A Study of RC148 As a Single Agent and Combination Therapy in Patients with Locally Advanced Unresectable or Metastatic Malignant Solid Tumors

Inclusion Criteria: 1. Be able to participate in the study voluntarily and willing to provide written informed consent. 2. male or female ≥18 years (phase Ⅰ), 18 to 75 years old (Including 18 and 75 years, phase Ⅱ). 3. Must have an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1. 4. Projected life expectancy of at least 12 weeks. 5. At least one measurable target lesion based on imaging according to RECIST v1.1 criteria (For patients who have received prior radiotherapy, radiotherapy-treated lesions may be considered as target lesions if the lesion is measurable according to RECIST v1.1 criteria and there is evidence of significant progression after radiotherapy.); 6. Requirements for inclusion of subjects at different stages: Phase I (RC148 monotherapy): Patients with locally advanced unresectable or metastatic malignant solid tumors whose disease has progressed with standard therapy, or who are unable to tolerate standard therapy, or in whom the subject refuses standard therapy; Phase II (Combination Therapies): Cohort 1 (non-small cell lung cancer): Patients with locally advanced unresectable or metastatic malignant solid tumors with disease progression on standard therapy, or intolerance of standard therapy, or refusal of standard therapy. Cohort 2 (HER2-expressing cervical cancer): Subjects with advanced non-small cell lung cancer diagnosed by histological or cytological examination, locally advanced or metastatic, with AGA- confirmed by prior genetic testing, who have received a PD-1/PD-L1 inhibitor and platinum-based chemotherapy as a first or second-line advanced treatment, and who have not received docetaxel chemotherapy. Cohort 3 (HER2 expressing gastric cancer): Histologically and/or cytologically confirmed locally advanced or metastatic gastric adenocarcinoma (including gastroesophageal junction adenocarcinoma) with HER2 expression (IHC ≥1+). Subjects who have progressed or are intolerant to standard first-line therapy only (PD-1/PD-L1 inhibitor + platinum-containing chemotherapy ± trastuzumab, and not including paclitaxel). Disease progression during neoadjuvant therapy and within 6 months of the end of adjuvant therapy will also be considered a failure of first-line therapy. Cohort 4 (MSLN-expressing lung adenocarcinoma): Histologically or cytologically confirmed lung adenocarcinoma without other pathologic components; driver gene negative, MSLN-expressing (IHC ≥1+) advanced lung adenocarcinoma subjects who have received PD-1/PD-L1 inhibitor and platinum-based chemotherapy (combination or sequential) and have not received paclitaxel-based chemotherapy. Cohort 5 (platinum-resistant ovarian, fallopian tube, or primary peritoneal cancer): pathologic type needs to be high-grade serous ovarian cancer; Subjects who have progressed on prior 1-4 lines of antitumor therapies; Definition of platinum-resistance: 1) Patients who have received 1 line of platinum-based therapy must have received at least 4 cycles of platinum, must have had a response (CR or PR), and then progressed between \>3 months and ≤6 months after the date of the last platinum; 2) Patients who have received 2 or 3 lines of platinum-based therapies must have received at least 4 cycles of platinum and have progressed on or within 6 months after the last dose of platinum. Cohort 6 (platinum-sensitive ovarian, fallopian tube, or primary peritoneal cancer): Pathological type needs to be high-grade serous EOC; Subjects who have received 1-4 lines of prior antitumor therapies were included. Cohort 7 (MSLN-expressing cervical cancer): Subjects with recurrent or metastatic cervical cancer expressing mesothelin (MSLN) (IHC ≥1+) that is histologically confirmed, ineligible for surgery or radiotherapy, and has progressed after at least 1L of platinum-based chemotherapy. 7. Participants agree to provide pre-treatment archived/biopsied tumor samples for biomarker-related testing such as retrospective programmed cell death protein 1 (PD-L1) expression levels. Biopsies will be considered at screening only if archived samples are not available. Fresh tumor biopsies will not be considered if significant risk procedures are required per the discretion of the Investigator. 8. Adequate bone marrow, liver, and renal function defined as: No platelet or red blood cell transfusion within 14 days prior to performing routine blood tests, no correction with thrombopoietin (TPO), erythropoietin (EPO), granulocyte colony-stimulating factor (G-CSF), or interleukin-11 (IL-11), absolute neutrophil count (ANC) ≥ 1.5 × 10\^9/L, platelets ≥ 100 × 10\^9/L, and Hemoglobin ≥ 90g/L. Serum total bilirubin ≤1.5 × upper limit of normal (ULN), ALT, AST ≤2.5 × ULN (≤5 × ULN in case of known liver metastases), albumin ≥30 g/L International Normalized Ratio (INR) ≤1.5×ULN, Activated Partial Thromboplastin Time (APTT) ≤1.5×ULN. Serum creatinine ≤ 1.5 x ULN. Urinalysis results for urinary protein \<++. 9. For subjects in Cohort 1 (Non-Small Cell Lung Cancer) and Cohort 4 (Lung Adenocarcinoma) of the Phase II Combined Protocol, pulse oximetry (O2 saturation) measured under unoxygenated conditions was required to be \>92%. 10. Cardiac function: left ventricular ejection fraction ≥50%. 11. Male or female subjects with fertility must agree to take effective contraceptive measures during the study period and within 6 months after the end of the last medication, such as double-barrier contraceptive methods, condoms, oral or injectable contraceptives, intrauterine contraceptive device. Exclusion Criteria: 1. Pregnant or lactating. 2. Cohort 1 in Phase II, patients with histologically or cytologically confirmed non-small cell lung cancer, other than squamous lung cancer and lung adenocarcinoma, (including subjects with squamous or adenocarcinoma in combination with other pathologic types of non-small cell lung cancer;) prior treatment with docetaxel, or an antitumor agent that targets VEGF/VEGFR; a