A Phase I Study of SIM0388 in Participants With Malignant Ascites.

Inclusion Criteria: * Voluntary participation and signature of informed consent form;. * ≥ 18 years of age, male or female. * Participants with histologically and/or cytologically confirmed advanced/metastatic solid tumors;. * Failure of at least one line of standard systemic anti-tumor therapy, unsuitability for standard systemic therapy, or absence of standard systemic therapy options. * Moderate or greater ascites confirmed by ultrasonography * ECOG performance status of 0, 1or 2. * Life expectancy ≥ 3 months. * Adequate hematologic and organ function. * Women of childbearing potential (WOCBP) must have a negative serum pregnancy test. WOCBP and male subjects agree to use adequate contraception. Exclusion Criteria: * Participant is currently participating or has participated in a study of an investigational agent or using an investigational device within 4 weeks of first dose of study treatment * Prior history of intraperitoneal paclitaxel-based therapy. * Use of strong CYP3A4 inhibitors or inducers within 7 days before the first dose or anticipated use during the study. * Failure to recover from adverse events caused by prior interventions to ≤Grade 1 * Complete intestinal obstruction within 30 days prior to the first dose. * Myocardial infarction within 6 months, current unstable angina, primary cardiomyopathy, cerebrovascular events, congestive heart failure, symptomatic coronary artery disease requiring medication, arrhythmia requiring medication, QTcF interval \>470 ms, or uncontrolled hypertension. * Uncontrolled primary brain tumors or CNS metastases. * Active infection. * Known history of HIV infection. * Active hepatitis B or hepatitis C infection. * Hypersensitivity to any active or inactive ingredient of SIM0388. * Pregnant or lactating women. * Any condition (medical history, disease, treatment, or lab abnormality) that may interfere with study results, impede full participation, or deemed by the investigator to contradict the subject's best interests.