Inclusion Criteria:
* 1\. Participants who voluntarily participate in this study and sign the written Informed Consent Form (ICF) after being fully informed.
* 2\. Male or female participants aged 18 to 75 years (inclusive).
* 3\. Participants with histologically or cytologically confirmed locally advanced unresectable or metastatic solid tumors who have experienced disease progression on or after standard therapy , or are intolerant to standard therapy, or for whom no effective standard of care is available.
* 4\. Participants who are able to provide fresh or archival tumor tissue during the screening period. Tumor tissue will be collected for biomarker testing at a central laboratory, including immunohistochemistry for EGFR and HER3 .
* 5\. Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1 .
* 6\. Life expectancy ≥3 months.
* 7\. According to RECIST v1.1, the participant must have at least one measurable lesion .
* 8\. Participants with good organ function as demonstrated by screening laboratory test results.
* 9\. The fertile participants agreed to take effective contraceptive measures during the study and after its conclusion; and must have a negative serum human chorionic gonadotropin (HCG) test within 7 days before dosing.
* 10\. Participants should be willing and able to complete regular visits, treatment plans, laboratory tests, and other study procedures.
Exclusion Criteria:
* 1\. Participants who have previously received ADC containing exatecan , or an ADC primarily directed against EGFR and/or HER3.
* 2\. Participants who have received the following treatments:
1. Participants who have undergone major surgery within 4 weeks before the first dose;
2. Participants who have received radiotherapy involving the bone marrow or extensive radiotherapy within 4 weeks before the first dose; or local radiotherapy within 2 weeks before the first dose;
3. Participants who are receiving continuous systemic corticosteroid therapy ; low-dose corticosteroids are permitted if the dose of systemic corticosteroids has been stable for 4 weeks;
4. Participants who have received anti-tumor treatments within 4 weeks before the first dose, or are still within 5 half-lives of the last dose of the most recent anticancer therapy (whichever is longer). Traditional Chinese medicines with approved anticancer indications within 2 weeks prior to the first administration of study drug.
* 3\. Participants with other malignant tumor within the past 5 years, other than the tumor treated in this study, with the exception of locally cured tumors .
* 4\. Participants with related AEs (except for alopecia and ≤ Grade 2 sensory neuropathy) caused by previous treatment that have not recovered to ≤ Grade 1 or baseline level.
* 5\. Participants with known weight loss of \>10% within 2 months before the first dose of the study drug or other indicators showing severe malnutrition.
* 6\. Participants with serious complications or medical histories involving important organs.
* 7\. Participants with known active central nervous system (CNS) metastasis.
* 8\. Participants with any of the cardiovascular/cerebrovascular disorders, symptoms, or manifestations.
* 9\. Participants with the following conditions will be excluded at screening: active syphilis, history of human immunodeficiency virus (HIV) infection, active hepatitis B virus (HBV) or active hepatitis C virus (HCV), with the exception of asymptomatic chronic hepatitis B or C virus carriers.
* 10\. Participants with a history of interstitial pneumonia or other moderate to severe lung disorders that seriously affect lung function.
* 11\. Participants with severe infection during the screening period.
* 12\. Participants with other diseases that may affect the efficacy and safety of the study drug.
* 13\. Participants with uncontrolled pericardial effusion, uncontrolled pleural effusion, or clinically significant moderate or greater ascites during the screening period.
* 14\. Participants with unstable thrombotic events requiring therapeutic intervention within 6 months before screening; however, thrombosis related to infusion devices is not included.
* 15\. Participants who have received a live vaccine within 30 days before the first dose, or plan to receive a live vaccine during the study period.
* 16\. Participants who have received strong CYP3A4 inhibitors and inducers therapy within 1 week before dosing, or are expected to require long-term use of strong CYP3A4 inhibitors and inducers during the study intervention and within 30 days after the last dose .
* 17\. Participants with history of solid organ transplant.
* 18\. Participants with known or suspected history of severe allergy to any component of the study drug or its analogues.
* 19\. Pregnant and lactating women.
* 20\. Participants who are deemed unsuitable for this study (e.g., poor compliance, etc.) by the investigator.
