imaging duringscreening;

5. Live vaccines or attenuated live vaccines administered within 4 weeks prior to thefirst dose, or planned to be administered during the study; use of inactivatedvaccines 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). ForHBsAg-positive subjects, anti-hepatitis B therapy is required during the study;subjects with active hepatitis C (HCV antibody positive and HCV-RNA levels above thelower limit of detection) is also an exclusion;

7. Known active pulmonary tuberculosis (TB); subjects with suspected active TB mustundergo 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 historyof known severe hypersensitivity reactions to other monoclonal antibodies;

10. Other reasons for ineligibility as evaluated by the investigator.